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Sample records for surface-emitting lasers vcsel

  1. VCSELs Fundamentals, Technology and Applications of Vertical-Cavity Surface-Emitting Lasers

    CERN Document Server

    2013-01-01

    The huge progress which has been achieved in the field is covered here, in the first comprehensive monograph on vertical-cavity surface-emitting lasers (VCSELs) since eight years. Apart from chapters reviewing the research field and the laser fundamentals, there are comprehensive updates on red and blue emitting VCSELs, telecommunication VCSELs, optical transceivers, and parallel-optical links for computer interconnects. Entirely new contributions are made to the fields of vectorial three-dimensional optical modeling, single-mode VCSELs, polarization control, polarization dynamics, very-high-speed design, high-power emission, use of high-contrast gratings, GaInNAsSb long-wavelength VCSELs, optical video links, VCSELs for optical mice and sensing, as well as VCSEL-based laser printing. The book appeals to researchers, optical engineers and graduate students.

  2. Systematic characterization of a 1550 nm microelectromechanical (MEMS)-tunable vertical-cavity surface-emitting laser (VCSEL) with 7.92 THz tuning range for terahertz photomixing systems

    Science.gov (United States)

    Haidar, M. T.; Preu, S.; Cesar, J.; Paul, S.; Hajo, A. S.; Neumeyr, C.; Maune, H.; Küppers, F.

    2018-01-01

    Continuous-wave (CW) terahertz (THz) photomixing requires compact, widely tunable, mode-hop-free driving lasers. We present a single-mode microelectromechanical system (MEMS)-tunable vertical-cavity surface-emitting laser (VCSEL) featuring an electrothermal tuning range of 64 nm (7.92 THz) that exceeds the tuning range of commercially available distributed-feedback laser (DFB) diodes (˜4.8 nm) by a factor of about 13. We first review the underlying theory and perform a systematic characterization of the MEMS-VCSEL, with particular focus on the parameters relevant for THz photomixing. These parameters include mode-hop-free CW tuning with a side-mode-suppression-ratio >50 dB, a linewidth as narrow as 46.1 MHz, and wavelength and polarization stability. We conclude with a demonstration of a CW THz photomixing setup by subjecting the MEMS-VCSEL to optical beating with a DFB diode driving commercial photomixers. The achievable THz bandwidth is limited only by the employed photomixers. Once improved photomixers become available, electrothermally actuated MEMS-VCSELs should allow for a tuning range covering almost the whole THz domain with a single system.

  3. III-Nitride Vertical-Cavity Surface-Emitting Lasers

    Science.gov (United States)

    Leonard, John T.

    Vertical-cavity surface-emitting lasers (VCSELs) have a long history of development in GaAs-based and InP-based systems, however III-nitride VCSELs research is still in its infancy. Yet, over the past several years we have made dramatic improvements in the lasing characteristics of these highly complex devices. Specifically, we have reduced the threshold current density from ˜100 kA/cm2 to ˜3 kA/cm2, while simultaneously increasing the output power from ˜10 muW to ˜550 muW. These developments have primarily come about by focusing on the aperture design and intracavity contact design for flip-chip dual dielectric DBR III-nitride VCSELs. We have carried out a number of studies developing an Al ion implanted aperture (IIA) and photoelectrochemically etched aperture (PECA), while simultaneously improving the quality of tin-doped indium oxide (ITO) intracavity contacts, and demonstrating the first III-nitride VCSEL with an n-GaN tunnel junction intracavity contact. Beyond these most notable research fronts, we have analyzed numerous other parameters, including epitaxial growth, flip-chip bonding, substrate removal, and more, bringing further improvement to III-nitride VCSEL performance and yield. This thesis aims to give a comprehensive discussion of the relevant underlying concepts for nonpolar VCSELs, while detailing our specific experimental advances. In Section 1, we give an overview of the applications of VCSELs generally, before describing some of the potential applications for III-nitride VCSELs. This is followed by a summary of the different material systems used to fabricate VCSELs, before going into detail on the basic design principles for developing III-nitride VCSELs. In Section 2, we outline the basic process and geometry for fabricating flip-chip nonpolar VCSELs with different aperture and intracavity contact designs. Finally, in Section 3 and 4, we delve into the experimental results achieved in the last several years, beginning with a discussion on

  4. Polymer-coated vertical-cavity surface-emitting laser diode vapor sensor

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Nielsen, Claus Højgaard; Larsen, Niels Bent

    2010-01-01

    We report a new method for monitoring vapor concentration of volatile organic compounds using a vertical-cavity surface-emitting laser (VCSEL). The VCSEL is coated with a polymer thin film on the top distributed Bragg reflector (DBR). The analyte absorption is transduced to the electrical domain ...

  5. Submonolayer Quantum Dots for High Speed Surface Emitting Lasers

    Directory of Open Access Journals (Sweden)

    Zakharov ND

    2007-01-01

    Full Text Available AbstractWe report on progress in growth and applications of submonolayer (SML quantum dots (QDs in high-speed vertical-cavity surface-emitting lasers (VCSELs. SML deposition enables controlled formation of high density QD arrays with good size and shape uniformity. Further increase in excitonic absorption and gain is possible with vertical stacking of SML QDs using ultrathin spacer layers. Vertically correlated, tilted or anticorrelated arrangements of the SML islands are realized and allow QD strain and wavefunction engineering. Respectively, both TE and TM polarizations of the luminescence can be achieved in the edge-emission using the same constituting materials. SML QDs provide ultrahigh modal gain, reduced temperature depletion and gain saturation effects when used in active media in laser diodes. Temperature robustness up to 100 °C for 0.98 μm range vertical-cavity surface-emitting lasers (VCSELs is realized in the continuous wave regime. An open eye 20 Gb/s operation with bit error rates better than 10−12has been achieved in a temperature range 25–85 °Cwithout current adjustment. Relaxation oscillations up to ∼30 GHz have been realized indicating feasibility of 40 Gb/s signal transmission.

  6. Vertical-cavity surface-emitting laser vapor sensor using swelling polymer reflection modulation

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Nielsen, Claus Højgård; Dohn, Søren

    2012-01-01

    Vapor detection using a low-refractive index polymer for reflection modulation of the top mirror in a vertical-cavity surface-emitting laser (VCSEL) is demonstrated. The VCSEL sensor concept presents a simple method to detect the response of a sensor polymer in the presence of volatile organic co...... compounds. We model the physics as a change in the top mirror loss caused by swelling of the polymer upon absorbing the target volatile organic compound. Further we show how acetone vapors at 82 000 ppm concentration can change the polymer coated VCSEL output power by 20 mu W....

  7. Optically pumped GaN vertical cavity surface emitting laser with high index-contrast nanoporous distributed Bragg reflector.

    Science.gov (United States)

    Lee, Seung-Min; Gong, Su-Hyun; Kang, Jin-Ho; Ebaid, Mohamed; Ryu, Sang-Wan; Cho, Yong-Hoon

    2015-05-04

    Laser operation of a GaN vertical cavity surface emitting laser (VCSEL) is demonstrated under optical pumping with a nanoporous distributed Bragg reflector (DBR). High reflectivity, approaching 100%, is obtained due to the high index-contrast of the nanoporous DBR. The VCSEL system exhibits low threshold power density due to the formation of high Q-factor cavity, which shows the potential of nanoporous medium for optical devices.

  8. Controllable spiking patterns in long-wavelength vertical cavity surface emitting lasers for neuromorphic photonics systems

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado, Antonio, E-mail: antonio.hurtado@strath.ac.uk [Institute of Photonics, SUPA Department of Physics, University of Strathclyde, TIC Centre, 99 George Street, Glasgow G1 1RD (United Kingdom); Javaloyes, Julien [Departament de Fisica, Universitat de les Illes Balears, c/Valldemossa km 7.5, 07122 Mallorca (Spain)

    2015-12-14

    Multiple controllable spiking patterns are achieved in a 1310 nm Vertical-Cavity Surface Emitting Laser (VCSEL) in response to induced perturbations and for two different cases of polarized optical injection, namely, parallel and orthogonal. Furthermore, reproducible spiking responses are demonstrated experimentally at sub-nanosecond speed resolution and with a controlled number of spikes fired. This work opens therefore exciting research avenues for the use of VCSELs in ultrafast neuromorphic photonic systems for non-traditional computing applications, such as all-optical binary-to-spiking format conversion and spiking information encoding.

  9. Acetone vapor sensing using a vertical cavity surface emitting laser diode coated with polystyrene

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Nielsen, Claus Højgaard; Larsen, Niels Bent

    2009-01-01

    We report theoretical and experimental on a new vapor sensor, using a single-mode vertical-cavity surface-emitting laser (VCSEL) coated with a polymer sensor coating, which can detect acetone vapor at a volume fraction of 2.5%. The sensor provides the advantage of standard packaging, small form......-factor, mechanical stability and low cost when combined with a monolithically integrated photodiode detector....

  10. GaN-based vertical-cavity surface emitting lasers with sub-milliamp threshold and small divergence angle

    Science.gov (United States)

    Yeh, P. S.; Chang, C.-C.; Chen, Y.-T.; Lin, D.-W.; Liou, J.-S.; Wu, C. C.; He, J. H.; Kuo, H.-C.

    2016-12-01

    A GaN-based vertical-cavity surface emitting laser (VCSEL) structure featuring a silicon-diffusion-defined current blocking layer for lateral confinement is described. Sub-milliamp threshold currents were achieved for both 3- and 5-μm-aperture VCSELs under continuous-wave operation at room temperature. The vertical cavity was defined by a top dielectric distributed Bragg reflector (DBR) and a bottom epitaxial DBR. The emission spectrum exhibited a single peak at 411.2 nm with a linewidth of 0.4 nm and a side mode suppression ratio of more than 10 dB before device packaging. The full-width-at-half-maximum divergence angle of the 3-μm-aperture VCSEL was as small as approximately 5° which is the lowest number reported. These results implied the 3-μm-aperture VCSEL was in near single-mode operation.

  11. Surface emitting ring quantum cascade lasers for chemical sensing

    Science.gov (United States)

    Szedlak, Rolf; Hayden, Jakob; Martín-Mateos, Pedro; Holzbauer, Martin; Harrer, Andreas; Schwarz, Benedikt; Hinkov, Borislav; MacFarland, Donald; Zederbauer, Tobias; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Acedo, Pablo; Lendl, Bernhard; Strasser, Gottfried

    2018-01-01

    We review recent advances in chemical sensing applications based on surface emitting ring quantum cascade lasers (QCLs). Such lasers can be implemented in monolithically integrated on-chip laser/detector devices forming compact gas sensors, which are based on direct absorption spectroscopy according to the Beer-Lambert law. Furthermore, we present experimental results on radio frequency modulation up to 150 MHz of surface emitting ring QCLs. This technique provides detailed insight into the modulation characteristics of such lasers. The gained knowledge facilitates the utilization of ring QCLs in combination with spectroscopic techniques, such as heterodyne phase-sensitive dispersion spectroscopy for gas detection and analysis.

  12. Comparison of nonpolar III-nitride vertical-cavity surface-emitting lasers with tunnel junction and ITO intracavity contacts

    KAUST Repository

    Leonard, J. T.

    2016-03-01

    We report on the lasing of III-nitride nonpolar, violet, vertical-cavity surface-emitting lasers (VCSELs) with III-nitride tunnel-junction (TJ) intracavity contacts and ion implanted apertures (IIAs). The TJ VCSELs are compared to similar VCSELs with tin-doped indium oxide (ITO) intracavity contacts. Prior to analyzing device results, we consider the relative advantages of III-nitride TJs for blue and green emitting VCSELs. The TJs are shown to be most advantageous for violet and UV VCSELs, operating near or above the absorption edge for ITO, as they significantly reduce the total internal loss in the cavity. However, for longer wavelength III-nitride VCSELs, TJs primarily offer the advantage of improved cavity design flexibility, allowing one to make the p-side thicker using a thick n-type III-nitride TJ intracavity contact. This offers improved lateral current spreading and lower loss, compare to using ITO and p-GaN, respectively. These aspects are particularly important for achieving high-power CW VCSELs, making TJs the ideal intracavity contact for any III-nitride VCSEL. A brief overview of III-nitride TJ growth methods is also given, highlighting the molecular-beam epitaxy (MBE) technique used here. Following this overview, we compare 12 mu m aperture diameter, violet emitting, TJ and ITO VCSEL experimental results, which demonstrate the significant improvement in differential efficiency and peak power resulting from the reduced loss in the TJ design. Specifically, the TJ VCSEL shows a peak power of similar to 550 mu W with a threshold current density of similar to 3.5 kA/cm(2), while the ITO VCSELs show peak powers of similar to 80 mu W and threshold current densities of similar to 7 kA/cm

  13. Comparison of nonpolar III-nitride vertical-cavity surface-emitting lasers with tunnel junction and ITO intracavity contacts

    Science.gov (United States)

    Leonard, J. T.; Young, E. C.; Yonkee, B. P.; Cohen, D. A.; Shen, C.; Margalith, T.; Ng, T. K.; DenBaars, S. P.; Ooi, B. S.; Speck, J. S.; Nakamura, S.

    2016-02-01

    We report on the lasing of III-nitride nonpolar, violet, vertical-cavity surface-emitting lasers (VCSELs) with IIInitride tunnel-junction (TJ) intracavity contacts and ion implanted apertures (IIAs). The TJ VCSELs are compared to similar VCSELs with tin-doped indium oxide (ITO) intracavity contacts. Prior to analyzing device results, we consider the relative advantages of III-nitride TJs for blue and green emitting VCSELs. The TJs are shown to be most advantageous for violet and UV VCSELs, operating near or above the absorption edge for ITO, as they significantly reduce the total internal loss in the cavity. However, for longer wavelength III-nitride VCSELs, TJs primarily offer the advantage of improved cavity design flexibility, allowing one to make the p-side thicker using a thick n-type III-nitride TJ intracavity contact. This offers improved lateral current spreading and lower loss, compare to using ITO and p-GaN, respectively. These aspects are particularly important for achieving high-power CW VCSELs, making TJs the ideal intracavity contact for any III-nitride VCSEL. A brief overview of III-nitride TJ growth methods is also given, highlighting the molecular-beam epitaxy (MBE) technique used here. Following this overview, we compare 12 μm aperture diameter, violet emitting, TJ and ITO VCSEL experimental results, which demonstrate the significant improvement in differential efficiency and peak power resulting from the reduced loss in the TJ design. Specifically, the TJ VCSEL shows a peak power of ~550 μW with a threshold current density of ~3.5 kA/cm2, while the ITO VCSELs show peak powers of ~80 μW and threshold current densities of ~7 kA/cm2.

  14. Vertical-cavity surface-emitting lasers enable high-density ultra-high bandwidth optical interconnects

    Science.gov (United States)

    Chitica, N.; Carlsson, J.; Svenson, L.-G.; Chacinski, M.

    2015-03-01

    Vertical-Cavity Surface-Emitting Lasers (VCSELs) are key components enabling power- and cost-efficient, high-density, ultra-high bandwidth parallel optical interconnects for data center and high-performance computing applications. This paper presents recent developments at TE Connectivity (TE) in the area of 25 Gb/s per channel-class VCSEL and optical transmitter technology for applications such as 100G and 400G Ethernet and Enhanced Data Rate InfiniBand pluggable and mid-board connectivity solutions.

  15. Tradeoffs of vertical-cavity surface emitting lasers modeling for the development of driver circuits in short distance optical links

    Science.gov (United States)

    Sialm, Gion; Erni, Daniel; Vez, Dominique; Kromer, Christian; Ellinger, Frank; Bona, Gian-Luca; Morf, Thomas; Jäckel, Heinz

    2005-10-01

    In short-distance optical links, the development of driving circuits for vertical-cavity surface-emitting lasers (VCSELs) requires precise and computationally efficient VCSEL models. A small-signal model of a VCSEL is computationally efficient and simple to implement; however, it does not take into account the nonlinear output behavior of the VCSEL. In contrast, VCSEL models that are highly based on first principles cannot be implemented in standard circuit device simulators, because the simulation of eye diagrams becomes too time consuming. We present another approach using VCSEL models, which are based on the 1-D rate equations. Our analysis shows that they combine efficient extraction and short simulation time with an accurate calculation of eye diagrams over a wide range of ambient temperatures. As different implementations of the rate equations exist, tradeoffs between three different versions are presented and compared with measured GaAs oxide-confined VCSELs. The first model has a linear and the second a logarithmic function of the gain versus the carrier density. The third model considers the additional transport time for carriers to reach the active region with quantum wells. For parameter extraction, a minimum set of parameters is identified, which can be determined from fundamental measurements.

  16. Optical Injection Locking of Vertical Cavity Surface-Emitting Lasers: Digital and Analog Applications

    Science.gov (United States)

    Parekh, Devang

    With the rise of mobile (cellphones, tablets, notebooks, etc.) and broadband wireline communications (Fiber to the Home), there are increasing demands being placed on transmitters for moving data from device to device and around the world. Digital and analog fiber-optic communications have been the key technology to meet this challenge, ushering in ubiquitous Internet and cable TV over the past 20 years. At the physical layer, high-volume low-cost manufacturing of semiconductor optoelectronic devices has played an integral role in allowing for deployment of high-speed communication links. In particular, vertical cavity surface emitting lasers (VCSEL) have revolutionized short reach communications and are poised to enter more markets due to their low cost, small size, and performance. However, VCSELs have disadvantages such as limited modulation performance and large frequency chirp which limits fiber transmission speed and distance, key parameters for many fiber-optic communication systems. Optical injection locking is one method to overcome these limitations without re-engineering the VCSEL at the device level. By locking the frequency and phase of the VCSEL by the direct injection of light from another laser oscillator, improved device performance is achieved in a post-fabrication method. In this dissertation, optical injection locking of VCSELs is investigated from an applications perspective. Optical injection locking of VCSELs can be used as a pathway to reduce complexity, cost, and size of both digital and analog fiber-optic communications. On the digital front, reduction of frequency chirp via bit pattern inversion for large-signal modulation is experimentally demonstrated showing up to 10 times reduction in frequency chirp and over 90 times increase in fiber transmission distance. Based on these results, a new reflection-based interferometric model for optical injection locking was established to explain this phenomenon. On the analog side, the resonance

  17. Circular polarization switching and bistability in an optically injected 1300 nm spin-vertical cavity surface emitting laser

    Energy Technology Data Exchange (ETDEWEB)

    Alharthi, S. S., E-mail: ssmalh@essex.ac.uk; Henning, I. D.; Adams, M. J. [School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, Colchester CO4 3SQ (United Kingdom); Hurtado, A. [School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, Colchester CO4 3SQ (United Kingdom); Institute of Photonics, Physics Department, University of Strathclyde, Wolfson Centre, 106 Rottenrow East, Glasgow G4 0NW, Scotland (United Kingdom); Korpijarvi, V.-M.; Guina, M. [Optoelectronics Research Centre (ORC), Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere (Finland)

    2015-01-12

    We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in future optical systems.

  18. Nonpolar III-nitride vertical-cavity surface-emitting lasers incorporating an ion implanted aperture

    KAUST Repository

    Leonard, J. T.

    2015-07-06

    © 2015 AIP Publishing LLC. We report on our recent progress in improving the performance of nonpolar III-nitride vertical-cavity surface-emitting lasers (VCSELs) by using an Al ion implanted aperture and employing a multi-layer electron-beam evaporated ITO intracavity contact. The use of an ion implanted aperture improves the lateral confinement over SiNx apertures by enabling a planar ITO design, while the multi-layer ITO contact minimizes scattering losses due to its epitaxially smooth morphology. The reported VCSEL has 10 QWs, with a 3nm quantum well width, 1nm barriers, a 5nm electron-blocking layer, and a 6.95- λ total cavity thickness. These advances yield a single longitudinal mode 406nm nonpolar VCSEL with a low threshold current density (∼16kA/cm2), a peak output power of ∼12μW, and a 100% polarization ratio. The lasing in the current aperture is observed to be spatially non-uniform, which is likely a result of filamentation caused by non-uniform current spreading, lateral optical confinement, contact resistance, and absorption loss.

  19. Electron spin injection from a regrown Fe layer in a spin-polarized vertical-cavity surface-emitting laser

    Science.gov (United States)

    Holub, M.; Bhattacharya, P.; Shin, J.; Saha, D.

    2007-04-01

    An electroluminescence circular polarization of 23% and threshold current reduction of 11% are obtained in an electrically pumped spin-polarized vertical-cavity surface-emitting laser. Electron spin injection is accomplished utilizing a regrown Fe/ n-AlGaAs Schottky tunnel barrier deposited around the base of the laser mesas. Negligible circular polarizations and threshold current reductions are measured for nonmagnetic and Fe-based control VCSELs, which provides convincing evidence of spin injection, transport, and detection in our spin-polarized laser.

  20. The simulation of thermal characteristics of 980 nm vertical cavity surface emitting lasers

    Science.gov (United States)

    Fang, Tianxiao; Cui, Bifeng; Hao, Shuai; Wang, Yang

    2018-02-01

    In order to design a single mode 980 nm vertical cavity surface emitting laser (VCSEL), a 2 μm output aperture is designed to guarantee the single mode output. The effects of different mesa sizes on the lattice temperature, the output power and the voltage are simulated under the condition of continuous working at room temperature, to obtain the optimum process parameters of mesa. It is obtained by results of the crosslight simulation software that the sizes of mesa radius are between 9.5 to 12.5 μm, which cannot only obtain the maximum output power, but also improve the heat dissipation of the device. Project supported by the Beijing Municipal Eduaction Commission (No. PXM2016_014204_500018) and the Construction of Scientific and Technological Innovation Service Ability in 2017 (No. PXM2017_014204_500034).

  1. A UWOC system based on a 6 m/5.2 Gbps 680 nm vertical-cavity surface-emitting laser

    Science.gov (United States)

    Li, Chung-Yi; Tsai, Wen-Shing

    2018-02-01

    This study proves that an underwater wireless optical communication (UWOC) based on a 6 m/5.2 Gbps 68 nm vertical-cavity surface-emitting laser (VCSEL)-based system is superior to a 405 nm UWOC system. This UWOC application is the first to use a VCSEL at approximately 680 nm. The experiment also proved that a 680 nm VCSEL has the same transmission distance as that of an approximately 405 nm laser diode. The 680 nm VCSEL has a 5.2 Gbps high transmission rate and can transmit up to 6 m. Thus, the setup is the best alternative solution for high-speed UWOC applications.

  2. Operation of a novel hot-electron vertical-cavity surface-emitting laser

    Science.gov (United States)

    Balkan, Naci; O'Brien-Davies, Angela; Thoms, A. B.; Potter, Richard J.; Poolton, Nigel; Adams, Michael J.; Masum, J.; Bek, Alpan; Serpenguzel, Ali; Aydinli, Atilla; Roberts, John S.

    1998-07-01

    The hot Electron Light Emission and Lasing in Semiconductor Heterostructures devices (HELLISH-1) is novel surface emitter consisting of a GaAs quantum well, within the depletion region, on the n side of Ga1-xAlxAs p- n junction. It utilizes hot electron transport parallel to the layers and injection of hot electron hole pairs into the quantum well through a combination of mechanisms including tunnelling, thermionic emission and diffusion of `lucky' carriers. Super Radiant HELLISH-1 is an advanced structure incorporating a lower distributed Bragg reflector (DBR). Combined with the finite reflectivity of the upper semiconductor-air interface reflectivity it defines a quasi- resonant cavity enabling emission output from the top surface with a higher spectral purity. The output power has increased by two orders of magnitude and reduced the full width at half maximum (FWHM) to 20 nm. An upper DBR added to the structure defines HELLISH-VCSEL which is currently the first operational hot electron surface emitting laser and lases at room temperature with a 1.5 nm FWHM. In this work we demonstrate and compare the operation of UB-HELLISH-1 and HELLISH-VCSEL using experimental and theoretical reflectivity spectra over an extensive temperature range.

  3. Commercial mode-locked vertical external cavity surface emitting lasers

    Science.gov (United States)

    Lubeigt, Walter; Bialkowski, Bartlomiej; Lin, Jipeng; Head, C. Robin; Hempler, Nils; Maker, Gareth T.; Malcolm, Graeme P. A.

    2017-02-01

    In recent years, M Squared Lasers have successfully commercialized a range of mode-locked vertical external cavity surface emitting lasers (VECSELs) operating between 920-1050nm and producing picosecond-range pulses with average powers above 1W at pulse repetition frequencies (PRF) of 200MHz. These laser products offer a low-cost, easy-to-use and maintenance-free tool for the growing market of nonlinear microscopy. However, in order to present a credible alternative to ultrafast Ti-sapphire lasers, pulse durations below 200fs are required. In the last year, efforts have been directed to reduce the pulse duration of the Dragonfly laser system to below 200fs with a target average power above 1W at a PRF of 200MHz. This paper will describe and discuss the latest efforts undertaken to approach these targets in a laser system operating at 990nm. The relatively low PRF operation of Dragonfly lasers represents a challenging requirement for mode-locked VECSELs due to the very short upper state carrier lifetime, on the order of a few nanoseconds, which can lead to double pulsing behavior in longer cavities as the time between consecutive pulses is increased. Most notably, the design of the Dragonfly VECSEL cavity was considerably modified and the laser system extended with a nonlinear pulse stretcher and an additional compression stage. The improved Dragonfly laser system achieved pulse duration as short as 130fs with an average power of 0.85W.

  4. VCSELs: A Research Review

    Science.gov (United States)

    Michalzik, Rainer

    This chapter attempts to briefly review the research history of vertical-cavity surface-emitting lasers (VCSELs). Based on the contents of previous monographs on VCSELs written in English, we motivate the selection of topics in the present book and give an introduction to the individual chapters. Moreover, we mention some other research that is not covered in a dedicated chapter in order to provide the readers with even deeper insights into VCSEL research. Future directions and opportunities are also indicated.

  5. Vertical-cavity surface-emitting lasers for medical diagnosis

    DEFF Research Database (Denmark)

    Ansbæk, Thor

    and high tuning rate. The VCSEL is highly single-mode and inherently polarization stable due to the use of a High-index Contrast subwavelength Grating (HCG). HCG VCSELs are presented with 1.5% relative tuning range at a tuning rate of 850 kHz. The thesis reports on the analysis of narrow linewidth Fabry...

  6. Nonlinear dynamic behaviors of an optically injected vertical-cavity surface-emitting laser

    International Nuclear Information System (INIS)

    Li Xiaofeng; Pan Wei; Luo Bin; Ma Dong; Wang Yong; Li Nuohan

    2006-01-01

    Nonlinear dynamics of a vertical-cavity surface-emitting laser (VCSEL) with external optical injection are studied numerically. We consider a master-slave configuration where the dynamic characteristics of the slave are affected by the optical injection from the master, and we also establish the corresponding Simulink model. The period-doubling route as well as the period-halving route is observed, where the regular, double-periodic, and chaotic pulsings are found. By adjusting the injection strength properly, the laser can be controlled to work at a given state. The effects of frequency detuning on the nonlinear behaviors are also investigated in terms of the bifurcation diagrams of photon density with the frequency detuning. For weak injection case, the nonlinear dynamics shown by the laser are quite different when the value of frequency detuning varies contrarily (positive and negative direction). If the optical injection is strong enough, the slave can be locked by the master even though the frequency detuning is relatively large

  7. Low threshold continuous-wave lasing of yellow-green InGaN-QD vertical-cavity surface-emitting lasers.

    Science.gov (United States)

    Weng, Guoen; Mei, Yang; Liu, Jianping; Hofmann, Werner; Ying, Leiying; Zhang, Jiangyong; Bu, Yikun; Li, Zengcheng; Yang, Hui; Zhang, Baoping

    2016-07-11

    Low threshold continuous-wave (CW) lasing of current injected InGaN quantum dot (QD) vertical-cavity surface-emitting lasers (VCSELs) was achieved at room temperature. The VCSEL was fabricated by metal bonding technique on a copper substrate to improve the heat dissipation ability of the device. For the first time, lasing was obtained at yellow-green wavelength of 560.4 nm with a low threshold of 0.61 mA, corresponding to a current density of 0.78 kA/cm2. A high degree of polarization of 94% were measured. Despite the operation in the range of "green gap" of GaN-based devices, single longitudinal mode laser emission was clearly achieved due to the high quality of active region based on InGaN QDs and the excellent thermal design of the VCSELs.

  8. Modeling of circular-grating surface-emitting lasers

    Science.gov (United States)

    Shams-Zadeh-Amiri, Ali M.

    Grating-coupled surface-emitting lasers became an area of growing interest due to their salient features. Emission from a broad area normal to the wafer surface, makes them very well suited in high power applications and two- dimensional laser arrays. These new possibilities have caused an interest in different geometries to fully develop their potential. Among them, circular-grating lasers have the additional advantage of producing a narrow beam with a circular cross section. This special feature makes them ideal for coupling to optical fibers. All existing theoretical models dealing with circular- grating lasers only consider first-order gratings, or second-order gratings, neglecting surface emission. In this thesis, the emphasis is to develop accurate models describing the laser performance by considering the radiation field. Toward this aim, and due to the importance of the radiation modes in surface-emitting structures, a theoretical study of these modes in multilayer planar structures has been done in a rigorous and systematic fashion. Problems like orthogonality of the radiation modes have been treated very accurately. We have considered the inner product of radiation modes using the distribution theory. Orthogonality of degenerate radiation modes is an important issue. We have examined its validity using the transfer matrix method. It has been shown that orthogonality of degenerate radiation modes in a very special case leads to the Brewster theorem. In addition, simple analytical formulas for the normalization of radiation modes have been derived. We have shown that radiation modes can be handled in a much easier way than has been thought before. A closed-form spectral dyadic Green's function formulation of multilayer planar structures has been developed. In this formulation, both rectangular and cylindrical structures can be treated within the same mathematical framework. The Hankel transform of some auxiliary functions defined on a circular aperture has

  9. Characterization of 2.3 μm GaInAsSb-based vertical-cavity surface-emitting laser structures using photo-modulated reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Chai, G. M. T. [Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Hosea, T. J. C., E-mail: j.hosea@surrey.ac.uk [Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Fox, N. E.; Hild, K.; Ikyo, A. B.; Marko, I. P.; Sweeney, S. J. [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Bachmann, A.; Arafin, S.; Amann, M.-C. [Walter Schottky Institut, Technische Universität Munchen, Am Coulombwall 4, D-85748 Garching (Germany)

    2014-01-07

    We report angle dependent and temperature dependent (9 K–300 K) photo-modulated reflectance (PR) studies on vertical-cavity surface-emitting laser (VCSEL) structures, designed for 2.3 μm mid-infrared gas sensing applications. Changing the temperature allows us to tune the energies of the quantum well (QW) transitions relative to the VCSEL cavity mode (CM) energy. These studies show that this VCSEL structure has a QW-CM offset of 21 meV at room temperature. Consequently the QW ground-state transition comes into resonance with the CM at 220 ± 2 K. The results from these PR studies are closely compared with those obtained in a separate study of actual operating devices and show how the PR technique may be useful for device optimisation without the necessity of having first to process the wafers into working devices.

  10. Attractor hopping between polarization dynamical states in a vertical-cavity surface-emitting laser subject to parallel optical injection

    Science.gov (United States)

    Denis-le Coarer, Florian; Quirce, Ana; Valle, Angel; Pesquera, Luis; Rodríguez, Miguel A.; Panajotov, Krassimir; Sciamanna, Marc

    2018-03-01

    We present experimental and theoretical results of noise-induced attractor hopping between dynamical states found in a single transverse mode vertical-cavity surface-emitting laser (VCSEL) subject to parallel optical injection. These transitions involve dynamical states with different polarizations of the light emitted by the VCSEL. We report an experimental map identifying, in the injected power-frequency detuning plane, regions where attractor hopping between two, or even three, different states occur. The transition between these behaviors is characterized by using residence time distributions. We find multistability regions that are characterized by heavy-tailed residence time distributions. These distributions are characterized by a -1.83 ±0.17 power law. Between these regions we find coherence enhancement of noise-induced attractor hopping in which transitions between states occur regularly. Simulation results show that frequency detuning variations and spontaneous emission noise play a role in causing switching between attractors. We also find attractor hopping between chaotic states with different polarization properties. In this case, simulation results show that spontaneous emission noise inherent to the VCSEL is enough to induce this hopping.

  11. On the importance of cavity-length and heat dissipation in GaN-based vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Liu, W. J.; Hu, X. L.; Ying, L. Y.; Chen, S. Q.; Zhang, J. Y.; Akiyama, H.; Cai, Z. P.; Zhang, B. P.

    2015-04-01

    Cavity-length dependence of the property of optically pumped GaN-based vertical-cavity surface-emitting lasers (VCSELs) with two dielectric distributed Bragg reflectors was investigated. The cavity lengths were well controlled by employing etching with inductively coupled plasma and chemical mechanical polishing. It was found that the lasing characteristics including threshold, slope efficiency and spontaneous emission coupling factor were substantially improved with reducing the cavity length. In comparison with the device pumped by a 400 nm pulsed laser, the lasing spectrum was featured by a red shift and simultaneous broadening with increasing the pumping energy of a 355 nm pulsed laser. Moreover, the lasing threshold was much higher when pumped by a 355 nm pulsed laser. These were explained by taking into account of the significant heating effect under 355 nm pumping. Our results demonstrate that a short cavity length and good heat-dissipation are essential to GaN-based VCSELs.

  12. Theory and Modeling of Lasing Modes in Vertical Cavity Surface Emitting Lasers

    Directory of Open Access Journals (Sweden)

    Benjamin Klein

    1998-01-01

    modes that the VCSEL can support are then determined by matching the gain necessary for the optical system in both magnitude and phase to the gain available from the laser's electronic system. Examples are provided.

  13. Research of the use of silver nanowires as a current spreading layer on vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Guo, Xia; Shi, Lei; Li, Chong; Dong, Jian; Liu, Bai; Hu, Shuai; He, Yan

    2016-11-01

    Silver nanowire (AgNW) film was proposed to apply on the surface of the vertical-cavity surface-emitting lasers (VCSELs) with large aperture in order to obtain a uniform current distribution in the active region and a better optical beam quality. Optimization of the AgNW film was carried out with the sheet resistance of 28.4 Ω/sq and the optical transmission of 94.8% at 850 nm. The performance of VCSELs with and without AgNW film was studied. When the AgNW film was applied to the surface of VCSELs, due to its better current spreading effect, the maximum output optical power increased from 23.4 mW to 24.4 mW, the lasing wavelength redshift decreased from 0.085 nm/mA to 0.077 nm/mA, the differential resistance decreased from 23.95 Ω to 21.13 Ω, and the far field pattern at 50 mA decreased from 21.6° to 19.2°. At the same time, the near field test results showed that the light in the aperture was more uniform, and the far field exhibited a better single peak characteristic. Various results showed that VCSELs with AgNW on the surface showed better beam quality. Project supported by the National Natural Science Foundation of China (Grant Nos. 61335004 and 61505003), the National High Technology Research and Development Program of China (Grant No. 2015AA017101), and the National Key Research and Development of China (Grant No. 2016YFB0400603).

  14. Dynamics of 1.55 μm Wavelength Single-Mode Vertical-Cavity Surface-Emitting Laser Output under External Optical Injection

    Directory of Open Access Journals (Sweden)

    Kyong Hon Kim

    2012-01-01

    Full Text Available We review the temporal dynamics of the laser output spectrum and polarization state of 1.55 μm wavelength single-mode (SM vertical-cavity surface-emitting lasers (VCSELs induced by external optical beam injection. Injection of an external continuous-wave laser beam to a gain-switched SM VCSEL near the resonance wavelength corresponding to its main polarization-mode output was critical for improvement of its laser pulse generation characteristics, such as pulse timing-jitter reduction, linewidth narrowing, pulse amplitude enhancement, and pulse width shortening. Pulse injection of pulse width shorter than the cavity photon lifetime into the SM VCSEL in the orthogonal polarization direction with respect to its main polarization mode caused temporal delay of the polarization recovery after polarization switching (PS, and its delay was found to be the minimum at an optimized bias current. Polarization-mode bistability was observed even in the laser output of an SM VCSEL of a standard circularly cylindrical shape and used for all-optical flip-flop operations with set and reset injection pulses of very low pulse energy of order of the 3.5~4.5 fJ.

  15. Linearly Polarized Dual-Wavelength Vertical-External-Cavity Surface-Emitting Laser (Postprint)

    National Research Council Canada - National Science Library

    Fan, Li; Fallahi, Mahmoud; Hader, Joerg; Zakharian, Aramais R; Moloney, Jerome V; Stolz, Wolfgang; Koch, Stephan W; Bedford, Robert; Murray, James T

    2007-01-01

    The authors demonstrate the multiwatt linearly polarized dual-wavelength operation in an optically pumped vertical-external-cavity surface-emitting laser by means of an intracavity tilted Fabry-Perot...

  16. A GaInAsP/InP Vertical Cavity Surface Emitting Laser for 1.5 m m operation

    Science.gov (United States)

    Sceats, R.; Balkan, N.; Adams, M. J.; Masum, J.; Dann, A. J.; Perrin, S. D.; Reid, I.; Reed, J.; Cannard, P.; Fisher, M. A.; Elton, D. J.; Harlow, M. J.

    1999-04-01

    We present the results of our studies concerning the pulsed operation of a bulk GaInAsP/InP vertical cavity surface emitting laser (VCSEL). The device is tailored to emit at around 1.5 m m at room temperature. The structure has a 45 period n-doped GaInAsP/InP bottom distributed Bragg reflector (DBR), and a 4 period Si/Al2O3 dielectric top reflector defining a 3-l cavity. Electroluminescence from a 16 m m diameter top window was measured in the pulsed injection mode. Spectral measurements were recorded in the temperature range between 125K and 240K. Polarisation, lasing threshold current and linewidth measurements were also carried out at the same temperatures. The threshold current density has a broad minimum at temperatures between 170K and 190K, (Jth=13.2 kA/cm2), indicating a good match between the gain and the cavity resonance in this temperature range. Maximum emitted power from the VCSEL is 0.18 mW at 180K.

  17. Nonpolar III-nitride vertical-cavity surface-emitting laser with a photoelectrochemically etched air-gap aperture

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, J. T., E-mail: jtleona01@gmail.com; Yonkee, B. P.; Cohen, D. A.; Megalini, L.; Speck, J. S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Lee, S. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); DenBaars, S. P.; Nakamura, S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)

    2016-01-18

    We demonstrate a III-nitride nonpolar vertical-cavity surface-emitting laser (VCSEL) with a photoelectrochemically (PEC) etched aperture. The PEC lateral undercut etch is used to selectively remove the multi-quantum well (MQW) region outside the aperture area, defined by an opaque metal mask. This PEC aperture (PECA) creates an air-gap in the passive area of the device, allowing one to achieve efficient electrical confinement within the aperture, while simultaneously achieving a large index contrast between core of the device (the MQW within the aperture) and the lateral cladding of the device (the air-gap formed by the PEC etch), leading to strong lateral confinement. Scanning electron microscopy and focused ion-beam analysis is used to investigate the precision of the PEC etch technique in defining the aperture. The fabricated single mode PECA VCSEL shows a threshold current density of ∼22 kA/cm{sup 2} (25 mA), with a peak output power of ∼180 μW, at an emission wavelength of 417 nm. The near-field emission profile shows a clearly defined single linearly polarized (LP) mode profile (LP{sub 12,1}), which is in contrast to the filamentary lasing that is often observed in III-nitride VCSELs. 2D mode profile simulations, carried out using COMSOL, give insight into the different mode profiles that one would expect to be displayed in such a device. The experimentally observed single mode operation is proposed to be predominantly a result of poor current spreading in the device. This non-uniform current spreading results in a higher injected current at the periphery of the aperture, which favors LP modes with high intensities near the edge of the aperture.

  18. Speed enhancement in VCSELs employing grating mirrors

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2013-01-01

    In recent years, various approaches to improve the speed of directly modulated vertical-cavity surface-emitting lasers (VCSELs) have been reported and demonstrated good improvement. In this paper, we propose and numerically investigate a new possibility of using high-index-contrast grating (HCG......) as mirror for VCSELs. By changing the grating design, one can control the reflection delay of the grating mirror, enabling the control of cavity photon lifetime. On the other hand, short energy penetration depth of the HCG results in smaller modal volume, compared to DBR VCSELs. An example structure shows...... that the HCG VCSEL has a 30-% higher 3-dB bandwidth than the DBR VCSEL....

  19. A Study of the interaction of radiation and semiconductor lasers: an analysis of transient and permanent effects induced on edge emitting and vertical cavity surface emitting laser diodes

    International Nuclear Information System (INIS)

    Pailharey, Eric

    2000-01-01

    The behavior of laser diodes under transient environment is presented in this work. The first section describes the basic phenomena of radiation interaction with matter. The radiative environments, the main characteristics of laser diodes and the research undertaken on the subject are presented and discussed. The tests on 1300 nm edge emitting laser diode are presented in the second section. The response to a transient ionizing excitation is explored using a 532 nm laser beam. The time of return to steady state after the perturbation is decomposed into several steps: decrease of the optical power during excitation, turn-on delay, relaxation oscillations and optical power offset. Their origins are analyzed using the device structure. To include all the phenomena in a numerical simulation of the device, an individual study of low conductivity materials used for the lateral confinement of the current density is undertaken. The effects of a single particle traversing the optical cavity and an analysis of permanent damages induced by neutrons are also determined. In the last section, 850 nm vertical cavity surface emitting laser diodes (VCSEL) are studied. The behavior of these devices which performances are in constant evolution, is investigated as a function of both temperature and polarization. Then VCSEL are submitted to transient ionizing irradiation and their responses are compared to those of edge emitting diodes. When proton implantation is used in the process, we observe the same behavior for both technologies. VCSEL were submitted to neutron fluence and we have studied the influence of the damages on threshold current, emission patterns and maximum of optical power. (author) [fr

  20. Modelling of the modulation properties of arsenide and nitride VCSELs

    Science.gov (United States)

    Wasiak, Michał; Śpiewak, Patrycja; Moser, Philip; Gebski, Marcin; Schmeckebier, Holger; Sarzała, Robert P.; Lott, James A.

    2017-02-01

    In this paper, using our model of capacitance in vertical-cavity surface-emitting lasers (VCSELs), we analyze certain differences between an oxide-confined arsenide VCSEL emitting in the NIR region, and a nitride VCSEL emitting violet radiation. In the nitride laser its high differential resistance, caused partially by the low conductivity of p-type GaN material and the bottom contact configuration, is one of the main reasons why the nitride VCSEL has much worse modulation properties than the arsenide VCSEL. Using the complicated arsenide structure, we also analyze different possible ways of constructing the laser's equivalent circuit.

  1. Swept-source optical coherence tomography powered by a 1.3-μm vertical cavity surface emitting laser enables 2.3-mm-deep brain imaging in mice in vivo

    Science.gov (United States)

    Choi, Woo June; Wang, Ruikang K.

    2015-10-01

    We report noninvasive, in vivo optical imaging deep within a mouse brain by swept-source optical coherence tomography (SS-OCT), enabled by a 1.3-μm vertical cavity surface emitting laser (VCSEL). VCSEL SS-OCT offers a constant signal sensitivity of 105 dB throughout an entire depth of 4.25 mm in air, ensuring an extended usable imaging depth range of more than 2 mm in turbid biological tissue. Using this approach, we show deep brain imaging in mice with an open-skull cranial window preparation, revealing intact mouse brain anatomy from the superficial cerebral cortex to the deep hippocampus. VCSEL SS-OCT would be applicable to small animal studies for the investigation of deep tissue compartments in living brains where diseases such as dementia and tumor can take their toll.

  2. LW VCSELs for SFP+ applications

    Science.gov (United States)

    Graham, Luke A.; Jewell, Jack L.; Maranowski, Kevin D.; Crom, Max V.; Feld, Stewart A.; Smith, Joseph M.; Beltran, James G.; Fanning, Thomas R.; Schnoes, Melinda; Gray, Matthew H.; Droege, David; Koleva, Vera; Dudek, Mike; Fiers, John; Patterson, Russ

    2008-02-01

    This article outlines development work at JDSU on InGaNAs based vertical cavity surface emitting lasers (VCSELs) operating at 1270nm and their use in 10Gbps SFP+ modules. DC and AC performance of die and transmit optical subassemblies (TOSAs) will be described. Due to their low power consumption, LW VCSELs are ideal for use in SFP+; module performance will be described as well.

  3. 2 W high efficiency PbS mid-infrared surface emitting laser

    Science.gov (United States)

    Ishida, A.; Sugiyama, Y.; Isaji, Y.; Kodama, K.; Takano, Y.; Sakata, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Zogg, H.

    2011-09-01

    High efficiency laser operation with output power exceeding 2 W was obtained for vertical external-cavity PbS based IV-VI compound surface emitting quantum-well structures. The laser showed external quantum efficiency as high as 16%. Generally, mid-infrared III-V or II-VI semiconductor laser operation utilizing interband electron transitions are restricted by Auger recombination and free carrier absorption. Auger recombination is much lower in the IV-VI semiconductors, and the free-carrier absorption is significantly reduced by an optically pumped laser structure including multi-step optical excitation layers.

  4. VCSEL Scaling, Laser Integration on Silicon, and Bit Energy

    Science.gov (United States)

    2017-03-01

    Silicon Photonics: Figure 1 shows the electronic circuitry and comparison key to analyzing photonic bit energies for transceivers used in data centers...VCSEL Scaling, Laser Integration on Silicon , and Bit Energy D.G. Deppe,1,2 Ja. Leshin,1 and Je. Leshin1 1CREOL, College of Optics & Photonics...laser; (000.0000) General [For codes, see www.opticsinfobase.org/submit/ocis.] Keywords: VCSELs, Nanoscale lasers, optical interconnects, silicon

  5. Spectral-Modulation Characteristics of Vertical-Cavity Surface-Emitting Lasers

    Science.gov (United States)

    Vas'kovskaya, M. I.; Vasil'ev, V. V.; Zibrov, S. A.; Yakovlev, V. P.; Velichanskii, V. L.

    2018-01-01

    The requirements imposed on vertical-cavity surface-emitting lasers in a number of metrological problems in which optical pumping of alkali atoms is used are considered. For lasers produced by different manufacturers, these requirements are compared with the experimentally observed spectral characteristics at a constant pump current and in the microwave modulation mode. It is shown that a comparatively small number of lasers in the microwave modulation mode make it possible to obtain the spectrum required for atomic clocks based on the coherent population-trapping effect.

  6. Transverse-mode-selectable microlens vertical-cavity surface-emitting laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Debernardi, Pierluigi; Lee, Yong Tak

    2010-01-01

    of the mode selection properties of the new structure is rigorously analyzed and compared to other structures reported in the literature. The possibility of engineering the emission shape while retaining strong single mode operation is highly desirable for low-cost mid-range optical interconnects applications......A new vertical-cavity surface-emitting laser structure employing a thin microlens is suggested and numerically investigated. The laser can be made to emit in either a high-power Gaussian-shaped single-fundamental mode or a high-power doughnut-shaped higher-order mode. The physical origin...

  7. Novel hybrid laser modes in composite VCSEL-DFB microcavities (Conference Presentation)

    Science.gov (United States)

    Mischok, Andreas; Wagner, Tim; Sudzius, Markas; Brückner, Robert; Fröb, Hartmut; Lyssenko, Vadim G.; Leo, Karl

    2017-02-01

    Two of the most successful microcresonator concepts are the vertical cavity surface emitting laser (VCSEL), where light is confined between distributed Bragg reflectors (DBRs), and the distributed feedback (DFB) laser, where a periodic grating provides positive optical feedback to selected modes in an active waveguide (WG) layer. Our work concerns the combination of both into a composite device, facilitating coherent interaction between both regimes and giving rise to novel laser modes in the system. In a first realization, a full VCSEL stack with an organic active layer is evaporated on top of a diffraction grating with a large period (approximately 1 micron), leading to diffraction of waveguided modes into the surface emission of the device. Here, the coherent interaction between VCSEL and WG modes, as observed in an anticrossing of the dispersion lines, facilitates novel hybrid lasing modes with macroscopic in-plane coherence [1]. In further studies, we decrease the grating period of such devices to realise DFB conditions in a second-order Bragg grating which strongly couples photons via first-order light diffraction to the VCSEL. This efficient coupling can be compared to more classical cascade-coupled cavities and is successfully described by a coupled oscillator model [2]. When both resonators are non-degenerate, they are able to function as independent structures without substantial diffraction losses. The realization of such novel devices provides a promising platform for photonic circuits based on organic microlasers. [1] A. Mischok et al., Adv. Opt. Mater., early online, DOI: 10.1002/adom.201600282, (2016) [2] T. Wagner et al., Appl. Phys. Lett., accepted, in production, (2016)

  8. Compact electro-absorption modulator integrated with vertical-cavity surface-emitting laser for highly efficient millimeter-wave modulation

    International Nuclear Information System (INIS)

    Dalir, Hamed; Ahmed, Moustafa; Bakry, Ahmed; Koyama, Fumio

    2014-01-01

    We demonstrate a compact electro-absorption slow-light modulator laterally-integrated with an 850 nm vertical-cavity surface-emitting laser (VCSEL), which enables highly efficient millimeter-wave modulation. We found a strong leaky travelling wave in the lateral direction between the two cavities via widening the waveguide width with a taper shape. The small signal response of the fabricated device shows a large enhancement of over 55 dB in the modulation amplitude at frequencies beyond 35 GHz; thanks to the photon-photon resonance. A large group index of over 150 in a Bragg reflector waveguide enables the resonance at millimeter wave frequencies for 25 μm long compact modulator. Based on the modeling, we expect a resonant modulation at a higher frequency of 70 GHz. The resonant modulation in a compact slow-light modulator plays a significant key role for high efficient narrow-band modulation in the millimeter wave range far beyond the intrinsic modulation bandwidth of VCSELs.

  9. Investigation of single-mode vertical-cavity surface-emitting lasers with graphene-bubble dielectric DBR

    Science.gov (United States)

    Guan, Baolu; Li, Pengtao; Arafin, Shamsul; Alaskar, Yazeed; Wang, Kang L.

    2018-02-01

    An inter-cavty contact single mode 850 nm VCSEL was fabricated with a graphene assisted self-assembly curved dielectric bubble Bragg mirror for the first time. Taking the advantage of graphene's uniform low surface energy, the low cost dielectric bubble DBR (Si3N4/SiO2) was deposited on top of the graphene/half-VCSEL structure via van der Waals Force (vdWF) without using any additional spacing elements and sacrificial layer release-etch process. The continuous-wave operating VCSELs with an aperture diameter of 7 μm exhibit single-mode output power of more than 1 mW with a slope efficiency of 0.2 W/A. The sidemode suppression ratios are >40 dB. This novel modification into the lasers can also be applied to a variety of other optoelectronic devices, such as resonance photodetecter and super narrow linewidth VCSEL.

  10. Continuously tunable monomode mid-infrared vertical external cavity surface emitting laser on Si

    Science.gov (United States)

    Khiar, A.; Rahim, M.; Fill, M.; Felder, F.; Hobrecker, F.; Zogg, H.

    2010-10-01

    A tunable PbTe based mid-infrared vertical external cavity surface emitting laser is described. The active part is a ˜1 μm thick PbTe layer grown epitaxially on a Bragg mirror on the Si-substrate. The cavity is terminated with a curved Si/SiO Bragg top mirror and pumped optically with a 1.55 μm laser. Cavity length is <100 μm in order that only one longitudinal mode is supported. By changing the cavity length, up to 5% wavelength continuous and mode-hop free tuning is achieved at fixed temperature. The total tuning extends from 5.6 to 4.7 μm at 100-170 K operation temperature.

  11. Photodegradation and polarization properties of vertical external surface-emitting organic laser

    International Nuclear Information System (INIS)

    Leang, Tatiana

    2014-01-01

    Although organic solid-state dye lasers can provide wavelength tunability in the whole visible spectrum and offers perspectives of low-cost compact lasers, they are still limited by several drawbacks, especially photodegradation. The geometry of a Vertical External Cavity Surface-emitting Organic Laser (VECSOL) enables organic lasers to reach high energies, excellent conversion efficiencies and good beam quality, it also enables an external control on many parameters, a feature that we have used here to study the photodegradation phenomenon as well as some polarization properties of organic solid-state lasers. In the first part of this thesis, we studied the lifetime of the laser upon varying several parameters (pump pulse-width, repetition rate, output coupling,...) and we found that the intracavity laser intensity, independently of the pump intensity, had a major on photodegradation rate. Moreover, we observed that the profile of the laser beam was also degrading with time: while it is Gaussian in the beginning it gradually shifts to an annular shape. In the second part, we investigated the polarization properties of VECSOLs, with a special emphasis on fluorescence properties of some typical dyes used in lasers. The crucial role played by resonant non-radiative energy transfers between dye molecules (HOMO-FRET) is evidenced and enables explaining the observed fluorescence depolarization, compared to the expected limiting fluorescence anisotropy. Energy transfers happen to play a negligible role above laser threshold, as the organic laser beam is shown to be linearly polarized in a wide range of experimental conditions when excitation occurs in the first singlet state. (author) [fr

  12. Characteristics of VCSELs and VCSEL arrays for optical data links

    Science.gov (United States)

    Gaw, Craig A.; Jiang, Wenbin; Lebby, Michael S.; Kiely, Philip A.; Claisse, Paul R.

    1997-05-01

    High performance, low cost, and highly reliable vertical cavity surface emitting lasers (VCSELs) have been developed and are currently being used in both parallel and serial optical interconnect applications. For example, Motorola's OPTOBUSTM parallel optical interconnect relies heavily on the unique characteristics of arrays of GaAs based VCSELs emitting at 850 nm to achieve its stringent performance goals at low cost. Representative parametric results of discrete VCSELs and VCSEL arrays will be compared, including `optical power output-current' and `current-voltage' curves, optical wall plug efficiencies, and modulation characteristics. The use of statistical parameter analysis across a wafer and subsequent parametric wafer maps has proven to be a valuable tool for maintaining control of the fabrication process. The consistency of VCSEL parameters across individual VCSEL arrays will be discussed. VCSELs are very robust devices. Life times at room ambient in excess of 3E6 hours have been reported by several groups. Degradation behavior of selected device parameters will be discussed. Failure analysis demonstrating the effect of proton implant depth on reliability will be presented. ESD damage at forward bias is shown to be process related, while ESD damage at reverse bias is shown to be material related. These VCSELs are ESD Class 1 devices.

  13. Design of photonic crystal surface emitting lasers with indium-tin-oxide top claddings

    Science.gov (United States)

    Huang, Shen-Che; Hong, Kuo-Bin; Chiu, Han-Lun; Lan, Shao-Wun; Chang, Tsu-Chi; Li, Heng; Lu, Tien-Chang

    2018-02-01

    Electrically pumped GaAs-based photonic crystal surface emitting lasers were fabricated using a simple fabrication process by directly capping the indium-tin-oxide transparent conducting thin film as the top cladding layer upon a photonic crystal layer. Optimization of the separate-confinement heterostructures of a laser structure is crucial to improving characteristics by providing advantageous optical confinements. The turn-on voltage, series resistance, threshold current, and slope efficiency of the laser with a 100 × 100 μm2 photonic crystal area operated at room temperature were 1.3 V, 1.5 Ω, 121 mA, and 0.2 W/A, respectively. Furthermore, we demonstrated a single-lobed lasing wavelength of 928.6 nm at 200 mA and a wavelength redshift rate of 0.05 nm/K in temperature-dependent measurements. The device exhibited the maximum output power of approximately 400 mW at an injection current of 2 A; moreover, divergence angles of less than 1° for the unpolarized circular-shaped laser beam were measured at various injection currents. Overall, the low threshold current, excellent beam quality, small divergence, high output power, and high-operating-temperature (up to 343 K) of our devices indicate that they can potentially fill the requirements for next-generation light sources and optoelectronic devices.

  14. Vertical-Cavity Surface-Emitting Lasers: Advanced Modulation Formats and Coherent Detection

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto

    transmission link with real-time demodulation. Furthermore, advanced modulation formats are considered in this thesis to expand the state-of-the-art in high-speed short-range data transmission system based on VCSELs. First, directly modulation of a VCSEL with a 4-level pulse amplitude modulation (PAM-4) signal...... at 50 Gb/s is achieved. This is the highest data rate ever transmitted with a single VCSEL at the time of this thesis work. The capacity of this system is increased to 100 Gb/s by using polarization multiplexing emulation and forward error correction techniques. Compared to a non return-to-zero on-off...

  15. 5-μm vertical external-cavity surface-emitting laser (VECSEL) for spectroscopic applications

    Science.gov (United States)

    Rahim, M.; Khiar, A.; Felder, F.; Fill, M.; Zogg, H.; Sigrist, M. W.

    2010-08-01

    Mid-IR tunable VECSELs (Vertical External-Cavity Surface-Emitting Lasers) emitting at 4-7 μm wavelengths and suitable for spectroscopic sensing applications are described. They are realized with lead-chalcogenide (IV-VI) narrow band gap materials. The active part, a single 0.6-2-μm thick PbTe or PbSe gain layer, is grown onto an epitaxial Bragg mirror consisting of two or three Pb1- y Eu y Te/BaF2 quarter-wavelength layer pairs. All layers are deposited by MBE in a single run employing a BaF2 or Si substrate, no further processing is needed. The cavity is completed with an external curved top mirror, which is again realized with an epitaxial Bragg structure. Pumping is performed optically with a 1.5-μm laser. Maximum output power for pulsed operation is currently up to >1 Wp at -173°C and >10 mW at 10°C. In continuous wave (CW) operation, 18 mW at 100 K are reached. Still higher operating temperatures and/or powers are expected with better heat-removal structures and better designs employing QW (Quantum-Wells). Advantages of mid-IR VECSELs compared to edge-emitting lasers are their very good beam quality (circular beam with 15 μm are accessible with Pb1- y X y Z (X=Sr, Eu, Sn, Z=Se, Te) and/or including QW.

  16. Real-time multi-target ranging based on chaotic polarization laser radars in the drive-response VCSELs.

    Science.gov (United States)

    Zhong, Dongzhou; Xu, Geliang; Luo, Wei; Xiao, Zhenzhen

    2017-09-04

    According to the principle of complete chaos synchronization and the theory of Hilbert phase transformation, we propose a novel real-time multi-target ranging scheme by using chaotic polarization laser radar in the drive-response vertical-cavity surface-emitting lasers (VCSELs). In the scheme, to ensure each polarization component (PC) of the master VCSEL (MVCSEL) to be synchronized steadily with that of the slave VCSEL, the output x-PC and y-PC from the MVCSEL in the drive system and those in the response system are modulated by the linear electro-optic effect simultaneously. Under this condition, by simulating the influences of some key parameters of the system on the synchronization quality and the relative errors of the two-target ranging, related operating parameters can be optimized. The x-PC and the y-PC, as two chaotic radar sources, are used to implement the real-time ranging for two targets. It is found that the measured distances of the two targets at arbitrary position exhibit strong real-time stability and only slight jitter. Their resolutions are up to millimeters, and their relative errors are very small and less than 2.7%.

  17. Transverse mode dynamics in vertical-cavity surface-emitting lasers: Spatiotemporal versus modal expansion descriptions

    International Nuclear Information System (INIS)

    Mulet, Josep; Balle, Salvador

    2002-01-01

    We discuss the range of validity of a modal description for the spatiotemporal dynamics of the optical field in vertical-cavity surface-emitting lasers. We focus on the secondary pulsations that appear during the turn-off transients when the injection current is modulated by a square-wave signal. We compare the results obtained with both a full spatiotemporal model [J. Mulet and S. Balle, IEEE J. Quantum. Electron. 38, 291 (2002)] and a modal expansion derived from this model. We find that the results obtained from the two descriptions agree for strong lateral guiding. However, for weak lateral guiding we find differences because the optical-field profile changes significantly due to spatial changes in the refractive index induced by the carrier density. The reason is that in the full spatiotemporal model a shrinkage of the mode profile occurs, which leads to an enhancement of the secondary pulsations. This effect is not included in the modal expansion, and it determines the limits of validity of such an approach for gain-guided devices

  18. Surface photovoltage spectroscopy as a valuable nondestructive characterization technique for GaAs/GaAlAs vertical-cavity surface-emitting laser structures

    CERN Document Server

    Liang, J S; Huang, Y S; Tien, C W; Chang, Y M; Chen, C W; Li, N Y; Tiong, K K; Pollak, F H

    2003-01-01

    We have investigated an 850 nm GaAs/GaAlAs (001) vertical-cavity surface-emitting laser (VCSEL) structure using angle- and temperature-dependent surface photovoltage spectroscopy (SPS). The SPS measurements were performed as functions of angle of incidence (0 deg. <= theta <= 60 deg.) and temperature (25 deg. C <= T <= 215 deg. C) for both the metal-insulator-semiconductor (MIS) and wavelength-modulated MIS configurations. Angle-dependent reflectance (R) measurements have also been performed to illustrate the superior features of the SPS technique. The SPS spectra exhibit both the fundamental conduction to heavy-hole excitonic transition of quantum well and cavity mode (CM) plus a rich interference pattern related to the mirror stacks, whereas in the R spectra only the CM and interference features are clearly visible. The variations of SPS spectra as functions of incident angle and temperature enable exploration of light emission from the quantum well confined in a microcavity with relation to the...

  19. Advanced vectorial simulation of VCSELs with nano structures invited paper

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2009-01-01

    The single-mode properties and design issues of three vertical-cavity surface-emitting laser (VCSEL) structures incorporating nano structures are rigorously investigated. Nano structuring enables to deliver selective pumping or loss to the fundamental mode as well as stabilizing the output polari...... polarization state. Comparison of three vectorial simulation methods reveals that the modal expansion method is suitable for treating the nano structured VCSEL designs....

  20. Optimization of VCSELs for Self-Mixing Sensing

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Chung, Il-Sug

    2010-01-01

    We have simulated the variations in optical output power from a vertical-cavity surface-emitting laser (VCSEL) subject to self-mixing feedback, which is very important for applications in sensing. In order to maximize the self-mixing signal for a given feedback we have optimized the epitaxial...... design of the VCSEL. The most important parameters are the number of quantum wells (gain), the number of Bragg mirrors (reflection), and the detector position....

  1. Subwavelength grating-mirror VCSEL with a thin oxide gap

    OpenAIRE

    Chung, Il-Sug; Mørk, Jesper; Gilet, Philippe; Chelnokov, Alexei

    2008-01-01

    A new vertical-cavity surface-emitting laser (VCSEL) structure based on a subwavelength grating mirror and a thin oxide gap is suggested and numerically investigated. The structure is shown to exhibit similar threshold gain, suppression of higher order transverse modes, and polarization stability as a grating-mirror VCSEL reported in the literature based on a thick air gap. The thin oxide gap structure has a number of advantages including easier fabrication, better mechanical stability, and v...

  2. High-speed VCSEL-based optical interconnects

    Science.gov (United States)

    Ishak, Waguih S.

    2001-11-01

    Vertical Cavity Surface Emitting Lasers (VCSEL) have made significant inroads into commercial realization especially in the area of data communications. Single VCSEL devices are key components in Gb Ethernet Transceivers. A multi-element VCSEL array is the key enabling technology for high-speed multi Gb/s parallel optical interconnect modules. In 1996, several companies introduced a new generation of fiber optic products based VCSEL technology such as multimode fiber transceivers for the ANSI Fiber Channel and Gigabit Ethernet IEEE 802.3 standards. VCSELs offer unique advantages over its edge-emitting counterparts in several areas. These include low-cost (LED-like) manufacturability, low current operation and array integrability. As data rates continue to increase, VCSELs offer the advantage of being able to provide the highest modulation bandwidth per milliamp of modulation current. Currently, most of the VCSEL-based products use short (780 - 980 nm) wavelength lasers. However, significant research efforts are taking place at universities and industrial research labs around the world to develop reliable, manufacturable and high-power long (1300 - 1550 nm) wavelength VCSELs. These lasers will allow longer (several km) transmission distances and will help alleviate some of the eye-safety issues. Perhaps, the most important advantage of VCSELs is the ability to form two-dimensional arrays much easier than in the case of edge-emitting lasers. These arrays (single and two-dimensional) will allow a whole new family of applications, specifically in very high-speed computer and switch interconnects.

  3. Oxide-confined VCSELs fabricated with a simple self-aligned process flow

    Science.gov (United States)

    Marigo-Lombart, L.; Calvez, S.; Arnoult, A.; Thienpont, H.; Panajotov, K.; Almuneau, G.

    2017-12-01

    We propose a simplified and easier fabrication process flow for the manufacturing of AlO x -confined vertical-cavity surface-emitting lasers (VCSELs) based on combining the oxidation step with a self-aligned process, allowing the mesa etching and two successive lift-off steps based on a single lithography step. The electro-optical confinement achieved by standard lateral oxidation enables a low threshold and a single mode behavior for the VCSEL. This simplified process can largely improve VCSEL manufacturing by reducing the processing time and costs compared to the standard VCSEL process.

  4. Investigation of cavity mode and excitonic transition in an InGaAs/GaAs/AlGaAs vertical-cavity surface emitting laser structure by variable-temperature micro-photoluminescence, reflectance and photomodulated reflectance

    International Nuclear Information System (INIS)

    Yu, J L; Chen, Y H; Jiang, C Y; Zhang, H Y

    2012-01-01

    Variable-temperature micro-photoluminescence (μ-PL), reflectance (R) and photomodulated reflectance (PR) have been used to study an InGaAs/GaAs/AlGaAs vertical-cavity surface emitting laser (VCSEL) structure. μ-PL and R spectra have been recorded at different temperatures between 80 K and 300 K By comparing μ-PL with R spectra, both the excitonic transition and cavity mode are clearly identified. The Variable-temperature μ-PL and PR results of the etched sample with the top distributed Bragg reflectors (DBR) being removed further confirmed our identification. Our results demonstrate that variable-temperature μ-PL is a powerful noninvasive tool to measure accurate the quantum well transition and the cavity mode alignment.

  5. Broadband subwavelength grating mirror and its application to vertical-cavity surface-emitting laser

    OpenAIRE

    Chung, Il-Sug; Mørk, Jesper; Gilet, Philippe; Chelnokov, Alexei

    2008-01-01

    Various high-index-contrast sub-wavelength grating (HCG) mirror designs have been investigated. It reveals that transverse magnetic (TM-) and transverse electric (TE-) HCG reflect the incident fields in quite different ways and that the TM-HCG enables very thin gap below the grating. Based on these results, a new HCG VCSEL design with a thin oxide gap has been suggested. The thin oxide gap structure has a number of advantages including easier fabrication, better mechanical stability, and very...

  6. Eigenmodes of spin vertical-cavity surface-emitting lasers with local linear birefringence and gain dichroism

    Science.gov (United States)

    Fördös, T.; Jaffrès, H.; Postava, K.; Seghilani, M. S.; Garnache, A.; Pištora, J.; Drouhin, H. J.

    2017-10-01

    We present a general method for the modeling of semiconductor lasers such as a vertical-cavity surface-emitting laser and a vertical-external-cavity surface-emitting laser containing multiple quantum wells and involving anisotropies that may reveal (i) a local linear birefringence due to the strain field at the surface or (ii) a birefringence in quantum wells due to phase amplitude coupling originating from the reduction of the biaxial D2 d symmetry group to the C2 v symmetry group at the III-V ternary semiconductor interfaces. From a numerical point of view, a scattering S-matrix recursive method is implemented using a gain or amplification tensor derived analytically from the Maxwell-Bloch equations. It enables one to model the properties of the emission (threshold, polarization, and mode splitting) from the laser with multiple quantum well active zones by searching for the resonant eigenmodes of the cavity. The method is demonstrated on real laser structures and is presently used for the extraction of optical permittivity tensors of surface strain and quantum wells in agreement with experiments. The method can be generalized to find the laser eigenmodes in the most general case of circular polarized pumps (unbalance between the spin-up and spin-down channels) and/or dichroism allowing an elliptically polarized light emission as recently demonstrated experimentally when the linear birefringence is almost compensated [Joly et al., Opt. Lett. 42, 651 (2017), 10.1364/OL.42.000651].

  7. Highly Selective Volatile Organic Compounds Breath Analysis Using a Broadly-Tunable Vertical-External-Cavity Surface-Emitting Laser.

    Science.gov (United States)

    Tuzson, Béla; Jágerská, Jana; Looser, Herbert; Graf, Manuel; Felder, Ferdinand; Fill, Matthias; Tappy, Luc; Emmenegger, Lukas

    2017-06-20

    A broadly tunable mid-infrared vertical-external-cavity surface-emitting laser (VECSEL) is employed in a direct absorption laser spectroscopic setup to measure breath acetone. The large wavelength coverage of more than 30 cm -1 at 3.38 μm allows, in addition to acetone, the simultaneous measurement of isoprene, ethanol, methanol, methane, and water. Despite the severe spectral interferences from water and alcohols, an unambiguous determination of acetone is demonstrated with a precision of 13 ppbv that is achieved after 5 min averaging at typical breath mean acetone levels in synthetic gas samples mimicking human breath.

  8. 4.5 μm wavelength vertical external cavity surface emitting laser operating above room temperature

    Science.gov (United States)

    Rahim, M.; Khiar, A.; Felder, F.; Fill, M.; Zogg, H.

    2009-05-01

    A midinfrared vertical external cavity surface emitting laser with 4.5 μm emission wavelength and operating above room temperature has been realized. The active part consists of a single 850 nm thick epitaxial PbSe gain layer. It is followed by a 2 1/2 pair Pb1-yEuyTe/BaF2 Bragg mirror. No microstructural processing is needed. Excitation is done optically with a 1.5 μm wavelength laser. The device operates up to 45 °C with 100 ns pulses and delivers 6 mW output power at 27 °C heat-sink temperature.

  9. On high speed transmission with the 850 nm VCSELs

    DEFF Research Database (Denmark)

    Turkiewicz, Jarosław P.; Chorchos, Łukasz; Puerta Ramírez, Rafael

    2016-01-01

    One of the key research challenges is development of energy efficient high bit rate data interconnects. The most promising solutions are based on 850 nm vertical cavity surface emitting lasers (VCSEL) and multi mode fibre (MMF). In this paper options to realize energy efficient 850 nm data interc...

  10. Broadband subwavelength grating mirror and its application to vertical-cavity surface-emitting laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper; Gilet, Philippe

    2008-01-01

    Various high-index-contrast sub-wavelength grating (HCG) mirror designs have been investigated. It reveals that transverse magnetic (TM-) and transverse electric (TE-) HCG reflect the incident fields in quite different ways and that the TM-HCG enables very thin gap below the grating. Based...... on these results, a new HCG VCSEL design with a thin oxide gap has been suggested. The thin oxide gap structure has a number of advantages including easier fabrication, better mechanical stability, and very strong single-mode properties....

  11. High-Speed Semiconductor Vertical-Cavity Surface-Emitting Lasers for Optical Data-Transmission Systems (Review)

    Science.gov (United States)

    Blokhin, S. A.; Maleev, N. A.; Bobrov, M. A.; Kuzmenkov, A. G.; Sakharov, A. V.; Ustinov, V. M.

    2018-01-01

    The main problems of providing a high-speed operation semiconductor lasers with a vertical microcavity (so-called "vertical-cavity surface-emitting lasers") under amplitude modulation and ways to solve them have been considered. The influence of the internal properties of the radiating active region and the electrical parasitic elements of the equivalent circuit of lasers are discussed. An overview of approaches that lead to an increase of the cutoff parasitic frequency, an increase of the differential gain of the active region, the possibility of the management of mode emission composition and the lifetime of photons in the optical microcavities, and reduction of the influence of thermal effects have been presented. The achieved level of modulation bandwidth of ˜30 GHz is close to the maximum achievable for the classical scheme of the direct-current modulation, which makes it necessary to use a multilevel modulation format to further increase the information capacity of optical channels constructed on the basis of vertical-cavity surface-emitting lasers.

  12. Nano electro-mechanical optoelectronic tunable VCSEL.

    Science.gov (United States)

    Huang, Michael C Y; Zhou, Ye; Chang-Hasnain, Connie J

    2007-02-05

    We report a novel electrostatic actuated nano-electromechanical optoelectronic (NEMO) tunable vertical-cavity surface-emitting laser (VCSEL) centered at 850 nm. By integrating a movable, single-layer (230 nm), high-index-contrast subwavelength grating (HCG) as the VCSEL top mirror, single mode emission (SMSR >40 dB) and continuous wavelength tuning (~2.5 nm) was obtained at room temperature under CW operation. The small footprint of HCG enables the scaling down of each of the cantilever dimensions by a factor of 10, leading to 1000 times reduction in mass, which potentially increases the mechanical resonant frequency and tuning speed.

  13. High-beam-quality, efficient operation of passively Q-switched Yb:YAG/Cr:YAG laser pumped by photonic-crystal surface-emitting laser

    Science.gov (United States)

    Guo, Xiaoyang; Tokita, Shigeki; Fujioka, Kana; Nishida, Hiro; Hirose, Kazuyoshi; Sugiyama, Takahiro; Watanabe, Akiyoshi; Ishizaki, Kenji; Noda, Susumu; Miyanaga, Noriaki; Kawanaka, Junji

    2017-07-01

    A passively Q-switched Yb:YAG/Cr:YAG laser pumped by a photonic-crystal surface-emitting laser (PCSEL) was developed. Yb:YAG crystal was cryogenically cooled by liquid nitrogen at 77 K. Excellent Gaussian beam profile ( M 2 = 1.02) and high slope efficiency of 58% were demonstrated without using a coupling optics between a laser material and PCSEL.

  14. Final report on LDRD project: Semiconductor surface-emitting microcavity laser spectroscopy for analysis of biological cells and microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Gourley, P.L.; McDonald, A.E. [Sandia National Labs., Albuquerque, NM (United States). Nanostructure and Semiconductor Physics Dept.; Gourley, M.F. [Washington Hospital Center, DC (United States); Bellum, J. [Coherent Technologies, Boulder, CO (United States)

    1997-08-01

    This article discusses a new intracavity laser technique that uses living or fixed cells as an integral part of the laser. The cells are placed on a GaAs based semiconductor wafer comprising one half of a vertical cavity surface-emitting laser. After placement, the cells are covered with a dielectric mirror to close the laser cavity. When photo-pumped with an external laser, this hybrid laser emits coherent light images and spectra that depend sensitively on the cell size, shape, and dielectric properties. The light spectra can be used to identify different cell types and distinguish normal and abnormal cells. The laser can be used to study single cells in real time as a cell-biology lab-on-a-chip, or to study large populations of cells by scanning the pump laser at high speed. The laser is well-suited to be integrated with other micro-optical or micro-fluidic components to lead to micro-optical-mechanical systems for analysis of fluids, particulates, and biological cells.

  15. Single-mode 850-nm vertical-cavity surface-emitting lasers with Zn-diffusion and oxide-relief apertures for > 50 Gbit/sec OOK and 4-PAM transmission

    Science.gov (United States)

    Shi, Jin-Wei; Wei, Chia-Chien; Chen, Jyehong; Ledentsov, N. N.; Yang, Ying-Jay

    2017-02-01

    Vertical-cavity surface-emitting lasers (VCSELs) has become the most important light source in the booming market of short-reach (targeted at 56 Gbit/sec data rate per channel (CEI-56G) with the total data rate up to 400 Gbit/sec. However, the serious modal dispersion of multi-mode fiber (MMF), limited speed of VCSEL, and its high resistance (> 150 Ω) seriously limits the >50 Gbit/sec linking distance (50 Gbit/sec transmission due to that it can save one-half of the required bandwidth. Nevertheless, a 4.7 dB optical power penalty and the linearity of transmitter would become issues in the 4-PAM linking performance. Besides, in the modern OI system, the optics transreceiver module must be packaged as close as possible with the integrated circuits (ICs). The heat generated from ICs will become an issue in speed of VSCEL. Here, we review our recent work about 850 nm VCSEL, which has unique Zn-diffusion/oxide-relief apertures and special p- doping active layer with strong wavelength detuning to further enhance its modulation speed and high-temperature (85°C) performances. Single-mode (SM) devices with high-speed ( 26 GHz), reasonable resistance ( 70 Ω) and moderate output power ( 1.5 mW) can be achieved. Error-free 54 Gbit/sec OOK transmission through 1km MMF has been realized by using such SM device with signal processing techniques. Besides, the volterra nonlinear equalizer has been applied in our 4-PAM 64 Gbit/sec transmission through 2-km OM4 MMF, which significantly enhance the linearity of device and outperforms fed forward equalization (FFE) technique. Record high bit-rate distance product of 128.km is confirmed for optical-interconnect applications.

  16. Modular PbSrS/PbS mid-infrared vertical external cavity surface emitting laser on Si

    Science.gov (United States)

    Khiar, A.; Rahim, M.; Fill, M.; Felder, F.; Zogg, H.; Cao, D.; Kobayashi, S.; Yokoyama, T.; Ishida, A.

    2011-07-01

    A mid-infrared vertical external cavity surface emitting laser (VECSEL) based on undoped PbS is described herein. A 200 nm-thick PbS active layer embedded between PbSrS cladding layers forms a double heterostructure. The layers are grown on a lattice and thermal expansion mismatched Si-substrate. The substrate is placed onto a flat bottom Bragg mirror again grown on a Si substrate, and the VECSEL is completed with a curved top mirror. Pumping is done optically with a 1.55 μm laser diode. This leads to an extremely simple modular fabrication process. Lasing wavelengths range from 3-3.8 μm at 100-260 K heat sink temperature. The lowest threshold power is ˜210 mWp and highest output power is ˜250 mWp. The influence of the different recombination mechanism as well as free carrier absorption on the threshold power is modeled.

  17. Subwavelength grating as both emission mirror and electrical contact for VCSELs in any material system

    OpenAIRE

    Tomasz Czyszanowski; Marcin Gebski; Maciej Dems; Michał Wasiak; Robert Sarzała; Krassimir Panajotov

    2017-01-01

    Semiconductor-metal subwavelength grating (SMSG) can serve a dual purpose in vertical-cavity surface-emitting lasers (VCSELs), as both optical coupler and current injector. SMSGs provide optical as well as lateral current confinement, eliminating the need for ring contacts and lateral build-in optical and current confinement, allowing their implementation on arbitrarily large surfaces. Using an SMSG as the top mirror enables fabrication of monolithic VCSELs from any type of semiconductor crys...

  18. Real time algorithm temperature compensation in tunable laser / VCSEL based WDM-PON system

    DEFF Research Database (Denmark)

    Iglesias Olmedo, Miguel; Rodes Lopez, Roberto; Pham, Tien Thang

    2012-01-01

    We report on a real time experimental validation of a centralized algorithm for temperature compensation of tunable laser/VCSEL at ONU and OLT, respectively. Locking to a chosen WDM channel is shown for temperature changes over 40°C.......We report on a real time experimental validation of a centralized algorithm for temperature compensation of tunable laser/VCSEL at ONU and OLT, respectively. Locking to a chosen WDM channel is shown for temperature changes over 40°C....

  19. Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array.

    Science.gov (United States)

    Granero, Luis; Zalevsky, Zeev; Micó, Vicente

    2011-04-01

    We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.

  20. Steady-state characteristics of lateral p-n junction vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Ryzhii, V.; Tsutsui, N.; Khmyrova, I.; Ikegami, T.; Vaccaro, P. O.; Taniyama, H.; Aida, T.

    2001-09-01

    We developed an analytical device model for lateral p-n junction vertical-cavity surface-emitting lasers (LJVCSELs) with a quantum well active region. The model takes into account the features of the carrier injection, transport, and recombination in LJVCSELs as well as the features of the photon propagation in the cavity. This model is used for the calculation and analysis of the LJVCSEL steady-state characteristics. It is shown that the localization of the injected electrons primarily near the p-n junction and the reabsorption of lateral propagating photons significantly effects the LJVCSELs performance, in particular, the LJVCSEL threshold current and power-current characteristics. The reincarnation of electrons and holes due to the reabsorption of lateral propagating photons can substantially decrease the threshold current.

  1. Lead-chalcogenide mid-infrared vertical external cavity surface emitting lasers with improved threshold: Theory and experiment

    Science.gov (United States)

    Fill, Matthias; Debernardi, Pierluigi; Felder, Ferdinand; Zogg, Hans

    2013-11-01

    Mid-infrared Vertical External Cavity Surface Emitting Lasers (VECSEL) based on narrow gap lead-chalcogenide (IV-VI) semiconductors exhibit strongly reduced threshold powers if the active layers are structured laterally for improved optical confinement. This is predicted by 3-d optical calculations; they show that lateral optical confinement is needed to counteract the anti-guiding features of IV-VIs due to their negative temperature dependence of the refractive index. An experimental proof is performed with PbSe quantum well based VECSEL grown on a Si-substrate by molecular beam epitaxy and emitting around 3.3 μm. With proper mesa-etching, the threshold intensity is about 8-times reduced.

  2. Lead-chalcogenide mid-infrared vertical external cavity surface emitting lasers with improved threshold: Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fill, Matthias [ETH Zurich, Laser Spectroscopy and Sensing Lab, 8093 Zurich (Switzerland); Phocone AG, 8005 Zurich (Switzerland); Debernardi, Pierluigi [IEIIT-CNR, Torino 10129 (Italy); Felder, Ferdinand [Phocone AG, 8005 Zurich (Switzerland); Zogg, Hans [ETH Zurich (Switzerland)

    2013-11-11

    Mid-infrared Vertical External Cavity Surface Emitting Lasers (VECSEL) based on narrow gap lead-chalcogenide (IV-VI) semiconductors exhibit strongly reduced threshold powers if the active layers are structured laterally for improved optical confinement. This is predicted by 3-d optical calculations; they show that lateral optical confinement is needed to counteract the anti-guiding features of IV-VIs due to their negative temperature dependence of the refractive index. An experimental proof is performed with PbSe quantum well based VECSEL grown on a Si-substrate by molecular beam epitaxy and emitting around 3.3 μm. With proper mesa-etching, the threshold intensity is about 8-times reduced.

  3. PbSe quantum well mid-infrared vertical external cavity surface emitting laser on Si-substrates

    Science.gov (United States)

    Fill, M.; Khiar, A.; Rahim, M.; Felder, F.; Zogg, H.

    2011-05-01

    Mid-infrared vertical external cavity surface emitting lasers based on PbSe/PbSrSe multi-quantum-well structures on Si-substrates are realized. A modular design allows growing the active region and the bottom Bragg mirror on two different Si-substrates, thus facilitating comparison between different structures. Lasing is observed from 3.3 to 5.1 μm wavelength and up to 52 °C heat sink temperature with 1.55 μm optical pumping. Simulations show that threshold powers are limited by Shockley-Read recombination with lifetimes as short as 0.1 ns. At higher temperatures, an additional threshold power increase occurs probably due to limited carrier diffusion length and carrier leakage, caused by an unfavorable band alignment.

  4. Passive cavity surface-emitting lasers: option of temperature-insensitive lasing wavelength for uncooled dense wavelength division multiplexing systems

    Science.gov (United States)

    Shchukin, V. A.; Ledentsov, N. N.; Slight, T.; Meredith, W.; Gordeev, N. Y.; Nadtochy, A. M.; Payusov, A. S.; Maximov, M. V.; Blokhin, S. A.; Blokhin, A. A.; Zadiranov, Yu. M.; Maleev, N. A.; Ustinov, V. M.; Choquette, K. D.

    2016-03-01

    A concept of passive cavity surface-emitting laser is proposed aimed to control the temperature shift of the lasing wavelength. The device contains an all-semiconductor bottom distributed Bragg reflector (DBR), in which the active medium is placed, a dielectric resonant cavity and a dielectric top DBR, wherein at least one of the dielectric materials has a negative temperature coefficient of the refractive index, dn/dT < 0. This is shown to be the case for commonly used dielectric systems SiO2/TiO2 and SiO2/Ta2O5. Two SiO2/TiO2 resonant structures having a cavity either of SiO2 or TiO2 were deposited on a substrate, their optical power reflectance spectra were measured at various temperatures, and refractive index temperature coefficients were extracted, dn/dT = 0.0021 K-1 for SiO2 and dn/dT = -0.0092 K-1 for TiO2. Using such dielectric materials allows designing passive cavity surface-emitting lasers having on purpose either positive, or zero, or negative temperature shift of the lasing wavelength dλ/dT. A design for temperature-insensitive lasing wavelength (dλ/dT = 0) is proposed. Employing devices with temperature-insensitive lasing wavelength in wavelength division multiplexing systems may allow significant reducing of the spectral separation between transmission channels and an increase in number of channels for a defined spectral interval enabling low cost energy efficient uncooled devices.

  5. Continuous wave operation of high power GaN-based blue vertical-cavity surface-emitting lasers using epitaxial lateral overgrowth

    Science.gov (United States)

    Hamaguchi, Tatsushi; Fuutagawa, Noriyuki; Izumi, Shouichiro; Murayama, Masahiro; Narui, Hironobu

    2016-02-01

    We have succeeded in achieving continuous-wave operation of gallium nitride (GaN) based vertical-cavity surfaceemitting lasers (VCSELs), which was fabricated by epitaxial lateral overgrowth (ELO) using dielectric distributed Bragg reflectors(DBRs) as masks for selective growth. The device exhibited CW operation at a wavelength of 453.9nm. The maximum output power was 1.1 mW, which is the highest value reported in previously published articles. The ELO process used for this study represents a breakthrough for challenges which were indicated by other former reports for GaN-based VCSELs and is suitable for mass production.

  6. Final report on LDRD project : narrow-linewidth VCSELs for atomic microsystems.

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Weng Wah; Geib, Kent Martin; Peake, Gregory Merwin; Serkland, Darwin Keith

    2011-09-01

    Vertical-cavity surface-emitting lasers (VCSELs) are well suited for emerging photonic microsystems due to their low power consumption, ease of integration with other optical components, and single frequency operation. However, the typical VCSEL linewidth of 100 MHz is approximately ten times wider than the natural linewidth of atoms used in atomic beam clocks and trapped atom research, which degrades or completely destroys performance in those systems. This report documents our efforts to reduce VCSEL linewidths below 10 MHz to meet the needs of advanced sub-Doppler atomic microsystems, such as cold-atom traps. We have investigated two complementary approaches to reduce VCSEL linewidth: (A) increasing the laser-cavity quality factor, and (B) decreasing the linewidth enhancement factor (alpha) of the optical gain medium. We have developed two new VCSEL devices that achieved increased cavity quality factors: (1) all-semiconductor extended-cavity VCSELs, and (2) micro-external-cavity surface-emitting lasers (MECSELs). These new VCSEL devices have demonstrated linewidths below 10 MHz, and linewidths below 1 MHz seem feasible with further optimization.

  7. Experimental Analysis of 60-GHz VCSEL and ECL Photonic Generation and Transmission of Impulse-Radio Ultra-Wideband Signals

    DEFF Research Database (Denmark)

    Beltran, Marta; Jensen, Jesper Bevensee; Llorente, Roberto

    2011-01-01

    Optical generation of impulse-radio ultra-wideband (UWB) signals in the 60-GHz band is proposed and experimentally demonstrated. External-cavity laser (ECL) and vertical-cavity surface-emitting laser (VCSEL) is employed for frequency up-conversion by heterodyne mixing with a UWB optical signal...

  8. Progress on High-Speed 980 nm VCSELs for Short-Reach Optical Interconnects

    Directory of Open Access Journals (Sweden)

    Alex Mutig

    2011-01-01

    Full Text Available Progress of high-speed vertical cavity surface emitting lasers (VCSEL operating around 980 nm is reviewed. A special focus is on their applications for future short-reach optical interconnects, for example, in high-performance computers (HPC. The wavelength of 980 nm has fundamental advantages for these applications and plays a significant role in VCSEL research today. The present data rates of 980 nm VCSELs exceed 40 Gbit/s, and excellent temperature stability has been reported. The major concepts leading to these impressive developments are presented.

  9. Advances and new functions of VCSEL photonics

    Science.gov (United States)

    Koyama, Fumio

    2014-11-01

    A vertical cavity surface emitting laser (VCSEL) was born in Japan. The 37 years' research and developments opened up various applications including datacom, sensors, optical interconnects, spectroscopy, optical storages, printers, laser displays, laser radar, atomic clock and high power sources. A lot of unique features have been already proven, such as low power consumption, a wafer level testing and so on. The market of VCSELs has been growing up rapidly and they are now key devices in local area networks based on multi-mode optical fibers. Optical interconnections in data centers and supercomputers are attracting much interest. In this paper, the advances on VCSEL photonics will be reviewed. We present the high-speed modulation of VCSELs based on a coupled cavity structure. For further increase in transmission capacity per fiber, the wavelength engineering of VCSEL arrays is discussed, which includes the wavelength stabilization and wavelength tuning based on a micro-machined cantilever structure. We also address a lateral integration platform and new functions, including high-resolution beam scanner, vortex beam creation and large-port free space wavelength selective switch with a Bragg reflector waveguide.

  10. Flattop mode shaping of a vertical cavity surface emitting laser using an external-cavity aspheric mirror.

    Science.gov (United States)

    Yang, Zhaohui; Leger, James

    2004-11-01

    Both square-shaped and circular-shaped flattop modes were experimentally demonstrated in extended-cavity broad-area VCSELs using aspheric feedback mirrors. These refractive aspheric mirrors were fabricated by electron-beam lithography on curved substrates. Excellent single-mode operation and improved power extraction efficiency were observed. The three-mirror structure of the VCSEL and the state-of-the-art fabrication of the aspheric mirror contribute to the superior VCSEL performance. The modal loss analysis using a rigid three-mirror-cavity simulation method is discussed.

  11. Near-infrared wafer-fused vertical-cavity surface-emitting lasers for HF detection

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Zelinger, Zdeněk; Nevrlý, V.; Dorogan, A.; Ferus, Martin; Iakovlev, V.; Sirbu, A.; Mereuta, A.; Caliman, A.; Suruceanu, G.; Kapon, E.

    2014-01-01

    Roč. 147, NOV 2014 (2014), s. 53-59 ISSN 0022-4073 R&D Projects: GA MŠk(CZ) LD14022 Grant - others:Ministerstvo financí, Centrum zahraniční pomoci(CZ) PF049 Institutional support: RVO:61388955 ; RVO:68081707 Keywords : High resolution absorption spectroscopy * Monitoring of hydrogen fluoride, methane , and ammonia * Tunable diode laser spectroscopy (TDLS) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.645, year: 2014

  12. Evolution of the Novalux extended cavity surface-emitting semiconductor laser (NECSEL)

    Science.gov (United States)

    McInerney, John G.

    2016-03-01

    Novalux Inc was an enterprise founded by Aram Mooradian in 1998 to commercialise a novel electrically pumped vertical extended cavity semiconductor laser platform, initially aiming to produce pump lasers for optical fiber telecommunication networks. Following successful major investment in 2000, the company developed a range of single- and multi-mode 980 nm pump lasers emitting from 100-500 mW with excellent beam quality and efficiency. This rapid development required solution of several significant problems in chip and external cavity design, substrate and DBR mirror optimization, thermal engineering and mode selection. Output coupling to single mode fiber was exceptional. Following the collapse of the long haul telecom market in late 2001, a major reorientation of effort was undertaken, initially to develop compact 60-100 mW hybrid monolithically integrated pumplets for metro/local amplified networks, then to frequency-doubled blue light emitters for biotech, reprographics and general scientific applications. During 2001-3 I worked at Novalux on a career break from University College Cork, first as R&D Director managing a small group tasked with producing new capabilities and product options based on the NECSEL platform, including high power, pulsed and frequency doubled versions, then in 2002 as Director of New Product Realization managing the full engineering team, leading the transition to frequency doubled products.

  13. Subwavelength grating-mirror VCSEL with a thin oxide gap

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper; Gilet, Philippe

    2008-01-01

    A new vertical-cavity surface-emitting laser (VCSEL) structure based on a subwavelength grating mirror and a thin oxide gap is suggested and numerically investigated. The structure is shown to exhibit similar threshold gain, suppression of higher order transverse modes, and polarization stability...... as a grating-mirror VCSEL reported in the literature based on a thick air gap. The thin oxide gap structure has a number of advantages including easier fabrication, better mechanical stability, and very strong single-mode properties....

  14. Subwavelength grating as both emission mirror and electrical contact for VCSELs in any material system

    Science.gov (United States)

    Czyszanowski, Tomasz; Gebski, Marcin; Dems, Maciej; Wasiak, Michał; Sarzała, Robert; Panajotov, Krassimir

    2017-01-01

    Semiconductor-metal subwavelength grating (SMSG) can serve a dual purpose in vertical-cavity surface-emitting lasers (VCSELs), as both optical coupler and current injector. SMSGs provide optical as well as lateral current confinement, eliminating the need for ring contacts and lateral build-in optical and current confinement, allowing their implementation on arbitrarily large surfaces. Using an SMSG as the top mirror enables fabrication of monolithic VCSELs from any type of semiconductor crystal. The construction of VCSELs with SMSGs requires significantly less p-type material, in comparison to conventional VCSELs. In this paper, using a three-dimensional, fully vectorial optical model, we analyse the properties of the stand-alone SMSG in a number of semiconductor materials for a broad range of wavelengths. Integrating the optical model with thermal and electrical numerical models, we then simulate the threshold operation of an exemplary SMSG VCSEL.

  15. Coupled-wave analysis for photonic-crystal surface-emitting lasers on air holes with arbitrary sidewalls.

    Science.gov (United States)

    Peng, Chao; Liang, Yong; Sakai, Kyosuke; Iwahashi, Seita; Noda, Susumu

    2011-11-21

    The coupled-wave theory (CWT) is extended to a photonic crystal structure with arbitrary sidewalls, and a simple, fast, and effective model for the quantitatively analysis of the radiative characteristics of two-dimensional (2D) photonic-crystal surface-emitting lasers (PC-SELs) has been developed. For illustrating complicated coupling effects accurately, sufficient numbers of waves are included in the formulation, by considering their vertical field profiles. The radiation of band-edge modes is analyzed for two in-plane air-hole geometries, in the case of two types of sidewalls: i.e. "tapered case" and "tilted case." The results of CWT analysis agree well with the results of finite-difference time-domain (FDTD) numerical simulation. From the analytical solutions of the CWT, the symmetry properties of the band-edge modes are investigated. In-plane asymmetry of the air holes is crucial for achieving high output power because it causes partial constructive interference. Asymmetric air holes and tilted sidewalls help in inducing in-plane asymmetries. By breaking the symmetries with respect to the two orthogonal symmetric axes of the band-edge modes, the two factors can be tuned independently, so that the radiation power is enhanced while preserving the mode selectivity performance. Finally, top-down reactive ion etching (RIE) approach is suggested for the fabrication of such a structure. © 2011 Optical Society of America

  16. Amplification of an Autodyne Signal in a Bistable Vertical-Cavity Surface-Emitting Laser with the Use of a Vibrational Resonance

    Science.gov (United States)

    Chizhevsky, V. N.

    2018-01-01

    For the first time, it is demonstrated experimentally that a vibrational resonance in a polarization-bistable vertical-cavity surface-emitting laser can be used to increase the laser response in autodyne detection of microvibrations from reflecting surfaces. In this case, more than 25-fold signal amplification is achieved. The influence of the asymmetry of the bistable potential on the microvibration-detection efficiency is studied.

  17. Novel Applications of High Speed Optical-Injection Locked Lasers

    Science.gov (United States)

    2010-07-31

    modulated vertical-cavity surface-emitting laser (VCSELs) are attractive candidates as cost-effective optical transmitters for metro -area networks (MANs...local area networks (LANs) and high-speed Ethernet applications. A directly modulated VCSEL is desirable because it is compact, cost-effective and

  18. Study on VCSEL laser heating chip in nuclear magnetic resonance gyroscope

    Science.gov (United States)

    Liang, Xiaoyang; Zhou, Binquan; Wu, Wenfeng; Jia, Yuchen; Wang, Jing

    2017-10-01

    In recent years, atomic gyroscope has become an important direction of inertial navigation. Nuclear magnetic resonance gyroscope has a stronger advantage in the miniaturization of the size. In atomic gyroscope, the lasers are indispensable devices which has an important effect on the improvement of the gyroscope performance. The frequency stability of the VCSEL lasers requires high precision control of temperature. However, the heating current of the laser will definitely bring in the magnetic field, and the sensitive device, alkali vapor cell, is very sensitive to the magnetic field, so that the metal pattern of the heating chip should be designed ingeniously to eliminate the magnetic field introduced by the heating current. In this paper, a heating chip was fabricated by MEMS process, i.e. depositing platinum on semiconductor substrates. Platinum has long been considered as a good resistance material used for measuring temperature The VCSEL laser chip is fixed in the center of the heating chip. The thermometer resistor measures the temperature of the heating chip, which can be considered as the same temperature of the VCSEL laser chip, by turning the temperature signal into voltage signal. The FPGA chip is used as a micro controller, and combined with PID control algorithm constitute a closed loop control circuit. The voltage applied to the heating resistor wire is modified to achieve the temperature control of the VCSEL laser. In this way, the laser frequency can be controlled stably and easily. Ultimately, the temperature stability can be achieved better than 100mK.

  19. All-VCSEL based digital coherent detection link for multi Gbit/s WDM passive optical networks

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Jensen, Jesper Bevensee; Zibar, Darko

    2010-01-01

    We report on experimental demonstration of a digital coherent detection link fully based on vertical cavity surface emitting lasers (VCSELs) for the transmitter as well as for the local oscillator light source at the receiver side. We demonstrate operation at 5 Gbps at a 1550 nm wavelength...... with record receiver sensitivity of -36 dBm after transmission over 40 km standard single mode fiber. Digital signal processing compensates for frequency offset between the transmitter and the local oscillator VCSELs, and for chromatic dispersion. This system allows for uncooled VCSEL operation and fully...

  20. Optically pumped vertical-cavity surface-emitting laser at 374.9 nm with an electrically conducting n-type distributed Bragg reflector

    Science.gov (United States)

    Liu, Yuh-Shiuan; Saniul Haq, Abul Fazal Muhammad; Mehta, Karan; Kao, Tsung-Ting; Wang, Shuo; Xie, Hongen; Shen, Shyh-Chiang; Yoder, P. Douglas; Ponce, Fernando A.; Detchprohm, Theeradetch; Dupuis, Russell D.

    2016-11-01

    An optically pumped vertical-cavity surface-emitting laser with an electrically conducting n-type distributed Bragg reflector was achieved at 374.9 nm. An epitaxially grown 40-pair n-type AlGaN/GaN distributed Bragg reflector was used as the bottom mirror, while the top mirror was formed by a dielectric distributed Bragg reflector composed of seven pairs of HfO2/SiO2. A numerical simulation for the optical mode clearly demonstrated that a high confinement factor was achieved and the threshold pumping power density at room temperature was measured as 1.64 MW/cm2. The achieved optically pumped laser demonstrates the potential of utilizing an n-type distributed Bragg reflector for surface-emitting optical devices.

  1. Printed Large-Area Single-Mode Photonic Crystal Bandedge Surface-Emitting Lasers on Silicon (Open Access Publisher’s Version)

    Science.gov (United States)

    2016-01-04

    beam shape, catastrophic optical damage free, and two-dimensional integration capabilities with CMOS electronics , vertical-cavity surface-emitting...longitudinal and transverse mode over a large lasing area , narrow linewidth, high power output, small beam divergence angle, polarization control...crystal lasers—ultimate nanolasers and broad - area coherent lasers [Invited]. J. Opt. Soc. Am. B 27, B1–B8 (2010). 13. Painter, O. et al. Two-dimensional

  2. Mode-locking of an InAs Quantum Dot Based Vertical External Cavity Surface Emitting Laser Using Atomic Layer Graphene

    Science.gov (United States)

    2015-07-16

    Vertical External Cavity Surface Emitting Lasers). 2)! Installation of a FTIR based temperature dependent reflectivity setup for characterizing VECSELs...and SESAMs (Semiconductor Saturable Absorber Mirrors). 3)! Demonstration of up to 6 Watts CW with InAs QD (Quantum Dot) VECSELs (1250 nm) and 15...AFRL and at other university collaborators such as the University of Arizona. 2.#Installation#of#a# FTIR #based#temperature#dependent#reflectivity

  3. Broad tunable photonic microwave generation based on period-one dynamics of optical injection vertical-cavity surface-emitting lasers.

    Science.gov (United States)

    Ji, Songkun; Hong, Yanhua; Spencer, Paul S; Benedikt, Johannes; Davies, Iwan

    2017-08-21

    Photonic microwave generation based on period-one dynamics of an optically injected VCSEL has been study experimentally. The results have shown that the frequency of the generated microwave signal can be broadly tunable through the adjustment of the injection power and the frequency detuning. Strong optical injection power and higher frequency detuning are favorable for obtaining a high frequency microwave signal. These results are similar to those found in systems based on distributed feedback lasers and quantum dot lasers. The variation of the microwave power at the fundamental frequency and the second-harmonic distortion have also been characterized.

  4. Relative intensity noise of temperature-stable, energy-efficient 980 nm VCSELs

    Directory of Open Access Journals (Sweden)

    Hui Li

    2017-02-01

    Full Text Available The relative intensity noise (RIN of temperature-stable, energy-efficient oxide confined vertical-cavity surface-emitting lasers (VCSELs have been investigated. Low energy consumption data transmission is achieved by using small oxide-aperture diameter VCSELs biased at small currents. We demonstrate that energy efficiency is not in conflict with our VCSELs’ RIN characteristics. The experimental results indicate that small oxide-aperture diameter VCSELs, which are most suitable for energy-efficient, temperature-stable operation, exhibit lower laser RIN due to less mode competition inside the smaller optical cavity volume. Our energy-efficient VCSELs fulfill the RIN requirements of the 32G Fibre Channel standard.

  5. Demonstration of Raman-based, dispersion-managed VCSEL technology for fibre-to-the-hut application

    Science.gov (United States)

    Rotich Kipnoo, E. K.; Kiboi Boiyo, D.; Isoe, G. M.; Chabata, T. V.; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

    2017-03-01

    For the first time, we experimentally investigate the use of vertical cavity surface emitting lasers (VCSELs) in the fibre-to-the-home (FTTH) flavour for Africa, known as fibre-to-the-hut. Fibre-to-the-hut is a VCSEL based passive optical network technology designed and optimized for African continent. VCSELs have attracted attention in optical communication due to its vast advantages; low power consumption, relatively cheap costs among others. A 4.25 Gb/s uncooled VCSEL is used in a dispersion managed, Raman assisted network achieving beyond 100 km of error free transmission suited for FTTHut scenario. Energy-efficient high performance VCSEL is modulated using a 27-1 PRBS pattern and the signal transmitted on a G.655 fibre utilizing the minimum attenuation window.

  6. Use of VCSEL arrays for parallel optical interconnects

    Science.gov (United States)

    Lebby, Michael S.; Gaw, Craig A.; Jiang, Wenbin; Kiely, Philip A.; Shieh, Chan L.; Claisse, Paul R.; Ramdani, Jamal; Hartman, Davis H.; Schwartz, Daniel B.; Grula, Jerry

    1996-04-01

    The use of vertical cavity surface emitting lasers (VCSELs) in a parallel optical interconnect for Motorola's OPTOBUSTM interconnect was made public over 1 year ago. This was the first time VCSELs were introduced into a product which took advantage of the excellent qualities of VCSELs over edge-emitting lasers. Motorola's OPTOBUSTM interconnect is a ten channel parallel bi-directional data link based on two 10 channel multimode fiber ribbons. One of the key differences in this type of interconnect compared with previous data link designs is the use of the VCSELs as the optical source for the link's fiber optic transmitter. A single 1 X 10 VCSEL array from a GaAs wafer is die attached to a 10 channel GUIDECASTTM optical interface unit which couples the emission from each laser device to its corresponding fiber ribbon channel and thus negates the use of expensive manufacturing techniques such as active alignment and pig-tailing. The OPTOBUSTM interconnect achieves its performance goals (which include low cost) via the unique characteristics of the GaAs VCSELs arrays. For example, the 850 nm devices produce a circular symmetric beam with a half angle of about 10 degrees allowing the coupling loss into the waveguide to be less than 3 dB. In addition, to maintain low manufacturing costs, each VCSEL array is individually and automatically probe tested (just as in the silicon industry) to verify that each VCSEL achieves the OPTOBUSTM interconnect's stringent electrical, optical, thermal and mechanical specifications. Typical computer generated wafer maps from automated production tooling and statistical parametric results are discussed. The combination of low threshold currents with superior thermal and optical performance allow the devices to be modulated under fixed bias conditions. Typical drive currents of 3X threshold are used to obtain nominal FDA Class 1 safety optical power levels from the GUIDECASTTM optical interface unit.

  7. 1060-nm Tunable Monolithic High Index Contrast Subwavelength Grating VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug; Semenova, Elizaveta

    2013-01-01

    We present the first tunable vertical-cavity surface-emitting laser (VCSEL) where the top distributed Bragg reflector has been completely substituted by an air-cladded high-index-contrast subwavelength grating (HCG) mirror. In this way, an extended cavity design can be realized by reducing...... the reflection at the semiconductor #x2013;air interface using an anti-reflective coating (ARC). We demonstrate how the ARC can be integrated in a monolithic structure by oxidizing AlGaAs with high Al-content. The HCG VCSEL has the potential to achieve polarization stable single-mode output with high tuning...... efficiency. The HCG VCSEL shows a total tuning range of 16 nm around an emission wavelength of 1060 nm with 1-mW output power....

  8. VCSEL fault location apparatus and method

    Science.gov (United States)

    Keeler, Gordon A [Albuquerque, NM; Serkland, Darwin K [Albuquerque, NM

    2007-05-15

    An apparatus for locating a fault within an optical fiber is disclosed. The apparatus, which can be formed as a part of a fiber-optic transmitter or as a stand-alone instrument, utilizes a vertical-cavity surface-emitting laser (VCSEL) to generate a test pulse of light which is coupled into an optical fiber under test. The VCSEL is subsequently reconfigured by changing a bias voltage thereto and is used as a resonant-cavity photodetector (RCPD) to detect a portion of the test light pulse which is reflected or scattered from any fault within the optical fiber. A time interval .DELTA.t between an instant in time when the test light pulse is generated and the time the reflected or scattered portion is detected can then be used to determine the location of the fault within the optical fiber.

  9. Optimization of VCSELs incorporating monolithic subwavelength high-refractive-index contrast surface grating mirrors

    Science.gov (United States)

    Gebski, Marcin; Marciniak, Magdalena; Dems, Maciej; Czyszanowski, Tomasz; Lott, James A.

    2017-02-01

    We present results of computer simulations of vertical cavity surface emitting lasers (VCSELs) using novel, highreflectivity monolithic high refractive-index contrast grating (MHCG) mirrors and their more advanced version, partially covered by a thin metal layer - metallic MHCG (mMHCG) mirrors. The first experimental realization of this new class of mirrors is presented and discussed. We show that the metal layer does not deteriorate the high reflectivity of an mMHCG mirror, but in contrary, is a crucial element which allows high reflectivity and additionally opens a way for a more efficient electrical pumping of a VCSEL. Comparison of results of thermal-electrical-carrier-gain self-consistent simulations of both MHCG- and mMHCG-based VCSELs is presented and discussed. It is shown that using mHCG mirror as a top mirror of a VCSEL improves electrical characteristics and greatly decreases the differential resistance of the device.

  10. Non-paraxial contributions to the far-field pattern of surface-emitting lasers: a manifestation of the momentum-space wavefunctions of quantum billiards

    International Nuclear Information System (INIS)

    Yu, Y T; Huang, Y J; Chiang, P Y; Lin, Y C; Huang, K F; Chen, Y F

    2011-01-01

    We investigated experimentally non-paraxial contributions to the high-order far-field pattern of large-area vertical-cavity surface-emitting lasers in order to explore by analogy the momentum-space wave distributions of quantum billiards. Our results reveal that non-paraxial contributions significantly influence the morphology of the high-order far-field pattern. A fast reliable method is developed for transforming the experimental far-field patterns to the correct Fourier transform of the corresponding near-field lasing modes. In this way we visualize the momentum-space (p–q) wavefunctions of quantum billiards

  11. Modal gain and confinement factors in top- and bottom-emitting photonic-crystal VCSEL

    International Nuclear Information System (INIS)

    Czyszanowski, T; Thienpont, H; Panajotov, K; Dems, M

    2008-01-01

    We investigate the modal characteristics of a phosphide photonic-crystal vertical-cavity surface-emitting diode laser (VCSEL) by using the three-dimensional, full vectorial plane wave admittance method. A single-defect, photonic crystal is defined as a regular, hexagonal net of holes with varying depths. The modal gain and confinement factors are compared for two VCSEL structures: with emission either through the DBR with the photonic crystal or through the DBR free of photonic crystal. Significant improvement in the beam quality is demonstrated for the second design

  12. Reach Extension and Capacity Enhancement of VCSEL-Based Transmission Over Single-Lane MMF Links

    DEFF Research Database (Denmark)

    Tatarczak, Anna; Motaghiannezam, S. M. Reza; Kocot, Chris

    2017-01-01

    This paper reviews and examines several techniques for expanding the carrying capacity of multimode fiber (MMF) using vertical cavity surface emitting lasers (VCSELs). The first approach utilizes short wavelength division multiplexing in combination with MMF optimized for operation between 850 an...... effectiveness of VCSEL-based MMF links in current and future data center environments....... and 950 nm. Both nonreturn to zero (NRZ) and four-level pulse amplitude modulation (PAM4) signaling are measured and demonstrate up to 170-Gb/s postforward error correction transmission over 300 m. For single wavelength transmission, the use of selective modal launch to increase the optical bandwidth...

  13. Mid-infrared PbTe vertical external cavity surface emitting laser on Si-substrate with above 1 W output power

    Science.gov (United States)

    Rahim, M.; Fill, M.; Felder, F.; Chappuis, D.; Corda, M.; Zogg, H.

    2009-12-01

    Mid-infrared vertical external cavity surface emitting lasers (VECSELs) emitting above 1 W output power in pulsed mode and up to 17 mW in continuous mode at -172 °C were realized. Emission wavelength changes from 5 μm at -172 °C to 3.6 μm at 20 °C heat sink temperature. The active medium is a one wavelength thick PbTe layer grown by molecular beam epitaxy on a Si-substrate. It is followed by a 2.5 pair Pb1-yEuyTe/EuTe epitaxial Bragg mirror. The cavity is completed with an external curved Pb1-yEuyTe/BaF2 mirror. The VECSEL is optically pumped with 1.55 μm wavelength laser and In-soldered to Cu heat sink. No microstructural processing is needed.

  14. Thermal lensing effects on lateral leakage in GaN-based vertical-cavity surface-emitting laser cavities.

    Science.gov (United States)

    Hashemi, Ehsan; Bengtsson, Jörgen; Gustavsson, Johan; Calciati, Marco; Goano, Michele; Haglund, Åsa

    2017-05-01

    Lateral leakage of light has been identified as a detrimental loss source in many suggested and experimentally realized GaN-based VCSELs. In the present work we include thermal effects to realistically account for the substantial Joule heating in these devices. In contrast to what could be expected from the previous results, the induced thermal lensing does not make antiguided cavities more positively guided, so that they approach the unguided regime with extremely high lateral leakage. Rather, thermal lensing strongly suppresses lateral leakage for both antiguided and guided cavities. This is explained in terms of lowered launch of power from the central part of the cavity and/or lower total internal reflection in the peripheral part; the former effect is active in all cavities whereas the latter only contributes to the very strongly reduced leakage in weakly antiguided cavities. Thermal lensing suppresses lateral leakage both for the fundamental and the first higher order mode, but a strong modal discrimination is still achieved for the antiguided cavities. Thus, strongly antiguided cavities could be used to achieve single-mode devices, but at the cost of slightly higher threshold gain and stronger temperature dependent performance characteristics.

  15. Monolithic subwavelength high refractive-index-contrast grating VCSELs

    Science.gov (United States)

    Gebski, Marcin; Dems, Maciej; Lott, James A.; Czyszanowski, Tomasz

    2016-03-01

    In this paper we present optical design and simulation results of vertical-cavity surface-emitting lasers (VCSELs) that incorporate monolithic subwavelength high refractive-index-contrast grating (MHCG) mirrors - a new variety of HCG mirror that is composed of high index material surrounded only on one side by low index material. We show the impact of an MHCG mirror on the performance of 980 nm VCSELs designed for high bit rate and energy-efficient optical data communications. In our design, all or part of the all-semiconductor top coupling distributed Bragg reflector mirror is replaced by an undoped gallium-arsenide MHCG. We show how the optical field intensity distribution of the VCSEL's fundamental mode is controlled by the combination of the number of residual distributed Bragg reflector (DBR) mirror periods and the physical design of the topmost gallium-arsenide MHCG. Additionally, we numerically investigate the confinement factors of our VCSELs and show that this parameter for the MHCG DBR VCSELs may only be properly determined in two or three dimensions due to the periodic nature of the grating mirror.

  16. Performance of a 60-GHz DCM-OFDM and BPSK-Impulse Ultra-Wideband System with Radio-Over-Fiber and Wireless Transmission Employing a Directly-Modulated VCSEL

    DEFF Research Database (Denmark)

    Beltrán, Marta; Jensen, Jesper Bevensee; Yu, Xianbin

    2011-01-01

    The performance of radio-over-fiber optical transmission employing vertical-cavity surface-emitting lasers (VCSELs), and further wireless transmission, of the two major ultra-wideband (UWB) implementations is reported when operating in the 60-GHz radio band. Performance is evaluated at 1.44 Gbit...

  17. Time-resolved spectral characterization of ring cavity surface emitting and ridge-type distributed feedback quantum cascade lasers by step-scan FT-IR spectroscopy.

    Science.gov (United States)

    Brandstetter, Markus; Genner, Andreas; Schwarzer, Clemens; Mujagic, Elvis; Strasser, Gottfried; Lendl, Bernhard

    2014-02-10

    We present the time-resolved comparison of pulsed 2nd order ring cavity surface emitting (RCSE) quantum cascade lasers (QCLs) and pulsed 1st order ridge-type distributed feedback (DFB) QCLs using a step-scan Fourier transform infrared (FT-IR) spectrometer. Laser devices were part of QCL arrays and fabricated from the same laser material. Required grating periods were adjusted to account for the grating order. The step-scan technique provided a spectral resolution of 0.1 cm(-1) and a time resolution of 2 ns. As a result, it was possible to gain information about the tuning behavior and potential mode-hops of the investigated lasers. Different cavity-lengths were compared, including 0.9 mm and 3.2 mm long ridge-type and 0.97 mm (circumference) ring-type cavities. RCSE QCLs were found to have improved emission properties in terms of line-stability, tuning rate and maximum emission time compared to ridge-type lasers.

  18. Visible laser and superluminescent diode based free space and underwater communications

    KAUST Repository

    Ooi, Boon S.

    2017-01-30

    We report on our recent progress in high-modulation-efficiency, InGaN-based integrated waveguide modulator-laser diodes (IWM-LDs), high-speed violet and blue emitting superluminescent diodes (SLDs), InGaN-based vertical-cavity surface-emitting lasers (VCSELs), and their applications for gigahertz laser based free-space and underwater wireless optical communications.

  19. All-optical 2-bit header recognition and packet switching using polarization bistable VCSELs.

    Science.gov (United States)

    Hayashi, Daisuke; Nakao, Kazuya; Katayama, Takeo; Kawaguchi, Hitoshi

    2015-04-06

    We propose and evaluate an all-optical 2-bit header recognition and packet switching method using two 1.55-µm polarization bistable vertical-cavity surface-emitting lasers (VCSELs) and three optical switches. Polarization bistable VCSELs acted as flip-flop devices by using AND-gate operations of the header and set pulses, together with the reset pulses. Optical packets including 40-Gb/s non-return-to-zero pseudo-random bit-sequence payloads were successfully sent to one of four ports according to the state of two bits in the headers with a 4-bit 500-Mb/s return-to-zero format. The input pulse powers were 17.2 to 31.8 dB lower than the VCSEL output power. We also examined an extension of this method to multi-bit header recognition and packet switching.

  20. Study of the Radiation-Hardness of VCSEL and PIN

    CERN Document Server

    Gan, K K; Fernando, W; Kagan, H P; Kass, R D; Lebbai, M R M; Merritt, H; Moore, J R; Nagarkar, A; Rizatdinova, F; Skubic, P L; Smith, D S; Strang, M

    2009-01-01

    The silicon trackers of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN (Geneva) use optical links for data transmission. An upgrade of the trackers is planned for the Super LHC (SLHC), an upgraded LHC with ten times higher luminosity. We study the radiation-hardness of VCSELs (Vertical-Cavity Surface-Emitting Laser) and GaAs and silicon PINs using 24 GeV/c protons at CERN for possible application in the data transmission upgrade. The optical power of VCSEL arrays decreases significantly after the irradiation but can be partially annealed with high drive currents. The responsivities of the PIN diodes also decrease significantly after irradiation, but can be recovered by operating at higher bias voltage. This provides a simple mechanism to recover from the radiation damage.

  1. Power-stabilized tunable narrow-band source using a VCSEL and an EDFA for FBG sensor interrogation

    International Nuclear Information System (INIS)

    Mizunami, Toru; Hirose, Shuji; Yoshinaga, Takeshi; Yamamoto, Ken-ichi

    2013-01-01

    Wavelength tuning with a current of a long-wavelength vertical-cavity surface-emitting laser (VCSEL) was studied for application to wavelength readout of fiber Bragg grating (FBG) sensors. 1.5 µm single-longitudinal-mode VCSELs with a spectral line width of 30 MHz were used. To decrease the variation in the output power with the current, saturated amplification of the VCSEL output by an erbium-doped fiber amplifier (EDFA) was proposed. In the experiment, the wavelength readout of an FBG by variation in the VCSEL current was studied first, and then amplification characteristics using a commercially available EDFA module were measured. Two VCSELs with different wavelengths and tuning ranges were used as input and compared. For a VCSEL with a wavelength tuning range of 2.5 nm, there was a threefold change in the VCSEL output power. However, the variation in the amplified output power was within ±14%. For another VCSEL with a wavelength tuning range of 3.9 nm, the variation in the amplified output power was within ±18% for variation in the VCSEL output power by 2.2 times. The power slope with respect to the wavelength was also decreased by the stabilization. Computer simulation was performed to study the wavelength shift in the measured Bragg wavelength induced by the power slope. The simulation showed that the wavelength shift can be reduced to 1/2.5–1/5 by the stabilization compared with that using a single VCSEL. Application to long-period grating sensors was also discussed. (paper)

  2. VCSELs with a high-index-contrast grating for mode-division multiplexing

    DEFF Research Database (Denmark)

    Ran, Qijiang; Mørk, Jesper

    2013-01-01

    A novel vertical-cavity surface-emitting laser (VCSEL) structure for space division multiplexing (SDM) is proposed and numerically investigated. This laser structure employs a high-index-contrast grating (HCG) as a light-emitting mirror. The reflectivity of the HCG mirror is spatially modulated...... to excite a specific transverse mode, while its transmission phase is kept spatially constant. This laser can provide the selective excitation of a specific transverse mode, leading to a high coupling efficiency to a few mode fiber. Compared to the phase plate approach in current SDM systems, the HCG...

  3. High-efficiency VCSEL arrays for illumination and sensing in consumer applications

    Science.gov (United States)

    Seurin, Jean-Francois; Zhou, Delai; Xu, Guoyang; Miglo, Alexander; Li, Daizong; Chen, Tong; Guo, Baiming; Ghosh, Chuni

    2016-03-01

    There has been increased interest in vertical-cavity surface-emitting lasers (VCSELs) for illumination and sensing in the consumer market, especially for 3D sensing ("gesture recognition") and 3D image capture. For these applications, the typical wavelength range of interest is 830~950nm and power levels vary from a few milli-Watts to several Watts. The devices are operated in short pulse mode (a few nano-seconds) with fast rise and fall times for time-of-flight applications (ToF), or in CW/quasi-CW for structured light applications. In VCSELs, the narrow spectrum and its low temperature dependence allows the use of narrower filters and therefore better signal-to-noise performance, especially for outdoor applications. In portable devices (mobile devices, wearable devices, laptops etc.) the size of the illumination module (VCSEL and optics) is a primary consideration. VCSELs offer a unique benefit compared to other laser sources in that they are "surface-mountable" and can be easily integrated along with other electronics components on a printed circuit board (PCB). A critical concern is the power-conversion efficiency (PCE) of the illumination source operating at high temperatures (>50 deg C). We report on various VCSEL based devices and diffuser-integrated modules with high efficiency at high temperatures. Over 40% PCE was achieved in broad temperature range of 0-70 °C for either low power single devices or high power VCSEL arrays, with sub- nano-second rise and fall time. These high power VCSEL arrays show excellent reliability, with extracted mean-time-to-failure (MTTF) of over 500 years at 60 °C ambient temperature and 8W peak output.

  4. Modeling and characterization of VCSEL-based avionics full-duplex ethernet (AFDX) gigabit links

    Science.gov (United States)

    Ly, Khadijetou S.; Rissons, A.; Gambardella, E.; Bajon, D.; Mollier, J.-C.

    2008-02-01

    Low cost and intrinsic performances of 850 nm Vertical Cavity Surface Emitting Lasers (VCSELs) compared to Light Emitting Diodes make them very attractive for high speed and short distances data communication links through optical fibers. Weight saving and Electromagnetic Interference withstanding requirements have led to the need of a reliable solution to improve existing avionics high speed buses (e.g. AFDX) up to 1Gbps over 100m. To predict and optimize the performance of the link, the physical behavior of the VCSEL must be well understood. First, a theoretical study is performed through the rate equations adapted to VCSEL in large signal modulation. Averaged turn-on delays and oscillation effects are analytically computed and analyzed for different values of the on- and off state currents. This will affect the eye pattern, timing jitter and Bit Error Rate (BER) of the signal that must remain within IEEE 802.3 standard limits. In particular, the off-state current is minimized below the threshold to allow the highest possible Extinction Ratio. At this level, the spontaneous emission is dominating and leads to significant turn-on delay, turn-on jitter and bit pattern effects. Also, the transverse multimode behavior of VCSELs, caused by Spatial Hole Burning leads to some dispersion in the fiber and degradation of BER. VCSEL to Multimode Fiber coupling model is provided for prediction and optimization of modal dispersion. Lastly, turn-on delay measurements are performed on a real mock-up and results are compared with calculations.

  5. Progress on high-power 808nm VCSELs and applications

    Science.gov (United States)

    Zhou, Delai; Seurin, Jean-Francois; Xu, Guoyang; Van Leeuwen, Robert; Miglo, Alexander; Wang, Qing; Kovsh, Alexey; Ghosh, Chuni

    2017-02-01

    High power 808nm semiconductor lasers are widely used for pumping neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal to produce high-brightness lasing at 1064nm. In addition, there are growing interest to use such high power 808nm lasers in the field of automotive infra-red (IR) illumination and medical aesthetic treatment. Vertical-cavity surface-emitting lasers (VCSELs) have emerged as a promising candidate and attracted increased interests for those applications, due to their combined advantages of high efficiency, low diverging circular beam, narrow emission spectrum with reduced temperature sensitivity, low-cost manufacturability, simpler coupling optics, and increased reliability, especially at high temperatures. They can emit very high power with very high power density as they can be conveniently configured into large two-dimensional arrays and modules of arrays. We report recent development on such high-power, high-efficiency 808nm VCSELs with industrial leading 55% power conversion efficiency (PCE). Top emitting VCSELs were grown by MOCVD and processed into single devices and 2D arrays using selective wet oxidation process and substrate removal technique for efficient current confinement and heat removal. Peak PCE of 51% and peak power of 800W were achieved from 5x5mm array, corresponding to peak power density of 4kW/cm2. Pumped with new generation of 2.3kW VCSEL module, Q-switched laser pulse energy at 1064nm reached 46.9mJ, more than doubled from previously reported results.

  6. Near Field and Far Field Effects in the Taguchi-Optimized Design of AN InP/GaAs-BASED Double Wafer-Fused Mqw Long-Wavelength Vertical-Cavity Surface-Emitting Laser

    Science.gov (United States)

    Menon, P. S.; Kandiah, K.; Mandeep, J. S.; Shaari, S.; Apte, P. R.

    Long-wavelength VCSELs (LW-VCSEL) operating in the 1.55 μm wavelength regime offer the advantages of low dispersion and optical loss in fiber optic transmission systems which are crucial in increasing data transmission speed and reducing implementation cost of fiber-to-the-home (FTTH) access networks. LW-VCSELs are attractive light sources because they offer unique features such as low power consumption, narrow beam divergence and ease of fabrication for two-dimensional arrays. This paper compares the near field and far field effects of the numerically investigated LW-VCSEL for various design parameters of the device. The optical intensity profile far from the device surface, in the Fraunhofer region, is important for the optical coupling of the laser with other optical components. The near field pattern is obtained from the structure output whereas the far-field pattern is essentially a two-dimensional fast Fourier Transform (FFT) of the near-field pattern. Design parameters such as the number of wells in the multi-quantum-well (MQW) region, the thickness of the MQW and the effect of using Taguchi's orthogonal array method to optimize the device design parameters on the near/far field patterns are evaluated in this paper. We have successfully increased the peak lasing power from an initial 4.84 mW to 12.38 mW at a bias voltage of 2 V and optical wavelength of 1.55 μm using Taguchi's orthogonal array. As a result of the Taguchi optimization and fine tuning, the device threshold current is found to increase along with a slight decrease in the modulation speed due to increased device widths.

  7. Single-material Bragg reflectors and their applications in VCSELs

    Science.gov (United States)

    Choi, Hee Ju; Ju, Gun Wu; Song, Yong Min; Lee, Yong Tak

    2018-01-01

    We present single-material distributed Bragg reflectors (DBRs) fabricated by oblique-angle deposition of amorphous silicon (a-Si). The high and low refractive indices of a-Si films were obtained at two incident vapour flux angles ( θ α) of 0° and 80° by determining the quarter-wavelength thicknesses of 67 nm at 0° and 128 nm at 80°. The fabricated single-material Bragg reflectors with only five pairs provide high reflectivity values of over 95%. The proposed DBRs were applied to intra-cavity contacted vertical-cavity surface-emitting lasers (VCSELs) to reduce fabrication costs and step. For the fabricated five pair a-Si/a-Si DBRs on VCSELs, the normalized stop bandwidth of 31.63% was measured while high reflectivity values over 95% were maintained over a wide wavelength range of 710 - 1020 nm. The fabricated VCSELs with D a = 7 μm obtained output power and threshold current, which are reasonable measured results.

  8. Monolithic high-index contrast grating: a material independent high-reflectance VCSEL mirror.

    Science.gov (United States)

    Gębski, M; Dems, M; Szerling, A; Motyka, M; Marona, L; Kruszka, R; Urbańczyk, D; Walczakowski, M; Pałka, N; Wójcik-Jedlińska, A; Wang, Q J; Zhang, D H; Bugajski, M; Wasiak, M; Czyszanowski, T

    2015-05-04

    In this paper we present an extensive theoretical and numerical analysis of monolithic high-index contrast grating, facilitating simple manufacture of compact mirrors for very broad spectrum of vertical-cavity surface-emitting lasers (VCSELs) emitting from ultraviolet to mid-infrared. We provide the theoretical background explaining the phenomenon of high reflectance in monolithic subwavelength gratings. In addition, by using a three-dimensional, fully vectorial optical model, verified by comparison with the experiment, we investigate the optimal parameters of high-index contrast grating enabling more than 99.99% reflectance in the diversity of photonic materials and in the broad range of wavelengths.

  9. Many-valley electron transport in AlGaAs VCSELs

    Science.gov (United States)

    Calciati, Marco; Tibaldi, Alberto; Bertazzi, Francesco; Goano, Michele; Debernardi, Pierluigi

    2017-05-01

    Carrier transport in GaAs-based vertical-cavity surface-emitting lasers (VCSELs) is investigated by means of an in-house multiphysics code, with particular emphasis on the description of many-valley effects in the conduction band of AlGaAs barriers. These effects, which are revealed to have a significant impact on the overall VCSEL performance, are accounted for by an effective density of states obtained with a closed-form model. This description has been included in a simplified simulation framework, where most of the distributed Bragg reflector pairs are replaced by an equivalent homogeneous layer. This leads to a major reduction of the computational cost, especially important in view of the computer-aided design of 3D devices.

  10. A comparative study of thermal characteristics of GaN-based VCSELs with three different typical structures

    Science.gov (United States)

    Mei, Yang; Xu, Rong-Bin; Xu, Huan; Ying, Lei-Ying; Zheng, Zhi-Wei; Zhang, Bao-Ping; Li, Mo; Zhang, Jian

    2018-01-01

    Thermal characteristics of GaN-based vertical cavity surface emitting lasers (VCSELs) with three typical structures were investigated both theoretically and experimentally. The simulation results based on a steady state quasi three-dimensional cylindrical model show that the thermal resistance (R th) is affected by cavity length, mesa size, as well as the bottom distributed Bragg reflector (DBR) size, and the detail further depends on different structures. Among different devices, GaN VCSEL with a hybrid cavity formed by one nitride bottom DBR and another dielectric top DBR is featured with lower R th, which is meanwhile affected strongly by the materials of the epitaxial bottom DBR. The main issues affecting the thermal dissipation in VCSELs with double dielectric DBRs are the bottom dielectric DBR and the dielectric current-confinement layer. To validate the simulation results, GaN-based VCSEL bonded on a copper plate was fabricated. R th of this device was measured and the results agreed well with the simulation. This work provides a better understanding of the thermal characteristics of GaN-based VCSELs and is useful in optimizing the structure design and improving the device performance.

  11. Comparison of single-/few-/multi-mode 850 nm VCSELs for optical OFDM transmission.

    Science.gov (United States)

    Kao, Hsuan-Yun; Tsai, Cheng-Ting; Leong, Shan-Fong; Peng, Chun-Yen; Chi, Yu-Chieh; Huang, Jian Jang; Kuo, Hao-Chung; Shih, Tien-Tsorng; Jou, Jau-Ji; Cheng, Wood-Hi; Wu, Chao-Hsin; Lin, Gong-Ru

    2017-07-10

    For high-speed optical OFDM transmission applications, a comprehensive comparison of the homemade multi-/few-/single-transverse mode (MM/FM/SM) vertical cavity surface emitting laser (VCSEL) chips is performed. With microwave probe, the direct encoding of pre-leveled 16-QAM OFDM data and transmission over 100-m-long OM4 multi-mode-fiber (MMF) are demonstrated for intra-datacenter applications. The MM VCSEL chip with the largest emission aperture of 11 μm reveals the highest differential quantum efficiency which provides the highest optical power of 8.67 mW but exhibits the lowest encodable bandwidth of 21 GHz. In contrast, the SM VCSEL chip fabricated with the smallest emission aperture of only 3 μm provides the highest 3-dB encoding bandwidth up to 23 GHz at a cost of slight heat accumulation. After optimization, with the trade-off set between the receiving signal-to-noise ratio (SNR) and bandwidth, the FM VCSEL chip guarantees the highest optical OFDM transmission bit rate of 96 Gbit/s under back-to-back case with its strongest throughput. Among three VCSEL chips, the SM VCSEL chip with nearly modal-dispersion free feature is treated as the best candidate for carrying the pre-leveled 16-QAM OFDM data over 100-m OM4-MMF with same material structure but exhibits different oxide-layer confined gain cross-sections with one another at 80-Gbit/s with the smallest receiving power penalty of 1.77 dB.

  12. Optical power of VCSELs stabilized to 35 ppm/°C without a TEC

    Science.gov (United States)

    Downing, John

    2015-03-01

    This paper reports a method and system comprising a light source, an electronic method, and a calibration procedure for stabilizing the optical power of vertical-cavity surface-emitting lasers (VCSELs) and laser diodes (LDs) without the use thermoelectric coolers (TECs). The system eliminates the needs for custom interference coatings, polarization adjustments, and the exact alignment required by the optical method reported in 2013 [1]. It can precisely compensate for the effects of temperature and wavelength drift on photodiode responsivity as well as changes in VCSEL beam quality and polarization angle over a 50°C temperature range. Data obtained from light sources built with single-mode polarization-locked VCSELs demonstrate that 30 ppm/°C stability can be readily obtained. The system has advantages over TECstabilized laser modules that include: 1) 90% lower relative RMS optical power and temperature sensitivity, 2) a five-fold enhancement of wall-plug efficiency, 3) less component testing and sorting, 4) lower manufacturing costs, and 5) automated calibration in batches at time of manufacture is practical. The system is ideally suited for battery-powered environmental and in-home medical monitoring applications.

  13. Resonant MEMS tunable VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug; Semenova, Elizaveta

    2013-01-01

    We demonstrate how resonant excitation of a microelectro-mechanical system can be used to increase the tuning range of a vertical-cavity surface-emitting laser two-fold by enabling both blue- and red-shifting of the wavelength. In this way a short-cavity design enabling wide tuning range can be r...

  14. Transverse Mode Dynamics of VCSELs Undergoing Current Modulation

    Science.gov (United States)

    Goorjian, Peter M.; Ning, C. Z.; Agrawal, Govind

    2000-01-01

    Transverse mode dynamics of a 20-micron-diameter vertical-cavity surface-emitting laser (VCSEL) undergoing gain switching by deep current modulation is studied numerically. The direct current (dc) level is set slightly below threshold and is modulated by a large alternating current (ac). The resulting optical pulse train and transverse-mode patterns are obtained numerically. The ac frequency is varied from 2.5 GHz to 10 GHz, and the ac amplitude is varied from one-half to four times that of the dc level. At high modulation frequencies, a regular pulse train is not generated unless the ac amplitude is large enough. At all modulation frequencies, the transverse spatial profile switches from single-mode to multiple-mode pattern as the ac pumping level is increased. Optical pulse widths vary in the range 5-30 ps. with the pulse width decreasing when either the frequency is increased or the ac amplitude is decreased. The numerical modeling uses an approximation form of the semiconductor Maxwell-Bloch equations. Temporal evolution of the spatial profiles of the laser (and of carrier density) is determined without any assumptions about the type or number of modes. Keywords: VCSELs, current modulation, gain switching, transverse mode dynamics, computational modeling

  15. The 120Gbps VCSEL Array Based Optical Transmitter (ATx) development for the High-Luminosity LHC (HL-LHC) experiments

    Science.gov (United States)

    Guo, D.; Liu, C.; Chen, J.; Chramowicz, J.; Deng, B.; Gong, D.; Hou, S.; Jin, G.; Kwan, S.; Liang, F.; Li, X.; Liu, G.; Liu, T.; Prosser, A.; Su, D.-S.; Teng, P.-K.; Xu, T.; Ye, J.; Zhao, X.; Xiang, A. C.; Liang, H.

    2014-02-01

    The integration of a Verticle Cavity Surface-Emitting Laser (VCSEL) array and a driving Application-Specific Integrated Circuit (ASIC) in a custom optical array transmitter module (ATx) for operation in the detector front-end is constructed, assembled and tested. The ATx provides 12 parallel channels with each channel operating at 10 Gbps. The optical transmitter eye diagram passes the eye mask and the bit-error rate (BER) less than 10-12 transmission is achieved at 10 Gbps/ch. The overall insertion loss including the radiation induced attenuation is sufficiently low to meet the proposed link budget requirement.

  16. Fabrication Processes for Surface-Emitting via External 45-DEGREE Reflectors, High-Power via Arrayed Ridge - Single-Mode Phase-Locked Aluminum Gallium Arsenide/gallium Arsenide Semiconductor Laser Sources.

    Science.gov (United States)

    Porkolab, Gyorgy Arpad

    The fabrication of monolithically integrated configurations of semiconductor lasers incorporating multiple functions is still an open issue today in engineering. A useful set of functions to integrate are: surface-emitting, high -power, phase-locked, single-mode, and collimated laser beam output. In this work new materials and advanced fabrication processes are developed for integrating the first four of the five functions listed. The interest in semiconductor lasers is due to their greater than 90% internal quantum efficiency in converting current-flux to photon-flux, their small size and weight, and their wavelength range from 400 to 1,550 nm. Multitudes of applications are possible for semiconductor laser sources ranging from the low-volume market of satellite-based communications systems to the high-volume market of image display screens. Semimetallic amorphous carbon (SMAC) thin film is introduced as an etch mask for chemically assisted ion beam etching (CAIBE) resulting in smooth etched facets in AlGaAs/GaAs at normal- and 45-degrees- incidence angles. A self-aligned etch technique is introduced using 4 separate photoresist selector-masks on top of a fixed SMAC master -mask on top of the AlGaAs/GaAs substrate to perform 4 separate CAIBE etches at 3 different angles and to 3 different depths to create self-aligned 3-dimensional microstructures of 1.3-μm deep ridge waveguides (RWG), 6-μm deep laser facets, and 11- μm long back-to-back 45-degree reflectors arranged in 3 by 100 arrays. Trenches on topside and underside of laser facets are introduced to deflect current away from laser facets. Silicon-rich nitro-oxide thin film is introduced as triple-use encapsulation to provide chemical passivation of AlGaAs/GaAs, optical anti-reflection coating by being refractive-index matched to AlGaAs/GaAs, and electrical insulation. A pincer-action sample-holder for CAIBE is introduced allowing samples to heat up by ion beam heating. Various surface preparations

  17. Self-aligned BCB planarization method for high-frequency signal injection in a VCSEL with an integrated modulator

    Science.gov (United States)

    Marigo-Lombart, Ludovic; Doucet, Jean-Baptiste; Lecestre, Aurélie; Reig, Benjamin; Rousset, Bernard; Thienpont, Hugo; Panajotov, Krassimir; Almuneau, Guilhem

    2016-04-01

    The huge increase of datacom capacities requires lasers sources with more and more bandwidth performances. Vertical-Cavity Surface-Emitting Lasers (VCSEL) in direct modulation is a good candidate, already widely used for short communication links such as in datacenters. Recently several different approaches have been proposed to further extend the direct modulation bandwidth of these devices, by improving the VCSEL structure, or by combining the VCSEL with another high speed element such as lateral slow light modulator or transistor/laser based structure (TVCSEL). We propose to increase the modulation bandwidth by vertically integrating a continuous-wave VCSEL with a high-speed electro-modulator. This vertical structure implies multiple electrodes with sufficiently good electrical separation between the different input electrical signals. This high frequency modulation requires both good electrical insulation between metal electrodes and an optimized design of the coplanar lines. BenzoCyclobutene (BCB) thanks to its low dielectric constant, low losses, low moisture absorption and good thermal stability, is often used as insulating layer. Also, BCB planarization offers the advantages of simpler and more reliable technological process flow in such integrated VCSEL/modulator structures with important reliefs. As described by Burdeaux et al. a degree of planarization (DOP) of about 95% can be achieved by simple spin coating whatever the device thickness. In most of the cases, the BCB planarization process requires an additional photolithography step in order to open an access to the mesa surface, thus involving a tight mask alignment and resulting in a degraded planarization. In this paper, we propose a self-aligned process with improved BCB planarization by combining a hot isostatic pressing derived from nanoimprint techniques with a dry plasma etching step.

  18. Reliability of vertical-cavity lasers at Hewlett-Packard

    Science.gov (United States)

    Herrick, Robert W.; Lei, Chun; Keever, Mark R.; Lim, Sui F.; Deng, Hongyu; Dudley, Jim J.; Bhagat, Jay K.

    1999-04-01

    Vertical-Cavity Surface-Emitting Lasers (VCSELs) have rapidly been adopted for use in data communications modules due largely to the improvement in reliability over that of competing compact disc lasers. While very long mean lifetimes for VCSELs have been published elsewhere (> 5 X 106 h MTTF at 40C), telecommunications switching applications require further reduction in the early failure rate to meet targets of < 0.5% failures over 25 years at 50 - 70 degree(s)C. Therefore, a extensive reliability program is needed to measure both the wear-out lifetime and the random failure rate of the devices. The results of accelerated life tests will be presented, and we will discuss the methodology used to estimate the failure rate. Models of current and thermal acceleration will be presented. Degradation mechanisms observed in HP lasers will be briefly discussed. We also present preliminary results from HP oxide-aperture VCSELs.

  19. Semiconductor lasers driven by self-sustained chaotic electronic oscillators and applications to optical chaos cryptography.

    Science.gov (United States)

    Kingni, Sifeu Takougang; Mbé, Jimmi Hervé Talla; Woafo, Paul

    2012-09-01

    In this work, we numerically study the dynamics of vertical cavity surface emitting laser (VCSEL) firstly when it is driven by Chua's oscillator, secondly in case where it is driven by a broad frequency spectral bandwidth chaotic oscillator developed by Nana et al. [Commun. Nonlinear Sci. Numer. Simul. 14, 2266 (2009)]. We demonstrated that the VCSEL generated robust chaotic dynamics compared to the ones found in VCSEL subject to a sinusoidally modulated current and therefore it is more suitable for chaos encryption techniques. The synchronization characteristics and the communication performances of unidirectional coupled VCSEL driven by the broad frequency spectral bandwidth chaotic oscillators are investigated numerically. The results show that high-quality synchronization and transmission of messages can be realized for suitable system parameters. Chaos shift keying method is successfully applied to encrypt a message at a high bitrate.

  20. 1.55-μm VCSEL with polarization-independent HCG mirror on SOI.

    Science.gov (United States)

    Tsunemi, Yoshihiro; Yokota, Nobuhide; Majima, Shota; Ikeda, Kazuhiro; Katayama, Takeo; Kawaguchi, Hitoshi

    2013-11-18

    We designed and fabricated a vertical-cavity surface-emitting laser (VCSEL) incorporating a polarization-independent high-index-contrast subwavelength grating (HCG) mirror on silicon-on-insulator (SOI) for a novel polarization-bistable device on a silicon substrate. The VCSEL consists of the HCG mirror, an active layer with InGaAsP quantum wells having optical gain around 1.55 μm, and an Al0.9Ga0.1As/Al0.16Ga0.84As DBR. We used direct wafer bonding for the bonding between the active layer and the AlGaAs DBR, and benzocyclobutene (BCB) bonding for the bonding between the active layer and the polarization-independent HCG mirror. The reflectivity of the HCG embedded with BCB was measured, resulting in a 200-nm-high reflectivity band with reflectivity higher than 99% and a small polarization dependence of ± 1%. We achieved lasing of the fabricated HCG-VCSEL at 1527 nm under an optical short pulse excitation with an average power of 50 mW (~0.2 mJ/cm2) at 240 K.

  1. (In,Ga,Al)P-GaP laser diodes grown on high-index GaAs surfaces emitting in the green, yellow and bright red spectral range

    Science.gov (United States)

    Ledentsov, N. N.; Shchukin, V. A.; Shernyakov, Yu M.; Kulagina, M. M.; Payusov, A. S.; Gordeev, N. Yu; Maximov, M. V.; Cherkashin, N. A.

    2017-02-01

    We report on low threshold current density (<400 A cm-2) injection lasing in (Al x Ga1-x )0.5In0.5P-GaAs-based diodes down to the green spectral range (<570 nm). The epitaxial structures are grown on high-index (611)A and (211)A GaAs substrates by metal-organic vapor phase epitaxy and contain tensile-strained GaP-enriched insertions aimed at reflection of the injected nonequilibrium electrons preventing their escape from the active region. Extended waveguide concept results in a vertical beam divergence with a full width at half maximum of 15° for (611)A substrates. The lasing at the wavelength of 569 nm is realized at 85 K. In an orange-red laser diode structure low threshold current density (190 A cm-2) in the orange spectral range (598 nm) is realized at 85 K. The latter devices demonstrated room temperature lasing at 628 nm at ˜2 kA cm-2 and a total power above 3 W. The red laser diodes grown on (211)A substrates demonstrated a far field characteristic for vertically multimode lasing indicating a lower optical confinement factor for the fundamental mode as compared to the devices grown on (611)A. However, as expected from previous research, the temperature stability of the threshold current and the wavelength stability were significantly higher for (211)A-grown structures.

  2. Using a Single VCSEL Source Employing OFDM Downstream Signal and Remodulated OOK Upstream Signal for Bi-directional Visible Light Communications.

    Science.gov (United States)

    Yeh, Chien-Hung; Wei, Liang-Yu; Chow, Chi-Wai

    2017-11-20

    In this work, we propose and demonstrate for the first time up to our knowledge, using a 682 nm visible vertical-cavity surface-emitting laser (VCSEL) applied in a bi-directional wavelength remodulated VLC system with a free space transmission distance of 3 m. To achieve a high VLC downstream traffic, spectral efficient orthogonal-frequency-division-multiplexing quadrature-amplitude-modulation (OFDM-QAM) with bit and power loading algorithms are applied on the VCSEL in the central office (CO). The OFDM downstream wavelength is remodulated by an acousto-optic modulator (AOM) with OOK modulation to produce the upstream traffic in the client side. Hence, only a single VCSEL laser is needed for the proposed bi-directional VLC system, achieving 10.6 Gbit/s OFDM downstream and 2 Mbit/s remodulated OOK upstream simultaneously. For the proposed system, as a single laser source with wavelength remodulation is used, the laser wavelength and temperature managements at the client side are not needed; and the whole system could be cost effective and energy efficient.

  3. A radiation tolerant 5 Gb/s Laser Driver in 130 nm CMOS technology

    Science.gov (United States)

    Mazza, G.; Rivetti, A.; Moreira, P.; Wyllie, K.; Soos, C.; Troska, J.; Gui, P.

    2012-01-01

    The GigaBit Transceiver (GBT) project aims at the design of a radiation tolerant chip set for high speed optical data transmission. The chipset includes the GigaBit Laser Driver (GBLD), a radiation tolerant ASIC designed in a standard CMOS 130 nm technology. The GBLD is a laser driver designed to work to up to 5 Gb/s and capable to drive both Vertical Cavity Surface Emitting Lasers (VCSELs) and Edge Emitting Lasers (EELs). The GBLD can provide a modulation current up to 24 mA and a bias current up to 43 mA with the pre-emphasis function to compensate for external capacitive load.

  4. The VCSEL-based array optical transmitter (ATx) development towards 120-Gbps link for collider detector: development update

    Science.gov (United States)

    Guo, D.; Liu, C.; Chen, J.; Chramowicz, J.; Gong, D.; Hou, S.; Huang, D.; Jin, G.; Li, X.; Liu, T.; Prosser, A.; Teng, P. K.; Ye, J.; Zhou, Y.; You, Y.; Xiang, A. C.; Liang, H.

    2015-01-01

    A compact radiation-tolerant array optical transmitter module (ATx) is developed to provide data transmission up to 10Gbps per channel with 12 parallel channels for collider detector applications. The ATx integrates a Vertical Cavity Surface-Emitting Laser (VCSEL) array and driver circuitry for electrical to optical conversion, an edge warp substrate for the electrical interface and a micro-lens array for the optical interface. This paper reports the continuing development of the ATx custom package. A simple, high-accuracy and reliable active-alignment method for the optical coupling is introduced. The radiation-resistance of the optoelectronic components is evaluated and the inclusion of a custom-designed array driver is discussed.

  5. Single-Mode VCSELs

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  6. VCSEL Based Coherent PONs

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee; Rodes, Roberto; Caballero Jambrina, Antonio

    2014-01-01

    modulated VCSEL transmitters at bit rates up to 10 Gbps in the C-band as well as in the O-band are presented. The broad linewidth and frequency chirp associated with directly modulated VCSELs are utilized in an envelope detection receiver scheme which is demonstrated digitally (off-line) as well as analog...

  7. Low-frequency fluctuations in vertical cavity lasers: Experiments versus Lang-Kobayashi dynamics

    International Nuclear Information System (INIS)

    Torcini, Alessandro; Barland, Stephane; Giacomelli, Giovanni; Marin, Francesco

    2006-01-01

    The limits of applicability of the Lang-Kobayashi (LK) model for a semiconductor laser with optical feedback are analyzed. The model equations, equipped with realistic values of the parameters, are investigated below the solitary laser threshold where low-frequency fluctuations (LFF's) are usually observed. The numerical findings are compared with experimental data obtained for the selected polarization mode from a vertical cavity surface emitting laser (VCSEL) subject to polarization selective external feedback. The comparison reveals the bounds within which the dynamics of the LK model can be considered as realistic. In particular, it clearly demonstrates that the deterministic LK model, for realistic values of the linewidth enhancement factor α, reproduces the LFF's only as a transient dynamics towards one of the stationary modes with maximal gain. A reasonable reproduction of real data from VCSEL's can be obtained only by considering the noisy LK or alternatively deterministic LK model for extremely high α values

  8. Time skewing and amplitude nonlinearity mitigation by feedback equalization for 56 Gbps VCSEL-based PAM-4 links

    Science.gov (United States)

    You, Yue; Zhang, Wenjia; Sun, Lin; Du, Jiangbing; Liang, Chenyu; Yang, Fan; He, Zuyuan

    2018-03-01

    The vertical cavity surface emitting laser (VCSEL)-based multimode optical transceivers enabled by pulse amplitude modulation (PAM)-4 will be commercialized in near future to meet the 400-Gbps standard short reach optical interconnects. It is still challenging to achieve over 56/112-Gbps with the multilevel signaling as the multimode property of the device and link would introduce the nonlinear temporal response for the different levels. In this work, we scrutinize the distortions that relates to the multilevel feature of PAM-4 modulation, and propose an effective feedback equalization scheme for 56-Gbps VCSEL-based PAM-4 optical interconnects system to mitigate the distortions caused by eye timing-skew and nonlinear power-dependent noise. Level redistribution at Tx side is theoretically modeled and constructed to achieve equivalent symbol error ratios (SERs) of four levels and improved BER performance. The cause of the eye skewing and the mitigation approach are also simulated at 100-Gbps and experimentally investigated at 56-Gbps. The results indicate more than 2-dB power penalty improvement has been achieved by using such a distortion aware equalizer.

  9. Injection-locked single-mode VCSEL for orthogonal multiplexing and amplitude noise suppression

    DEFF Research Database (Denmark)

    Chipouline, Arkadi; Lyubopytov, Vladimir S.; Malekizandi, Mohammadreza

    2017-01-01

    an injection-locked 1550 nm VCSEL as a slave laser providing separation of amplitude and phase modulations, carrying independent information flows. To validate the possibility of phase modulation extraction by an injection-locked VCSEL, an experimental setup shown in Fig. 1 has been built....

  10. Design and comparison of GaAs, GaAsP and InGaAlAs quantum-well active regions for 808-nm VCSELs.

    Science.gov (United States)

    Zhang, Yan; Ning, Yongqiang; Zhang, Lisen; Zhang, Jinsheng; Zhang, Jianwei; Wang, Zhenfu; Zhang, Jian; Zeng, Yugang; Wang, Lijun

    2011-06-20

    Vertical-cavity surface-emitting lasers emitting at 808 nm with unstrained GaAs/Al0.3Ga0.7As, tensilely strained GaAs(x)P(1-x)/Al0.3Ga0.7As and compressively strained In(1-x-y)Ga(x)Al(y)As/Al0.3Ga0.7As quantum-well active regions have been investigated. A comprehensive model is presented to determine the composition and width of these quantum wells. The numerical simulation shows that the gain peak wavelength is near 800 nm at room temperature for GaAs well with width of 4 nm, GaAs0.87P0.13 well with width of 13 nm and In0.14Ga0.74Al0.12As well with width of 6 nm. Furthermore, the output characteristics of the three designed quantum-well VCSELs are studied and compared. The results indicate that In0.14Ga0.74Al0.12As is the most appropriate candidate for the quantum well of 808-nm VCSELs.

  11. The application of cost-effective lasers in coherent UDWDM-OFDM-PON aided by effective phase noise suppression methods.

    Science.gov (United States)

    Liu, Yue; Yang, Chuanchuan; Yang, Feng; Li, Hongbin

    2014-03-24

    Digital coherent passive optical network (PON), especially the coherent orthogonal frequency division multiplexing PON (OFDM-PON), is a strong candidate for the 2nd-stage-next-generation PON (NG-PON2). As is known, OFDM is very sensitive to the laser phase noise which severely limits the application of the cost-effective distributed feedback (DFB) lasers and more energy-efficient vertical cavity surface emitting lasers (VCSEL) in the coherent OFDM-PON. The current long-reach coherent OFDM-PON experiments always choose the expensive external cavity laser (ECL) as the optical source for its narrow linewidth (usuallyOFDM-PON and study the possibility of the application of the DFB lasers and VCSEL in coherent OFDM-PON. A typical long-reach coherent ultra dense wavelength division multiplexing (UDWDM) OFDM-PON has been set up. The numerical results prove that the OBE method can stand severe phase noise of the lasers in this architecture and the DFB lasers as well as VCSEL can be used in coherent OFDM-PON. In this paper, we have also analyzed the performance of the RF-pilot-aided (RFP) phase noise suppression method in coherent OFDM-PON.

  12. VCSEL-based sensors for distance and velocity

    Science.gov (United States)

    Moench, Holger; Carpaij, Mark; Gerlach, Philipp; Gronenborn, Stephan; Gudde, Ralph; Hellmig, Jochen; Kolb, Johanna; van der Lee, Alexander

    2016-03-01

    VCSEL based sensors can measure distance and velocity in three dimensional space and are already produced in high quantities for professional and consumer applications. Several physical principles are used: VCSELs are applied as infrared illumination for surveillance cameras. High power arrays combined with imaging optics provide a uniform illumination of scenes up to a distance of several hundred meters. Time-of-flight methods use a pulsed VCSEL as light source, either with strong single pulses at low duty cycle or with pulse trains. Because of the sensitivity to background light and the strong decrease of the signal with distance several Watts of laser power are needed at a distance of up to 100m. VCSEL arrays enable power scaling and can provide very short pulses at higher power density. Applications range from extended functions in a smartphone over industrial sensors up to automotive LIDAR for driver assistance and autonomous driving. Self-mixing interference works with coherent laser photons scattered back into the cavity. It is therefore insensitive to environmental light. The method is used to measure target velocity and distance with very high accuracy at distances up to one meter. Single-mode VCSELs with integrated photodiode and grating stabilized polarization enable very compact and cost effective products. Besides the well know application as computer input device new applications with even higher accuracy or for speed over ground measurement in automobiles and up to 250km/h are investigated. All measurement methods exploit the known VCSEL properties like robustness, stability over temperature and the potential for packages with integrated optics and electronics. This makes VCSEL sensors ideally suited for new mass applications in consumer and automotive markets.

  13. Volume production of polarization controlled single-mode VCSELs

    Science.gov (United States)

    Grabherr, Martin; King, Roger; Jäger, Roland; Wiedenmann, Dieter; Gerlach, Philipp; Duckeck, Denise; Wimmer, Christian

    2008-02-01

    Over the past 3 years laser based tracking systems for optical PC mice have outnumbered the traditional VCSEL market datacom by far. Whereas VCSEL for datacom in the 850 nm regime emit in multipe transverse modes, all laser based tracking systems demand for single-mode operation which require advanced manufacturing technology. Next generation tracking systems even require single-polarization characteristics in order to avoid unwanted movement of the pointer due to polarization flips. High volume manufacturing and optimized production methods are crucial for achieving the addressed technical and commercial targets of this consumer market. The resulting ideal laser source which emits single-mode and single-polarization at low cost is also a promising platform for further applications like tuneable diode laser absorption spectroscopy (TDLAS) or miniature atomic clocks when adapted to the according wavelengths.

  14. Low power consumption O-band VCSEL sources for upstream channels in PON systems

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Rodes Lopez, Roberto; Tafur Monroy, Idelfonso

    2012-01-01

    This paper presents an experimental validation of a low power optical network unit employing vertical-cavity surface-emitting lasers as upstream sources for passive optical networks with an increased power budget, enabling even larger splitting ratios....

  15. High brightness diode lasers controlled by volume Bragg gratings

    Science.gov (United States)

    Glebov, Leonid

    2017-02-01

    Volume Bragg gratings (VBGs) recorded in photo-thermo-refractive (PTR) glass are holographic optical elements that are effective spectral and angular filters withstanding high power laser radiation. Reflecting VBGs are narrow-band spectral filters while transmitting VBGs are narrow-band angular filters. The use of these optical elements in external resonators of semiconductor lasers enables extremely resonant feedback that provides dramatic spectral and angular narrowing of laser diodes radiation without significant power and efficiency penalty. Spectral narrowing of laser diodes by reflecting VBGs demonstrated in wide spectral region from near UV to 3 μm. Commercially available VBGs have spectral width ranged from few nanometers to few tens of picometers. Efficient spectral locking was demonstrated for edge emitters (single diodes, bars, modules, and stacks), vertical cavity surface emitting lasers (VCSELs), grating coupled surface emitting lasers (GCSELs), and interband cascade lasers (ICLs). The use of multiplexed VBGs provides multiwavelength emission from a single emitter. Spectrally locked semiconductor lasers demonstrated CW power from milliwatts to a kilowatt. Angular narrowing by transmitting VBGs enables single transverse mode emission from wide aperture diode lasers having resonators with great Fresnel numbers. This feature provides close to diffraction limit divergence along a slow axis of wide stripe edge emitters. Radiation exchange between lasers by means of spatially profiled or multiplexed VBGs enables coherent combining of diode lasers. Sequence of VBGs or multiplexed VBGs enable spectral combining of spectrally narrowed diode lasers or laser modules. Thus the use of VBGs for diode lasers beam control provides dramatic increase of brightness.

  16. Advances in Red VCSEL Technology

    Directory of Open Access Journals (Sweden)

    Klein Johnson

    2012-01-01

    Full Text Available Red VCSELs offer the benefits of improved performance and lower power consumption for medical and industrial sensing, faster printing and scanning, and lower cost, higher speed interconnects based upon plastic optical fiber (POF. However, materials challenges make it more difficult to achieve the desired performance than at the well-developed wavelength of 850 nm. This paper will describe the state of the art of red VCSEL performance and the results of development efforts to achieve improved output power and a broader temperature range of operation. It will also provide examples of the applications of red VCSELs and the benefits they offer. In addition, the packaging flexibility offered by VCSELs, and some examples of non-Hermetic package demonstrations will be discussed. Some of the red VCSEL performance demonstrations include output power of 14 mW CW at room temperature, a record maximum temperature of 115∘C for CW operation at an emission wavelength of 689 nm, time to 1% failure at room temperature of approximately 200,000 hours, lifetime in a 50∘C, 85% humidity environment in excess of 3500 hours, digital data rate of 3 Gbps, and peak pulsed array power of greater than 100 mW.

  17. High-index-contrast subwavelength grating VCSEL

    Science.gov (United States)

    Gilet, Philippe; Olivier, Nicolas; Grosse, Philippe; Gilbert, Karen; Chelnokov, Alexei; Chung, Il-Sug; Mørk, Jesper

    2010-02-01

    In this article, we report our results on 980nm high-index-contrast subwavelength grating (HCG) VCSELs for optical interconnection applications. In our structure, a thin undoped HCG layer replaces a thick p-type Bragg mirror. The HCG mirror can feasibly achieve polarization-selective reflectivities close to 100%. The investigated structure consists of a HCG mirror with an underneath λ/4-thick oxide gap, four p-type GaAlAs/GaAs pairs for current spreading, three InGaAs/GaAs quantum wells, and an n-type GaAlAs/GaAs Bragg mirror. The HCG structure was defined by e-beam lithography and dry etching. The current oxide aperture and the oxide gap underneath the HCG were simultaneously formed by the selective wet oxidation process. Compared to air-gap high contrast grating mirrors demonstrated elsewhere, our grating mirrors are particular since they are supported by thinner λ/4 aluminium oxide layer, and thus are mechanically robust and thinner than usual designs. Sub-milliamp threshold currents and single-transverse-mode operation was obtained. A hero device exhibited maximum singlemode output power of more than 4 mW at room temperature and 1 mw at 70°C, which are the highest values ever reported from the HCG structures. These results build a bridge between a standard VCSEL and a hybrid laser on silicon, making them of potential use for the realization of silicon photonics.

  18. High-Speed, Radiation-Tolerant Laser Drivers in 0.13 μm CMOS Technology for HEP Applications

    Science.gov (United States)

    Mazza, Giovanni; Tavernier, Filip; Moreira, Paulo; Calvo, Daniela; De Remigis, Paolo; Olantera, Lauri; Soos, Csaba; Troska, Jan; Wyllie, Ken

    2014-12-01

    The gigabit laser driver (GBLD) and low-power GBLD (LpGBLD) are two radiation-tolerant laser drivers designed to drive laser diodes at data rates up to 4.8 Gb/s. They have been designed in the framework of the gigabit-transceiver (GBT) and versatile-link projects to provide fast optical links capable of operation in the radiation environment of future high-luminosity high-energy physics experiments. The GBLD provides laser bias and modulation currents up to 43 mA and 24 mA, respectively. It can thus be used to drive vertical cavity surface emitting laser (VCSEL) and edge-emitting laser diodes. A pre-emphasis circuit, which can provide up to 12 mA in 70 ps pulses, has also been implemented to compensate for high external capacitive loads. The current driving capabilities of the LpGBLD are 2 times smaller that those of the GBLD as it has been optimized to drive VCSELs in order to minimize the power consumption. Both application-specific integrated circuits are designed in 0.13 μm commercial complementary metal-oxide semiconductor technology and are powered by a single 2.5 V supply. The power consumption of the core circuit is 89 mW for the GBLD and 55 mW for the LpGBLD.

  19. High-Speed, Radiation-Tolerant Laser Drivers in 0.13 $\\mu$m CMOS Technology for HEP Applications

    CERN Document Server

    AUTHOR|(CDS)2073369; Moreira, Paulo; Calvo, Daniela; De Remigis, Paolo; Olantera, Lauri; Soos, Csaba; Troska, Jan; Wyllie, Ken

    2014-01-01

    The gigabit laser driver (GBLD) and low-power GBLD (LpGBLD) are two radiation-tolerant laser drivers designed to drive laser diodes at data rates up to 4.8 Gb/s. They have been designed in the framework of the gigabit-transceiver (GBT) and versatile-link projects to provide fast optical links capable of operation in the radiation environment of future high-luminosity high-energy physics experiments. The GBLD provides laser bias and modulation currents up to 43 mA and 24 mA, respectively. It can thus be used to drive vertical cavity surface emitting laser (VCSEL) and edge-emitting laser diodes. A pre-emphasis circuit, which can provide up to 12 mA in 70 ps pulses, has also been implemented to compensate for high external capacitive loads. The current driving capabilities of the LpGBLD are 2 times smaller that those of the GBLD as it has been optimized to drive VCSELs in order to minimize the power consumption. Both application-specific integrated circuits are designed in 0.13 m commercial complementary metal-o...

  20. Thermal annealing effects on AlGaAsSb/GaSb laser structure: Bandgap energy blueshift and thermal conductivity enhancement

    Science.gov (United States)

    Ilahi, S.; Yacoubi, N.; Genty, F.

    2017-07-01

    In this paper, we have investigated the effects of thermal annealing on optical properties and thermal conductivity of AlGaAsSb/GaSb laser structure using photo-thermal deflection spectroscopy PDS. In fact, optical absorption spectrum and thermal conductivity have been determined by comparison between experimental and theoretical phase of PDS signal. We have found that band gap energy is blue shifted of 70 meV for the as grown to the sample annealed for 1 h. Indeed, the highest thermal conductivity is found around of 11 W/m.K for AlGaAsSb/GaSb annealed for 1 h, which presents a promising result for vertical-cavity surface-emitting lasers (VCSELs).

  1. Continuous wave and modulation performance of 1550nm band wafer-fused VCSELs with MBE-grown InP-based active region and GaAs-based DBRs

    Science.gov (United States)

    Babichev, A. V.; Karachinsky, L. Ya.; Novikov, I. I.; Gladyshev, A. G.; Mikhailov, S.; Iakovlev, V.; Sirbu, A.; Stepniak, G.; Chorchos, L.; Turkiewicz, J. P.; Agustin, M.; Ledentsov, N. N.; Voropaev, K. O.; Ionov, A. S.; Egorov, A. Yu.

    2017-02-01

    We report for the first time on wafer-fused InGaAs-InP/AlGaAs-GaAs 1550 nm vertical-cavity surface-emitting lasers (VCSELs) incorporating a InAlGaAs/InP MQW active region with re-grown tunnel junction sandwiched between top and bottom undoped AlGaAs/GaAs distributed Bragg reflectors (DBRs) all grown by molecular beam epitaxy. InP-based active region includes seven compressively strained quantum wells (2.8 nm) optimized to provide high differential gain. Devices with this active region demonstrate lasing threshold current 2 mW in the temperature range of 10-70°C. The wall-plug efficiency (WPE) value-reaches 20 %. Lasing spectra show single mode CW operation with a longitudinal side mode suppression ratio (SMSR) up to 45 dB at > 2 mW output power. Small signal modulation response measurements show a 3-dB modulation bandwidth of 9 GHz at pump current of 10 mA and a D-factor value of 3 GHz/(mA)1/2. Open-eye diagram at 30 Gb/s of standard NRZ is demonstrated. Achieved CW and modulation performance is quite sufficient for fiber to the home (FTTH) applications where very large volumes of low-cost lasers are required.

  2. Optimization of self-mixing modulation in VCSELs for sensing applications

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Hvam, Jørn Märcher

    2009-01-01

    Ga1-xAs). The calculations are based on matrix multiplication for calculating effective reflectivity and transmission with external feedback, combined with a logarithmic gain model and standard laser rate equations. To improve the sensitivity towards self-mixing interference in VCSELs by simple...... epitaxial means and this should enable us to e.g. measure smaller bending deflections of cantilever sensors...

  3. Performance Evaluation for DFB and VCSEL-based 60 GHz Radio-over-Fiber System

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Lebedev, Alexander; Vegas Olmos, Juan José

    2013-01-01

    In this paper, we report on a detailed analysis and performance comparison work between 60 GHz radio-over-fiber systems based on a DFB laser and a C-band VCSEL. Coherent photonic up-conversion method is applied for the 60 GHz millimeter-wave signal generation. The generated signals are evaluated...

  4. Performance of a fire detector based on a compact laser spectroscopic carbon monoxide sensor.

    Science.gov (United States)

    Hangauer, A; Chen, J; Strzoda, R; Fleischer, M; Amann, M-C

    2014-06-02

    In this paper we show the suitability of a miniaturized tunable diode laser spectroscopy (TDLS)-based carbon-monoxide (CO) sensor for fire detection applications. The sensor utilizes a vertical-cavity surface-emitting laser (VCSEL) and inherent calibration scheme with reference gas filled in the photodetector housing. The fire-detection experiments are carried out under realistic conditions as described in the European standard EN54. The CO generation of all class C fires (according to EN54) could be well resolved. The cross-sensitivity to other substances was found to be very low: the maximum CO false response from cigarette smoke, hairspray and general aerosols reaches a low value of a few μL/L and only if the substance is directly applied into the sensor gas inlet. Therefore this sensor overcomes the disadvantage of high false alarm rate given by smoke detectors and is also in small size which is suitable for household and industrial applications. Hence, the VCSEL-based TDLS sensor is shown to have sufficient performance for fire-detection. It has advantages such as capability for fail-safe operation and, low cross-sensitivities as compared to existing point fire detector technology which is presently limited by these factors.

  5. Continuous-wave Optically Pumped Lasing of Hybrid Perovskite VCSEL at Green Wavelength

    KAUST Repository

    Alias, Mohd Sharizal

    2017-05-08

    We demonstrate the lasing of a perovskite vertical-cavity surface-emitting laser at green wavelengths, which operates under continuous-wave optical pumping at room-temperature by embedding hybrid perovskite between dielectric mirrors deposited at low-temperature.

  6. 850-nm oxide VCSEL development at Hewlett-Packard

    Science.gov (United States)

    Deng, Hongyu; Dudley, James J.; Lim, Sui F.; Lei, Chun; Liang, Bing; Tashima, M.; Hodge, Lee A.; Zhang, Xuemei; Herniman, John; Herrick, Robert W.

    1999-04-01

    Oxide confined VCSELs are being developed at Hewlett-Packard for the next-generation low cost fiber optics communication applications. Compared to the existing 850 nm implant confined VCSELs, the oxide VCSELs have lower operating voltages, higher slope efficiencies, and better modal bandwidth characteristics. Preliminary data on epitaxy and oxidation control uniformity, device performance, and reliability will be discussed.

  7. 130-nm tunable grating-mirror VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2014-01-01

    We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity configurat......We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity...... configuration instead of the extended cavity configuration can bring 130-nm tuning range around 1330-nm wavelength. The air-coupled cavity is known to reduce the quantum confinement factor in VCSELs, increasing threshold. In our air-coupled cavity HCG VCSEL case, the very short power penetration length...... in the HCG minimizes this reduction of the quantum confinement factor, not as significant as in the air-coupled cavity DBR VCSEL....

  8. Ultrahigh-speed hybrid laser for silicon photonic integrated chips

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Park, Gyeong Cheol; Ran, Qijiang

    2013-01-01

    and light-emitting diode (LED) structures have been proposed so far. Our hybrid laser is one of these efforts [2]. The hybrid laser consists of a dielectric reflector, a III-V semiconductor active material, and a high-index-contrast grating (HCG) reflector formed in the silicon layer of a silicon......-oninsulator (SOI) wafer. ‘Hybrid’ indicates that a III-V active material is wafer-bonded to a silicon SOI wafer. In the hybrid laser, light is vertically amplified between the dielectric and the HCG reflectors, while the light output is laterally emitted to a normal Si ridge waveguide that is connected to the HCG...... reflector. The HCG works as a vertical mirror as well as a vertical-to-lateral coupler. Very small field penetration into the HCG allows for 3-4 times smaller modal volume than typical vertical-cavity surface-emitting lasers (VCSELs). This leads to high direct modulation speed. Details on device operating...

  9. Microfabrication in free-standing gallium nitride using UV laser micromachining

    International Nuclear Information System (INIS)

    Gu, E.; Howard, H.; Conneely, A.; O'Connor, G.M.; Illy, E.K.; Knowles, M.R.H.; Edwards, P.R.; Martin, R.W.; Watson, I.M.; Dawson, M.D.

    2006-01-01

    Gallium nitride (GaN) and related alloys are important semiconductor materials for fabricating novel photonic devices such as ultraviolet (UV) light-emitting diodes (LEDs) and vertical cavity surface-emitting lasers (VCSELs). Recent technical advances have made free-standing GaN substrates available and affordable. However, these materials are strongly resistant to wet chemical etching and also, low etch rates restrict the use of dry etching. Thus, to develop alternative high-resolution processing for these materials is increasingly important. In this paper, we report the fabrication of microstructures in free-standing GaN using pulsed UV lasers. An effective method was first developed to remove the re-deposited materials due to the laser machining. In order to achieve controllable machining and high resolution in GaN, machining parameters were carefully optimised. Under the optimised conditions, precision features such as holes (through holes, blind or tapered holes) on a tens of micrometer length scale have been machined. To fabricate micro-trenches in GaN with vertical sidewalls and a flat bottom, different process strategies of laser machining were tested and optimised. Using this technique, we have successfully fabricated high-quality micro-trenches in free-standing GaN with various widths and depths. The approach combining UV laser micromachining and other processes is also discussed. Our results demonstrate that the pulsed UV laser is a powerful tool for fabricating precision microstructures and devices in gallium nitride

  10. The material system (AlGaIn)(AsSb). Properties and suitability for GaSb based vertical-resonator laser diodes

    International Nuclear Information System (INIS)

    Dier, Oliver

    2008-01-01

    The present thesis studies the particular properties of GaSb-based materials, where they differ from pure arsenides or phosphides, and also the impact of theses properties on long-wavelength vertical-cavity surface-emitting lasers (VCSELs). The goal is the first realisation of an electrically pumped VCSEL with a current aperture in this material system. After the basics, which are necessary for the understanding of the physical effects, the special features of antimony-containing materials are discussed with a focus on topics like band-structure, doping issues and miscibility gaps, which are relevant for devices. A VCSEL-structure optimized for long-wavelength applications is presented using an appropriate description of the device in its optical, electrical and thermal properties. A focus of this work is on the growth of laser-structures by molecular beam epitaxy. Annealing studies on this material showed a good prediction of the final wavelength after the temperature step, which is necessary due to the overgrowth of the tunnel-junction. The full-width at half maximum of the low-temperature photoluminescence signal shows a very low value of 3.95 meV for the quaternary active region. By using the type-II-band alignment of GaSb:Si and InAsSb:Si a low-resistive tunneljunction has been realised. After completion of the device processing a strong electroluminescence outside the DBR stopband and resonant modes within the stopband were found. A linear shift of the emission wavelength with temperature of 0.23 nm/K between -11 C and +30 C was found. (orig.)

  11. 130-nm tunable grating-mirror VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2014-01-01

    We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity...

  12. Laser Science and Applications

    Science.gov (United States)

    El-Nadi, Lotfia M.; Mansour, Mohy S.

    2010-04-01

    Attosecond high harmonic pulses: generation and characterization / C. H. Nam and K. T. Kim -- High power lasers and interactions / C. Chatwin and R. Young -- Laser accelerators / L. M. El-Nadi ... [et al.] -- Energy levels, oscillator strengths, lifetimes, and gain distributions of S VII, CI VIII, and Ar IX / Wessameldin. S. Abdelaziz and Th. M. El-Sherbini -- The gain distribution according to theoretical level structure and decay dynamics of W[symbol] / H. M. Hamed ... [et al.] -- Raman spectroscopy and low temperature photoluminescence ZnSe[symbol]Te[symbol] ternary alloys / A. Salah ... [et al.] -- Automated polarization-discrimination technique to minimize lidar detected skylight background noise, part I / Y. Y. Hassebo, K. Elsayed and S. Ahmed -- Laser interferometric measurements of the physical properties for He, Ne gases and their mixture / N. M. Abdel-Moniem ... [et al.] -- Analytical studies of laser beam propagation through the atmosphere / M. I. El-Saftawy, A. M. Abd El-Hamed and N. Sh. Kalifa -- Laser techniques in conservation of artworks: problems and breakthroughs / R. Salimbeni and S. Siano -- Technology-aided heritage conservation laser cleaning for buildings / M. S. Nada -- Technology significance in conservation of the built heritage 3D visualization impact / M. S. Nada -- Simulation of optical resonators for Vertical-Cavity Surface-Emitting Lasers (VCSEL) / M. S. Mansour ... [et al.] -- Optical design alternatives: a survey study / A. A. K. Ismail, I. A. S. Ismail and S. H. Ahmed -- Materials for digital optical design; a survey study / A. A. K. Ismail, I. A. S. Ismail and S. H. Ahmed -- Proposed design for optical digital circuits / A. A. K. Ismail, I. A. S. Ismail and S. H. Ahmed -- Photo-induced effect on bacterial cells / M. H. El Batanouny ... [et al.] -- Laser and non-coherent light effect on peripheral blood normal and acute lymphoblastic leukemic cells by using different types of photosensitizers / M. H. El Batanouny ... [et al

  13. THz wave parametric oscillator with a surface-emitted ring-cavity configuration

    Science.gov (United States)

    Yang, Zhen; Wang, Yuye; Xu, Degang; Tang, Longhuang; Xu, Wentao; Duan, Pan; Yan, Chao; Yao, Jianquan

    2016-11-01

    A surface-emitted ring-cavity terahertz (THz) wave parametric oscillator has been demonstrated for high-energy THz output and fast frequency tuning. Through the special optical design with a Galvano optical scanner and four-mirror ring-cavity structure, a maximum THz output of 12.9 μJ/pulse is achieved at 1.359 THz under the pump pulse energy of 172.8 mJ with the repetition rate of 10 Hz. A further research on the performance of the SE ring-cavity TPO has done to explore more characteristics of THz output. The THz pulse instability and the influence of cavity loss has analyzed. Moreover, the pump depletion rate of the ring-cavity configuration is much lower than the conventional surface-emitted terahertz wave parametric oscillator at the same experimental conditions.

  14. High-energy terahertz wave parametric oscillator with a surface-emitted ring-cavity configuration.

    Science.gov (United States)

    Yang, Zhen; Wang, Yuye; Xu, Degang; Xu, Wentao; Duan, Pan; Yan, Chao; Tang, Longhuang; Yao, Jianquan

    2016-05-15

    A surface-emitted ring-cavity terahertz (THz) wave parametric oscillator has been demonstrated for high-energy THz output and fast frequency tuning in a wide frequency range. Through the special optical design with a galvano-optical scanner and four-mirror ring-cavity structure, the maximum THz wave output energy of 12.9 μJ/pulse is achieved at 1.359 THz under the pump energy of 172.8 mJ. The fast THz frequency tuning in the range of 0.7-2.8 THz can be accessed with the step response of 600 μs. Moreover, the maximum THz wave output energy from this configuration is 3.29 times as large as that obtained from the conventional surface-emitted THz wave parametric oscillator with the same experimental conditions.

  15. Numerical methods for modeling photonic-crystal VCSELs

    DEFF Research Database (Denmark)

    Dems, Maciej; Chung, Il-Sug; Nyakas, Peter

    2010-01-01

    We show comparison of four different numerical methods for simulating Photonic-Crystal (PC) VCSELs. We present the theoretical basis behind each method and analyze the differences by studying a benchmark VCSEL structure, where the PC structure penetrates all VCSEL layers, the entire top-mirror DBR...... to the effective index method. The simulation results elucidate the strength and weaknesses of the analyzed methods; and outline the limits of applicability of the different models....

  16. WDM Nanoscale Laser Diodes for Si Photonic Interconnects

    Science.gov (United States)

    2016-07-25

    formed on silicon platforms, such as SiN on SiO2, or other materials. The VCSEL also has key features needed for high speed, including low thermal...mounting on silicon . The nanoscale VCSELs can achieve small optical modes and present a compact laser diode that is also robust. In this work we have used...Report Title The goal of this work has been to develop nanoscale VCSELs for integration into various optical systems, including for mounting on silicon

  17. The material system (AlGaIn)(AsSb). Properties and suitability for GaSb based vertical-resonator laser diodes; Das Materialsystem (AlGaIn)(AsSb). Eigenschaften und Eignung fuer GaSb-basierte Vertikalresonator-Laserdioden

    Energy Technology Data Exchange (ETDEWEB)

    Dier, Oliver

    2008-07-01

    The present thesis studies the particular properties of GaSb-based materials, where they differ from pure arsenides or phosphides, and also the impact of theses properties on long-wavelength vertical-cavity surface-emitting lasers (VCSELs). The goal is the first realisation of an electrically pumped VCSEL with a current aperture in this material system. After the basics, which are necessary for the understanding of the physical effects, the special features of antimony-containing materials are discussed with a focus on topics like band-structure, doping issues and miscibility gaps, which are relevant for devices. A VCSEL-structure optimized for long-wavelength applications is presented using an appropriate description of the device in its optical, electrical and thermal properties. A focus of this work is on the growth of laser-structures by molecular beam epitaxy. Annealing studies on this material showed a good prediction of the final wavelength after the temperature step, which is necessary due to the overgrowth of the tunnel-junction. The full-width at half maximum of the low-temperature photoluminescence signal shows a very low value of 3.95 meV for the quaternary active region. By using the type-II-band alignment of GaSb:Si and InAsSb:Si a low-resistive tunneljunction has been realised. After completion of the device processing a strong electroluminescence outside the DBR stopband and resonant modes within the stopband were found. A linear shift of the emission wavelength with temperature of 0.23 nm/K between -11 C and +30 C was found. (orig.)

  18. Polarization dynamics of VCSELs in external cavities

    Science.gov (United States)

    Marconi, M.; Javaloyes, J.; Barland, S.; Balle, S.; Giudici, M.

    2014-05-01

    We review the dynamics of VCSELs that experience both Polarization-Selective Feedback (PSF) and Crossed- Polarization Reinjection (XPR). Different regimes of regular pulsation were found. For strong enough XPR levels, the VCSEL emission in each of its linearly-polarized components displays a square-wave modulation which regularity is greatly enhanced by small levels of PSF. Such a square-wave is in antiphase for the two polarizations, and it turns out to be stable and robust over broad intervals of current. The frequency of the square-wave is determined by the length of the XPR arm. For weak levels of PSF and XPR, the VCSEL emits a regular train of short optical pulses arising from the locking of the modes in the PSF cavity. The frequency of the pulse train is stable on short time scales, but it wanders with a characteristic time scale of hundreds of roundtrips in the PSF cavity. The experimental results are successfully explained by an extension of the Spin-Flip Model that incorporates gain saturation and the effects of PSF and XPR.

  19. Atomic Interferometry, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Vertical cavity surface emitting lasers (VCSELs) is a new technology which can be used for developing high performance laser components for atom-based sensors...

  20. Beam Steering Analysis in Optically Phased Vertical Cavity Surface Emitting Laser Array

    Science.gov (United States)

    Xun, Meng; Sun, Yun; Xu, Chen; Xie, Yi-Yang; Jin, Zhi; Zhou, Jing-Tao; Liu, Xin-Yu; Wu, De-Xin

    2018-03-01

    Not Available Supported by the ‘Supporting First Action’ Joint Foundation for Outstanding Postdoctoral Program under Grant Nos Y7YBSH0001 and Y7BSH14001, the National Natural Science Foundation of China under Grant No 61434006, and the National Key Basic Research Program of China under Grant No 2017YFB0102302.

  1. Design of a surface-emitting, subwavelength metal-clad disk laser in the visible spectrum

    OpenAIRE

    Huang, Jingqing; Kim, Se-Heon; Scherer, Axel

    2010-01-01

    We analyze metal-clad disk cavities designed for nanolasers in the visible red spectrum with subwavelength device size and mode volume. Metal cladding suppresses radiation loss and supports low order modes with room temperature Q of 200 to 300. Non-degenerate single-mode operation with enhanced spontaneous emission coupling factor β is expected with the TE_(011) mode that has a 0.46(λ_0/n)^3 mode volume and Q = 210 in a device of size 0.12λ_0^3. Threshold gain calculations show that room temp...

  2. 14 MeV neutron-induced transverse mode shifts in multimode VCSELs

    CERN Document Server

    Pailharey, E; D'Hose, C; Musseau, O

    2000-01-01

    Research on optical communication behavior in radiative environments is a key point for the design of diagnostic links for the large physical instruments (Laser MegaJoule at CEA, Large Hadron Collider at CERN). For years, the radiation tolerance of several types of emitters (LED and LD) have been tested with promising results for the LDs. New technologies and devices (VCSEL) have recently appeared as promising candidates to replace conventional edge emitting LDs. The shorter wavelength VCSELs (below 1 mu m) are well adapted for short distance data links, due to their low threshold current, high efficiency and large possibilities for integration. 850 nm VCSELs are tested under 14 MeV neutron irradiation. Three different aperture (8 mu m monomode, 15 mu m and 20 mu m multimode) COTS devices are irradiated up to 3.4*10/sup 13/ n/cm/sup 2/. Transverse pattern behavior is studied using infrared camera imaging, while optical power modifications are measured as a function of bias current. Displacement damage induces...

  3. Temperature dependence of 1.55 μm VCSELs

    Science.gov (United States)

    Masum, J.; Balkan, N.; Adams, M. J.

    1998-08-01

    The temperature for minimum threshold carrier concentration in 1.55 μm VCSELs can be significantly lower than that at which the peak gain matches the cavity resonance. A simple model is implemented to investigate the magnitude of this temperature difference and to aid the design of VCSELs for room temperature operation.

  4. 30 Gbps bottom-emitting 1060 nm VCSEL

    DEFF Research Database (Denmark)

    Tatarczak, Anna; Zheng, Y.; Rodes, G. A.

    2014-01-01

    1060 nm VCSEL-based data transmission over 50 m OM3 MMF at 30 Gbit/s is experimentally demonstrated. A highly-strained bottom-emitting QW VCSEL with p-type modulation doping is used with 3.77 mA bias and 0.55 V data amplitude....

  5. Deep in situ dry-etch monitoring of III-V multilayer structures using laser reflectometry and reflectivity modeling

    CERN Document Server

    Moussa, H; Meriadec, C; Manin, L; Sagnes, I; Raj, R

    2002-01-01

    Deep reactive ion etching of III-V multilayer structures is an important issue for long wavelength vertical cavity surface emitting laser (VCSELs) where full laser structures are usually very thick. Test etchings were performed on GaAs/Al sub x Ga sub 1 sub - sub x As Bragg mirror structures and monitored using laser reflectometry at 651.4 nm. In order to perform very deep etching, up to 9 mu m, we designed and fabricated a special two-level mask made up of a thick nitride layer and a thin nickel layer. The etching rate is a complex function of many parameters and may change from run to run for similar structures. Therefore, it is important to have a method to control accurately the process in situ by continuously matching, experimental curves with the results of the reflectivity modeling. Here, we present a model, based on the Abeles matrix method, of the normal incidence reflectivity of a multilayer stack as a function of etch depth. Comparison between the model and the observed reflectivity variation durin...

  6. Strong Exciton-photon Coupling in Semiconductor Microcavities

    DEFF Research Database (Denmark)

    Jensen, Jacob Riis; Borri, Paola; Hvam, Jørn Märcher

    1999-01-01

    The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high directiona......The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high......-optical switches based on semiconductor microcavities....

  7. Nonlinear Optics and Nonlinear Dynamics in Semiconductor Lasers Subject to External Optical Injection

    National Research Council Canada - National Science Library

    Simpson, Thomas

    2000-01-01

    ...) arrays, and analysis of chaotic dynamics that can be induced by optical injection. Under external optical injection, all semiconductor lasers tested, conventional edge emitting Fabry Perot laser diodes, VCSELs, and distributed feedback (DFB...

  8. Bidirectional uncompressed HD video distribution over fiber employing VCSELs

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Vegas Olmos, Juan José; Rodes, G. A.

    2012-01-01

    We report on a bidirectional system in which VCSELs are simultaneously modulated with two uncompressed HD video signals. The results show a large power budget and a negligible penalty over 10 km long transmission links.......We report on a bidirectional system in which VCSELs are simultaneously modulated with two uncompressed HD video signals. The results show a large power budget and a negligible penalty over 10 km long transmission links....

  9. 1.3-μm InGaAsN VCSELs for telecom and datacom applications

    Science.gov (United States)

    Jackson, Andrew W.; Naone, Ryan L.; Chirovsky, Leo M. F.; Feld, Stewart A.; Galt, David; Dalberth, Mark J.; Smith, Joseph M.; Thompson, Lance R.; Lange, Michael D.; Kisker, David W.

    2001-11-01

    VCSELs operating at 1.3 microns are the ideal laser source for meeting the exploding demand for bandwidth in local area and metro area networks. NCSELs will eventually replace the vast majority of 1.3 micron FP and DFB edge emitting lasers currently used in these applications, since they offer lower manufacturing cost, on wafer testability, extremely narrow linewidth, a circular output beam, high speed direct modulation, and the ability to be integrated into arrays. The primary challenge in 1.3 micron VCSELs has been to find an active region material that can be grown directly on high thermal conductivity and high reflectivity GaAs/AlGaAs distributed Bragg reflectors DBRs. In this work, we have developed MBE grown InGaAsN quantum wells that can be grown directly on GaAs substrates and integrated directly into high performance oxide VCSEL structures. We have demonstrated record room temperature CW single mode output powers in excess of 1 mW at an emission wavelength of 1287 nm. CW lasing has been observed as high as 125 degree(s)C, illustrating the excellent thermal performance of both the InGaAsN quantum wells and the GaAs/AlGaAs DBRs. Open eye diagrams were observed at 10 Gb/s, paving the way for OC-192 SONET and 10 Gb/s Ethernet applications.

  10. Flexible MultiCAP Modulation and its Application to 850 nm VCSEL-MMF Links

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2017-01-01

    , power consumption adaptivity. First, simulations results are presented to show the capacity of the proposed scheme under different bandwidth restrictions, and then, as a proof of concept, its feasibility is experimentally demonstrated in 850 nm vertical-cavity surface-emitting laser based transmissions...... over 100 m of OM4 multimode fiber. Data rates up to 40.6 Gb/s with spectral efficiencies up to 4 bit/s/Hz are achieved. All measured bit error rates were below the 7% overhead forward error correction threshold of 3.8 x 10(-3)....

  11. High-index-contrast subwavelength grating VCSEL

    DEFF Research Database (Denmark)

    Gilet, Philippe; Olivier, Nicolas; Grosse, Philippe

    2010-01-01

    In this article, we report our results on 980nm high-index-contrast subwavelength grating (HCG) VCSELs for optical interconnection applications. In our structure, a thin undoped HCG layer replaces a thick p-type Bragg mirror. The HCG mirror can feasibly achieve polarization-selective reflectivities...... close to 100%. The investigated structure consists of a HCG mirror with an underneath /4-thick oxide gap, four p-type GaAlAs/GaAs pairs for current spreading, three InGaAs/GaAs quantum wells, and an n-type GaAlAs/GaAs Bragg mirror. The HCG structure was defined by e-beam lithography and dry etching....... The current oxide aperture and the oxide gap underneath the HCG were simultaneously formed by the selective wet oxidation process. Compared to air-gap high contrast grating mirrors demonstrated elsewhere, our grating mirrors are particular since they are supported by thinner /4 aluminium oxide layer, and thus...

  12. Vertical electro-absorption modulator design and its integration in a VCSEL

    Science.gov (United States)

    Marigo-Lombart, L.; Calvez, S.; Arnoult, A.; Thienpont, H.; Almuneau, G.; Panajotov, K.

    2018-04-01

    Electro-absorption modulators, either embedded in CMOS technology or integrated with a semiconductor laser, are of high interest for many applications such as optical communications, signal processing and 3D imaging. Recently, the integration of a surface-normal electro-absorption modulator into a vertical-cavity surface-emitting laser has been considered. In this paper we implement a simple quantum well electro-absorption model and design and optimize an asymmetric Fabry-Pérot semiconductor modulator while considering all physical properties within figures of merit. We also extend this model to account for the impact of temperature on the different parameters involved in the calculation of the absorption, such as refractive indices and exciton transition broadening. Two types of vertical modulator structures have been fabricated and experimentally characterized by reflectivity and photocurrent measurements demonstrating a very good agreement with our model. Finally, preliminary results of an electro-absorption modulator vertically integrated with a vertical-cavity surface-emitting laser device are presented, showing good modulation performances required for high speed communications.

  13. Mode selection laser

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a semiconductor mode selection laser, particularly to a VCSEL laser (200) having mode selection properties. The mode selection capability of the laser is achieved by configuring one of the reflectors (15,51) in the resonance cavity so that a reflectivity of the reflector...... (15) varies spatially in one dimension or two dimensions. Accordingly, the reflector (15) with spatially varying reflectivity is part both of the resonance cavity and the mode selection functionality of the laser. A plurality of the lasers configured with different mode selectors, i.e. different...... spatial reflector variations, may be combined to generate a laser beam containing a plurality of orthogonal modes. The laser beam may be injected into a few- mode optical fiber, e.g. for the purpose of optical communication. The VCSEL may have intra-cavity contacts (31,37) and a Tunnel junction (33...

  14. Optically pumped 1550nm wavelength tunable MEMS VCSEL

    DEFF Research Database (Denmark)

    Sahoo, Hitesh Kumar; Ansbæk, Thor; Ottaviano, Luisa

    2016-01-01

    The paper presents the design and fabrication of an optically pumped 1550nm tunable MEMS VCSEL with anenclosed MEMS. The MEMS is defined in SOI and the active material, an InP wafer with quantum wells arebonded to the SOI and the last mirror is made from the deposition of dielectric materials. Th....... The design bringsin flexibility to fabricate MEMS VCSELs over a wider range of wavelengths. The paper discusses results fromthe simulations and bonding results from fabrication. The device will push the boundaries for wavelength sweepspeed and bandwidth.......The paper presents the design and fabrication of an optically pumped 1550nm tunable MEMS VCSEL with anenclosed MEMS. The MEMS is defined in SOI and the active material, an InP wafer with quantum wells arebonded to the SOI and the last mirror is made from the deposition of dielectric materials...

  15. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.

    2002-01-01

    -power surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier...... is biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...

  16. Study of the Radiation Hardness of VCSEL and PIN Arrays

    CERN Document Server

    Gan, K.K.; Kagan, H.P.; Kass, R.D.; Law, A.; Rau, A.; Smith, D.S.; Lebbai, M.R.M.; Skubic, P.L.; Abi, B.; Rizardinova, F.

    2008-01-01

    The silicon trackers of the ATLAS experiment at LHC (CERN) use optical links for data transmission. VCSEL arrays operating at 850 nm are used to transmit optical signals while PIN arrays are used to convert the optical signals into electrical signals. We investigate the feasibility of using the devices at the Super LHC (SLHC). We irradiated VCSEL and GaAs PIN arrays from three vendors and silicon PIN arrays from one vendor. All arrays can be operated up to the SLHC dosage except the GaAs PIN arrays which have very low responsivities after irradiation and hence are probably not suitable for the SLHC application.

  17. A low-threshold high-index-contrast grating (HCG)-based organic VCSEL

    Science.gov (United States)

    Shayesteh, Mohammad Reza; Darvish, Ghafar; Ahmadi, Vahid

    2015-12-01

    We propose a low-threshold high-index-contrast grating (HCG)-based organic vertical-cavity surface-emitting laser (OVCSEL). The device has the feasibility to apply both electrical and optical excitation. The microcavity of the laser is a hybrid photonic crystal (HPC) in which the top distributed Bragg reflector (DBR) is replaced by a sub-wavelength high-contrast-grating layer, and provides a high-quality factor. The simulated quality factor of the microcavity is shown to be as high as 282,000. We also investigate the threshold behavior and the dynamics of the OVCSEL optically pumped with sub-picosecond pulses. Results from numerical simulation show that lasing threshold is 75 nJ/cm2.

  18. Progress Toward Measuring CO2 Isotopologue Fluxes in situ with the LLNL Miniature, Laser-based CO2 Sensor

    Science.gov (United States)

    Osuna, J. L.; Bora, M.; Bond, T.

    2015-12-01

    One method to constrain photosynthesis and respiration independently at the ecosystem scale is to measure the fluxes of CO2­ isotopologues. Instrumentation is currently available to makes these measurements but they are generally costly, large, bench-top instruments. Here, we present progress toward developing a laser-based sensor that can be deployed directly to a canopy to passively measure CO2 isotopologue fluxes. In this study, we perform initial proof-of-concept and sensor characterization tests in the laboratory and in the field to demonstrate performance of the Lawrence Livermore National Laboratory (LLNL) tunable diode laser flux sensor. The results shown herein demonstrate measurement of bulk CO2 as a first step toward achieving flux measurements of CO2 isotopologues. The sensor uses a Vertical Cavity Surface Emitting Laser (VCSEL) in the 2012 nm range. The laser is mounted in a multi-pass White Cell. In order to amplify the absorption signal of CO2 in this range we employ wave modulation spectroscopy, introducing an alternating current (AC) bias component where f is the frequency of modulation on the laser drive current in addition to the direct current (DC) emission scanning component. We observed a strong linear relationship (r2 = 0.998 and r2 = 0.978 at all and low CO2 concentrations, respectively) between the 2f signal and the CO2 concentration in the cell across the range of CO2 concentrations relevant for flux measurements. We use this calibration to interpret CO2 concentration of a gas flowing through the White cell in the laboratory and deployed over a grassy field. We will discuss sensor performance in the lab and in situ as well as address steps toward achieving canopy-deployed, passive measurements of CO2 isotopologue fluxes. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-675788

  19. Surface Emitting, High Efficiency Near-Vacuum Ultraviolet Light Source with Aluminum Nitride Nanowires Monolithically Grown on Silicon.

    Science.gov (United States)

    Zhao, S; Djavid, M; Mi, Z

    2015-10-14

    To date, it has remained challenging to realize electrically injected light sources in the vacuum ultraviolet wavelength range (∼200 nm or shorter), which are important for a broad range of applications, including sensing, surface treatment, and photochemical analysis. In this Letter, we have demonstrated such a light source with molecular beam epitaxially grown aluminum nitride (AlN) nanowires on low cost, large area Si substrate. Detailed angle dependent electroluminescence studies suggest that, albeit the light is TM polarized, the dominant light emission direction is from the nanowire top surface, that is, along the c axis, due to the strong light scattering effect. Such an efficient surface emitting device was not previously possible using conventional c-plane AlN planar structures. The AlN nanowire LEDs exhibit an extremely large electrical efficiency (>85%), which is nearly ten times higher than the previously reported AlN planar devices. Our detailed studies further suggest that the performance of AlN nanowire LEDs is predominantly limited by electron overflow. This study provides important insight on the fundamental emission characteristics of AlN nanowire LEDs and also offers a viable path to realize an efficient surface emitting near-vacuum ultraviolet light source through direct electrical injection.

  20. Towards 100 Gbps over 100m MMF using a 850nm VCSEL

    DEFF Research Database (Denmark)

    Iglesias Olmedo, Miguel; Tatarczak, Anna; Zuo, Tianjian

    2014-01-01

    Employing MultiCAP signaling, successful 70.4 Gbps transmission over 100m of OM3 MMF using off-the-shelf 850 nm VCSEL with 10.1 GHz 3-dB bandwidth is experimentally demonstrated indicating the feasibility of achieving 100 Gbps with a single 25 GHz VCSEL. © 2014 OSA.......Employing MultiCAP signaling, successful 70.4 Gbps transmission over 100m of OM3 MMF using off-the-shelf 850 nm VCSEL with 10.1 GHz 3-dB bandwidth is experimentally demonstrated indicating the feasibility of achieving 100 Gbps with a single 25 GHz VCSEL. © 2014 OSA....

  1. True photonic band-gap mode-control in VCSEL structures

    DEFF Research Database (Denmark)

    Romstad, F.; Madsen, M.; Birkedal, Dan

    2003-01-01

    Photonic band-gap mode confinement in novel nano-structured large area VCSEL structures is confirmed by the amplified spontaneous emission spectrum. Both guide and anti-guide VCSEL structures are experimentally characterised to verify the photonic band-gap effect.......Photonic band-gap mode confinement in novel nano-structured large area VCSEL structures is confirmed by the amplified spontaneous emission spectrum. Both guide and anti-guide VCSEL structures are experimentally characterised to verify the photonic band-gap effect....

  2. Semiconductor lasers stability, instability and chaos

    CERN Document Server

    Ohtsubo, Junji

    2017-01-01

    This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...

  3. 80-nm-tunable high-index-contrast subwavelength grating long-wavelength VCSEL: Proposal and numerical simulations

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper; Sirbu, Alexei

    2010-01-01

    A widely-tunable single-mode long wavelength vertical-cavity surface-emitting laser structure employing a MEMStunable high-index-contrast subwavelength grating (HCG) is suggested and numerically investigated. A very large 80- nm linear tuning range was obtained as the HCG was actuated by -220...... to the selective pumping of the fundamental mode and the moderate mode selection by the HCG itself. Analytic expressions for tuning range and tuning sensitivity were derived, using the penetration depth of the HCG for the first time....

  4. Study on differences between high contrast grating reflectors for TM and TE polarizations and their impact on VCSEL designs

    DEFF Research Database (Denmark)

    Chung, Il-Sug

    2015-01-01

    -refractive-index media surrounding the HCG. This enables to achieve a very short effective cavity length for VCSELs, which is essential for ultrahigh speed VCSELs and MEMS-tunable VCSELs. The obtained understandings on polarization dependences will be able to serve as important design guidelines for various HCG...

  5. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Woo June Choi; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

    2014-08-31

    We demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilises 1.3-μm high-speed sweptsource optical coherence tomography (SS-OCT). The swept source is based on a micro-electro-mechanical (MEMS)-tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth, which enables the visualisation of microstructures within a few mm from the skin surface. We show that the skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic. (laser biophotonics)

  6. High-Capacity Short-Range Optical Communication Links

    DEFF Research Database (Denmark)

    Tatarczak, Anna

    offered by data centers. As the popularity of cloud computing soars, the demand for high-speed, short-range data center links grows. Vertical cavity surface emitting lasers (VCSEL) and multimode fibers (MMF) prove especially well-suited for such scenarios. VCSELs have high modulation bandwidths......, are energy efficient, reliable, and cheap to fabricate. MMFs are highly tolerant to coupling misalignment and bending. However, because of the large spectral width of VCSELs and, consequently, chromatic and modal dispersion effects in the fiber, the VCSEL-MMF links have a limited bandwidth{distance product...

  7. Amplitude Noise Suppression and Orthogonal Multiplexing Using Injection-Locked Single-Mode VCSEL

    DEFF Research Database (Denmark)

    Lyubopytov, Vladimir; von Lerber, Tuomo; Lassas, Matti

    2017-01-01

    We experimentally demonstrate BER reduction and orthogonal modulation using an injection locked single-mode VCSEL. It allows us suppressing an amplitude noise of optical signal and/or double the capacity of an information channel....

  8. A passively aligned VCSEL transmitter operating at fixed current over a wide temperature range.

    Science.gov (United States)

    Park, Jonghyun; Kim, Taeyong; Kim, Sung-Han; Kim, Sang-Bae

    2009-03-30

    We have investigated low-current operation characteristics of a passively aligned VCSEL transmitter driven at fixed "on" and "off" current over a wide temperature range. GaAs/AlGaAs-based 850-nm oxide VCSELs with the minimum threshold current of 0.79 mA at 50 masculineC and small temperature dependence of the threshold current, d(2)I(th)/dT(2), as low as 0.114 muA/ masculineC(2) have been fabricated and used for the transmitter module. The superior temperature characteristics enable fixed-current operation of the VCSEL transmitter that complies with Gigabit Ethernet standard over a wide temperature range from -20 to 120 masculineC. This result paves the way to a VCSEL transmitter featured by low-power consumption, low-cost with a simple driving circuit and passive alignment, and a wide operation temperature range.

  9. Improving the capacity of short-reach VCSEL-based MMF optical links

    DEFF Research Database (Denmark)

    Tatarczak, Anna; Lu, Xiaofeng; Tafur Monroy, Idelfonso

    2016-01-01

    We summarize strategies for increasing a capacity of short-reach links that base on an 850 nm VCSEL and an MMF. Presented methods include advanced modulation formats, equalization, WDM, quasi-single mode sources and a selective mode launch.......We summarize strategies for increasing a capacity of short-reach links that base on an 850 nm VCSEL and an MMF. Presented methods include advanced modulation formats, equalization, WDM, quasi-single mode sources and a selective mode launch....

  10. Robust design of subwavelength grating mirror for mid-infrared VCSEL application

    OpenAIRE

    Chevallier, Christyves; Genty, Frédéric; Fressengeas, Nicolas; Jacquet, Joel

    2011-01-01

    Oral Presentation - The final publication is available at http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=6041173; International audience; We present the design of a Si/Si3N4 subwavelength grating mirror optimized for an integration in mid-infrared VCSEL. The definition of a quality factor adapted to VCSEL requirements and maximized by an optimization algorithm allowed us to obtain a polarization selective and high reflectivity structure. The robustness with respect to fabrication err...

  11. Multiple-beam output of a surface-emitted terahertz-wave parametric oscillator by using a slab MgO:LiNbO₃ crystal.

    Science.gov (United States)

    Wang, Weitao; Zhang, Xingyu; Wang, Qingpu; Cong, Zhenhua; Chen, Xiaohan; Liu, Zhaojun; Qin, Zengguang; Li, Ping; Tang, Guanqi; Li, Ning; Wang, Cong; Li, Yongfu; Cheng, Wenyong

    2014-02-15

    A MgO:LiNbO₃ slab configuration for the surface-emitted terahertz-wave parametric oscillator (TPO) is presented. The pump and the oscillating Stokes beams were totally reflected at the slab surface and propagated zigzaggedly in the slab MgO:LiNbO₃ crystal. Up to five terahertz beams were emitted perpendicularly to the surface of the crystal. The total output energy of the five THz-wave beams was 3.56 times as large as that obtained from the conventional surface-emitted TPO at the same experimental conditions. The intensity distributions of the THz wave beams were measured, and they were unsymmetrical in the horizontal direction while symmetrical in the vertical direction.

  12. Broadband MEMS-tunable high-index-contrast subwavelength grating long-wavelength VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Iakovlev, Vladimir; Sirbu, Alexei

    2010-01-01

    A widely-tunable single-mode 1.3 μm vertical-cavity surface-emitting laser structure incorporating a microelectromechanical system-tunable high-index-contrast subwavelength grating (HCG) mirror is suggested and numerically investigated. A linear tuning range of 100 nm and a wavelength tuning...... efficiency of 0.203 are predicted. The large tuning range and efficiency are attributed to the incorporation of the tuning air gap as part of the optical cavity and to the use of a short cavity structure. The short cavity length can be achieved by employing a HCG design of which the reflection mechanism does...... not rely on resonant coupling. The absence of resonance coupling leads to a 0.59 λ-thick penetration depth of the HCG and enables to use a 0.25 λ-thick tuning air gap underneath the HCG. This considerably reduces the effective cavity length, leading to larger tuning range and efficiency. The basic...

  13. Comparing 52 Gbps Duobinary and 4-PAM Transmission Over 100m OM-3 Fiber With 25GHz Class VCSELs

    DEFF Research Database (Denmark)

    Suhr, Lau Frejstrup; Lyubomirsky, Ilya; Daghighian, Henry M.

    This paper compares VCSEL based transmission of 52 Gbps duobinary-NRZ and 4-PAM over 100m OM-3 fiber employing a linear equalizer in the receiver.......This paper compares VCSEL based transmission of 52 Gbps duobinary-NRZ and 4-PAM over 100m OM-3 fiber employing a linear equalizer in the receiver....

  14. Wide temperature operation of 850-nm VCSEL and isolator-free operation of 1300-nm VCSEL for a variety of applications

    Science.gov (United States)

    Nishikata, Kevin; Ariga, Maiko; Iwai, Norihiro; Ikenaga, Yoshihiko; Setiagung, Casimirus; Kageyama, Takeo; Shimizu, Hitoshi; Yokouchi, Noriyuki; Kasukawa, Akihiko; Koyama, Fumio

    2005-03-01

    Furukawa Electric is looking at a variety of applications using VCSEL. New applications such as sensors, automobile, and home electric appliances require new characteristics of stable CW operation, higher modulation, wider temperature range, and higher density array. Automobile Local Area Network called MOST (Media Orientated System Transport) is now popular using 650 nm LED plus Plastic Optical Fiber with a 1 mm core. For higher operation temperature and higher transmission speed, the system with 850 nm VCSEL plus HCS (Hard Clad Silica) fiber with a core of 200 microns Silica has been investigating. We investigated 850 nm oxide VCSEL performances of LI, RIN, Eye, BERT and reliability in a wide temperature range from -40 to 125°C In order to obtain low-cost modules for data-communication, it is critical to eliminate high-cost components such as an isolator and a lens containing in the module. We confirmed 2.5 Gbps stable operation without the isolator for 1300 nm GaInNAsSb oxide VCSEL experimentally and theoretically. The RIN was stable around -145 dB/Hz with an optical feedback light less than -30 dB and drastically increased at this point. It was -110 dB/Hz with -13 dB. For an increasing demand of high bandwidth for the interconnection between computers and routers, it is important to investigate the maximum frequency of an existing 1300 nm GaInNAsSb VCSEL. We showed the intrinsic maximum modulation frequency of 23 GHz by fitting K-factor that was 0.385 nsec.

  15. Half-cycle QAM modulation for VCSEL-based optical links

    DEFF Research Database (Denmark)

    Pham, Tien Thang; Rodes Lopez, Roberto; Jensen, Jesper Bevensee

    2012-01-01

    Abstract (40-Word Limit): Novel spectrally efficient half-cycle QAM modulation is experimentally demonstrated. 10 Gbps 4-QAM signal in 7.5-GHz bandwidth was successfully transmitted over 20 km SMF using an un-cooled 1.5 µm VCSEL with no equalization applied.......Abstract (40-Word Limit): Novel spectrally efficient half-cycle QAM modulation is experimentally demonstrated. 10 Gbps 4-QAM signal in 7.5-GHz bandwidth was successfully transmitted over 20 km SMF using an un-cooled 1.5 µm VCSEL with no equalization applied....

  16. Semiconductor-metal subwavelength grating VCSELs: new concept of emission mirror enabling vertical current injection

    Science.gov (United States)

    Czyszanowski, Tomasz; Gebski, Marcin; Dems, Maciej; Panajotov, Krassimir

    2017-02-01

    We propose semiconductor-metal subwavelength grating (SMSG) which can be implemented as VCSEL mirror. Such new type of SMSG plays a double role of the electric contact and mirror simultaneously. It facilitates high optical power reflectance, perfectly vertical current injection. Such construction eliminates the inbuilt current confinement and allows scaling of emitted power by simple variation of SMSG spatial dimensions. To give the credibility to proposed design we perform numerical analysis of VCSEL with SMSG using fully vectorial optical model. We discuss properties of the proposed design realized in arsenide-based material configuration.

  17. GBLD10+: a compact low-power 10 Gb/s VCSEL driver

    OpenAIRE

    Zhang, T; Kulis, S; Gui, P; Tavernier, F; Moreira, P

    2016-01-01

    We report the design and implementation of the GBLD10+, a low-power 10 Gb/s VCSEL driver for High Energy Physics (HEP) applications. With new circuit techniques, the driver consumes only 31 mW and occupies a small area of 400 μm × 1750 μm including the IO PADs and sealrings. These characteristics allow for multiple GBLD10+ ICs to be assembled side by side in a compact module, with each one directly wire bonded to one VCSEL diode. This makes the GBLD10+ a suitable candidate for the Versatile L...

  18. GBLD10+: a compact low-power 10 Gb/s VCSEL driver

    Science.gov (United States)

    Zhang, T.; Kulis, S.; Gui, P.; Tavernier, F.; Moreira, P.

    2016-01-01

    We report the design and implementation of the GBLD10+, a low-power 10 Gb/s VCSEL driver for High Energy Physics (HEP) applications. With new circuit techniques, the driver consumes only 31 mW and occupies a small area of 400 μm × 1750 μm including the IO PADs and sealrings. These characteristics allow for multiple GBLD10+ ICs to be assembled side by side in a compact module, with each one directly wire bonded to one VCSEL diode. This makes the GBLD10+ a suitable candidate for the Versatile Link PLUS (VL+) project, offering flexibility in configuring multiple transmitters and receivers.

  19. SC-FDE for MMF short reach optical interconnects using directly modulated 850 nm VCSELs

    DEFF Research Database (Denmark)

    Teichmann, Victor S. C.; Barreto, Andre N.; Pham, Tien Thang

    2012-01-01

    We propose the use of single-carrier frequency-domain equalization (SC-FDE) for the compensation of modal dispersion in short distance optical links using multimode fibers and 850 nm VCSELs. By post-processing of experimental data, we demonstrate, at 7.9% overhead, the error-free transmission (ov...

  20. MIMO-OFDM WDM PON with DM-VCSEL for femtocells application

    DEFF Research Database (Denmark)

    Binti Othman, Maisara; Deng, Lei; Pang, Xiaodan

    2011-01-01

    We report on experimental demonstration of 2x2 MIMO-OFDM 5.6-GHz radio over fiber signaling over 20 km WDM-PON with directly modulated (DM) VCSELs for femtocells application. MIMO-OFDM algorithms effectively compensate for impairments in the wireless link. Error-free signal demodulation of 64...

  1. Adaptive MultiCAP modulation for short range VCSEL based transmissions

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2016-01-01

    We propose an adaptive approach for multi-band carrierless amplitude/phase modulation, with advantages of adaptive bit rate and energy savings. Successful performance is demonstrated on 850 nm multi-mode VCSEL based transmissions achieving up to 40.6 Gb/s....

  2. Diagnostic and characterization of the VCSEL diodes based on GaSb

    Czech Academy of Sciences Publication Activity Database

    Matulková, Irena; Cihelka, Jaroslav; Vyskočil, Jan; Zelinger, Zdeněk; Hulicius, Eduard; Šimeček, Tomislav; Civiš, Svatopluk

    2010-01-01

    Roč. 99, 1-2 (2010), s. 333-338 ISSN 0946-2171 R&D Projects: GA AV ČR IAA400400705 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100521 Keywords : VCSEL diodes * FTIR * GaSb Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.239, year: 2010

  3. 7TH International Symposium: Nanostructure: Physics and Technology

    Science.gov (United States)

    1999-01-01

    presented. 1 Introduction Red (620-700 nm) vertical cavity surface emitting lasers (VCSELs) are candidates for plas- tic fiber communications, compact disk...The high disoder system under weak magnetic field B exhibits a divergently growing longitudinal Pxx resistivity with decreasing temperature T, but a

  4. Characterization of 850nm-15μm GaAs/AlGaAs quantum-well ...

    African Journals Online (AJOL)

    In this report, operating characteristics and performance of 15μm diameter vertical cavity surface emitting lasers (VCSELs) emitting at 850nm and fabricated by gas source molecular beam-epitaxy (GSMBE) is presented. The device characterisation is performed by observing the continuous wave (cw) operation under room ...

  5. A 5 Gb/s Radiation Tolerant Laser Driver

    CERN Document Server

    Amaral, L; Da Silva, S; Mazza, G; Meroli, S; Moreira, P; Rivetti, A; Troska, J; Wyllie, K

    2009-01-01

    A laser driver for data transmission at 5 Gb/s has been developed as a part of the Giga Bit Transceiver (GBT) project. The Giga Bit Laser Driver (GBLD) targets High Energy Physics (HEP) applications for which radiation tolerance is mandatory. The GBLD ASIC can drive both VCSELs and some types of edge emitting lasers. It is essentially composed of two drivers capable of sinking up to 12 mA each from the load at a maximum data rate of 5 Gb/s, and of a current sink for the laser bias current. The laser driver include also pre-emphasis and duty cycle control capabilities.

  6. VCSELs and silicon light sources exploiting SOI grating mirrors

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2012-01-01

    In this talk, novel vertical-cavity laser structure consisting of a dielectric Bragg reflector, a III-V active region, and a high-index-contrast grating made in the Si layer of a silicon-on-insulator (SOI) wafer will be presented. In the Si light source version of this laser structure, the SOI gr...

  7. Chip-level interconnections realized via the laser-induced forward transfer technique

    OpenAIRE

    Kaur, Kamalpreet; Missinne, Jeroen; Van Steenberge, Geert

    2014-01-01

    In this paper, successful flip-chip bonding and DC characterization of single photodiode and VCSEL chips via Laser-Induced Forward Transfer (LIFT) printed micro-bumps of indium, silver nano-particle (AgNP) based inks and pastes, is reported.

  8. Fundamentals of semiconductor lasers

    CERN Document Server

    Numai, Takahiro

    2015-01-01

    This book explains physics under the operating principles of semiconductor lasers in detail based on the experience of the author, dealing with the first manufacturing of phase-shifted DFB-LDs and recent research on transverse modes.   The book also bridges a wide gap between journal papers and textbooks, requiring only an undergraduate-level knowledge of electromagnetism and quantum mechanics, and helps readers to understand journal papers where definitions of some technical terms vary, depending on the paper. Two definitions of the photon density in the rate equations and two definitions of the phase-shift in the phase-shifted DFB-LD are explained, and differences in the calculated results are indicated, depending on the definitions.    Readers can understand the physics of semiconductor lasers and analytical tools for Fabry-Perot LDs, DFB-LDs, and VCSELs and will be stimulated to develop semiconductor lasers themselves.

  9. Investigation of the Static and Dynamic Characteristics for a Wafer-Fused C-band VCSEL in the Mode of the Optical-Electric Converter

    Science.gov (United States)

    Belkin, M. E.

    2018-01-01

    The results of an experimental study for a long wavelength vertical cavity surface-emitting laser of a wafer-fused construction as an effective resonant cavity enhanced photodetector of analog optical signals are described. The device is of interest for a number of promising microwave photonics applications and for creation of a low-cost photoreceiver in a high-speed fiber optics telecommunication system with dense wavelength division multiplexing. The schematic of the testbed, the original technique allowing to calculate the passband of the built-in optical cavity, and the results of measuring dark current, current responsivity, amplitude- and phase-frequency characteristics during the process of photo-detection are demonstrated.

  10. Experimental Demonstration of 84 Gb/s PAM-4 Over up to 1.6 km SSMF Using a 20-GHz VCSEL at 1525 nm

    DEFF Research Database (Denmark)

    Eiselt, Nicklas; Griesser, Helmut; Wei, Jinlong

    2017-01-01

    We demonstrate 84-Gb/s four-level pulse amplitude modulation (PAM-4) over up to 1.6-km standard single mode fiber using a 20-GHz single mode short cavity vertical cavity surface emitting laser diode at a transmission wavelength of 1525 nm. Different equalizer approaches including a common...... feedforward equalizer, a nonlinear Volterra equalizer (NLVE), a maximum likelihood sequence estimator (MLSE) and their combinations are evaluated working either as an equalizer for a standard PAM-4 or a partial response PAM-4 signal with seven levels. It is demonstrated that a standard FFE is not enough...... for a transmission distance of >0.6 km, while the use of an NLVE or FFE + MLSE is able to improve the transmission distance towards 1 km. The use of partial-response PAM-4 FFE in combination with a short memory MLSE is able to efficiently equalize the bandwidth limitations, showing more than 10-times BER improvement...

  11. Lasers

    OpenAIRE

    Passeron, Thierry

    2012-01-01

    International audience; Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be succesfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-aulait macules should not b...

  12. Laser

    OpenAIRE

    Du, K.; Loosen, P.; Herziger, G.

    1991-01-01

    Laser, consisting of a beam path multiple-folded by means of two cavity end mirrors and having at least one reflector folding the laser beam retroreflectively, the axis of which is arranged offset in parallel to the axis of a further reflector. So that the laser exhibits an improved beam quality while retaining its comparatively low adjustment sensitivity, the beam path is folded at least twice by means of the retoreflective reflector.

  13. Multi-longitudinal-mode micro-laser model

    Science.gov (United States)

    Staliunas, Kestutis

    2017-10-01

    We derive a convenient model for broad aperture micro-lasers, such as microchip lasers, broad area semiconductor lasers, or VCSELs, taking into account several longitudinal mode families. We provide linear stability analysis, and show characteristic spatio-temporal dynamics in such multi-longitudinal mode laser models. Moreover, we derive the coupled mode model in the presence of intracavity refraction index modulation (intracavity photonic crystal). Contribution to the Topical Issue "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.

  14. A 5 Gb/s Radiation Tolerant Laser Driver

    OpenAIRE

    Amaral, L; Checcucci, B; Da Silva, S; Mazza, G; Meroli, S; Moreira, P; Rivetti, A; Troska, J; Wyllie, K

    2009-01-01

    A laser driver for data transmission at 5 Gb/s has been developed as a part of the Giga Bit Transceiver (GBT) project. The Giga Bit Laser Driver (GBLD) targets High Energy Physics (HEP) applications for which radiation tolerance is mandatory. The GBLD ASIC can drive both VCSELs and some types of edge emitting lasers. It is essentially composed of two drivers capable of sinking up to 12 mA each from the load at a maximum data rate of 5 Gb/s, and of a current sink for the laser bias current. Th...

  15. Electrical Spin Injection and Threshold Reduction in a Semiconductor Laser

    Science.gov (United States)

    Holub, M.; Shin, J.; Saha, D.; Bhattacharya, P.

    2007-04-01

    A spin-polarized vertical-cavity surface-emitting laser is demonstrated with electrical spin injection from an Fe/Al0.1Ga0.9As Schottky tunnel barrier. Laser operation with a spin-polarized current results in a maximum threshold current reduction of 11% and degree of circular polarization of 23% at 50 K. A cavity spin polarization of 16.8% is estimated from spin-dependent rate equation analysis of the observed threshold reduction.

  16. Semiconductor Lasers Stability, Instability and Chaos

    CERN Document Server

    Ohtsubo, Junji

    2013-01-01

    This third edition of “Semiconductor Lasers, Stability, Instability and Chaos” was significantly extended.  In the previous edition, the dynamics and characteristics of chaos in semiconductor lasers after the introduction of the fundamental theory of laser chaos and chaotic dynamics induced by self-optical feedback and optical injection was discussed. Semiconductor lasers with new device structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are interesting devices from the viewpoint of chaotic dynamics since they essentially involve chaotic dynamics even in their free-running oscillations. These topics are also treated with respect to the new developments in the current edition. Also the control of such instabilities and chaos control are critical issues for applications. Another interesting and important issue of semiconductor laser chaos in this third edition is chaos synchronization between two lasers and the application to optical secure communication. One o...

  17. Lasers.

    Science.gov (United States)

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  18. [Lasers].

    Science.gov (United States)

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  19. Low-voltage, high-speed and compact electro-absorption modulator laterally integrated with 980-nm VCSEL.

    Science.gov (United States)

    Dalir, Hamed; Takahashi, Yuta; Koyama, Fumio

    2014-10-20

    We present a compact electro-absorption slow-light modulator laterally-integrated with a 980-nm VCSEL. We figured out the small signal modulation response for different modulator lengths. While the 3-dB small-signal modulation bandwidth of conventional directly modulated VCSELs on the same epi-wafer structure was limited below 10 GHz, we obtained a modulation bandwidth over 21 GHz for a 30 µm long modulator. We also demonstrated large signal modulation up to 25 Gbps with a low driving voltage below 600 mV(pp) and an extinction ratio of 4 dB for the modulator length of 50 µm. Prospects of much higher speed (> 40 Gbps) were examined with reducing the size of the modulator. Also, the tapered waveguide coupling structure enables "quasi-unidirectional coupling", which reduces the optical feedback in a VCSEL from the integrated modulator.

  20. Towards a SFP+ module for WDM applications using an ultra-widely-tunable high-speed MEMS-VCSEL

    Science.gov (United States)

    Paul, Sujoy; Cesar, Julijan; Malekizandi, Mohammadreza; Haidar, Mohammad T.; Heermeier, Niels; Ortsiefer, Markus; Neumeyr, Christian; Gréus, Christoph; Eiselt, Michael H.; Ibrahim, Irfan; Schmidt, Henning; Schmidt, Jörg; Küppers, Franko

    2017-02-01

    In this work, we have used a tunable VCSEL for high-speed optical data transmission. To obtain wide tunability, a MEMS-DBR is surface micromachined onto a short-cavity high-speed VCSEL operating at 1550 nm. Ultra-wide continuous tuning is realized with electro-thermal actuation of the MEMS with built-in stress gradient within SiOx/SiNy dielectric layers. The MEMS-VCSEL operates in single-mode with SMSR > 40 dB across the entire tuning range. Quasi-error-free transmission of direct-modulation at record 15 Gbps is reported for 20 nm tuning, showing the potential towards the standard requirements for the SFP+ modules in the tail-ends of the WDM transmission system.

  1. Sub-cycle QAM modulation for VCSEL-based optical fiber links

    DEFF Research Database (Denmark)

    Pham, Tien-Thang; Rodes Lopez, Roberto; Jensen, Jesper Bevensee

    2013-01-01

    QAM modulation utilizing subcarrier frequency lower than the symbol rate is both theoretically and experimentally investigated. High spectral efficiency and concentration of power in low frequencies make sub-cycle QAM signals attractive for optical fiber links with direct modulated light sources....... Real-time generated 10-Gbps 4-level QAM signal in a 7.5-GHz bandwidth utilizing subcarrier frequency at a half symbol rate was successfully transmitted over 20-km SMF using an un-cooled 1.5-μm VCSEL. Only 2.5-dB fiber transmission power penalty was observed with no equalization applied....

  2. All-VCSEL Transmitters With Remote Optical Injection for WDM-OFDM-PON

    DEFF Research Database (Denmark)

    Deng, Lei; Zhao, Ying; Pang, Xiaodan

    2014-01-01

    are used as low-cost, directly modulated upstream and downstream transmitters. The slave VCSEL at the optical network unit is remotely injection-locked by modulated downstream signals, and no need for additional injection-locking optical sources and external modulators. In our experiment, bidirectional...... transmission of 1.25 Gb/s 4-quadrature amplitude modulation (4QAM)-OFDM signal over 26-km single mode fiber has been successfully demonstrated. Moreover, we investigate the residual amplitude modulation (RAM) caused by the conversion of injected AM into slave AM. In addition, the experimental results show...

  3. Semiconductor light sources for near- and mid-infrared spectral ranges

    Science.gov (United States)

    Karachinsky, L. Ya; Babichev, A. V.; Gladyshev, A. G.; Denisov, D. V.; Filimonov, A. V.; Novikov, I. I.; Egorov, A. Yu

    2017-11-01

    1550 nm band wafer-fused vertical-cavity surface-emitting lasers (VCSELs) and 5-10 μm band multi-stages quantum-cascade lasers (QCL) grown by molecular beam epitaxy (MBE) were fabricated and studied. VCSELs show high output optical power up to 6 mW in single-mode regime (SMSR > 40 dB) and open-eye diagrams at 30 Gbps of standard NRZ at 20°C. QCL heterostructures show high structural quality (fluctuations of composition and thickness copper heatsinks show lasing at ∼ 6, 7.5 and 9 μm.

  4. VCSEL-Based DWDM PON With 4 BIT/S/HZ Spectral Efficiency Using Carrierless Amplitude Phase Modulation

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Wieckowski, Marcin; Pham, Tien Thang

    2011-01-01

    We experimental demonstrate successful performance of VCSEL-based WDM link supporting advanced 16-level carrierless amplitude/phase modulation up to 1.25 Gbps, over 26 km SSMF with spectral efficiency of 4 bit/s/Hz for application in high capacity PONs....

  5. One Dimensional Polymeric Organic Photonic Crystals for DFB Lasers

    Directory of Open Access Journals (Sweden)

    F. Scotognella

    2008-01-01

    Full Text Available We present a very simple method to realize a one-dimensional photonic crystal (1D PC, consisting of a dye-doped polymeric multilayer. Due to the high photonic density of states at the edges of the photonic band-gap (PBG, a surface emitting distributed feedback (DFB laser is obtained with this structure. Furthermore, the incidence angle dependence of the PBG of the polymeric multilayer is reported.

  6. Radiation-hard/high-speed parallel optical links

    International Nuclear Information System (INIS)

    Gan, K.K.; Buchholz, P.; Heidbrink, S.; Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S.; Vogt, M.; Ziolkowski, M.

    2016-01-01

    We have designed and fabricated a compact parallel optical engine for transmitting data at 5 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The performance of the optical engine up at 5 Gb/s is satisfactory.

  7. The miniature optical transmitter and transceiver for the High-Luminosity LHC (HL-LHC) experiments

    International Nuclear Information System (INIS)

    Liu, C; Zhao, X; Deng, B; Gong, D; Guo, D; Li, X; Liang, F; Liu, G; Liu, T; Xiang, A C; Ye, J; Chen, J; Huang, D; Hou, S; Teng, P-K

    2013-01-01

    We present the design and test results of the Miniature optical Transmitter (MTx) and Transceiver (MTRx) for the high luminosity LHC (HL-LHC) experiments. MTx and MTRx are Transmitter Optical Subassembly (TOSA) and Receiver Optical Subassembly (ROSA) based. There are two major developments: the Vertical Cavity Surface Emitting Laser (VCSEL) driver ASIC LOCld and the mechanical latch that provides the connection to fibers. In this paper, we concentrate on the justification of this work, the design of the latch and the test results of these two modules with a Commercial Off-The-Shelf (COTS) VCSEL driver

  8. Integration of GaAs-based VCSEL array on SiN platform with HCG reflectors for WDM applications

    Science.gov (United States)

    Kumari, Sulakshna; Gustavsson, Johan S.; Wang, Ruijun; Haglund, Emanuel P.; Westbergh, Petter; Sanchez, Dorian; Haglund, Erik; Haglund, Åsa; Bengtsson, Jörgen; Le Thomas, Nicolas; Roelkens, Gunther; Larsson, Anders; Baets, Roel

    2015-02-01

    We present a GaAs-based VCSEL structure, BCB bonded to a Si3N4 waveguide circuit, where one DBR is substituted by a free-standing Si3N4 high-contrast-grating (HCG) reflector realized in the Si3N4 waveguide layer. This design enables solutions for on-chip spectroscopic sensing, and the dense integration of 850-nm WDM data communication transmitters where individual channel wavelengths are set by varying the HCG parameters. RCWA shows that a 300nm-thick Si3N4 HCG with 800nm period and 40% duty cycle reflects strongly (HCG's influence on the VCSEL wavelength, allowing for a 15-nm-wide wavelength setting range with low threshold gain (<1000 cm-1).

  9. Photonic heterostructure High Contrast Grating as a novel polarization control and light confinement system in HCG VCSEL

    Science.gov (United States)

    Gebski, M.; Dems, M.; Chen, J.; Qijie, W.; Dao Hua, Z.; Czyszanowski, T.

    2014-05-01

    In this paper we present results of computer optical simulations of VCSEL with modified high refractive index contrast grating (HCG) as a top mirror. We consider the HCG of two different designs which determine the lateral aperture. Such HCG mirror provides selective guiding effect. We show that proper design of aperture of HCG results in almost sixfold increase in cavity Q-factor for zero order mode and a discrimination of higher order modes.

  10. Vcsel structure

    DEFF Research Database (Denmark)

    2015-01-01

    .5, and wherein an index of refraction of low-index sections of the grating structure is less than 2. The core grating region defines a projection in a direction normal to the grating layer. The grating reflector further comprises a cap layer abutting the grating layer, and an index of refraction of the cap layer...

  11. 21.2% wall-plug efficiency green laser based on an electrically pumped VECSEL through intracavity second harmonic generation

    Science.gov (United States)

    Zhao, Pu; Xu, Bing; van Leeuwen, Robert; Chen, Tong; Watkins, Laurence; Zhou, Delai; Seurin, Jean-Francois; Gao, Peng; Xu, Guoyang; Wang, Qing; Ghosh, Chuni

    2015-03-01

    We have achieved a 21.2% wall-plug efficiency green laser at 532 nm based on an electrically pumped vertical externalcavity surface emitting laser (VECSEL) through intracavity second harmonic generation. The continuous-wave green output power was 3.34 W. The VECSEL gain device is cooled by using a thermoelectric cooler, which can greatly benefit packaging. Both power and efficiency can be further scaled up by optimizing external-cavity design and improving the performance of VECSEL gain device.

  12. The GBLD: a radiation tolerant laser driver for high energy physics applications

    Science.gov (United States)

    Mazza, G.; Tavernier, F.; Moreira, P.; Rivetti, A.; Soos, C.; Troska, J.; Wyllie, K.

    2013-01-01

    The GigaBit Laser Driver (GBLD) is a radiation tolerant ASIC which is part of the GigaBit Transceiver (GBT) chipset. It is aimed to drive both edge emitting and VCSEL laser diodes at a data rate in excess of 5 Gb/s. The GBLD can provide a modulation current up to 24 mA and a bias current up to 43 mA. Pre- and de-emphasis functions are implemented to compensate for high external capacitive loads and asymmetric laser response. The chip is designed in a 130 nm CMOS technology and is powered by a single 2.5 V supply.

  13. Comparison of 850-nm and 1550-nm VCSELs for low-cost short-reach IM/DD and OFDM SMF/MMF links

    DEFF Research Database (Denmark)

    Karinou, Fotini; Deng, Lei; Rodes Lopez, Roberto

    2013-01-01

    In this paper, we experimentally compare the suitability of two VCSEL designs of different wavelength and technology as inexpensive, off-the-shelf transmitter components to enable low-cost and energy-efficient optical interconnects employing conventional (NRZ IM/DD) and advanced (OFDM) modulation....... In particular, we assess the performance of a multimode (MM) 850-nm and a single-mode (SM) 1550-nm VCSEL over 100 m/1 km of 50.7-μm diameter OM-4 MMF links and 100 m/5 km SMF links. OFDM-QPSK is investigated in order to substitute IM/DD in order to increase the capacity in the aforementioned VCSEL-based, MMF...

  14. VCSEL Transmission at 10 Gb/s for 20 km Single Mode Fiber WDM-PON without Dispersion Compensation or Injection Locking

    DEFF Research Database (Denmark)

    Gibbon, Timothy Braidwood; Prince, Kamau; Pham, Tien Thang

    2011-01-01

    how off-center wavelength filtering of the VCSEL spectrum at an array waveguide grating can be used to mitigate the effect of chirp and the dispersion penalty. Transmission at 10Gb/s VCSEL over 23.6 km of single mode fiber is experimentally demonstrated, with a dispersion penalty of only 2.9 d......B. Simulated results are also presented which show that off-center wavelength filtering can extend the 10 Gb/s network reach from 11.7 km to 25.8 km for a 4 dB dispersion penalty. This allows for cheap and simple dispersion mitigation in next generation VCSEL based optical access networks....

  15. Quad 14Gbps L-Band VCSEL-based System for WDM Migration of 4-lanes 56 Gbps Optical Data Links

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Rodes Lopez, Roberto; Pham, Tien Thang

    2012-01-01

    We report on migrating multiple lane link into a single WDM L-band VCSEL-based system. Experimental validation successfully achieves 10 km of SMF reach with 4x14Gbps and less than 0.5dB inter-channel crosstalk penalty.......We report on migrating multiple lane link into a single WDM L-band VCSEL-based system. Experimental validation successfully achieves 10 km of SMF reach with 4x14Gbps and less than 0.5dB inter-channel crosstalk penalty....

  16. Performance comparison of 850-nm and 1550-nm VCSELs exploiting OOK, OFDM, and 4-PAM over SMF/MMF links for low-cost optical interconnects

    DEFF Research Database (Denmark)

    Karinou, Fotini; Deng, Lei; Rodes Lopez, Roberto

    2013-01-01

    modulation (4-PAM), for the 1550-nm transmitter over SMF and MMF links and we compare it to the data-rate equivalent NRZ-OOK. The extensive performance comparison under various transmission scenarios shows the superiority of 1550-nm single-mode VCSEL compared to its multi-mode 850-nm counterpart. Moreover......, OFDM/DD and 4-PAM in conjunction with low-cost, inexpensive VCSELs as transmitters prove to be an enabling technology for next-generation WDM, point-to-point, short-reach, SMF/MMF optical interconnects and potential candidates to substitute NRZ-OOK. Nevertheless, the sensitivity requirements are higher...

  17. IM/DD vs. 4-PAM Using a 1550-nm VCSEL over Short-Range SMF/MMF Links for Optical Interconnects

    DEFF Research Database (Denmark)

    Karinou, Fotini; Rodes Lopez, Roberto; Prince, Kamau

    2013-01-01

    We experimentally compare the performance of 10.9-Gb/s IM/DD and 5-GBd 4-PAM modulation formats over 5-km SMF and 1-km MMF links, employing a commercially-available 1550-nm VCSEL as an enabling technology for use in optical interconnects.......We experimentally compare the performance of 10.9-Gb/s IM/DD and 5-GBd 4-PAM modulation formats over 5-km SMF and 1-km MMF links, employing a commercially-available 1550-nm VCSEL as an enabling technology for use in optical interconnects....

  18. 56 Gb/s DMT transmission with VCSELs in 1.5 um wavelength range over up to 12 km for DWDM intra-data center connects

    DEFF Research Database (Denmark)

    Dochhan, Annika; Eiselt, Nicklas; Hohenleitner, Robert

    2016-01-01

    We demonstrate up to 12 km, 56 Gb/s DMT transmission using high-speed VCSELs in the 1.5 um wavelength range for future 400Gb/s intra-data center connects, enabled by vestigial sideband filtering of the transmit signal.......We demonstrate up to 12 km, 56 Gb/s DMT transmission using high-speed VCSELs in the 1.5 um wavelength range for future 400Gb/s intra-data center connects, enabled by vestigial sideband filtering of the transmit signal....

  19. Performance analysis of communication links based on VCSEL and silicon photonics technology for high-capacity data-intensive scenario.

    Science.gov (United States)

    Boletti, A; Boffi, P; Martelli, P; Ferrario, M; Martinelli, M

    2015-01-26

    To face the increased demand for bandwidth, cost-effectiveness and simplicity of future Ethernet data communications, a comparison between two different solutions based on directly-modulated VCSEL sources and Silicon Photonics technologies is carried out. Also by exploiting 4-PAM modulation, the transmission of 50-Gb/s and beyond capacity per channel is analyzed by means of BER performance. Applications for optical backplane, very short reach and in case of client-optics networks and intra and inter massive data centers communications (up to 10 km) are taken into account. A comparative analysis based on the power consumption is also proposed.

  20. High-Q, Low-Threshold Monolithic Perovskite Thin-Film Vertical-Cavity Lasers.

    Science.gov (United States)

    Chen, Songtao; Zhang, Cheng; Lee, Joonhee; Han, Jung; Nurmikko, Arto

    2017-04-01

    A vertical-cavity surface-emitting perovskite laser is achieved using a microcavity configuration where CH 3 NH 3 PbI 3 thin solid films are embedded within a custom GaN-based high-quality (Q-factor) resonator. This single-mode perovskite laser reaches a low threshold (≈7.6 µJ cm -2 ) at room temperature and emits spatially coherent Gaussian laser beams. The devices allow direct access to the study of perovskite gain dynamics and material robustness. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Optical Polarization Modulation and Gain Anisotropy in an Electrically Injected Spin Laser

    Science.gov (United States)

    Basu, D.; Saha, D.; Bhattacharya, P.

    2009-03-01

    The effects of spin-induced gain anisotropy on output polarization and threshold current reduction of electrically pumped spin-polarized lasers have been studied. Analytical forms of these parameters are derived by considering diffusive transport from the spin injector to the active region. The calculated values of the parameter are in excellent agreement with values obtained from measurements made at 200 K on an InAs/GaAs quantum dot spin-polarized vertical cavity surface-emitting laser. Electrical modulation of the output polarization of the laser is demonstrated with a peak modulation index of 0.6.

  2. Absolute noninvasive measurement of CO2 mole fraction emitted by E. coli and S. aureus using calibration-free 2f WMS applied to a 2004  nm VCSEL.

    Science.gov (United States)

    Zarin, A S; Chakraborty, Arup Lal; Upadhyay, Abhishek

    2017-06-01

    We report the first demonstration, to the best of our knowledge, of accurate real-time noninvasive measurement of the absolute cumulative mole fraction of metabolic carbon dioxide emitted by Escherichia coli and Staphylococcus aureus over a period of several hours of their life cycles using a recently developed calibration-free wavelength modulation spectroscopy technique. A 1 mW vertical-cavity surface-emitting laser is used to interrogate a single rotational vibrational absorption line of carbon dioxide at 2003.5 nm. The measurements are immune to laser intensity fluctuations and variable optical coupling that is inevitable in such free-space coupled experiments that run over 10-18 h. The cumulative carbon dioxide mole fraction follows the characteristic modified Gompertz model that is typical of bacterial growth in batch cultures. The characteristic growth parameters are extracted from this curve. The technique can be readily extended to study multiple volatile organic compounds that bacteria are known to emit.

  3. 56 Gb/s DMT transmission with VCSELs in 1.5 um wavelength range over up to 12 km for DWDM intra-data center connects

    DEFF Research Database (Denmark)

    Dochhan, Annika; Eiselt, Nicklas; Hohenleitner, Robert

    2016-01-01

    We demonstrate up to 12 km, 56 Gb/s DMT transmission using high-speed VCSELs in the 1.5 um wavelength range for future 400Gb/s intra-data center connects, enabled by vestigial sideband filtering of the transmit signal....

  4. 24-Dimensional Modulation Formats for 100 Gbit/s IM-DD Transmission Systems Using 850 nm Single-Mode VCSEL

    DEFF Research Database (Denmark)

    Lu, Xiaofeng; Lyubopytov, Vladimir; Tafur Monroy, Idelfonso

    2017-01-01

    Twenty-four dimensional modulation format with 2 bit/symbol spectrum efficiency is proposed and investigated in an up to 100 Gbit/s VCSEL-based IM-DD transmission system with respect to the channel bandwidth and the power budget....

  5. Polarization Properties of Laser Solitons

    Directory of Open Access Journals (Sweden)

    Pedro Rodriguez

    2017-04-01

    Full Text Available The objective of this paper is to summarize the results obtained for the state of polarization in the emission of a vertical-cavity surface-emitting laser with frequency-selective feedback added. We start our research with the single soliton; this situation presents two perpendicular main orientations, connected by a hysteresis loop. In addition, we also find the formation of a ring-shaped intensity distribution, the vortex state, that shows two homogeneous states of polarization with very close values to those found in the soliton. For both cases above, the study shows the spatially resolved value of the orientation angle. It is important to also remark the appearance of a non-negligible amount of circular light that gives vectorial character to all the different emissions investigated.

  6. Experimental demonstration of 56 Gbit/s PAM-4 over 15 km and 84 Gbit/s PAM-4 over 1 km SSMF at 1525 nm using a 25G VCSEL

    DEFF Research Database (Denmark)

    Eiselt, Nicklas; Griesser, Helmut; Wei, Jinlong

    2016-01-01

    Record 28-GBd PAM-4 transmission over 15 km SSMF and 42-GBd PAM-4 over 1 km SSMF using a low-power 25G VCSEL are demonstrated at 1525 nm without optical dispersion compensation and only simple transceiver DSPs.......Record 28-GBd PAM-4 transmission over 15 km SSMF and 42-GBd PAM-4 over 1 km SSMF using a low-power 25G VCSEL are demonstrated at 1525 nm without optical dispersion compensation and only simple transceiver DSPs....

  7. Electrically injected InAs/GaAs quantum dot spin laser operating at 200 K

    Science.gov (United States)

    Basu, D.; Saha, D.; Wu, C. C.; Holub, M.; Mi, Z.; Bhattacharya, P.

    2008-03-01

    A spin-polarized vertical cavity surface emitting laser, with InAs /GaAs self-organized quantum dots as the active gain media, has been fabricated and characterized. Electron spin injection is achieved via a MnAs /GaAs Schottky tunnel contact. The laser is operated at 200K and, at this temperature, the degree of circular polarization in the output is 8% and the maximum threshold current reduction is 14%. These effects are not observed in identical control devices with nonmagnetic contacts.

  8. A miniature frequency-stabilized VCSEL system emitting at 795 nm based on LTCC modules

    Science.gov (United States)

    Gruet, Florian; Vecchio, Fabrizio; Affolderbach, Christoph; Pétremand, Yves; de Rooij, Nico F.; Maeder, Thomas; Mileti, Gaetano

    2013-08-01

    We present a compact frequency-stabilized laser system locked to the Rubidium absorption line of a micro-fabricated reference cell. A printed circuit board (PCB) is used to carry all the components and part of the electronics, and low-temperature co-fired ceramic (LTCC) modules are used to temperature-stabilize the laser diode and the miniature Rubidium cell (cell inner dimensions: 5 mm diameter and 2 mm height). The measured frequency stability of the laser, in terms of Allan deviation, is ≤8×10-10 for integration times of 103-105s. The current overall dimensions of the system are 70×40×50 mm3, with good potential for realization of a frequency-stabilized laser module with few cm3 volume.

  9. Quantum dots: lasers and amplifiers

    CERN Document Server

    Bimberg, D

    2003-01-01

    Continuous wave room-temperature output power of approx 3 W for edge emitters and of 1.2 mW for vertical-cavity surface-emitting lasers is realized for GaAs-based devices using InAs quantum dots (QDs) operating at 1.3 mu m. Characteristic temperatures up to 170 K below 330 K are realized. Simultaneously, differential efficiency exceeds 80% for these devices. Lasers emitting up to 12 W at 1140-1160 nm are useful as pump sources for Tm sup 3 sup + -doped fibres for frequency up-conversion to 470 nm. Both types of lasers show transparency current densities of 6 A cm sup - sup 2 per dot layer, eta sub i sub n sub t = 98% and alpha sub i around 1.5 cm sup - sup 1. Long operation lifetimes (above 3000 h at 50 deg C heatsink temperature at 1.5 W CW) and improved radiation hardness as compared to quantum well (QW) devices are manifested. Cut-off frequencies of about 10 GHz at 1100 nm and 6 GHz at 1300 nm and low alpha factors resulting in reduced filamentation and improved M sup 2 values in single-mode operation are ...

  10. Fundamentals of metasurface lasers based on resonant dark states

    Science.gov (United States)

    Droulias, Sotiris; Jain, Aditya; Koschny, Thomas; Soukoulis, Costas M.

    2017-10-01

    Recently, our group proposed a metamaterial laser design based on explicitly coupled dark resonant states in low-loss dielectrics, which conceptually separates the gain-coupled resonant photonic state responsible for macroscopic stimulated emission from the coupling to specific free-space propagating modes, allowing independent adjustment of the lasing state and its coherent radiation output. Due to this functionality, it is now possible to make lasers that can overcome the trade-off between system dimensions and Q factor, especially for surface emitting lasers with deeply subwavelength thickness. Here, we give a detailed discussion of the key functionality and benefits of this design, such as radiation damping tunability, directionality, subwavelength integration, and simple layer-by-layer fabrication. We examine in detail the fundamental design tradeoffs that establish the principle of operation and must be taken into account and give guidance for realistic implementations.

  11. A CMOS 0.13 mu m, 5-Gb/s laser driver for high energy physics applications

    CERN Document Server

    Mazza, G; Moreira, P; Rivetti, A; Soos, C; Troska, J; Wyllie, K

    2012-01-01

    The GigaBit Laser Driver (GBLD) is a radiation tolerant ASIC designed to drive both edge emitting lasers and VCSELs at data rates up to 5 Gb/s. It is part of the GigaBit Transceiver (GBT) and Versatile Link projects, which are designing a bi-directional optical data transmission system capable of operating in the radiation environment of a typical HEP experiment. The GBLD can provide laser diode modulation currents up to 24 mA and laser bias currents up to 43 mA. Pre- and de-emphasis functions are implemented to compensate for high external capacitive loads and asymmetric laser response. The chip, designed in a 0.13 $\\mu$m CMOS technology, is powered by a single 2.5 V power supply and can be programmed via an $I2C$ interface.

  12. A CMOS 0.13 μm, 5 Gb/s Laser Driver for High Energy Physics Applications

    Science.gov (United States)

    Mazza, Giovanni; Gui, Ping; Moreira, Paulo; Rivetti, Angelo; Soos, Csaba; Troska, Jan; Wyllie, Ken

    2012-12-01

    The GigaBit Laser Driver (GBLD) is a radiation tolerant ASIC designed to drive both edge emitting lasers and VCSELs at data rates up to 5 Gb/s. It is part of the GigaBit Transceiver (GBT) and Versatile Link projects, which are designing a bi-directional optical data transmission system capable of operating in the radiation environment of a typical HEP experiment. The GBLD can provide laser diode modulation currents up to 24 mA and laser bias currents up to 43 mA. Pre- and de-emphasis functions are implemented to compensate for high external capacitive loads and asymmetric laser response. The chip, designed in a 0.13 μm CMOS technology, is powered by a single 2.5 V power supply and can be programmed via an I2C interface.

  13. Comparison of PAM and CAP modulations robustness against mode partition noise in optical links

    Science.gov (United States)

    Stepniak, Grzegorz

    2017-08-01

    Mode partition noise (MPN) of the laser employed at the transmitter can significantly degrade the transmission performance. In the paper, we introduce a simulation model of MPN in vertical cavity surface emitting laser (VCSEL) and simulate transmission of pulse amplitude modulation (PAM) and carrierless amplitude phase (CAP) signals in multimode fiber (MMF) link. By turning off other effects, like relative intensity noise (RIN), we focus solely on the influence of MPN on transmission performance degradation. Robustness of modulation and equalization type against MPN is studied.

  14. Introduction.

    Science.gov (United States)

    Agrawal, G; Ning, C Z; Miguel, M

    1999-08-02

    Several recent developments have resulted in considerable progress in the study of transverse effects and spatial mode dynamics in semiconductor lasers. Demands on higher and higher output powers have led to the development of wide-stripe lasers, coupled laser arrays, integrated master-oscillator power amplifiers (MOPAs), and other more complex laser structures for which spatial dependence of the laser mode becomes important. This is especially true for the vertical-cavity surface-emitting lasers (VCSELs), devices that have recently become commercially available and are being proposed for a multitude of interesting applications. In the case of a VCSEL, the transverse-mode behavior is inherently more complex compared with the traditional edge-emitting lasers because of a large Fresnel number associated with VCSELs. The recent interest in spatio-temporal dynamics of such lasers as an example of well-controlled, spatially extended, self-organizing systems has led to new understanding about patterns, defects, and other coherent and incoherent structures, all being important to large-aperture diode lasers.

  15. Investigating the threshold properties of very small VCSELs through relaxation-resonance-induced amplification

    Science.gov (United States)

    Wang, T.; Puccioni, G. P.; Lippi, G. L.

    2016-04-01

    We experimentally show how the nonlinear amplification properties of a micro-laser operating in the threshold region, sinusoidally modulated near its resonance (relaxation oscillations), can lead to several important advantages. First, suitably adjusting the bias point and the modulation amplitude, it is possible to obtain reliable trains of large amplitude, synchronous, well-resolved, narrow pulses, with injection currents moderate values of the injection current: the extension to nano-laser modulation is discussed. Second, adjusting the modulation amplitude and the working point it is possible to investigate the threshold properties of the laser: the computation of the second-order autocorrelation as a function of modulation amplitude shows a resonance-like phenomenon where the degree of correlation is degraded by the presence of the external action, only for small modulation amplitude, until true coherence sets in. This allows for a determination, with good accuracy, of the onset of E.M. field coherence. Since this resonance is quite sensitive to the modulation frequency, it also allows for a good determination of the optimal frequency at which the pulse trains can be generated. A physical discussion of these properties, in the context of threshold and coherence, is offered.

  16. A 10 Gb/s laser driver in 130 nm CMOS technology for high energy physics applications

    OpenAIRE

    Zhang, T; Tavernier, F; Moreira, P; Gui, P

    2015-01-01

    The GigaBit Laser Driver (GBLD) is a key on-detector component of the GigaBit Transceiver (GBT) system at the transmitter side. As part of the design efforts towards the upgrade of the electrical components of the LHC experiments, a 10 Gb/s GBLD (GBLD10) has been developed in a 130 nm CMOS technology. The GBLD10 is based on the distributed-amplifier (DA) architecture and achieves data rates up to 10 Gb/s. It is capable of driving VCSELs with modulation currents up to 12 mA. Moreover, a pre-em...

  17. High phase noise tolerant pilot-tone-aided DP-QPSK optical communication systems

    DEFF Research Database (Denmark)

    Zhang, Xu; Pang, Xiaodan; Deng, Lei

    2012-01-01

    In this paper we experimentally demonstrate a novel, high phase-noise tolerant, optical dual polarization (DP) quadrature phase-shift keying (QPSK) communication system based on pilot-tone-aided phase noise cancellation (PNC) algorithm. Vertical cavity surface emitting lasers (VCSELs......) with approximate 300 MHz linewidth are used as transmitters and local oscillators for coherent detection of optical DP-QPSK signals. The proposed system, with central wavelength at 1540.68 nm, operates at 40 Gb/s over 80 km single mode fiber (SMF) as part of a passive optical network (PON). The deployment of pilot...

  18. System tests of radiation hard optical links for the ATLAS semiconductor tracker

    International Nuclear Information System (INIS)

    Charlton, D.G.; Dowell, J.D.; Homer, R.J.; Jovanovic, P.; Kenyon, I.R.; Mahout, G.; Shaylor, H.R.; Wilson, J.A.; Rudge, A.; Fopma, J.; Mandic, I.; Nickerson, R.B.; Shield, P.; Wastie, R.; Weidberg, A.R.; Eek, L.-O.; Go, A.; Lund-Jensen, B.; Pearce, M.; Soederqvist, J.; Morrissey, M.; White, D.J.

    2000-01-01

    A prototype optical data and Timing, Trigger and Control transmission system based on LEDs and PIN-diodes has been constructed. The system would be suitable in terms of radiation hardness and radiation length for use in the ATLAS SemiConductor Tracker. Bit error rate measurements were performed for the data links and for the links distributing the Timing, Trigger and Control data from the counting room to the front-end modules. The effects of cross-talk between the emitters and receivers were investigated. The advantages of using Vertical Cavity Surface Emitting Lasers (VCSELs) instead of LEDs are discussed

  19. Radiation-hard/high-speed array-based optical engine

    International Nuclear Information System (INIS)

    Gan, K.K.; Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S.; Buchholz, P.; Heidbrink, S.; Vogt, M.; Ziolkowski, M.

    2016-01-01

    We have designed and fabricated a compact array-based optical engine for transmitting data at 10 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The DAC settings are stored in SEU (single event upset) tolerant registers. Several devices were irradiated with 24 GeV/c protons and the performance of the devices is satisfactory after the irradiation.

  20. InGaAs/GaAs frequency tunable twin-guide quantum-well laser designed for steerable surface emission

    Science.gov (United States)

    Rosenberger, Matthias; Koeck, Anton; Gmachl, Claire F.; Gornik, Erich; Riechert, Henning; Bernklau, D.

    1993-11-01

    Based on a frequency tunable twin-guide (TTG) InGaAs/GaAs multiple quantum well (MQW) laser structure, we developed a novel design concept for a surface emitting laser device enabling spatial beam steering. Utilizing a change in the refractive index of the parallel monolithically integrated modulator diode due to carrier injection, we observe a continuous emission frequency (wavelength) shift up to (Delta) f equals 85 GHz ((Delta) (lambda) equals -0.35 nm). For this preliminary structure the experimental results are consistent with our model calculations. Based on the theoretical model, for an optimized device a tuning range of (Delta) f equals 1600 GHz ((Delta) (lambda) >= 5 nm) is expected. For the novel surface emitting device design, we make use of an additional structure on top of the TTG laser including a second waveguide and a grating. This will enable a wavelength dependent surface emission angle, i.e., continuous beam steering, by coupling the laser and the surface mode. A calculational model was developed to estimate the steering characteristics in dependence on the dielectric device structure including mode guiding and the surface grating shape.

  1. Laser Technology.

    Science.gov (United States)

    Gauger, Robert

    1993-01-01

    Describes lasers and indicates that learning about laser technology and creating laser technology activities are among the teacher enhancement processes needed to strengthen technology education. (JOW)

  2. Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers

    International Nuclear Information System (INIS)

    Deri, R.J.

    2011-01-01

    Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a ∼ 200 (micro)s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and

  3. Progress and prospect of quantum dot lasers

    Science.gov (United States)

    Arakawa, Yasuhiko

    2001-10-01

    Optical properties and growth of self-assembled quantum dots (SAQDs) for optoelectronic device applications are discussed. After briefly reviewing the history of research on QD lasers, we discuss growth of InAs SQDs including the light emission at the wavelength of 1.52)mum with a narrow linewidth (22 meV) and the area-controlled growth which demonstrates formation of SAQDs in selected local areas on a growth plane using a SiO)-2) mask with MOCVD growth. Then properties of the InGaAs AQDs are investigated by the near- field photoluminescence excitation spectroscopy which reveals gradually increasing continuum absorption connected with the two-dimensional-like (2D-like) wetting layer, resulting in faster relaxation of electrons due to a crossover between OD and 2D character in the density of states. Moreover, we have investigated InGaN self-assembled QDs on a GaN layer achieving the average diameter as small as 8.4nm and a strong light at room temperature. A laser structure with the stacked InGAN QDs embedded in the active layer was fabricated and room temperature operation of blue InGaN QD lasers was achieved under optical excitation. Carrier confinement in QDs was examined using near-field $DAL- photoluminescence measurement: A very sharp spectral line emitted from excitons in individual InGaN QDs was observed. Establishing AlGaN/GaN DBR of high quality, we succeeded in lasing action in InGaN blue light emitting VCSELs. Enhancement of spontaneous emission is demonstrated. Finally, perspective of QD lasers.

  4. A 10 Gb/s laser driver in 130 nm CMOS technology for high energy physics applications

    Science.gov (United States)

    Zhang, T.; Tavernier, F.; Moreira, P.; Gui, P.

    2015-02-01

    The GigaBit Laser Driver (GBLD) is a key on-detector component of the GigaBit Transceiver (GBT) system at the transmitter side. As part of the design efforts towards the upgrade of the electrical components of the LHC experiments, a 10 Gb/s GBLD (GBLD10) has been developed in a 130 nm CMOS technology. The GBLD10 is based on the distributed-amplifier (DA) architecture and achieves data rates up to 10 Gb/s. It is capable of driving VCSELs with modulation currents up to 12 mA. Moreover, a pre-emphasis function has been included in the proposed laser driver in order to compensate for the capacitive load and channel losses.

  5. A hybrid CATV/16-QAM-OFDM visible laser light communication system

    International Nuclear Information System (INIS)

    Lin, Chun-Yu; Li, Chung-Yi; Lu, Hai-Han; Chen, Chia-Yi; Jhang, Tai-Wei; Ruan, Sheng-Siang; Wu, Kuan-Hung

    2014-01-01

    A visible laser light communication (VLLC) system employing a vertical cavity surface emitting laser and spatial light modulator with hybrid CATV/16-QAM-OFDM modulating signals over a 5 m free-space link is proposed and demonstrated. With the assistance of a push-pull scheme, low-noise amplifier, and equalizer, good performances of composite second-order and composite triple beat are obtained, accompanied by an acceptable carrier-to-noise ratio performance for a CATV signal, and a low bit error rate value and clear constellation map are achieved for a 16-QAM-OFDM signal. Such a hybrid CATV/16-QAM-OFDM VLLC system would be attractive for providing services including CATV, Internet and telecommunication services. (paper)

  6. The Newest Laser Processing

    International Nuclear Information System (INIS)

    Lee, Baek Yeon

    2007-01-01

    This book mentions laser processing with laser principle, laser history, laser beam property, laser kinds, foundation of laser processing such as laser oscillation, characteristic of laser processing, laser for processing and its characteristic, processing of laser hole including conception of processing of laser hole and each material, and hole processing of metal material, cut of laser, reality of cut, laser welding, laser surface hardening, application case of special processing and safety measurement of laser.

  7. Ultralow-threshold electrically pumped quantum-dot photonic-crystal nanocavity laser

    Science.gov (United States)

    Ellis, Bryan; Mayer, Marie A.; Shambat, Gary; Sarmiento, Tomas; Harris, James; Haller, Eugene E.; Vučković, Jelena

    2011-05-01

    Efficient, low-threshold and compact semiconductor laser sources are under investigation for many applications in high-speed communications, information processing and optical interconnects. The best edge-emitting and vertical-cavity surface-emitting lasers have thresholds on the order of 100 µA (refs 1,2), but dissipate too much power to be practical for many applications, particularly optical interconnects. Optically pumped photonic-crystal nanocavity lasers represent the state of the art in low-threshold lasers; however, to be practical, techniques to electrically pump these structures must be developed. Here, we demonstrate a quantum-dot photonic-crystal nanocavity laser in gallium arsenide pumped by a lateral p-i-n junction formed by ion implantation. Continuous-wave lasing is observed at temperatures up to 150 K. Thresholds of only 181 nA at 50 K and 287 nA at 150 K are observed--the lowest thresholds ever observed in any type of electrically pumped laser.

  8. Multiphoton microscopy in every lab: the promise of ultrafast semiconductor disk lasers

    Science.gov (United States)

    Emaury, Florian; Voigt, Fabian F.; Bethge, Philipp; Waldburger, Dominik; Link, Sandro M.; Carta, Stefano; van der Bourg, Alexander; Helmchen, Fritjof; Keller, Ursula

    2017-07-01

    We use an ultrafast diode-pumped semiconductor disk laser (SDL) to demonstrate several applications in multiphoton microscopy. The ultrafast SDL is based on an optically pumped Vertical External Cavity Surface Emitting Laser (VECSEL) passively mode-locked with a semiconductor saturable absorber mirror (SESAM) and generates 170-fs pulses at a center wavelength of 1027 nm with a repetition rate of 1.63 GHz. We demonstrate the suitability of this laser for structural and functional multiphoton in vivo imaging in both Drosophila larvae and mice for a variety of fluorophores (including mKate2, tdTomato, Texas Red, OGB-1, and R-CaMP1.07) and for endogenous second-harmonic generation in muscle cell sarcomeres. We can demonstrate equivalent signal levels compared to a standard 80-MHz Ti:Sapphire laser when we increase the average power by a factor of 4.5 as predicted by theory. In addition, we compare the bleaching properties of both laser systems in fixed Drosophila larvae and find similar bleaching kinetics despite the large difference in pulse repetition rates. Our results highlight the great potential of ultrafast diode-pumped SDLs for creating a cost-efficient and compact alternative light source compared to standard Ti:Sapphire lasers for multiphoton imaging.

  9. Toward continuous-wave operation of organic semiconductor lasers.

    Science.gov (United States)

    Sandanayaka, Atula S D; Matsushima, Toshinori; Bencheikh, Fatima; Yoshida, Kou; Inoue, Munetomo; Fujihara, Takashi; Goushi, Kenichi; Ribierre, Jean-Charles; Adachi, Chihaya

    2017-04-01

    The demonstration of continuous-wave lasing from organic semiconductor films is highly desirable for practical applications in the areas of spectroscopy, data communication, and sensing, but it still remains a challenging objective. We report low-threshold surface-emitting organic distributed feedback lasers operating in the quasi-continuous-wave regime at 80 MHz as well as under long-pulse photoexcitation of 30 ms. This outstanding performance was achieved using an organic semiconductor thin film with high optical gain, high photoluminescence quantum yield, and no triplet absorption losses at the lasing wavelength combined with a mixed-order distributed feedback grating to achieve a low lasing threshold. A simple encapsulation technique greatly reduced the laser-induced thermal degradation and suppressed the ablation of the gain medium otherwise taking place under intense continuous-wave photoexcitation. Overall, this study provides evidence that the development of a continuous-wave organic semiconductor laser technology is possible via the engineering of the gain medium and the device architecture.

  10. Blue laser diode (LD) and light emitting diode (LED) applications

    International Nuclear Information System (INIS)

    Bergh, Arpad A.

    2004-01-01

    The family of blue LEDs, edge emitting and surface emitting lasers, enable a number of applications. Blue lasers are used in digital applications such as optical storage in high density DVDs. The resolution of the spot size and hence the storage density is diffraction limited and is inversely proportional to the square of the wavelength of the laser. Other applications include printing, optical scanners, and high-resolution photo-lithography. As light emitters, blue LEDs are used for signaling and in direct view large area emissive displays. They are also making inroads into signage and LCD back-lighting, mobile platforms, and decorative accent lighting in curtains, furniture, etc. Blue LEDs produce white light either with phosphor wavelength converters or in combination with red and green LEDs. The full potential of LED light sources will require three devices to enable complete control over color and intensity. Sensing and medical/bio applications have a major impact on home security, on monitoring the environment, and on health care. New emerging diagnostic and therapeutic applications will improve the quality and reduce the cost of health care. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Toward continuous-wave operation of organic semiconductor lasers

    Science.gov (United States)

    Sandanayaka, Atula S. D.; Matsushima, Toshinori; Bencheikh, Fatima; Yoshida, Kou; Inoue, Munetomo; Fujihara, Takashi; Goushi, Kenichi; Ribierre, Jean-Charles; Adachi, Chihaya

    2017-01-01

    The demonstration of continuous-wave lasing from organic semiconductor films is highly desirable for practical applications in the areas of spectroscopy, data communication, and sensing, but it still remains a challenging objective. We report low-threshold surface-emitting organic distributed feedback lasers operating in the quasi–continuous-wave regime at 80 MHz as well as under long-pulse photoexcitation of 30 ms. This outstanding performance was achieved using an organic semiconductor thin film with high optical gain, high photoluminescence quantum yield, and no triplet absorption losses at the lasing wavelength combined with a mixed-order distributed feedback grating to achieve a low lasing threshold. A simple encapsulation technique greatly reduced the laser-induced thermal degradation and suppressed the ablation of the gain medium otherwise taking place under intense continuous-wave photoexcitation. Overall, this study provides evidence that the development of a continuous-wave organic semiconductor laser technology is possible via the engineering of the gain medium and the device architecture. PMID:28508042

  12. Vortex Laser based on III-V semiconductor metasurface: direct generation of coherent Laguerre-Gauss modes carrying controlled orbital angular momentum.

    Science.gov (United States)

    Seghilani, Mohamed S; Myara, Mikhael; Sellahi, Mohamed; Legratiet, Luc; Sagnes, Isabelle; Beaudoin, Grégoire; Lalanne, Philippe; Garnache, Arnaud

    2016-12-05

    The generation of a coherent state, supporting a large photon number, with controlled orbital-angular-momentum L = ħl (of charge l per photon) presents both fundamental and technological challenges: we demonstrate a surface-emitting laser, based on III-V semiconductor technology with an integrated metasurface, generating vortex-like coherent state in the Laguerre-Gauss basis. We use a first order phase perturbation to lift orbital degeneracy of wavefunctions, by introducing a weak anisotropy called here "orbital birefringence", based on a dielectric metasurface. The azimuthal symmetry breakdown and non-linear laser dynamics create "orbital gain dichroism" allowing selecting vortex handedness. This coherent photonic device was characterized and studied, experimentally and theoretically. It exhibits a low divergence (50 dB vortex purity), and single frequency operation in a stable low noise regime (0.1% rms). Such high performance laser opens the path to widespread new photonic applications.

  13. Ultrawide continuously tunable 1.55-μm vertical air-cavity wavelength-selective elements for VCSELs using micromachined electrostatic actuation

    Science.gov (United States)

    Hillmer, Hartmut H.; Daleiden, Juergen; Prott, Cornelia; Roemer, Friedhard; Irmer, Soeren; Ataro, Edwin; Tarraf, Amer; Gutermuth, D.; Kommallein, I.; Strassner, Martin

    2003-08-01

    Surface-micromachined 1.55μm vertical-resonator-based devices, capable of wide, continuous, monotonic and kink-free tuning are designed, technologically implemented and characterized. Tuning is achieved by mechanically actuating one or several membranes in a vertical resonator including two ultra-highly reflective DBR mirrors. The tuning is controlled by a single parameter (actuation voltage). The two different layers composing the mirrors reveal a very strong refractive index contrast. Filters including InP/air-gap DBR's (3.5 periods) using GaInAs sacrificial layers reveal a continuous tuning of up to 9% of the absolute wavelength. Varying a reverse voltage (U=0 .. -3.2V) between the membranes, a tuning range up to 142nm was obtained by electrostatic actuation. The correlation of the wavelength and the applied voltage is accurately reproducible without any hysteresis. Theoretical model calculations are performed for symmetric and asymmetric device structures, varying layer thickness and compositions. Models of highly sophisticated color tuning can be found in nature, e.g. in tunable spectral light filtering by trogon and butterfly wings. Bionics transfers the principles of success of nature into natural science, engineering disciplines and applications (here filters and VCSELs for optical communication on the basis of WDM). Light interferes constructively and destructively with nano- and microstructures of appropriate shape, dimensions and materials, both in the artificial DBR structures fabricated in our labs as well as in the natural ones.

  14. Strain dependence on polarization properties of AlGaN and AlGaN-based ultraviolet lasers grown on AlN substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Zachary, E-mail: zabryan@ncsu.edu; Bryan, Isaac; Sitar, Zlatko; Collazo, Ramón [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Mita, Seiji [HexaTech, Inc., 991 Aviation Pkwy., Suite 800, Morrisville, North Carolina 27560 (United States); Tweedie, James [Adroit Materials, 2054 Kildaire Farm Rd., Suite 205, Cary, North Carolina 27518 (United States)

    2015-06-08

    Since the band ordering in AlGaN has a profound effect on the performance of UVC light emitting diodes (LEDs) and even determines the feasibility of surface emitting lasers, the polarization properties of emitted light from c-oriented AlGaN and AlGaN-based laser structures were studied over the whole composition range, as well as various strain states, quantum confinements, and carrier densities. A quantitative relationship between the theoretical valence band separation, determined using k•p theory, and the experimentally measured degree of polarization is presented. Next to composition, strain was found to have the largest influence on the degree of polarization while all other factors were practically insignificant. The lowest crossover point from the transverse electric to transverse magnetic polarized emission of 245 nm was found for structures pseudomorphically grown on AlN substrates. This finding has significant implications toward the efficiency and feasibility of surface emitting devices below this wavelength.

  15. Laser Therapy

    Science.gov (United States)

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Laser Resurfacing Uses for Laser Resurfacing Learn more ...

  16. Lasers technology

    International Nuclear Information System (INIS)

    2014-01-01

    The Laser Technology Program of IPEN is developed by the Center for Lasers and Applications (CLA) and is committed to the development of new lasers based on the research of new optical materials and new resonator technologies. Laser applications and research occur within several areas such as Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. Additional goals of the Program are human resource development and innovation, in association with Brazilian Universities and commercial partners

  17. Biwavelength transceiver module for parallel simultaneous bidirectional optical interconnections

    Science.gov (United States)

    Nguyen, Nga T. H.; Ukaegbu, Ikechi A.; Sangirov, Jamshid; Cho, Mu-Hee; Lee, Tae-Woo; Park, Hyo-Hoon

    2013-12-01

    The design of a biwavelength transceiver (TRx) module for parallel simultaneous bidirectional optical interconnects is described. The TRx module has been implemented using two different wavelengths, 850 and 1060 nm, to send and receive signals simultaneously through a common optical interface while optimizing cost and performance. Filtering mirrors are formed in the optical fibers which are embedded on a V-grooved silicon substrate for reflecting and filtering optical signals from/to vertical-cavity surface-emitting laser (VCSEL)/photodiode (PD). The VCSEL and PD are flip-chip bonded on individual silicon optical benches, which are attached on the silicon substrate for optical signal coupling from the VCSEL to fiber and from fiber to the PD. A high-speed and low-loss ceramic printed circuit board, which has a compact size of 0.033 cc, has been designed to carry transmitter and receiver chips for easy packaging of the TRx module. Applied for quad small form-factor pluggable applications at 40-Gbps operation, the four-channel biwavelength TRx module showed clear eye diagrams with a bit error rate (BER) of 10-12 at input powers of -5 and -5.8 dBm for 1060 and 850 nm operation modes, respectively.

  18. Radiation-hard/high-speed parallel optical links

    Science.gov (United States)

    Gan, K. K.; Buchholz, P.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Wiese, A.; Ziolkowski, M.

    2014-11-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel VCSEL (Vertical Cavity Surface Emitting Laser) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. The performance of the first prototype ASIC up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Some preliminary results of the design will be presented.

  19. Radiation-hard/high-speed parallel optical links

    International Nuclear Information System (INIS)

    Gan, K.K.; Buchholz, P.; Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S.; Wiese, A.; Ziolkowski, M.

    2014-01-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel VCSEL (Vertical Cavity Surface Emitting Laser) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. The performance of the first prototype ASIC up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Some preliminary results of the design will be presented

  20. Laser Dyes

    Indian Academy of Sciences (India)

    treatments, including port-wine stain and tattoo removal, diag- nostic measurements, lithotripsy, activation of photosensitive drugs for photodynamic therapy, etc. In the field of medical applications, dye lasers have potential advantages over other lasers. Dye lasers are unique sources of tunable coherent radiation, from the ...

  1. HF laser

    International Nuclear Information System (INIS)

    Suzuki, Kazuya; Iwasaki, Matae

    1977-01-01

    A review is made of the research and development of HF chemical laser and its related work. Many gaseous compounds are used as laser media successfully; reaction kinetics and technological problems are described. The hybrid chemical laser of HF-CO 2 system and the topics related to the isotope separation are also included. (auth.)

  2. Mirrorless lasers

    Indian Academy of Sciences (India)

    wavelength of operation thereby tuning the laser. Another way of ... of operation. Considering the crucial role of mirrors in a laser, the phrase 'mirrorless lasers' seems to be a paradoxical one. However, in what follows, we will see how one can indeed ..... A possible military application is to have a small area in a person's.

  3. Lasers (Rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1969-01-01

    A laser is an instrument that produces an enormously intense pencil-thin beam of light. In this booklet we shall learn what there is about the laser that gives it so much promise. We shall investigate what it is, how it works, and the different kinds of lasers there are.

  4. Microchip Lasers

    Science.gov (United States)

    2016-10-31

    USA E-mail: zayhowski@ll.mit.edu Abstract Microchip lasers are a rich family of solid-state lasers defined by their small size, robust integration...reliability, and potential for low-cost mass production. Continuous-wave microchip lasers cover a wide range of wavelengths, often operate single

  5. Infrared laser spectroscopic trace gas sensing

    Science.gov (United States)

    Sigrist, Markus

    2016-04-01

    Chemical sensing and analyses of gas samples by laser spectroscopic methods are attractive owing to several advantages such as high sensitivity and specificity, large dynamic range, multi-component capability, and lack of pretreatment or preconcentration procedures. The preferred wavelength range comprises the fundamental molecular absorption range in the mid-infared between 3 and 15 μm, whereas the near-infrared range covers the (10-100 times weaker) higher harmonics and combination bands. The availability of near-infrared and, particularly, of broadly tunable mid-infrared sources like external cavity quantum cascade lasers (EC-QCLs), interband cascade lasers (ICLs), difference frequency generation (DFG), optical parametric oscillators (OPOs), recent developments of diode-pumped lead salt semiconductor lasers, of supercontinuum sources or of frequency combs have eased the implementation of laser-based sensing devices. Sensitive techniques for molecular absorption measurements include multipass absorption, various configurations of cavity-enhanced techniques such as cavity ringdown (CRD), or of photoacoustic spectroscopy (PAS) including quartz-enhanced (QEPAS) or cantilever-enhanced (CEPAS) techniques. The application requirements finally determine the optimum selection of laser source and detection scheme. In this tutorial talk I shall discuss the basic principles, present various experimental setups and illustrate the performance of selected systems for chemical sensing of selected key atmospheric species. Applications include an early example of continuous vehicle emission measurements with a mobile CO2-laser PAS system [1]. The fast analysis of C1-C4 alkanes at sub-ppm concentrations in gas mixtures is of great interest for the petrochemical industry and was recently achieved with a new type of mid-infrared diode-pumped piezoelectrically tuned lead salt vertical external cavity surface emitting laser (VECSEL) [2]. Another example concerns measurements on short

  6. Mid infrared resonant cavity detectors and lasers with epitaxial lead-chalcogenides

    Science.gov (United States)

    Zogg, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Quack, N.

    2010-09-01

    Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and gas spectroscopy. One way to realize such tunable devices is by using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range. Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolour IR-FPA or "IR-AFPA", adaptive focal plane arrays. We report the first room temperature mid-IR VECSEL (vertical external cavity surface emitting laser) with a wavelength above 3 μm. The active region is just 850 nm PbSe, followed by a 2.5 pair Bragg mirror. Output power is > 10 mW at RT.

  7. Laser photocoagulation - eye

    Science.gov (United States)

    Laser coagulation; Laser eye surgery; Photocoagulation; Laser photocoagulation - diabetic eye disease; Laser photocoagulation - diabetic retinopathy; Focal photocoagulation; Scatter (or pan retinal) photocoagulation; Proliferative ...

  8. Advanced high-bandwidth optical fuzing technology

    Science.gov (United States)

    Liu, Jony J.; von der Lippe, Christian M.

    2005-10-01

    A robust and compact photonic proximity sensor is developed for optical fuze in munitions applications. The design of the optical fuze employed advanced optoelectronic technologies including high-power vertical-cavity surface-emitting lasers (VCSELs), the p-i-n or metal-semiconductor-metal (MSM) photodetectors, SiGe ASIC driver, and miniature optics. The development combines pioneering work and unique expertise at ARDEC, ARL, and Sandia National Laboratories and synergizes the key optoelectronic technologies in components and system designs. This compact sensor will replace conventional costly assemblies based on discrete lasers, photodetectors, and bulky optics and provide a new capability for direct fire applications. It will be mass manufacturable in low cost and simplicity. In addition to the specific applications for gun-fired munitions, numerous civilian uses can be realized by this proximity sensor in automotive, robotics, and aerospace applications. This technology is also applicable to robotic ladar and short-range 3-D imaging.

  9. High-frequency dynamics of spin-polarized carriers and photons in a laser

    Science.gov (United States)

    Saha, D.; Basu, D.; Bhattacharya, P.

    2010-11-01

    The high-frequency dynamics of spin-polarized carriers and photons in a spin laser have been studied. The transient response of the device obtained from the rate equations is characterized by two sets of relaxation oscillations in the carrier and photon distributions corresponding to the two polarization modes. Consequently two distinct resonant peaks are observed in the small-signal modulation response. The calculated transient characteristics indicate that the best results are obtained from a spin laser when only the favored polarization mode, with lower threshold, is operational. Under this condition the small-signal modulation bandwidth is higher than that in a conventional laser, the threshold current is lower and the output polarization can be 100% with appropriate bias conditions, independent of the spin polarization of carriers in the active region. Measurements were made at 230 K on a InAs/GaAs quantum dot spin vertical cavity surface emitting laser. A time-averaged output polarization of 55% is measured with an active region spin polarization of 5-6% . The experimental results are in good agreement with calculated data.

  10. [Pigmentary lasers].

    Science.gov (United States)

    Passeron, Thierry; Toubel, Gérard

    2009-10-01

    The pigmentary disorders are a very heterogeneous group with a high therapeutic demand from the patients. The lasers have provided a major advance in the treatment of some pigmentary lesions. The indication and the optimal parameters are actually quite well defined. However, pigmentary lasers have limits and some dermatosis can even be worsened after laser treatment. Those limitations as well as the potential side effects have to clearly be explained to the patients that often seek for a miracle cure.

  11. Laser accelerator

    OpenAIRE

    Vigil, Ricardo

    2014-01-01

    Approved for public release; distribution is unlimited In 1979,W. B. Colson and S. K. Ride proposed a new kind of electron accelerator using a uniform magnetic field in combination with a circularly-polarized laser field. A key concept is to couple the oscillating electric field to the electron’s motion so that acceleration is sustained. This dissertation investigates the performance of the proposed laser accelerator using modern high powered lasers and mag-netic fields that are significan...

  12. Laser fusion

    International Nuclear Information System (INIS)

    Eliezer, S.

    1982-02-01

    In this paper, the physics of laser fusion is described on an elementary level. The irradiated matter consists of a dense inner core surrounded by a less dense plasma corona. The laser radiation is mainly absorbed in the outer periphery of the plasma. The absorbed energy is transported inward to the ablation surface where plasma flow is created. Due to this plasma flow, a sequence of inward going shock waves and heat waves are created, resulting in the compression and heating of the core to high density and temperature. The interaction physics between laser and matter leading to thermonuclear burn is summarized by the following sequence of events: Laser absorption → Energy transport → Compression → Nuclear Fusion. This scenario is shown in particular for a Nd:laser with a wavelength of 1 μm. The wavelength scaling of the physical processes is also discussed. In addition to the laser-plasma physics, the Nd high power pulsed laser is described. We give a very brief description of the oscillator, the amplifiers, the spatial filters, the isolators and the diagnostics involved. Last, but not least, the concept of reactors for laser fusion and the necessary laser system are discussed. (author)

  13. Biocavity Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Gourley, P.L.; Gourley, M.F.

    2000-10-05

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  14. High power lasers & systems

    OpenAIRE

    Chatwin, Chris; Young, Rupert; Birch, Philip

    2015-01-01

    Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

  15. Characterization of energy-efficient and colorless ONUs for future TWDM-PONs.

    Science.gov (United States)

    Wong, Elaine; Mueller, Michael; Amann, Markus C

    2013-09-09

    The Full Services Access Network group has recently selected the time and wavelength division multiplexed passive optical network (TWDM-PON) as the base technology solution for next-generation PON stage-2 (NG-PON2). Meeting the core requirements of NG-PON2 necessitates the following additional features in the transceivers of the optical network unit (ONU) that is located at subscriber premises: (a) legacy system compliant; (b) wavelength tunable; (c) cost-efficient; and (d) energy-efficient. To address these features, we investigate the properties of short-cavity vertical-cavity surface-emitting lasers (SC-VCSELs) for implementation as colorless ONU transmitters in future TWDM-PONs. Specifically, we investigate the tunability and transmission performance of the SC-VCSEL across the C-minus wavelength band for legacy system compliance. We report on error-free transmission across a 800 GHz tuning range with a potential aggregate upstream capacity of 80 Gbps over a system reach of 40 km and with a split ratio of 1:128 per wavelength channel. Results were achieved without dispersion compensation and electronic equalization. We also evaluate the energy efficiency of the SC-VCSEL in active, doze, and sleep mode. When in active mode, the SC-VCSEL transmitter block consumes 91.7% less power than a distributed feedback (DFB) laser transmitter block. When transitioning between doze and active modes, the transmitter block has a short settling time of only 205 ns, thus increasing the power-saving duration and consequently reducing the overall power consumption of the ONU. Through numerical analysis, evaluation of the energy-savings of the SC-VCSEL ONU over the DFB ONU under various modes of operation, demonstrates up to 84% of energy-savings. The capacity, tuning range, split ratio, system reach, and energy-savings arising from SC-VCSEL ONU implementation as reported in this work, exceed the minimum requirements of NG-PON2 for future TWDM-PON deployments.

  16. Mirrorless lasers

    Indian Academy of Sciences (India)

    conventional laser, the random laser had one partially reflecting mirror for providing an output port, and a surface or volume scatterer at the other end to provide non-resonant feedback. The volume scatterer was a suspension of chalk particles (about 20 microns di- ameter), in water and surface scatterer was a plate with a ...

  17. excimer laser

    Indian Academy of Sciences (India)

    2014-01-07

    Jan 7, 2014 ... is necessary to deposit one order higher input electric power into gas medium than those required for XeCl and KrF lasers. ... neon/helium at a pressure of a few bars was excited by transverse electric discharge. The. Figure 6. Laser pulse ... and also to drive discharge rapidly. The discharge chamber was ...

  18. Laser yellowing

    Indian Academy of Sciences (India)

    environmental degradation of surfaces. Pulsed lasers are generally used for ... sorb contamination very strongly while the underlying substrate is left untouched thus rendering the process self-limiting. ... contaminated with two different encrustations, using short free running Nd:YAG and long Q-switched Nd:YAG laser ...

  19. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  20. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  1. Photonics technology development for optical fuzing

    Science.gov (United States)

    Geib, K. M.; Serkland, D. K.; Keeler, G. A.; Peake, G. M.; Mar, A.; von der Lippe, C. M.; Liu, J. J.

    2005-09-01

    This paper describes the photonic component development taking place at Sandia National Laboratories, ARDEC and the Army Research Laboratory in support of an effort to develop a robust, compact, and affordable photonic proximity sensor for munitions fuzing applications. Successful implementation of this sensor will provide a new capability for direct fire applications. The technologies under investigation for the optical fuze design covered in this paper are vertical-cavity surface-emitting lasers (VCSELs), vertical-external-cavity surface-emitting lasers (VECSELs), integrated resonant-cavity photodetectors (RCPDs), and refractive micro-optics. The culmination of this work will be low cost, robust, fully integrated, g-hardened components suitable for proximity fuzing applications. The use of advanced photonic components will enable replacement of costly assemblies that employ discrete lasers, photodetectors, and bulk optics. The integrated devices will be mass produced and impart huge savings for a variety of Army applications. The specific application under investigation is for gun-fired munitions. Nevertheless, numerous civilian uses exist for this proximity sensor in automotive, robotics and aerospace applications. This technology is also applicable to robotic ladar and short-range 3-D imaging.

  2. Laser Refractography

    CERN Document Server

    Rinkevichyus, B.S; Raskovskaya, I.L

    2010-01-01

    This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

  3. Laser Dentistry

    Science.gov (United States)

    ... a Better Job? Start by Visiting the Dentist Pacifiers Have Negative and Positive Effects Temporomandibular Joint Disorder ... speed up tooth whitening procedures. What are the benefits of using dental lasers? There are several advantages. ...

  4. Laser accelerators

    International Nuclear Information System (INIS)

    Willis, W.J.

    1977-01-01

    A brief discussion is given on the feasibility of using lasers to accelerate particle beams. A rough theory of operation is developed, and numerical results are obtained for an example equivalent to the Fermilab Accelerator

  5. Laser endoscopy.

    Science.gov (United States)

    McElvein, R B

    1981-11-01

    A carbon dioxide laser operating in the invisible infrared range (10.6 mu) generates a beam of energy that is almost completely absorbed by biological tissue with release of intense heat and rapid destruction. A laser attached to a rigid bronchoscope has been used in 18 patients ranging in age from 21 to 62 years to treat a variety of causes of airway obstruction. These include tracheal stenosis and granulation tissue (6 patients), adenoma (1), web (2), and carcinoma (9). The results were good in 15 and poor in 3 patients. However, all patients had an improved airway after laser treatment with the best results occurring in patients with benign, inflammatory disease. The advantages of the laser are a lack of bleeding, minimal edema after treatment, and minimal scar formation. The disadvantages are the expense of the machine, and the need for general anesthesia and direct visualization of the lesion.

  6. Il laser

    CERN Document Server

    Smith, William V

    1974-01-01

    Verso il 1960, il laser era ancora "una soluzione alla ricerca di un problema", ma fin dagli anni immediatamente successivi si è rivelato uno strumento insostituibile per le applicazioni più svariate.

  7. Laser bronchoscopy.

    Science.gov (United States)

    Duhamel, D R; Harrell, J H

    2001-11-01

    Because the lung cancer epidemic shows no signs of abating, little doubt exists that the need for interventional bronchoscopists will persist for many years to come. The Nd:YAG laser and the rigid bronchoscope remain crucial weapons in the fight against lung cancer. With more than 4000 published interventions pertaining to it, this combination is ideal for treating central airways obstruction. The safety and efficacy of laser bronchoscopy has been well established, and the reported incidence of complications is impressively low. If complications were to arise, a skilled bronchoscopist can manage them easily by using the beneficial attributes of the rigid bronchoscope. Many complications can be avoided by implementing the established safety procedures and techniques. A solid understanding of laser physics and tissue interactions is a necessity to anyone performing laser surgery. The team approach, relying on communication among the bronchoscopist, anesthesiologist, laser technician, and nurses, leads to a safer and more successful procedure. It is important to remember, however, that this is typically a palliative procedure, and therefore the focus should be on alleviating symptoms and improving quality of life. Unfortunately, because not every patient is a candidate for laser bronchoscopy, there are specific characteristics of endobronchial lesions that make them more or less amenable to resection. Each year a promising new technology is being developed, such as argon plasma coagulation, cryotherapy, and endobronchial electrosurgery. Although it is unclear what role these technologies will have, prospective controlled studies must be done to help clarify this question. The future may lay in combining these various technologies along with Nd:YAG laser bronchoscopy to maximize the therapeutic, palliative, and possibly even curative effect. As the experience of the medical community with Nd:YAG laser bronchoscopy continues to grow and as more health-care professionals

  8. Green lasers

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin

    2010-01-01

    Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range......Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range...

  9. Chinese marketplace of lasers and laser materials

    Science.gov (United States)

    Zhu, Huanan

    1992-05-01

    Today I want to introduce the subject of laser materials in China. I will discuss the general background of lasers and laser materials in China. Second, I want to show you some recent rapid development of lasers and laser materials in China. Third, I want to give you an overview of key R&D centers and manufacturers of lasers and laser materials. Fourth, I want to analyze some important export trends from China. Finally, I want to say something about the active international cooperation in the field of lasers and laser materials.

  10. High Dimensional Modulation and MIMO Techniques for Access Networks

    DEFF Research Database (Denmark)

    Binti Othman, Maisara

    Exploration of advanced modulation formats and multiplexing techniques for next generation optical access networks are of interest as promising solutions for delivering multiple services to end-users. This thesis addresses this from two different angles: high dimensionality carrierless...... the capacity per wavelength of the femto-cell network. Bit rate up to 1.59 Gbps with fiber-wireless transmission over 1 m air distance is demonstrated. The results presented in this thesis demonstrate the feasibility of high dimensionality CAP in increasing the number of dimensions and their potentially......) optical access network. 2 X 2 MIMO RoF employing orthogonal frequency division multiplexing (OFDM) with 5.6 GHz RoF signaling over all-vertical cavity surface emitting lasers (VCSEL) WDM passive optical networks (PONs). We have employed polarization division multiplexing (PDM) to further increase...

  11. Optical data transmission ASICs for the high-luminosity LHC (HL-LHC) experiments

    International Nuclear Information System (INIS)

    Li, X; Huang, G; Sun, X; Liu, G; Deng, B; Gong, D; Guo, D; Liu, C; Liu, T; Xiang, A C; Ye, J; Zhao, X; Chen, J; You, Y; He, M; Hou, S; Teng, P-K; Jin, G; Liang, H; Liang, F

    2014-01-01

    We present the design and test results of two optical data transmission ASICs for the High-Luminosity LHC (HL-LHC) experiments. These ASICs include a two-channel serializer (LOCs2) and a single-channel Vertical Cavity Surface Emitting Laser (VCSEL) driver (LOCld1V2). Both ASICs are fabricated in a commercial 0.25-μm Silicon-on-Sapphire (SoS) CMOS technology and operate at a data rate up to 8 Gbps per channel. The power consumption of LOCs2 and LOCld1V2 are 1.25 W and 0.27 W at 8-Gbps data rate, respectively. LOCld1V2 has been verified meeting the radiation-tolerance requirements for HL-LHC experiments

  12. Laser material processing

    CERN Document Server

    Steen, William

    2010-01-01

    This text moves from the basics of laser physics to detailed treatments of all major materials processing techniques for which lasers are now essential. New chapters cover laser physics, drilling, micro- and nanomanufacturing and biomedical laser processing.

  13. Laser-Vorrichtung

    OpenAIRE

    Klein, J.

    1992-01-01

    The laser device has a laser oscillator and a downstream laser amplifier which has an entry zone for the laser beam, which comes from the laser oscillator before it is amplified, and an exit for the amplified laser beam. The laser amplifier also has a convolutional mirror which is opposite the entry zone for the laser beam to be amplified. The laser device is designed so that the amplifying medium in the laser amplifier can be optimally utilized if the laser device has a compact design. To th...

  14. Sleep/doze controlled dynamic bandwidth allocation algorithms for energy-efficient passive optical networks.

    Science.gov (United States)

    Dias, Maluge Pubuduni Imali; Wong, Elaine

    2013-04-22

    In this work, we present a comparative study of two just-in-time (JIT) dynamic bandwidth allocation algorithms (DBAs), designed to improve the energy-efficiency of the 10 Gbps Ethernet passive optical networks (10G-EPONs). The algorithms, termed just-in-time with varying polling cycle times (JIT) and just-in-time with fixed polling cycle times (J-FIT), are designed to achieve energy-savings when the idle time of an optical network unit (ONU) is less than the sleep-to-active transition time. This is made possible by a vertical-cavity surface-emitting laser (VCSEL) ONU that can transit into sleep or doze modes during its idle time. We evaluate the performance of the algorithms in terms of polling cycle time, power consumption, percentage of energy-savings, and average delay. The energy-efficiency of a VCSEL ONU that can transition into sleep or doze mode is compared to an always-ON distributed feedback (DFB) laser ONU. Simulation results indicate that both JIT and J-FIT DBA algorithms result in improved energy-efficiency whilst J-FIT performs better in terms of energy-savings at low network loads. The J-FIT DBA however, results in increased average delay in comparison to the JIT DBA. Nonetheless, this increase in average delay is within the acceptable range to support the quality of service (QoS) requirements of the next-generation access networks.

  15. Laser Heterodyning

    CERN Document Server

    Protopopov, Vladimir V

    2009-01-01

    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  16. Low-power approaches for parallel, free-space photonic interconnects

    Energy Technology Data Exchange (ETDEWEB)

    Carson, R.F.; Lovejoy, M.L.; Lear, K.L.; WSarren, M.E.; Seigal, P.K.; Craft, D.C.; Kilcoyne, S.P.; Patrizi, G.A.; Blum, O.

    1995-12-31

    Future advances in the application of photonic interconnects will involve the insertion of parallel-channel links into Multi-Chip Modules (MCMS) and board-level parallel connections. Such applications will drive photonic link components into more compact forms that consume far less power than traditional telecommunication data links. These will make use of new device-level technologies such as vertical cavity surface-emitting lasers and special low-power parallel photoreceiver circuits. Depending on the application, these device technologies will often be monolithically integrated to reduce the amount of board or module real estate required by the photonics. Highly parallel MCM and board-level applications will also require simplified drive circuitry, lower cost, and higher reliability than has been demonstrated in photonic and optoelectronic technologies. An example is found in two-dimensional point-to-point array interconnects for MCM stacking. These interconnects are based on high-efficiency Vertical Cavity Surface Emitting Lasers (VCSELs), Heterojunction Bipolar Transistor (HBT) photoreceivers, integrated micro-optics, and MCM-compatible packaging techniques. Individual channels have been demonstrated at 100 Mb/s, operating with a direct 3.3V CMOS electronic interface while using 45 mW of electrical power. These results demonstrate how optoelectronic device technologies can be optimized for low-power parallel link applications.

  17. Laser Dyes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 9. Laser Dyes. G S Shankarling K J Jarag. General Article Volume 15 Issue 9 September ... Author Affiliations. G S Shankarling1 K J Jarag1. Dyestuff Technology, Department Institute of Chemical Technology, Matunga Mumbai 400 019, India.

  18. Laser heterodyning

    National Research Council Canada - National Science Library

    Protopopov, V. V

    2009-01-01

    ..., radiometry, laser radars and lidars, microscopy and other areas. Therefore, it is remarkable that such a widely used optical phenomenon has never before been comprehensively reviewed in a single work, as has been done many times for other subjects such as interferometry. I think there are several possible reasons for this. Perhap...

  19. Laser yellowing

    Indian Academy of Sciences (India)

    Author Affiliations. M B Sai Prasad1 Salvatore Siano2. Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India; CNR-IFAC, Polo Scientifico di Sesto Fiorentino, Via Madonna del Piano, 10, Sesto Fiorentino (FI)-50019, Italy ...

  20. Laser device

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention provides a light source for light circuits on a silicon platform. A vertical laser cavity is formed by a gain region arranged between a first mirror structure and a second mirror structure, both acting as mirrors, by forming a grating region including an active material...

  1. Mirrorless lasers

    Indian Academy of Sciences (India)

    Abstract. Experimental realization of mirrorless lasers in the last decade have resulted in hectic activity in this field, due to their novelty, simplicity and ruggedness and their great potential for application. In this article, I will review the various developments in this field in roughly chronological order, and discuss some possible ...

  2. Nanowire Lasers

    Directory of Open Access Journals (Sweden)

    Couteau C.

    2015-05-01

    Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  3. Excimer Laser Technology

    CERN Document Server

    Basting, Dirk

    2005-01-01

    This comprehensive survey on Excimer Lasers investigates the current range of the technology, applications and devices of this commonly used laser source, as well as the future of new technologies, such as F2 laser technology. Additional chapters on optics, devices and laser systems complete this compact handbook. A must read for laser technology students, process application researchers, engineers or anyone interested in excimer laser technology. An effective and understandable introduction to the current and future status of excimer laser technology.

  4. Bio-optimized energy transfer in densely packed fluorescent protein enables near-maximal luminescence and solid-state lasers.

    Science.gov (United States)

    Gather, Malte C; Yun, Seok Hyun

    2014-12-08

    Bioluminescent organisms are likely to have an evolutionary drive towards high radiance. As such, bio-optimized materials derived from them hold great promise for photonic applications. Here, we show that biologically produced fluorescent proteins retain their high brightness even at the maximum density in solid state through a special molecular structure that provides optimal balance between high protein concentration and low resonance energy transfer self-quenching. Dried films of green fluorescent protein show low fluorescence quenching (-7 dB) and support strong optical amplification (gnet=22 cm(-1); 96 dB cm(-1)). Using these properties, we demonstrate vertical cavity surface emitting micro-lasers with low threshold (lasers) and self-assembled all-protein ring lasers. Moreover, solid-state blends of different proteins support efficient Förster resonance energy transfer, with sensitivity to intermolecular distance thus allowing all-optical sensing. The design of fluorescent proteins may be exploited for bio-inspired solid-state luminescent molecules or nanoparticles.

  5. High-speed 1550 nm VCSEL data transmission link employing 25 Gbaud 4-PAM modulation and Hard Decision Forward Error Correction

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Mueller, M.; Li, Bomin

    2013-01-01

    Current short-range optical interconnects capacity is moving from 100 Gb/s to 400 Gb/s and beyond. Directly modulation of several laser sources is used to minimize bandwidth limitations of current optical and electrical components. Either this total capacity is provided by wavelengthdivision- mul...

  6. Laser Accelerator

    Science.gov (United States)

    2014-09-01

    Photocathode emitters eject electrons from the cathode by the photoelectric effect. A drive laser source shines light energy onto a metal or...synchronized so that the electrons ejected via the photoelectric effect are properly accelerated. 15 Figure 2.4: Cross-section of a triple spoke cavity, from...2.3: Available Pulsed Magnets at PFF LANL. SP = Short Pulse. MP = Mid-Pulse, after [19] Cell No. Magnet Pulse Duration (ms) Bore (mm) 1 50 T SP 25 24

  7. Project LASER

    Science.gov (United States)

    1990-01-01

    NASA formally launched Project LASER (Learning About Science, Engineering and Research) in March 1990, a program designed to help teachers improve science and mathematics education and to provide 'hands on' experiences. It featured the first LASER Mobile Teacher Resource Center (MTRC), is designed to reach educators all over the nation. NASA hopes to operate several MTRCs with funds provided by private industry. The mobile unit is a 22-ton tractor-trailer stocked with NASA educational publications and outfitted with six work stations. Each work station, which can accommodate two teachers at a time, has a computer providing access to NASA Spacelink. Each also has video recorders and photocopy/photographic equipment for the teacher's use. MTRC is only one of the five major elements within LASER. The others are: a Space Technology Course, to promote integration of space science studies with traditional courses; the Volunteer Databank, in which NASA employees are encouraged to volunteer as tutors, instructors, etc; Mobile Discovery Laboratories that will carry simple laboratory equipment and computers to provide hands-on activities for students and demonstrations of classroom activities for teachers; and the Public Library Science Program which will present library based science and math programs.

  8. Novel Electro-Optical Coupling Technique for Magnetic Resonance-Compatible Positron Emission Tomography Detectors

    Directory of Open Access Journals (Sweden)

    Peter D. Olcott

    2009-03-01

    Full Text Available A new magnetic resonance imaging (MRI-compatible positron emission tomography (PET detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.

  9. Novel electro-optical coupling technique for magnetic resonance-compatible positron emission tomography detectors.

    Science.gov (United States)

    Olcott, Peter D; Peng, Hao; Levin, Craig S

    2009-01-01

    A new magnetic resonance imaging (MRI)-compatible positron emission tomography (PET) detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL) diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.

  10. Investigation and experimental validation of the contribution of optical interconnects in the SYMPHONIE massively parallel computer

    International Nuclear Information System (INIS)

    Scheer, Patrick

    1998-01-01

    Progress in microelectronics lead to electronic circuits which are increasingly integrated, with an operating frequency and an inputs/outputs count larger than the ones supported by printed circuit board and back-plane technologies. As a result, distributed systems with several boards cannot fully exploit the performance of integrated circuits. In synchronous parallel computers, the situation is worsen since the overall system performances rely on the efficiency of electrical interconnects between the integrated circuits which include the processing elements (PE). The study of a real parallel computer named SYMPHONIE shows for instance that the system operating frequency is far smaller than the capabilities of the microelectronics technology used for the PE implementation. Optical interconnections may cancel these limitations by providing more efficient connections between the PE. Especially, free-space optical interconnections based on vertical-cavity surface-emitting lasers (VCSEL), micro-lens and PIN photodiodes are compatible with the required features of the PE communications. Zero bias modulation of VCSEL with CMOS-compatible digital signals is studied and experimentally demonstrated. A model of the propagation of truncated gaussian beams through micro-lenses is developed. It is then used to optimise the geometry of the detection areas. A dedicated mechanical system is also proposed and implemented for integrating free-space optical interconnects in a standard electronic environment, representative of the one of parallel computer systems. A specially designed demonstrator provides the experimental validation of the above physical concepts. (author) [fr

  11. Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

    CERN Document Server

    Ziolkowski, M; Buchholz, P; Ciliox, A; Gan, K K; Holder, M; Johnson, M; Kagan, H; Kass, R; Nderitu, S; Rahimi, A; Rush, C J; Smith, S; Ter-Antonian, R; Zoeller, M M

    2004-01-01

    We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the CERN Large Hadron Collider (LHC). The first circuit is a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode to be used for 80 Mbit/s data transmission from the detector. The second circuit is a Bi-Phase Mark, decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode on the detector side. During ten years of operation at the LHC, the ATLAS optical link circuitry will be exposed to a maximum total fluence of 10/sup 15/ 1-MeV-equivalent neutrons per cm/sup 2/. We have successfully implemented both ASICs in a commercial 0.25 mu m CMOS technology using standard layout techniques to enhance the radiation tolerance. Both chips are four- channel devices compatible with common cathode PIN and VCSEL arrays. We present results from final prototype circuits and from irradiation studies of both circuits with 24 GeV protons up to a total dose of 57 Mrad. (3 refs).

  12. Fabrication of high performance microlenses for an integrated capillary channel electrochromatograph with fluorescence detection

    International Nuclear Information System (INIS)

    Wendt, J. R.; Warren, M. E.; Sweatt, W. C.; Bailey, C. G.; Matzke, C. M.; Arnold, D. W.; Allerman, A. A.; Carter, T. R.; Asbill, R. E.; Samora, S.

    1999-01-01

    We describe the microfabrication of an extremely compact optical system as a key element in an integrated capillary channel electrochromatograph with fluorescence detection. The optical system consists of a vertical cavity surface-emitting laser (VCSEL), two high performance microlenses, and a commercial photodetector. The microlenses are multilevel diffractive optics patterned by electron beam lithography and etched by reactive ion etching in fused silica. The design uses substrate-mode propagation within the fused silica substrate. Two generations of optical subsystems are described. The first generation design has a 6 mm optical length and is integrated directly onto the capillary channel-containing substrate. The second generation design separates the optical system onto its own substrate module and the optical path length is further compressed to 3.5 mm. The first generation design has been tested using direct fluorescence detection with a 750 nm VCSEL pumping a 10 -4 M solution of CY-7 dye. The observed signal-to-noise ratio of better than 100:1 demonstrates that the background signal from scattered pump light is low despite the compact size of the optical system and is adequate for system sensitivity requirements. (c) 1999 American Vacuum Society

  13. Modelling optical fibers acquisition and transmission systems for their use in nuclear environments

    International Nuclear Information System (INIS)

    Van-Uffelen, Marco

    2001-01-01

    In order to introduce connections based on optical fibres in the field of civil nuclear activities, it is important to have a good knowledge of their behaviour under irradiation. The objective of this research thesis is thus to develop a tool to predict the lifetime of such an optical connection which would allow a predictive maintenance. The adopted methodology relies on a modular approach and consists in the characterization of the behaviour of individual components under test conditions which are representative of addressed applications. Transfer functions are then chained to obtain the connection predictive model. Various components have been studied: mono- and multi-mode optical fibres, light-emitting diodes, vertical-cavity surface-emitting laser diodes (VCSEL), as well as Si and InGaAs sensors. These components have been submitted to a range of dose rates and cumulated dose under temperatures reaching 85 C. Based on on-line measurements, a pragmatic approach has been assessed to predict the evolution of optical losses induced in optical fibres during several months. The difference between measurements and predictions ranges between 10 and 20 per cent depending on the fibre type and on the wavelength. VCSELs display a high tolerance to gamma radiation and a steady operation at high temperatures, whereas sensors appear to be the weakest link [fr

  14. Laser power supply

    International Nuclear Information System (INIS)

    Bernstein, D.

    1975-01-01

    The laser power supply includes a regulator which has a high voltage control loop based on a linear approximation of a laser tube negative resistance characteristic. The regulator has independent control loops for laser current and power supply high voltage

  15. Laser therapy for cancer

    Science.gov (United States)

    ... Yag lasers. These lasers are used to treat cancer of the uterus, colon, and esophagus. The laser-emitting fibers are put inside a tumor to heat up and damage the cancer cells. This treatment has been used to shrink ...

  16. Laser fusion: an overview

    International Nuclear Information System (INIS)

    Boyer, K.

    1975-01-01

    The laser fusion concept is described along with developments in neodymium and carbon dioxide lasers. Fuel design and fabrication are reviewed. Some spin-offs of the laser fusion program are discussed. (U.S.)

  17. Laser therapy (image)

    Science.gov (United States)

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  18. Laser Research Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Laser Research lab is thecenter for the development of new laser sources, nonlinear optical materials, frequency conversion processes and laser-based sensors for...

  19. Laser safety at high profile laser facilities

    International Nuclear Information System (INIS)

    Barat, K.

    2010-01-01

    Complete text of publication follows. Laser safety has been an active concern of laser users since the invention of the laser. Formal standards were developed in the early 1970's and still continue to be developed and refined. The goal of these standards is to give users guidance on the use of laser and consistent safety guidance and requirements for laser manufacturers. Laser safety in the typical research setting (government laboratory or university) is the greatest challenge to the laser user and laser safety officer. This is due to two factors. First, the very nature of research can put the user at risk; consider active manipulation of laser optics and beam paths, and user work with energized systems. Second, a laser safety culture that seems to accept laser injuries as part of the graduate student educational process. The fact is, laser safety at research settings, laboratories and universities still has long way to go. Major laser facilities have taken a more rigid and serious view of laser safety, its controls and procedures. Part of the rationale for this is that these facilities draw users from all around the world presenting the facility with a work force of users coming from a wide mix of laser safety cultures. Another factor is funding sources do not like bad publicity which can come from laser accidents and a poor safety record. The fact is that injuries, equipment damage and lost staff time slow down progress. Hence high profile/large laser projects need to adapt a higher safety regimen both from an engineering and administrative point of view. This presentation will discuss all these points and present examples. Acknowledgement. This work has been supported by the University of California, Director, Office of Science.

  20. Laser satellite power systems

    Energy Technology Data Exchange (ETDEWEB)

    Walbridge, E.W.

    1980-01-01

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  1. Semiconductor Laser Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  2. Laser Protection TIL

    Data.gov (United States)

    Federal Laboratory Consortium — The Laser Protection TIL conducts research and analysis of laser protection materials along with integration schemes. The lab's objectives are to limit energy coming...

  3. Laser technology (selected articles)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-09

    This paper presents high-energy CW HF/DF chemical lasers developed under the U.S. Navy Sealite program and the Alpha program of the DARPA Triad program, and a brief account of Soviet chemical lasers. Continuous wave HF/DF chemical lasers were developed starting in the late sixties as high-power lasers of consistent interest to military circles. These are lasers that have the most matured technology among present-day high-energy lasers. It is hoped that in the near future CW HF/DF chemical lasers can be developed into a space laser weapon to deal with ICBMs. CW HF/DF chemical lasers are an integration of technologies in gas dynamics, chemistry, fluid chemistry, optics, and lasers. By using the branching chain reaction of heat liberation, inversion of the population ratio is generated to obtain lasers.

  4. The Geoscience Laser Altimeter System Laser Transmitter

    Science.gov (United States)

    Afzal, R. S.; Dallas, J. L.; Yu, A. W.; Mamakos, W. A.; Lukemire, A.; Schroeder, B.; Malak, A.

    2000-01-01

    The Geoscience Laser Altimeter System (GLAS), scheduled to launch in 2001, is a laser altimeter and lidar for tile Earth Observing System's (EOS) ICESat mission. The laser transmitter requirements, design and qualification test results for this space- based remote sensing instrument are presented.

  5. Ultra-thin silicon (UTSi) on insulator CMOS transceiver and time-division multiplexed switch chips for smart pixel integration

    Science.gov (United States)

    Zhang, Liping; Sawchuk, Alexander A.

    2001-12-01

    We describe the design, fabrication and functionality of two different 0.5 micron CMOS optoelectronic integrated circuit (OEIC) chips based on the Peregrine Semiconductor Ultra-Thin Silicon on insulator technology. The Peregrine UTSi silicon- on-sapphire (SOS) technology is a member of the silicon-on- insulator (SOI) family. The low-loss synthetic sapphire substrate is optically transparent and has good thermal conductivity and coefficient of thermal expansion properties, which meet the requirements for flip-chip bonding of VCSELs and other optoelectronic input-output components. One chip contains transceiver and network components, including four channel high-speed CMOS transceiver modules, pseudo-random bit stream (PRBS) generators, a voltage controlled oscillator (VCO) and other test circuits. The transceiver chips can operate in both self-testing mode and networking mode. An on- chip clock and true-single-phase-clock (TSPC) D-flip-flop have been designed to generate a PRBS at over 2.5 Gb/s for the high-speed transceiver arrays to operate in self-testing mode. In the networking mode, an even number of transceiver chips forms a ring network through free-space or fiber ribbon interconnections. The second chip contains four channel optical time-division multiplex (TDM) switches, optical transceiver arrays, an active pixel detector and additional test devices. The eventual applications of these chips will require monolithic OEICs with integrated optical input and output. After fabrication and testing, the CMOS transceiver array dies will be packaged with 850 nm vertical cavity surface emitting lasers (VCSELs), and metal-semiconductor- metal (MSM) or GaAs p-i-n detector die arrays to achieve high- speed optical interconnections. The hybrid technique could be either wire bonding or flip-chip bonding of the CMOS SOS smart-pixel arrays with arrays of VCSELs and photodetectors onto an optoelectronic chip carrier as a multi-chip module (MCM).

  6. Hard plastic cladding fiber (HPCF) based optical components for high speed short reach optical communications

    Science.gov (United States)

    Kim, Jun Ki; Kim, Dong Uk; Kim, Tae Young; Park, Chang Soo; Oh, Kyunghwan

    2006-09-01

    We developed the primary components applicable to HPCF links for short reach (SR) and very short reach (VSR) data communication systems. We fabricated 4x4 HPCF fused taper splitter, HPCF pigtailed VCSEL and PIN photodiode for high speed short reach communications and characterized back to back transmission performance of the link composed of these components by measuring eye diagrams and jitters. Adapting the fusion-tapering technique for glass optical fiber, we successfully fabricated a 4x4 HPCF fused taper coupler. The HPCF with a core diameter of 200μm and an outer diameter of 230μm had step refractive index of 1.45 and 1.40 for the core and the clad. The optimized fusion length and tapering waist which make minimum insertion loss of about 7dB and uniform output power splitting ratio with less than 0.5dB are 13mm and 150µm, respectively. As a light source for VSR networks, we chose a vertical cavity surface emitting laser (VCSEL) and developed a package with a HPCF pigtail. After positioning VCSEL and HPCF that made a minimum coupling loss, we glued the HPCF inside ceramic ferrule housing. In HPCF-PIN PD packaging, we added a micro polymer lens tip onto the HPCF ends to match the mode field area to the sensitive area of GaAs or InGaAs PIN PD. Coupling between a PIN PD chip and the lensed HPCF was optimized with the radius of curvature of 156µm with a low coupling loss of 0.3dB, which is compatible to conventional MMF-PD packaging. For 1.25 Gbps data rate, the eyes adequate to eye mask in gigabit Ethernet were wide open after all HPCF transmission link and no significant power penalty was observed.

  7. Laser safety and practice

    International Nuclear Information System (INIS)

    Low, K.S.

    1995-01-01

    Lasers are finding increasing routine applications in many areas of science, medicine and industry. Though laser radiation is non-ionizing in nature, the usage of high power lasers requires specific safety procedures. This paper briefly outlines the properties of laser beams and various safety procedures necessary in their handling and usage. (author)

  8. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  9. Laser cladding with powder

    NARCIS (Netherlands)

    Schneider, M.F.; Schneider, Marcel Fredrik

    1998-01-01

    This thesis is directed to laser cladding with powder and a CO2 laser as heat source. The laser beam intensity profile turned out to be an important pa6 Summary rameter in laser cladding. A numerical model was developed that allows the prediction of the surface temperature distribution that is

  10. Laser EXAFS

    International Nuclear Information System (INIS)

    Mallozzi, P.J.; Epstein, H.M.; Schwenzel, R.E.; Campbell, B.E.

    1983-01-01

    Apparatus for obtaining EXAFS data of a material, comprising means for directing radiant energy from a laser onto a target in such manner as to produce X-rays at the target of a selected spectrum and intensity, suitable for obtaining the EXAFS spectrum of the material, means for directing X-rays from the target onto spectral dispersive means so located as to direct the spectrally resolved X-rays therefrom onto recording means, and means for positioning a sample of material in the optical path of the X-rays, the recording means providing a reference spectrum of X-rays not affected by the sample and absorption spectrum of X-rays modified by transmission through the sample

  11. Laser Microdissection.

    Science.gov (United States)

    Frost, Andra R; Eltoum, Isam-Eldin; Siegal, Gene P; Emmert-Buck, Michael R; Tangrea, Michael A

    2015-10-01

    Laser microdissection (LM) offers a relatively rapid and precise method of isolating and removing specified cells from complex tissues for subsequent analysis of their RNA, DNA, protein or metabolite content, thereby allowing assessment of the role of different cell types in the normal physiological or disease processes being studied. In this unit, protocols for the preparation of mammalian frozen tissues, fixed tissues, and cytologic specimens for LM, including tissue freezing, tissue processing and paraffin embedding, histologic sectioning, cell processing, hematoxylin and eosin staining, immunohistochemistry, and image-guided cell targeting are presented. Also provided are recipes for generating lysis buffers for the recovery of nucleic acids and proteins. The Commentary section addresses the types of specimens that can be utilized for LM and approaches to staining of specimens for cell visualization. Emphasis is placed on the preparation of tissue or cytologic specimens as this is critical to effective LM. Copyright © 2015 John Wiley & Sons, Inc.

  12. Current military laser applications

    Energy Technology Data Exchange (ETDEWEB)

    Flinchbaugh, D.E.

    1975-08-01

    Several important military applications with the predominant laser type used are reviewed. Most of these lasers are infrared lasers of one sort or another. Airborne tactical programs utilizing laser designator/illuminators are pictorially summarized, including range finding, target seeking, designation, tracking, reconnaissance, and surveillance. A typical designator optical system configuration is presented and discussed. Examples of operational laser systems are given. It is seen that many of the laser applications in the civilian community have either direct or indirect analogs in the military field. A self-contained HF/DF chemical laser weapon that recirculates its by-products is examined.

  13. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    -laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single......The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre...

  14. Laser ablation principles and applications

    CERN Document Server

    1994-01-01

    Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

  15. Electrical addressing and temporal tweezing of localized pulses in passively mode-locked semiconductor lasers

    Science.gov (United States)

    Javaloyes, J.; Camelin, P.; Marconi, M.; Giudici, M.

    2017-08-01

    This work presents an overview of a combined experimental and theoretical analysis on the manipulation of temporal localized structures (LSs) found in passively Vertical-Cavity Surface-Emitting Lasers coupled to resonant saturable absorber mirrors. We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures, also called localized pulses. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi-instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode-locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time-dependent current landscape.

  16. IV-VI mid-IR tunable lasers and detectors with external resonant cavities

    Science.gov (United States)

    Zogg, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Quack, N.; Blunier, S.; Dual, J.

    2009-08-01

    Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and spectroscopy. Such devices may be realized using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range. Vertical external cavity surface emitting lasers (VECSEL) may be applied for gas spectroscopy. Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolor IR-FPA or IR-AFPA (IR-adaptive focal plane arrays). We review mid-infrared RCEDs and VECSELs using narrow gap IV-VI (lead chalcogenide) materials like PbTe and PbSe as the active medium. IV-VIs are fault tolerant and allow easy wavelength tuning. The VECSELs operate up to above room temperature and emit in the 4 - 5 μm range with a PbSe active layer. RCEDs with PbTe absorbing layers above 200 K operating temperature have higher sensitivities than the theoretical limit for a similar broad-band detector coupled with a passive tunable band-filter.

  17. Infrared laser system

    Science.gov (United States)

    Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph S.

    1977-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

  18. Laser-surface interactions

    CERN Document Server

    Ganeev, Rashid A

    2014-01-01

    This book is about the interaction of laser radiation with various surfaces at variable parameters of radiation. As a basic principle of classification we chose the energetic or intensity level of interaction of laser radiation with the surfaces. These two characteristics of laser radiation are the most important parameters defining entire spectrum of the processes occurring on the surfaces during interaction with electromagnetic waves. This is a first book containing a whole spectrum of the laser-surface interactions distinguished by the ranges of used laser intensity. It combines the surface response starting from extremely weak laser intensities (~1 W cm-2) up to the relativistic intensities (~1020 W cm-2 and higher). The book provides the basic information about lasers and acquaints the reader with both common applications of laser-surface interactions (laser-related printers, scanners, barcode readers, discs, material processing, military, holography, medicine, etc) and unusual uses of the processes on t...

  19. Infrared laser system

    International Nuclear Information System (INIS)

    Cantrell, C.D.; Carbone, R.J.

    1977-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture

  20. Ceramic Laser Materials

    Science.gov (United States)

    Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

  1. Raman fiber lasers

    CERN Document Server

    2017-01-01

    This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

  2. Laser cooling of solids

    OpenAIRE

    Nemova, Galina

    2009-01-01

    Parallel to advances in laser cooling of atoms and ions in dilute gas phase, which has progressed immensely, resulting in physics Nobel prizes in 1997 and 2001, major progress has recently been made in laser cooling of solids. I compare the physical nature of the laser cooling of atoms and ions with that of the laser cooling of solids. I point out all advantages of this new and very promising area of laser physics. Laser cooling of solids (optical refrigeration) at the present time can be lar...

  3. Excimer laser applications

    International Nuclear Information System (INIS)

    Fantoni, R.

    1988-01-01

    This lecture deals with laser induced material photoprocessing, especially concerning those processes which are initiated by u.v. lasers (mostly excimer laser). Advantages of using the u.v. radiation emitted by excimer lasers, both in photophysical and photochemical processes of different materials, are discussed in detail. Applications concerning microelectronics are stressed with respect to other applications in different fields (organic chemistry, medicine). As further applications of excimer lasers, main spectroscopic techniques for ''on line'' diagnostics which employ excimer pumped dye lasers, emitting tunable radiation in the visible and near u.v. are reviewed

  4. Lasers in ophthalmology.

    Science.gov (United States)

    Gilmour, Margi A

    2002-05-01

    Laser technology continues to progress with the addition of new lasers, new delivery systems, and new applications. The introduction of lasers to veterinary ophthalmology has radically changed the level of care that we can provide to our patients. The development of the diode laser has particularly had an impact on veterinary ophthalmology. The diode's affordability, portability, and broad applications for veterinary patients have allowed laser surgery to become a routine part of veterinary ophthalmology practice. Educating the public and veterinary community in available laser techniques will generate improved ophthalmic care and provide more data on which to build future applications.

  5. Laser materials processing with diode lasers

    OpenAIRE

    Li, Lin; Lawrence, Jonathan; Spencer, Julian T.

    1996-01-01

    Laser materials processing is currently dominated by CO2, Nd-YAG and Excimer lasers. Continuous advances in semiconductor laser technology over the last decade have increased the average power output of the devices annualy by two fold, resulting in the commercial availability of the diode lasers today with delivery output powers in excess of 60W in CW mode and 5kW in qasi-CW mode. The advantages of compactness, high reliability, high efficiency and potential low cost, due to the mass producti...

  6. 1982 laser program annual report

    International Nuclear Information System (INIS)

    Hendricks, C.D.; Grow, G.R.

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications

  7. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.

    2014-01-01

    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  8. Fiber Laser Array

    National Research Council Canada - National Science Library

    Simpson, Thomas

    2002-01-01

    ...., field-dependent, loss within the coupled laser array. During this program, Jaycor focused on the construction and use of an experimental apparatus that can be used to investigate the coherent combination of an array of fiber lasers...

  9. Laser in operative dentistry

    Directory of Open Access Journals (Sweden)

    E. Yasini

    1994-06-01

    Full Text Available Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry, etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks around the region of laser radiation. Also due to high temperature of these lasers, pulp damage is inevitable. So today, by using the Excimer laser especially the argon floride type with a wavelength of 193 nm, the problem of heat stress have been solved, but the use of lasers in dentistry, especially for cavity preparation needs more researches and evaluations.

  10. Laser Processing and Chemistry

    CERN Document Server

    Bäuerle, Dieter

    2011-01-01

    This book gives an overview of the fundamentals and applications of laser-matter interactions, in particular with regard to laser material processing. Special attention is given to laser-induced physical and chemical processes at gas-solid, liquid-solid, and solid-solid interfaces. Starting with the background physics, the book proceeds to examine applications of lasers in “standard” laser machining and laser chemical processing (LCP), including the patterning, coating, and modification of material surfaces. This fourth edition has been enlarged to cover the rapid advances in the understanding of the dynamics of materials under the action of ultrashort laser pulses, and to include a number of new topics, in particular the increasing importance of lasers in various different fields of surface functionalizations and nanotechnology. In two additional chapters, recent developments in biotechnology, medicine, art conservation and restoration are summarized. Graduate students, physicists, chemists, engineers, a...

  11. Laser surgery - skin

    Science.gov (United States)

    Surgery using a laser ... used is directly related to the type of surgery being performed and the color of the tissue ... Laser surgery can be used to: Close small blood vessels to reduce blood loss Remove warts , moles , sunspots, and ...

  12. Wavelength sweepable laser source

    DEFF Research Database (Denmark)

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  13. Waveguide gas laser

    Science.gov (United States)

    Zedong, C.

    1982-05-01

    Waveguide gas lasers are described. Transmission loss of hollow tube light waveguides, coupling loss, the calculation of output power, and the width of the oscillation belt are discussed. The structure of a waveguide CO2 laser is described.

  14. LASIK - Laser Eye Surgery

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Glaucoma Education Center Pediatric Ophthalmology Education Center Oculofacial Plastic ... Center Laser Surgery Education Center Redmond Ethics Center ...

  15. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    of single mode fiber laser power. Burr free cuts in 1 mm steel and aluminum and in 1 and 2 mm AISI 304 stainless steel is demonstrated over a wide range of cutting rates. The industrial realization of this approach is foreseen to be performed by either beam patterning by diffractive optical elements......The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  16. Tunable laser optics

    CERN Document Server

    Duarte, FJ

    2015-01-01

    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  17. Laser Journal (Selected Articles),

    Science.gov (United States)

    1982-09-10

    chronic -33- "ś 7, laryngitis, vocal chord nodule etc, and obtained good results. TREATMENT OF CHRONIC LARYNGITIS WITH HeNe LASER OPTICAL FIBRE Lu Junan...decrease, and excessive menstruation. OBSERVATION ON THE EFFECT OF YAG LASER OPTICAL NEEDLE UPON CANINE VOCAL CHORD AND TONGUE TISSUE Laser Medicine...Research Laboratory, Shanghai Medical School Number 1 Irradiation of canine vocal chord and tongue tissue with a 1.06 micron YAG laser through an optical

  18. Laser cutting system

    Science.gov (United States)

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  19. Tunable high pressure lasers

    Science.gov (United States)

    Hess, R. V.

    1976-01-01

    Atmospheric transmission of high energy CO2 lasers is considerably improved by high pressure operation which, due to pressure broadening, permits tuning the laser lines off atmospheric absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers and for vertical transmission through the entire atmosphere. Applications of tunable high pressure CO2 lasers to energy transmission and to remote sensing are discussed along with initial efforts in tuning high pressure CO2 lasers.

  20. Laser induced pyrolysis techniques

    International Nuclear Information System (INIS)

    Vanderborgh, N.E.

    1976-01-01

    The application of laser pyrolysis techniques to the problems of chemical analysis is discussed. The processes occurring during laser pyrolysis are first briefly reviewed. The problems encountered in laser pyrolysis gas chromatography are discussed using the analysis of phenanthrene and binary hydrocarbons. The application of this technique to the characterization of naturally occurring carbonaceous material such as oil shales and coal is illustrated

  1. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...

  2. Coatings for laser fusion

    International Nuclear Information System (INIS)

    Lowdermilk, W.H.

    1981-01-01

    Optical coatings are used in lasers systems for fusion research to control beam propagation and reduce surface reflection losses. The performance of coatings is important in the design, reliability, energy output, and cost of the laser systems. Significant developments in coating technology are required for future lasers for fusion research and eventual power reactors

  3. Laser processing of materials

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    minimal collateral thermal damage over conventional tissue welding. 7.6 Summary and future scope. Laser joining is one of the earliest recorded applications of laser material processing. That laser can heat a material irrespective of its chemistry, state, bonding or size/geometry, is obviously a big advantage in joining a ...

  4. Introducing the Yellow Laser

    Science.gov (United States)

    Lincoln, James

    2018-01-01

    The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye…

  5. Lasers for nonlinear microscopy.

    Science.gov (United States)

    Wise, Frank

    2013-03-01

    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

  6. Laser processing of materials

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/sadh/028/03-04/0495-0562. Keywords. Laser processing; laser–matter interaction; laser surface vitrification. Abstract. Light amplification by stimulated emission of radiation (laser) is a coherent and monochromatic beam of electromagnetic radiation that can propagate in a straight line with ...

  7. LaserFest Celebration

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Alan Chodos; Elizabeth A. Rogan

    2011-08-25

    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  8. Lasers in Cancer Treatment

    Science.gov (United States)

    ... Off-Label Drug Use in Cancer Treatment Complementary & Alternative Medicine (CAM) CAM for Patients CAM for Health Professionals Questions to Ask about Your Treatment Research Lasers in Cancer Treatment On This Page What is laser light? What is laser therapy, and how is it used in cancer treatment? ...

  9. Industrial integration of high coherence tunable single frequency semiconductor lasers based on VECSEL technology for scientific instrumentation in NIR and MIR

    Science.gov (United States)

    Lecocq, Vincent; Chomet, Baptiste; Ferrières, Laurence; Myara, Mikhaël.; Beaudoin, Grégoire; Sagnes, Isabelle; Cerutti, Laurent; Denet, Stéphane; Garnache, Arnaud

    2017-02-01

    Laser technology is finding applications in areas such as high resolution spectroscopy, radar-lidar, velocimetry, or atomic clock where highly coherent tunable high power light sources are required. The Vertical External Cavity Surface Emitting Laser (VECSEL) technology [1] has been identified for years as a good candidate to reach high power, high coherence and broad tunability while covering a wide emission wavelength range exploiting III-V semiconductor technologies. Offering such performances in the Near- and Middle-IR range, GaAs- and Sb-based VECSEL technologies seem to be a well suited path to meet the required specifications of demanding applications. Built up in this field, our expertise allows the realization of compact and low power consumption marketable products, with performances that do not exist on the market today in the 0.8-1.1 μm and 2-2.5 μm spectral range. Here we demonstrate highly coherent broadly tunable single frequency laser micro-chip, intracavity element free, based on a patented VECSEL technology, integrated into a compact module with driving electronics. VECSEL devices emitting in the Near and Middle-IR developed in the frame of this work [2] exhibit exciting features compared to diode-pumped solid-state lasers and DFB diode lasers; they combine high power (>100mW) high temporal coherence together with a low divergence diffraction limited TEM00 beam. They exhibit a class-A dynamics with a Relative Intensity Noise as low as -140dB/Hz and at shot noise level reached above 200MHz RF frequency (up to 160GHz), a free running narrow linewidth at sub MHz level (fundamental limit at Hz level) with high spectral purity (SMSR >55dB), a linear polarization (>50dB suppression ratio), and broadband continuous tunability greater than 400GHz (state of the art commercial technologies thanks to a combination of power-coherence-wavelength tunability performances and integration.

  10. [Measurement on gas temperature distribution by tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Li, Ning; Yan, Jian-hua; Wang, Fei; Chi, Yong; Cen, Ke-fa

    2008-08-01

    The technique of tunable diode laser absorption spectroscopy (TDLAS) can be used for gas temperature distribution measurement by scanning multiple gas absorption lines with a tunable diode laser. The fundamental of gas temperature distribution measurement by TDLAS is introduced in the present paper, and the discretization strategy of equation for gas absorption is also given here. Using constrained linear least-square fitting method, the gas temperature distribution can be calculated with the help of physical constraints under the condition of uniform gas concentration and pressure. Based on the spectral parameters of four CO absorption lines near 6330 cm(-1) from HITRAN database, the model of two-temperature distribution at 300 and 600 K with each path length of 55 cm was set up. The effects of relative measurement error and different path length constraints of temperature bins on the gas temperature distribution measurement results were simulated by constrained linear least-square fitting. The results show that the temperature distribution calculation error increases as the relative measurement error rises. A measurement error of 5% could lead to a maximum relative error of 11%, and an average relative error of 2.2% for calculation result. And the weak physical constraints of path length for temperature bins could increase the calculation result error during the process of constrained linear least-square fitting. By setting up the model of two-temperature distribution with gas cells at room temperature as the cold section and in tube furnace as the hot section, the experiment of gas temperature distribution measurement in lab was carried out. Using four absorption lines of CO near 6330 cm(-1) scanned by VCSEL diode laser, and fitting the background laser intensity without absorption by the cubic polynomial to get the baseline signal, the integrals of spectral absorbance for gas temperature distribution measurement can be calculated. The relative calculation

  11. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff; Hitz, C Breck; John Wiley & Sons

    2001-01-01

    Electrical Engineering Introduction to Laser Technology , Third Edition. Would you like to know how a laser works, and how it can be modified for your own specific tasks? This intuitive third edition-previously published as Understanding Laser Technology , First and Second Editions-introduces engineers, scientists, technicians, and novices alike to the world of modern lasers, without delving into the mathematical details of quantum electronics. It is the only introductory text on the market today that explains the underlying physics and engineering applicable to all lasers. A unique combinatio.

  12. The laser thermonuclear fusion

    International Nuclear Information System (INIS)

    Coutant, J.; Dautray, R.; Decroisette, M.; Watteau, J.P.

    1987-01-01

    Principle of the thermonuclear fusion by inertial confinement: required characteristics of the deuterium-tritium plasma and of the high power lasers to be used Development of high power lasers: active media used; amplifiers; frequency conversion; beam quality; pulse conditioning; existing large systems. The laser-matter interaction: collision and collective interaction of the laser radiation with matter; transport of the absorbed energy; heating and compression of deuterium-tritium; diagnoses and their comparison with the numerical simulation of the experiment; performances. Conclusions: difficulties to overcome; megajoule lasers; other energy source: particles beams [fr

  13. Laser Cutting, Development Trends

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    1999-01-01

    In this paper a short review of the development trends in laser cutting will be given.The technology, which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal, as it will expand in heavy industry and in cutting...... of 3-dimensional shapes.The CO2-laser will also in the near future be the dominating laser source in the market, although the new developments in ND-YAG-lasers opens for new possibilities for this laser type....

  14. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  15. Quantum well lasers

    CERN Document Server

    Zory, Jr, Peter S; Kelley, Paul

    1993-01-01

    This book provides the information necessary for the reader to achieve a thorough understanding of all aspects of QW lasers - from the basic mechanism of optical gain, through the current technolgoical state of the art, to the future technologies of quantum wires and quantum dots. In view of the growing importance of QW lasers, this book should be read by all those with an active interest in laser science and technology, from the advanced student to the experienced laser scientist.* The first comprehensive book-length treatment of quantum well lasers* Provides a detailed treatment

  16. New solid laser: Ceramic laser. From ultra stable laser to ultra high output laser

    International Nuclear Information System (INIS)

    Ueda, Kenichi

    2006-01-01

    An epoch-making solid laser is developed. It is ceramic laser, polycrystal, which is produced as same as glass and shows ultra high output. Ti 3+ :Al 2 O 3 laser crystal and the CPA (chirped pulse amplification) technique realized new ultra high output lasers. Japan has developed various kinds of ceramic lasers, from 10 -2 to 67 x 10 3 w average output, since 1995. These ceramic lasers were studied by gravitational radiation astronomy. The scattering coefficient of ceramic laser is smaller than single crystals. The new fast ignition method is proposed by Institute of Laser Engineering of Osaka University, Japan. Ultra-intense short pulse laser can inject the required energy to the high-density imploded core plasma within the core disassembling time. Ti 3+ :Al 2 O 3 crystal for laser, ceramic YAG of large caliber for 100 kW, transparent laser ceramic from nano-crystals, crystal grain and boundary layer between grains, the scattering coefficient of single crystal and ceramic, and the derived release cross section of Yb:YAG ceramic are described. (S.Y.)

  17. Laser beam shaping techniques

    Energy Technology Data Exchange (ETDEWEB)

    DICKEY,FRED M.; WEICHMAN,LOUIS S.; SHAGAM,RICHARD N.

    2000-03-16

    Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

  18. ORION laser target diagnostics

    International Nuclear Information System (INIS)

    Bentley, C. D.; Edwards, R. D.; Andrew, J. E.; James, S. F.; Gardner, M. D.; Comley, A. J.; Vaughan, K.; Horsfield, C. J.; Rubery, M. S.; Rothman, S. D.; Daykin, S.; Masoero, S. J.; Palmer, J. B.; Meadowcroft, A. L.; Williams, B. M.; Gumbrell, E. T.; Fyrth, J. D.; Brown, C. R. D.; Hill, M. P.; Oades, K.

    2012-01-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  19. ORION laser target diagnostics.

    Science.gov (United States)

    Bentley, C D; Edwards, R D; Andrew, J E; James, S F; Gardner, M D; Comley, A J; Vaughan, K; Horsfield, C J; Rubery, M S; Rothman, S D; Daykin, S; Masoero, S J; Palmer, J B; Meadowcroft, A L; Williams, B M; Gumbrell, E T; Fyrth, J D; Brown, C R D; Hill, M P; Oades, K; Wright, M J; Hood, B A; Kemshall, P

    2012-10-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  20. Micromachining with copper lasers

    Science.gov (United States)

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  1. Adiabatic soliton laser.

    Science.gov (United States)

    Bednyakova, Anastasia; Turitsyn, Sergei K

    2015-03-20

    The key to generating stable optical pulses is mastery of nonlinear light dynamics in laser resonators. Modern techniques to control the buildup of laser pulses are based on nonlinear science and include classical solitons, dissipative solitons, parabolic pulses (similaritons) and various modifications and blending of these methods. Fiber lasers offer remarkable opportunities to apply one-dimensional nonlinear science models for the design and optimization of very practical laser systems. Here, we propose a new concept of a laser based on the adiabatic amplification of a soliton pulse in the cavity-the adiabatic soliton laser. The adiabatic change of the soliton parameters during evolution in the resonator relaxes the restriction on the pulse energy inherent in traditional soliton lasers. Theoretical analysis is confirmed by extensive numerical modeling.

  2. Laser safety in dentistry

    Science.gov (United States)

    Wigdor, Harvey A.

    1997-05-01

    One of the major causes of anxiety in the dental clinic is the dental handpiece. Because dentists wish to provide a method which can replace the drill there has often been a premature use of the laser in dentistry. Various lasers have been introduced into the clinic before research has shown the laser used is of clinical benefit. Any new treatment method must not compromise the health of the patient being treated. Thus a method of evaluating the clinical abilities of dentists and their understanding the limitations of the laser used must be developed. Dentist must be trained in the basic interaction of the laser on oral tissues. The training has to concentrate on the variation of the laser wavelength absorption in the different tissues of the oral cavity. Because of the differences in the optical properties of these tissues great care must be exercised by practitioners using lasers on patients.

  3. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  4. Lasers in space

    Science.gov (United States)

    Michaelis, M. M.; Forbes, A.; Bingham, R.; Kellett, B. J.; Mathye, A.

    2008-05-01

    A variety of laser applications in space, past, present, future and far future are reviewed together with the contributions of some of the scientists and engineers involved, especially those that happen to have South African connections. Historically, two of the earliest laser applications in space, were atmospheric LIDAR and lunar ranging. These applications involved atmospheric physicists, several astronauts and many of the staff recruited into the Soviet and North American lunar exploration programmes. There is a strong interest in South Africa in both LIDAR and lunar ranging. Shortly after the birth of the laser (and even just prior) theoretical work on photonic propulsion and space propulsion by laser ablation was initiated by Georgii Marx, Arthur Kantrowitz and Eugen Saenger. Present or near future experimental programs are developing in the following fields: laser ablation propulsion, possibly coupled with rail gun or gas gun propulsion; interplanetary laser transmission; laser altimetry; gravity wave detection by space based Michelson interferometry; the de-orbiting of space debris by high power lasers; atom laser interferometry in space. Far future applications of laser-photonic space-propulsion were also pioneered by Carl Sagan and Robert Forward. They envisaged means of putting Saenger's ideas into practice. Forward also invented a laser based method for manufacturing solid antimatter or SANTIM, well before the ongoing experiments at CERN with anti-hydrogen production and laser-trapping. SANTIM would be an ideal propellant for interstellar missions if it could be manufactured in sufficient quantities. It would be equally useful as a power source for the transmission of information over light year distances. We briefly mention military lasers. Last but not least, we address naturally occurring lasers in space and pose the question: "did the Big Bang lase?"

  5. Laser system using ultra-short laser pulses

    Science.gov (United States)

    Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

    2009-10-27

    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  6. All-Polymer Lasers

    Science.gov (United States)

    Wu, Yeheng; Lott, Joseph; Kazmierczak, Tomasz; Song, Hyunmin; Baer, Eric; Singer, Kenneth; Weder, Christoph

    2008-03-01

    We have fabricated all-polymer lasers both as distributed feedback lasers (DFB) and distributed Bragg reflector (DBR) lasers. For the DBR lasers, a layer of polymer doped with the laser dye is laminated between two multilayer polymer mirrors. The mirrors were made using the co-extrusion process combining PMMA alternated with polystyrene with 128 layers for each mirror. Two dyes were employed, Rhodamine 6G (R6G), and 1,4-bis-(α-cyano-4-methoxystyryl)-2,5-dimethoxybenzene (C1RG). They were pumped with a nanosecond laser and emitted at about 570 and 510 nm respectively. For DFB lasers, the low refractive index layers were doped with C1RG or R6G. PMMA and PMMA-PVDF were the hosts for the C1RG and R6G respectively. A total of eight co-extruded 32-layer films were stacked together to make a DFB laser. For the DBR lasers, we were able to observe thresholds as low as 100nJ. The highest conversion efficiency obtained about 14% in the forward direction. We also observed trends of lasing threshold, even spaced lasing modes and penetration of the film. Matrix method simulations taking into account layer thickness variations were consistent with experimental results. For the DFB lasers, the lowest lasing threshold observed was 52 μW.

  7. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  8. Laser scanning laser diode photoacoustic microscopy system.

    Science.gov (United States)

    Erfanzadeh, Mohsen; Kumavor, Patrick D; Zhu, Quing

    2018-03-01

    The development of low-cost and fast photoacoustic microscopy systems enhances the clinical applicability of photoacoustic imaging systems. To this end, we present a laser scanning laser diode-based photoacoustic microscopy system. In this system, a 905 nm, 325 W maximum output peak power pulsed laser diode with 50 ns pulsewidth is utilized as the light source. A combination of aspheric and cylindrical lenses is used for collimation of the laser diode beam. Two galvanometer scanning mirrors steer the beam across a focusing aspheric lens. The lateral resolution of the system was measured to be ∼21 μm using edge spread function estimation. No averaging was performed during data acquisition. The imaging speed is ∼370 A-lines per second. Photoacoustic microscopy images of human hairs, ex vivo mouse ear, and ex vivo porcine ovary are presented to demonstrate the feasibility and potentials of the proposed system.

  9. Laser Stabilization with Laser Cooled Strontium

    DEFF Research Database (Denmark)

    Christensen, Bjarke Takashi Røjle

    the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter......-combination line at 689 nm in a strongly saturated regime. The dynamics of the atomic induced phase shift and absorption of the probe light were experimentally studied in details with the purpose of applications to laser stabilization. The atomic sample temperature was in the mK range which brought this system out....... The studies presented in this work open novel possibilities for alternative and simple strategies for surpassing the state-of-the-art laser stabilization and for realizing active light sources involving collective emission from narrow-line atoms....

  10. High power lasers in manufacturing

    OpenAIRE

    Chatwin, Chris R

    2017-01-01

    Lecture covers a brief history of lasers and the important beam parameters for manufacturing applications. It introduces the main laser types that are appropriate for manufacturing: carbon dioxide lasers, Nd YAG, Diode and fibre lasers, excimer lasers. It then looks at applications to different products and also micro-engineering

  11. Laser Safety Inspection Criteria

    International Nuclear Information System (INIS)

    Barat, K

    2005-01-01

    A responsibility of the Laser Safety Officer (LSO) is to perform laser safety audits. The American National Standard Z136.1 Safe use of Lasers references this requirement in several sections: (1) Section 1.3.2 LSO Specific Responsibilities states under Hazard Evaluation, ''The LSO shall be responsible for hazards evaluation of laser work areas''; (2) Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''; and (3) Appendix D, under Survey and Inspections, it states, ''the LSO will survey by inspection, as considered necessary, all areas where laser equipment is used''. Therefore, for facilities using Class 3B and or Class 4 lasers, audits for laser safety compliance are expected to be conducted. The composition, frequency and rigueur of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms. In many institutions, a sole Laser Safety Officer (LSO) or a number of Deputy LSO's perform these audits. For that matter, there are institutions that request users to perform a self-assessment audit. Many items on the common audit list and the associated findings are subjective because they are based on the experience and interest of the LSO or auditor in particular items on the checklist. Beam block usage is an example; to one set of eyes a particular arrangement might be completely adequate, while to another the installation may be inadequate. In order to provide more consistency, the National Ignition Facility Directorate at Lawrence Livermore National Laboratory (NIF-LLNL) has established criteria for a number of items found on the typical laser safety audit form. These criteria are distributed to laser users, and they serve two broad purposes: first, it gives the user an expectation of what will be reviewed by an auditor, and second, it is an

  12. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  13. Strong field laser physics

    CERN Document Server

    2008-01-01

    Since the invention of the laser in the 1960s, people have strived to reach higher intensities and shorter pulse durations. High intensities and ultrashort pulse durations are intimately related. Recent developments have shown that high intensity lasers also open the way to realize pulses with the shortest durations to date, giving birth to the field of attosecond science (1 asec = 10-18s). This book is about high-intensity lasers and their applications. The goal is to give an up to date introduction to the technology behind these laser systems and to the broad range of intense laser applications. These applications include AMO (atomic molecular and optical) physics, x-ray science, attosecond science, plasma physics and particle acceleration, condensed matter science and laser micromachining, and finally even high-energy physics.

  14. Principles of Lasers

    CERN Document Server

    Svelto, Orazio

    2010-01-01

    This new Fifth Edition of Principles of Lasers incorporates corrections to the previous edition. The text’s essential mission remains the same: to provide a wide-ranging yet unified description of laser behavior, physics, technology, and current applications. Dr. Svelto emphasizes the physical rather than the mathematical aspects of lasers, and presents the subject in the simplest terms compatible with a correct physical understanding. Praise for earlier editions: "Professor Svelto is himself a longtime laser pioneer and his text shows the breadth of his broad acquaintance with all aspects of the field … Anyone mastering the contents of this book will be well prepared to understand advanced treatises and research papers in laser science and technology." (Arthur L. Schawlow, 1981 Nobel Laureate in Physics) "Already well established as a self-contained introduction to the physics and technology of lasers … Professor Svelto’s book, in this lucid translation by David Hanna, can be strongly recommended for...

  15. Lasers Fundamentals and Applications

    CERN Document Server

    Thyagarajan, K

    2010-01-01

    Lasers: Fundamentals and Applications, serves as a vital textbook to accompany undergraduate and graduate courses on lasers and their applications. Ever since their invention in 1960, lasers have assumed tremendous importance in the fields of science, engineering and technology because of their diverse uses in basic research and countless technological applications. This book provides a coherent presentation of the basic physics behind the way lasers work, and presents some of their most important applications in vivid detail. After reading this book, students will understand how to apply the concepts found within to practical, tangible situations. This textbook includes worked-out examples and exercises to enhance understanding, and the preface shows lecturers how to most beneficially match the textbook with their course curricula. The book includes several recent Nobel Lectures, which will further expose students to the emerging applications and excitement of working with lasers. Students who study lasers, ...

  16. Nuclear-pumped lasers

    CERN Document Server

    Prelas, Mark

    2016-01-01

    This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

  17. Atomic iodine laser

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, G.A.; Gusinow, M.A.; Hays, A.K.; Padrick, T.D.; Palmer, R.E.; Rice, J.K.; Truby, F.K.; Riley, M.E.

    1978-05-01

    The atomic iodine photodissociation laser has been under intensive study for a number of years. The physics associated with this system is now well understood and it is possible to produce a 0.1 nsec (or longer) near-diffraction-limited laser pulse which can be amplified with negligible temporal distortion and little spatial deformation. The output of either a saturated or unsaturated amplifier consists of a high-fidelity near-diffraction-limited, energetic laser pulse. The report is divided into three chapters. Chapter 1 is a survey of the important areas affecting efficient laser operation and summarizes the findings of Chap. 2. Chapter 2 presents detailed discussions and evaluations pertinent to pumps, chemical regeneration, and other elements in the overall laser system. Chapter 3 briefly discusses those areas that require further work and the nature of the work required to complete the full-scale evaluation of the applicability of the iodine photodissociation laser to the inertial confinement program.

  18. Methods of laser spectroscopy

    International Nuclear Information System (INIS)

    Prior, Y.; Ben-Reuven, A.; Rosenbluh, M.

    1986-01-01

    This book presents information on the following topics: the one-atom maser and cavity quantum electrodynamics; Rydberg atoms and radiation; investigation of nonthermal population distributions with femtosecond optical pulses; intra- and intermolecular energy transfer of large molecules in solution after picosecond excitation; new techniques of time-resolved infrared and Raman spectroscopy using ultrashort laser pulses; spectral linewidth of semiconductor lasers; the hydrogen atom in a new light; laser frequency division and stabilization; modified optical Bloch equations for solids; CARS spectroscopy of transient species; off resonant laser induced ring emission; UV laser ionization spectroscopy and ion photochemistry; laser spectroscopy of proton-transfer in microsolvent clusters; recent advances in intramolecular electronic energy transfer; and photoionization and dissociation of the H 2 molecule near the ionization threshold

  19. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  20. Arduino based laser control

    OpenAIRE

    Bernal Muñoz, Ferran

    2015-01-01

    ARDUINO is a vey usefull platform for prototypes. In this project ARDUINO will be used for controling a Semiconductor Tuneable Laser. [ANGLÈS] Diode laser for communications control based on an Arduino board. Temperature control implementation. Software and hardware protection for the laser implementation. [CASTELLÀ] Control de un láser de comunicaciones ópticas desde el ordenador utilizando una placa Arduino. Implementación de un control de temperatura y protección software y hardware ...

  1. Laser Hydrography in Australia.

    Science.gov (United States)

    1982-02-01

    r#00-Ails 584 ELECTRONICS RESEARCH LAO ADELAIDE IAUSTRALIA) F/S B/10 LASER HYDfiORAPHY IN AUSTRALIA . (U) FEB 82 M F PENNYJIJNCLASSIFIED ERLO Z B 9...RESEARCH CENTRE SALISBURY SOUTH AUSTRALIA TECHNICAL REPORT ERL-0229-TR LASER HYDROGRAPHY IN AUSTRALIA M.F. PENNY LJ--.I LA. Approved for Public Releae...ERL-0229-TR LASER HYDROGRAPHY IN AUSTRALIA M.F. Penny SUMMARY In response to a Royal Australian Navy requirement, the Electronics Research Laboratory

  2. Space laser components reliability

    OpenAIRE

    Riede, Wolfgang; Schroeder, Helmut

    2015-01-01

    Space environment presents unique challenges for operation of optics and optical coatings as part of laser systems. Besides testing components and sub-systems on the component qualification level, the extended testing of complete laser systems like flight modules under acceptance level conditions is an effective way to determine the reliability and long term stability, mitigating the mission risk. Hence, optics as part of high power space laser systems have to be extensively tested in view...

  3. Laser In Veterinary Medicine

    Science.gov (United States)

    Newman, Carlton; Jaggar, David H.

    1982-12-01

    Lasers have been used for some time now on animals for experimental purposes prior to their use in human medical and surgical fields. However the use of lasers in veterinary medicine and surgery per se is a recent development. We describe the application of high and low intensity laser technology in a general overview of the current uses, some limitations to its use and future needs for future inquiry and development.

  4. Laser precision microfabrication

    CERN Document Server

    Sugioka, Koji; Pique, Alberto

    2010-01-01

    Miniaturization and high precision are rapidly becoming a requirement for many industrial processes and products. As a result, there is greater interest in the use of laser microfabrication technology to achieve these goals. This book composed of 16 chapters covers all the topics of laser precision processing from fundamental aspects to industrial applications to both inorganic and biological materials. It reviews the sate of the art of research and technological development in the area of laser processing.

  5. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  6. Low Power Greenhouse Gas Sensors for Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    David J. Lary

    2012-05-01

    Full Text Available We demonstrate compact, low power, lightweight laser-based sensors for measuring trace gas species in the atmosphere designed specifically for electronic unmanned aerial vehicle (UAV platforms. The sensors utilize non-intrusive optical sensing techniques to measure atmospheric greenhouse gas concentrations with unprecedented vertical and horizontal resolution (~1 m within the planetary boundary layer. The sensors are developed to measure greenhouse gas species including carbon dioxide, water vapor and methane in the atmosphere. Key innovations are the coupling of very low power vertical cavity surface emitting lasers (VCSELs to low power drive electronics and sensitive multi-harmonic wavelength modulation spectroscopic techniques. The overall mass of each sensor is between 1–2 kg including batteries and each one consumes less than 2 W of electrical power. In the initial field testing, the sensors flew successfully onboard a T-Rex Align 700E robotic helicopter and showed a precision of 1% or less for all three trace gas species. The sensors are battery operated and capable of fully automated operation for long periods of time in diverse sensing environments. Laser-based trace gas sensors for UAVs allow for high spatial mapping of local greenhouse gas concentrations in the atmospheric boundary layer where land/atmosphere fluxes occur. The high-precision sensors, coupled to the ease-of-deployment and cost effectiveness of UAVs, provide unprecedented measurement capabilities that are not possible with existing satellite-based and suborbital aircraft platforms.

  7. Laser eye injuries.

    Science.gov (United States)

    Barkana, Y; Belkin, M

    2000-01-01

    Laser instruments are used in many spheres of human activity, including medicine, industry, laboratory research, entertainment, and, notably, the military. This widespread use of lasers has resulted in many accidental injuries. Injuries are almost always retinal, because of the concentration of visible and near-infrared radiation on the retina. The retina is therefore the body tissue most vulnerable to laser radiation. The nature and severity of this type of retinal injury is determined by multiple laser-related and eye-related factors, the most important being the duration and amount of energy delivered and the retinal location of the lesion. The clinical course of significant retinal laser injuries is characterized by sudden loss of vision, often followed by marked improvement over a few weeks, and occasionally severe late complications. Medical and surgical treatment is limited. Laser devices hazardous to the human eye are currently in widespread use by armed forces. Furthermore, lasers may be employed specifically for visual incapacitation on future battlefields. Adherence to safety practices effectively prevents accidental laser-induced ocular injuries. However, there is no practical way to prevent injuries that are maliciously inflicted, as expected from laser weapons.

  8. Jet laser ion source

    International Nuclear Information System (INIS)

    Dem'yanov, A.V.; Sidorov, S.V.

    1994-01-01

    External laser injector of multicharged ions (MCI) is developed in which wide-aperture aberration-free wire gauze spherical shape electrodes are applied for effective MCI extraction from laser plasma and beam focusing. Axial plasma compression by solenoid magnetic field is used to reduce ion losses due to transverse movement of the scattering laser plasma. Transverse magnetic field created by another solenoid facilitates the effective laser plasma braking and consequently, leads to the narrowing of energy spectrum of plasma ions and its shift towards lower energies. 2 refs.; 3 figs

  9. Gigashot Optical Laser Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Deri, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-13

    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  10. Trends in laser micromachining

    Science.gov (United States)

    Gaebler, Frank; van Nunen, Joris; Held, Andrew

    2016-03-01

    Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

  11. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff

    2012-01-01

    The only introductory text on the market today that explains the underlying physics and engineering applicable to all lasersAlthough lasers are becoming increasingly important in our high-tech environment, many of the technicians and engineers who install, operate, and maintain them have had little, if any, formal training in the field of electro-optics. This can result in less efficient usage of these important tools. Introduction to Laser Technology, Fourth Edition provides readers with a good understanding of what a laser is and what it can and cannot do. The book explains what types of las.

  12. Physics of semiconductor lasers

    CERN Document Server

    Mroziewicz, B; Nakwaski, W

    2013-01-01

    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  13. Lasers in materials processing

    International Nuclear Information System (INIS)

    Davis, J.I.; Rockower, E.B.

    1981-01-01

    A status report on the uranium Laser Isotope Separation (LIS) Program at the Lawrence Livermore National Laboratory is presented. Prior to this status report, process economic analysis is presented so as to understand how the unique properties of laser photons can be best utilized in the production of materials and components despite the high cost of laser energy. The characteristics of potential applications that are necessary for success are identified, and those factors that have up to now frustrated attempts to find commercially viable laser induced chemical and physical process for the production of new or existing materials are pointed out

  14. Transscleral laser for ophthalmology

    Science.gov (United States)

    Pekarik, Alexander S.; Linnik, Leonid A.; Kadan, Victor N.

    1997-05-01

    Transscleral laser (YAG:Nd, (lambda) equals 1.06 micrometers ) for ophthalmology has been developed and assembled for pulse laser transscleral treatment of eyes structures by means of adaptive optical fibers tip. `Adaptivity' means that we have used some exactly defined levels of optical fiber tip contact pressure to eyes surface to replace intertissues liquid. Such kind of fiber tip permit us apply more laser irradiation power due to decreasing of laser beam absorption in the liquid of eyes tissue. The different laser power levels, pulse duration, exposure time have been considered in correspondence with many types of adaptive fiber optical tips to optimize both transscleral coagulation and cutting process. To exactly determine the dependencies of laser irradiation spatial distributions behind sclera via contact tips pressure levels we have used as a adequate enough model He-Ne laser and eyes tissue samples. Laser system consist of power supply, control unit, laser head with cooling system, adapter for different kind of optical fibers tips. All of the above has been mounted as one case.

  15. High power lasers

    CERN Document Server

    Niku-Lari, A

    1989-01-01

    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  16. Laser-induced interactions

    International Nuclear Information System (INIS)

    Green, W.R.

    1979-01-01

    This dissertation discusses some of the new ways that lasers can be used to control the energy flow in a medium. Experimental and theoretical considerations of the laser-induced collision are discussed. The laser-induced collision is a process in which a laser is used to selectively transfer energy from a state in one atomic or molecular species to another state in a different species. The first experimental demonstration of this process is described, along with later experiments in which lasers were used to create collisional cross sections as large as 10 - 13 cm 2 . Laser-induced collisions utilizing both a dipole-dipole interaction and dipole-quadrupole interaction have been experimentally demonstrated. The theoretical aspects of other related processes such as laser-induced spin-exchange, collision induced Raman emission, and laser-induced charge transfer are discussed. Experimental systems that could be used to demonstrate these various processes are presented. An experiment which produced an inversion of the resonance line of an ion by optical pumping of the neutral atom is described. This type of scheme has been proposed as a possible method for constructing VUV and x-ray lasers

  17. Scanning Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1988-01-01

    A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

  18. Laser fusion program overview

    International Nuclear Information System (INIS)

    Emmett, J.L.

    1977-01-01

    This program is structured to proceed through a series of well defined fusion milestones to proof of the scientific feasibility, of laser fusion with the Shiva Nova system. Concurrently, those key technical areas, such as advanced lasers, which are required to progress beyond proof of feasibility, are being studied. We have identified and quantified the opportunities and key technical issues in military applications, such as weapons effects simulations, and in civilian applications, such as central-station electric power production. We summarize the current status and future plans for the laser fusion program at LLL, emphasizing the civilian applications of laser fusion

  19. Mid-Infrared Lasers

    Data.gov (United States)

    National Aeronautics and Space Administration — Mid infrared solid state lasers for Differential Absorption Lidar (DIAL) systems required for understanding atmospheric chemistry are not available. This program...

  20. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  1. Laser aircraft. [using kerosene

    Science.gov (United States)

    Hertzberg, A.; Sun, K.; Jones, W. S.

    1979-01-01

    The concept of a laser-powered aircraft is discussed. Laser flight would be completely compatible with existing airports and air-traffic control, with the airplane using kerosene only power, up to a cruising altitude of 9 km where the laser satellite would lock on and beam laser energy to it. Two major components make up the laser turbofan, a heat exchanger for converting laser radiation into thermal energy, and conventional turbomachinery. The laser power satellite would put out 42 Mw using a solar-powered thermal engine to generate electrical power for the closed-cycle supersonic electric discharge CO laser, whose radiators, heat exchangers, supersonic diffuser, and ducting will amount to 85% of the total subsystem mass. Relay satellites will be used to intercept the beam from the laser satellite, correct outgoing beam aberrations, and direct the beam to the next target. A 300-airplane fleet with transcontinental range is projected to save enough kerosene to equal the energy content of the entire system, including power and relay satellites, in one year.

  2. The ring laser gyro

    Science.gov (United States)

    Chow, W. W.; Gea-Banacloche, J.; Pedrotti, L. M.; Sanders, V. E.; Schleich, W.; Scully, M. O.

    1985-01-01

    This paper presents a review of both active and passive ring laser devices. The operating principles of the ring laser are developed and discussed, with special emphasis given to the problems associated with the achievement of greater sensitivity and stability. First-principle treatments of the nature of quantum noise in the ring laser gyro and various methods designed to avoid low-rotation-rate lock-in are presented. Descriptions of state-of-the-art devices and current and proposed applications (including a proposed test of metric theories of gravity using a passive cavity ring laser) are given.

  3. Monolithic integration of dual optical elements on high power semiconductor lasers

    Science.gov (United States)

    Vaissie, Laurent

    This dissertation investigates the monolithic integration of dual optical elements on high power semiconductor lasers for emission around 980nm wavelength. In the proposed configuration, light is coupled out of the AlGaAs/GaAs waveguide by a low reflectivity grating coupler towards the substrate where a second monolithic optical element is integrated to improve the device performance or functionality. A fabrication process based on electron beam lithography and plasma etching was developed to control the grating coupler duty cycle and shape. The near-field intensity profile outcoupled by the grating is modeled using a combination of finite-difference time domain (FDTD) analysis of the nonuniform grating and a self-consistent model of the broad area active region. Improvement of the near-field intensity profile in good agreement with the FDTD model is demonstrated by varying the duty cycle from 20% to 55% and including the aspect ratio dependent etching (ARDE) for sub-micron features. The grating diffraction efficiency is estimated to be higher than 95% using a detailed analysis of the losses mechanisms of the device. The grating reflectivity is estimated to be as low as 2.10-4. The low reflectivity of the light extraction process is shown to increase the device efficiency and efficiently suppress lasing oscillations if both cleaved facets are replaced by grating couplers to produce 1.5W QCW with 11 nm bandwidth into a single spot a few mm above the device. Peak power in excess of 30W without visible COMD is achieved in this case. Having optimized, the light extraction process, we demonstrate the integration of three different optical functions on the substrate of the surface-emitting laser. First, a 40 level refractive microlens milled using focused ion beam shows a twofold reduction of the full-width half maximum 1mm above the device, showing potential for monolithic integration of coupling optics on the wafer. We then show that differential quantum efficiency of

  4. LASERS: A cryogenic slab CO laser

    Science.gov (United States)

    Ionin, Andrei A.; Kozlov, A. Yu; Seleznev, L. V.; Sinitsyn, D. V.

    2009-03-01

    A compact capacitive transverse RF-discharge-pumped slab CO laser with cryogenically cooled electrodes, which operates both in the cw and repetitively pulsed regimes, is fabricated. The laser operation is studied in the free running multifrequency regime at the vibrational - rotational transitions of the fundamental (V + 1 → V) vibrational bands of the CO molecule in the spectral region from 5.1 to 5.4 μm. Optimal operation conditions (gas mixture composition and pressure, RF pump parameters) are determined. It is shown that only gas mixtures with a high content of oxygen (up to 20% with respect to the concentration of CO molecules) can be used as an active medium of this laser. It is demonstrated that repetitively pulsed pumping is more efficient compared to cw pumping. In this case, quasi-cw lasing regime can be obtained. The maximum average output power of ~12 W was obtained for this laser operating on fundamental bands and its efficiency achieved ~14 %. The frequency-selective operation regime of the slab RF-discharge-pumped CO laser was realised at ~ 100 laser lines in the spectral region from 5.0 to 6.5 μm with the average output power of up to several tens of milliwatts in each line. Lasing at the transitions of the first vibrational overtone (V + 2 → V) of the CO molecule is obtained in the spectral region from 2.5 to 3.9 μm. The average output power of the overtone laser achieved 0.3 W. All the results were obtained without the forced gas mixture exchange in the discharge chamber. Under fixed experimental conditions, repetitively pulsed lasing (with fluctuations of the output characteristics no more than ±10 %) was stable for more than an hour.

  5. Laser Program annual report 1987

    International Nuclear Information System (INIS)

    O'Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W.

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies

  6. Laser Program annual report 1987

    Energy Technology Data Exchange (ETDEWEB)

    O' Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  7. Temperature controller of semiconductor laser

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Vít; Číp, Ondřej

    2003-01-01

    Roč. 73, č. 3 (2003), s. 10 - 12 ISSN 0928-5008 Institutional research plan: CEZ:AV0Z2065902 Keywords : temperature controller * semiconductor laser * laser diode Subject RIV: BH - Optics, Masers, Lasers

  8. [Characteristics of laser light].

    Science.gov (United States)

    Takac, S; Stojanović, S

    1999-01-01

    Laser is one of the greatest technical discoveries of the 20th century. It is important in basic sciences, but particularly in diagnosis and therapy of various pathologic conditions of human organism. It is electromagnetic radiation, not X-irradiation and, as such, it is not expected to produce new generation of iatrogenic malignancies. Laser falls between infrared and ultraviolet on the spectrum mainly in the visible light spectrum. Properties of laser light are: monochromacity (the same color), coherence (all of the light waves are in phase both spatially and temporally), collimation (all rays are parallel to each other and do not diverge significantly even over long distances). Lasers were first conceived by Einstein in 1917 when he wrote his "Zur Quantum Theorie der Strahlung" (the quantum theory of radiation) which enumerated concepts of stimulated and spontaneous emission and absorption. Drs. Arthur Schawlow and Charles Townes, in 1956, extended lasers into the optical frequency range and Maiman, in 1960, operated the first laser using ruby as the active medium (ruby laser). Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. To understand the acronym, it is necessary to understand the basic physics of the atom. However, if the atom that is in the excited state is struck by another photon of energy before it returns to the ground state, two photons of equal frequency and energy, travelling in the same direction and in perfect spatial and temporal harmony, are produced. This phenomenon is termed stimulated emission of radiation. An external power source hyperexcites the atoms in the laser medium so that the number of atoms possessing upper energy levels exceeds the number of atoms in a power energy level, a condition termed a population inversion. This "pumping system" which imparts additional energy to the atoms may be optical, mechanical, or chemical. These atoms in a hyperexcited state spontaneously emit photons of light. The

  9. Laser safety tools and training

    CERN Document Server

    Barat, Ken

    2008-01-01

    Lasers perform many unique functions in a plethora of applications, but there are many inherent risks with this continually burgeoning technology. Laser Safety: Tools and Training presents simple, effective ways for users in a variety of facilities to evaluate the hazards of any laser procedure and ensure they are following documented laser safety standards.Designed for use as either a stand-alone volume or a supplement to Laser Safety Management, this text includes fundamental laser and laser safety information and critical laser use information rarely found in a single source. The first lase

  10. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil

    1999-01-01

    ...) technology selective laser sintering (SLS). BME has successfully implemented a pilot facility to fabricate calcium phosphate implants using anatomical data coupled with the selective laser sintering process...

  11. LIL laser performance status

    International Nuclear Information System (INIS)

    Julien, X.; Adolf, A.; Bar, E.; Beau, V.; Bordenave, E.; Chies, Th.; Courchinoux, R.; Feral, Ch.; Gendeau, P.; Graillot, H.; Grosset-Grange, C.; Henry, O.; Higonenq, V.; Journot, E.; Lacampagne, L.; Lafond, E.; Le Deroff, L.; Martinez, A.; Patissou, L.; Roques, A.; Thauvin, L.; Di-Nicola, J.M.; Thiell, G.

    2011-01-01

    The Laser Integration Line (LIL) was first designed as a prototype to validate the concepts and the laser architecture of the Laser MegaJoule (LMJ). The LIL facility is a 4-beam laser representing a quad structure of the LMJ. A set of test campaigns were conducted to safely ramp up laser performance. The main goal was to measure quad-specific features such as beam synchronization and focal spot (size, smoothing contrast ratio or irradiation nonuniformity) versus the LMJ requirements. Following the laser commissioning, the LIL has become a major instrument dedicated to the achievement of plasma physics experiments for the French Simulation Program and was also opened to the academic scientific community. One of the attributes of the LIL facility is to be very flexible to accommodate the requests of plasma physicists during campaigns. The LIL is constantly evolving to best meet the needs of target physicists. Changes made or planned are either to improve the quality of laser beams, or to increase the LIL Energy-Power operating space. To optimize preparation and design of shot campaigns, the LIL performance status has been elaborated. It gives information about the characteristics of the laser in terms of near field and far field, defines the steps to maintain performance, explains how the facility responds to the request, details settings (smoothing, shaping of the focal spot, energy, temporal pulse shaping, beam pointing) and gives the limits in energy and power. In this paper, an overview of the LIL performance is presented. (authors)

  12. (308 nm) excimer laser

    Indian Academy of Sciences (India)

    have been found to be 2 × 106 shots for 20% reduction of energy without any halogen ... Excimer laser; xenon chloride; discharge pumped; C–C energy ... Construction. The cross sectional view of the laser system and the photograph of the developed system are shown in figures 1 and 2, respectively. The system mainly ...

  13. Lasers in nuclear physics

    International Nuclear Information System (INIS)

    Inamura, T.T.

    1988-01-01

    The hyperfine interaction has been reviewed from a point of view of nuclear physics. Recent progress of nuclear spectroscopy with lasers is presented as one of laser studies of fundamental physics currently pursued in Japan. Especially, the hyperfine anomaly is discussed in connection with the origin of nuclear magnetism. (author)

  14. Laser induced energy transfer

    International Nuclear Information System (INIS)

    Falcone, R.W.

    1979-01-01

    Two related methods of rapidly transferring stored energy from one excited chemical species to another are described. The first of these, called a laser induced collision, involves a reaction in which the energy balance is met by photons from an intense laser beam. A collision cross section of ca 10 - 17 cm 2 was induced in an experiment which demonstrated the predicted dependence of the cross section on wavelength and power density of the applied laser. A second type of laser induced energy transfer involves the inelastic scattering of laser radiation from energetically excited atoms, and subsequent absorption of the scattered light by a second species. The technique of producing the light, ''anti-Stokes Raman'' scattering of visible and infrared wavelength laser photons, is shown to be an efficient source of narrow bandwidth, high brightness, tunable radiation at vacuum ultraviolet wavelengths by using it to excite a rare gas transition at 583.7 A. In addition, this light source was used to make the first measurement of the isotopic shift of the helium metastable level at 601 A. Applications in laser controlled chemistry and spectroscopy, and proposals for new types of lasers using these two energy transfer methods are discussed

  15. Athermal laser launch telescopes

    NARCIS (Netherlands)

    Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.

    2011-01-01

    ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several

  16. 5. Laser plasma interaction

    International Nuclear Information System (INIS)

    Labaune, C.; Fuchs, J.; Bandulet, H.

    2002-01-01

    Imprint elimination, smoothing and preheat control are considerable problems in inertial fusion and their possible solution can be achieved by using low-density porous materials as a buffer in target design. The articles gathered in this document present various aspects of the laser-plasma interaction, among which we have noticed: -) numerical algorithmic improvements of the Vlasov solver toward the simulation of the laser-plasma interaction are proposed, -) the dependence of radiation temperatures and X-ray conversion efficiencies of hohlraum on the target structures and laser irradiation conditions are investigated, -) a study of laser interaction with ultra low-density (0,5 - 20 mg/cm 3 ) porous media analyzing backscattered light at incident laser frequency ω 0 and its harmonics 3*ω 0 /2 and 2*ω 0 is presented, -) investigations of laser interaction with solid targets and crater formation are carried out with the objective to determine the ablation loading efficiency, -) a self organization in an intense laser-driven plasma and the measure of the relative degree of order of the states in an open system based on the S-theorem are investigated, and -) the existence and stability of electromagnetic solitons generated in a relativistic interaction of an intense laser light with uniform under-dense cold plasma are studied

  17. Coaxial short pulsed laser

    International Nuclear Information System (INIS)

    Nelson, M.A.; Davies, T.J.

    1975-01-01

    This invention relates to a laser system of rugged design suitable for use in a field environment. The laser itself is of coaxial design with a solid potting material filling the space between components. A reservoir is employed to provide a gas lasing medium between an electrode pair, each of which is connected to one of the coaxial conductors

  18. Coherent Polariton Laser

    Science.gov (United States)

    Kim, Seonghoon; Zhang, Bo; Wang, Zhaorong; Fischer, Julian; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Höfling, Sven; Deng, Hui

    2016-01-01

    The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.

  19. Coherent Polariton Laser

    Directory of Open Access Journals (Sweden)

    Seonghoon Kim

    2016-03-01

    Full Text Available The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.

  20. Laser processing of materials

    Indian Academy of Sciences (India)

    Light amplification by stimulated emission of radiation (laser) is a coherent and monochromatic beam of electromagnetic radiation that can propagate in a straight line with negligible divergence and occur in a wide range of wavelength, energy/power and beam-modes/configurations. As a result, lasers find wide applications ...

  1. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  2. Learning about Lasers

    Science.gov (United States)

    Roberts, Larry

    2011-01-01

    The word laser is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. Lasers, invented in 1958, are used to cut and fuse materials, accurately survey long distances, communicate across fiber-optic phone lines, produce 3D pictures, make special effects, help navigation, and read bar codes for cash registers. A laser…

  3. Laser biostimulation in pediatrics

    Science.gov (United States)

    Utz, Irina A.; Lagutina, L. E.; Tuchin, Valery V.

    1995-01-01

    In the present paper the method and apparatus for percutaneous laser irradiation of blood (PLIB) in vessels (veins) are described. Results of clinical investigations of biostimulating effects under PLIB by red laser light (633 nm) in Cubiti and Saphena Magna veins are presented.

  4. Electrodeless excimer laser

    International Nuclear Information System (INIS)

    Lisi, N.

    2001-01-01

    In this paper it is proposed how to build an excimer laser based on an electrodeless discharge (or Dielectric Barrier Discharge). Such laser could operate with a low energy per pulse ( 2 excimer molecule, whose emission wavelength in the VUV range (157 nm) at high reprate is particularly interesting in the micro-lithography field [it

  5. for aqueous dye lasers

    Indian Academy of Sciences (India)

    2014-02-12

    Feb 12, 2014 ... inclusion complex of RhB with the container molecule cucurbit[7]uril (CB[7]). Keywords. Temperature-dependent fluorescence; Rhodamine B; cucurbit[7]uril; host–guest complex; dye laser. PACS Nos 36.20.kd; 83.60.pq; 87.64.kv. 1. Introduction. Rhodamine B (RhB) is an efficient and photostable laser dye ...

  6. Lasers: principles, applications and energetic measures; Lasers: principes, applications et mesures energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Subran, C.; Sagaut, J. [Opton Laser International, 91 - Orsay (France); Lapointe, S. [Gentec Electro-Optique (Canada)

    2009-12-15

    After having recalled the principles of a laser and the properties of the laser beam, the authors describe the following different types of lasers: solid state lasers, fiber lasers, semiconductor lasers, dye lasers and gas lasers. Then, their applications are given. Very high energy lasers can reproduce the phenomenon of nuclear fusion of hydrogen atoms. (O.M.)

  7. NASA Space Laser Technology

    Science.gov (United States)

    Krainak, Michael A.

    2015-01-01

    Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

  8. Auricular Acupuncture with Laser

    Science.gov (United States)

    Bahr, Frank

    2013-01-01

    Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies. PMID:23935695

  9. Regenerative similariton laser

    Directory of Open Access Journals (Sweden)

    Thibault North

    2016-05-01

    Full Text Available Self-pulsating lasers based on cascaded reshaping and reamplification (2R are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  10. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...... and finally data analysis based on the ISO approach. The device was calibrated and tested on commercially available laser systems. It showed good reproducibility. It was the target to be able to measure CW lasers with a power up to 200 W, focused down to spot diameters in the range of 10µm. In order...

  11. Femtosecond Laser Filamentation

    CERN Document Server

    Chin, See Leang

    2010-01-01

    Femtosecond Laser Filamentation gives a comprehensive review of the physics of propagation of intense femtosecond laser pulses in optical media (principally air) and the applications and challenges of this new technique. This book presents the modern understanding of the physics of femtosecond laser pulse propagation, including unusual new effects such as the self-transformation of the pulse into a white light laser pulse, intensity clamping, the physics of multiple filamentation and competition, and how filaments’ ability to melt glass leads to wave guide writing. The potential applications of laser filamentation in atmospheric sensing and the generation of other electromagnetic pulses from the UV to the radio frequency are treated, together with possible future challenges in the excitation of super-excited states of molecules. Exciting new phenomena such as filament induced ultrafast birefringence and the excitation of molecular rotational wave packets and their multiple revivals in air (gases) will also ...

  12. Introducing the yellow laser

    Science.gov (United States)

    Lincoln, James

    2018-02-01

    The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye protection for the young and inexperienced. It is important to note that 589 nm is the same wavelength as the Sodium-D line (doublet). This allows for the laser to serve as a replacement for sodium lamps, and, considering its rather high price, this added value should be balanced against its cost. What follows is a list of activities that showcase the yellow laser's unique promise as an engaging piece of technology that can be used in the teaching of physics.

  13. Teradiode's high brightness semiconductor lasers

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, record brightness levels for direct diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  14. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

    2000-04-01

    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  15. X-Ray Lasers

    Science.gov (United States)

    Eder, David C.

    1998-05-01

    We provide an overview of the status of x-ray laser development worldwide with particular attention given to activities at LLNL. Since the demonstration of x-ray lasing 14 years ago there has been major progress in achieving shorter wavelengths, higher energies per pulse, higher efficiency, shorter pulse durations, etc. Original x-ray lasers used large kJ class lasers to achieve lasing in mid-Z materials with electron collisional pumping in the highly stripped ion being the most successful process for populating the upper-laser state. The two most common electron configurations for these collisional x-ray lasers are Ne-like and Ni-like ions. Through the use of prepulses and short picosecond driving pulses, transient collisional x-ray lasing schemes have been demonstrated using lasers with only a few Joules per pulse. An interesting aspect of these lasers is the time lag in reaching ionization equilibrium helps in obtaining high gain coefficients. A different approach to x-ray lasing is also being studied where lasing occurs in a singly ionized ion following innershell photoionization. The major requirement of the driving laser in this case is an ultrashort pulse duration (rise time to achieve lasing prior to collisional ionization of outershell electrons. In the area of applications, most of the work has been for single pulse experiments such as plasma and biological imaging. However, many of the new x-ray lasers achieve high average power by having a reasonable repetition rate of order 10 Hz and we briefly discuss relevant applications for these x-ray lasers. This work performed under the auspices of US DOE by LLNL under Contract No. W-7405-Eng-48.

  16. Laser autodyne angioscopy

    Science.gov (United States)

    Gordov, Eugeni P.; Makogon, Michail M.; Pekarskii, Vikentii V.; Shipulin, Vladimir M.

    1994-07-01

    A novel approach to imagination of inner surface of arteria during performing laser and balloon angioplasty is suggested. To this end the laser light was transmitted via fiber to the zone of interest and radiation diffused by the walls of the vessel was adopted by receiver. Known technique to determine of contours of an object by measuring the time of the laser pulse propagation is unusable due to the small geometrical scales. Using the CW laser and feeding a portion of the backscattered signal power into the laser cavity (this kind of device was referred to as laser autodyne coherent receiver), the authors have been able to measure the object contour with spatial resolution of up to 2 microns. Such resolution and high sensitivity inherent to this technique should allows one to detect early in the development of the atherosclerosis. To obtain the 3D image of the vessel inside surface we offer two methods. In the first case the vessel side is scanned by moving the end of light quid. In the second one multimode laser is used and the image is drawing by scanning the transverse modes of this laser. The vessel side and atherosclerotic plaques have the different reflectivity spectrum and this fact can be used to increase the image contrast. The correct selection of the laser wavelength makes possible to work into the vessel with circulation of the blood. The calculation of laser autodyne intrascope performance and tentative experimental results are presented in this report. The advantages of this method for the angiography are in speed and adequately of control during performing angioplasty.

  17. Lasers in Materials Processing

    Science.gov (United States)

    Kukreja, L. M.; Paul, C. P.; Kumar, Atul; Kaul, R.; Ganesh, P.; Rao, B. T.

    Laser is undoubtedly one of the most important inventions of the twentieth century. Today, it is widely deployed for a cornucopia of applications including materials processing. Different lasers such as CO2, Nd:YAG, excimer, copper vapor, diode, fiber lasers, etc., are being used extensively for various materials processing applications like cutting, welding, brazing, surface treatment, peening, and rapid manufacturing by adopting conventional and unconventional routes with unprecedented precision. In view of its potential for providing solution to the emerging problems of the industrial materials processing and manufacturing technologies, a comprehensive program on laser materials processing and allied technologies was initiated at our laboratory. A novel feature-based design and additive manufacturing technologies facilitated the laser rapid manufacturing of complex engineering components with superior performance. This technology is being extended for the fabrication of anatomically shaped prosthetics with internal heterogeneous architectures. Laser peening of spring steels brought significant improvement in its fatigue life. Laser surface treatments resulted in enhanced intergranular corrosion resistance of AISI 316(N) and 304 stainless steel. Parametric dependence of laser welding of dissimilar materials, AISI 316M stainless steel with alloy D9, was established for avoiding cracks under optimum processing conditions. In the domain of laser cutting and piercing, the development of a power ramped pulsed mode with high pulse repetition frequency and low duty cycle scheme could produce highly circular, narrow holes with minimum spattered pierced holes. A review of these experimental and some theoretical studies is presented and discussed in this chapter. These studies have provided deeper insight of fascinating laser-based materials processing application for industrial manufacturing technologies.

  18. Laser Safety Inspection Criteria

    International Nuclear Information System (INIS)

    Barat, K.

    2005-01-01

    A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility Directorate has established criteria for a number of items found on the typical laser safety audit form. The criteria are distributed to laser users. It serves two broad purposes; first, it gives the user an expectation of what will be reviewed by an auditor. Second, it is an opportunity to explain audit items to the laser user and thus the reasons for some of these items, such as labelling of beam blocks

  19. Consistency analysis on laser signal in laser guided weapon simulation

    Science.gov (United States)

    Yin, Ruiguang; Zhang, Wenpan; Guo, Hao; Gan, Lin

    2015-10-01

    The hardware-in-the-loop simulation is widely used in laser semi-active guidance weapon experiments, the authenticity of the laser guidance signal is the key problem of reliability. In order to evaluate the consistency of the laser guidance signal, this paper analyzes the angle of sight, laser energy density, laser spot size, atmospheric back scattering, sun radiation and SNR by comparing the different working state between actual condition and hardware-in-the-loop simulation. Based on measured data, mathematical simulation and optical simulation result, laser guidance signal effects on laser seeker are determined. By using Monte Carlo method, the laser guided weapon trajectory and impact point distribution are obtained, the influence of the systematic error are analyzed. In conclusion it is pointed out that the difference between simulation system and actual system has little influence in normal guidance, has great effect on laser jamming. The research is helpful to design and evaluation of laser guided weapon simulation.

  20. Measurements of laser parameters for the Shiva laser fusion facility

    International Nuclear Information System (INIS)

    Ozarski, R.G.

    1979-01-01

    Large laser systems require numerous laser diagnostics to provide configuration, performance and maintenance data to permit efficient operation. The following diagnostics for a large laser system named Shiva are discussed: (1) description of Shiva laser system, (2) what measurements are desired and or required and why, (3) what measurement techniques and packages are employed and a brief description of the operating principles of the sensors employed, and (4) the laser diagnostic data acquisition and display system