WorldWideScience

Sample records for mode locked lasers

  1. Passively mode locked Raman laser

    CERN Document Server

    Liang, W; Savchenkov, A A; Matsko, A B; Seidel, D; Maleki, L

    2010-01-01

    We report on the observation of a novel mode locked optical comb generated at the Raman offset (Raman comb) in an optically pumped crystalline whispering gallery mode resonator. Mode locking is confirmed via measurement of the radio-frequency beat note produced by the optical comb on a fast photodiode. Neither the conventional Kerr comb nor hyper-parametric oscillation is observed when the Raman comb is present.

  2. Self-mode-locking semiconductor disk laser.

    Science.gov (United States)

    Gaafar, Mahmoud; Richter, Philipp; Keskin, Hakan; Möller, Christoph; Wichmann, Matthias; Stolz, Wolfgang; Rahimi-Iman, Arash; Koch, Martin

    2014-11-17

    The development of mode-locked semiconductor disk lasers received striking attention in the last 14 years and there is still a vast potential of such pulsed lasers to be explored and exploited. While for more than one decade pulsed operation was strongly linked to the employment of a saturable absorber, self-mode-locking emerged recently as an effective and novel technique in this field - giving prospect to a reduced complexity and improved cost-efficiency of such lasers. In this work, we highlight recent achievements regarding self-mode-locked semiconductor devices. It is worth to note, that although nonlinear effects in the active medium are expected to give rise to self-mode-locking, this has to be investigated with care in future experiments. However, there is a controversy whether results presented with respect to self-mode-locking truly show mode-locking. Such concerns are addressed in this work and we provide a clear evidence of mode-locking in a saturable-absorber-free device. By using a BBO crystal outside the cavity, green light originating from second-harmonic generation using the out-coupled laser beam is demonstrated. In addition, long-time-span pulse trains as well as radiofrequency-spectra measurements are presented for our sub-ps pulses at 500 MHz repetition rate which indicate the stable pulse operation of our device. Furthermore, a long-time-span autocorrelation trace is introduced which clearly shows absence of a pedestal or double pulses. Eventually, a beam-profile measurement reveals the excellent beam quality of our device with an M-square factor of less than 1.1 for both axes, showing that self-mode-locking can be achieved for the fundamental transverse mode.

  3. Integration of mode-locked diode lasers

    Science.gov (United States)

    Coleman, A. Catrina; Hou, Lianping; Marsh, John H.

    2016-03-01

    Monolithic mode-locked semiconductor lasers are attractive sources of short optical pulses with advantages over more conventional sources in compactness, robustness, performance stability, power consumption, and cost savings. The use of quantum well intermixing (QWI) to integrate passive sections and surface etched distributed Bragg reflectors (DBR) into monolithic laser cavity will be described. The performance of the devices will be presented.

  4. An automatic mode-locked system for passively mode-locked fiber laser

    Science.gov (United States)

    Li, Sha; Xu, Jun; Chen, Guoliang; Mei, Li; Yi, Bo

    2013-12-01

    This paper designs and implements one kind of automatic mode-locked system. It can adjust a passively mode-locked fiber laser to keep steady mode-locked states automatically. So the unsteadiness of traditional passively mode-locked fiber laser can be avoided. The system transforms optical signals into electrical pulse signals and sends them into MCU after processing. MCU calculates the frequency of the signals and judges the state of the output based on a quick judgment algorithm. A high-speed comparator is used to check the signals and the comparison voltage can be adjusted to improve the measuring accuracy. Then by controlling two polarization controllers at an angle of 45degrees to each other, MCU extrudes the optical fibers to change the polarization until it gets proper mode-locked output. So the system can continuously monitor the output signal and get it back to mode-locked states quickly and automatically. States of the system can be displayed on the LCD and PC. The parameters of the steady mode-locked states can be stored into an EEPROM so that the system will get into mode-locked states immediately next time. Actual experiments showed that, for a 6.238MHz passively mode-locked fiber lasers, the system can get into steady mode-locked states automatically in less than 90s after starting the system. The expected lock time can be reduced to less than 20s after follow up improvements.

  5. Dark solitons in mode-locked lasers

    CERN Document Server

    Ablowitz, Mark J; Nixon, Sean D; Frantzeskakis, Dimitri J

    2010-01-01

    Dark soliton formation in mode-locked lasers is investigated by means of a power-energy saturation model which incorporates gain and filtering saturated with energy, and loss saturated with power. It is found that general initial conditions evolve into dark solitons under appropriate requirements also met in the experimental observations. The resulting pulses are well approximated by dark solitons of the unperturbed nonlinear Schr\\"{o}dinger equation. Notably, the same framework also describes bright pulses in anomalous and normally dispersive lasers.

  6. Mode-Locked Semiconductor Lasers for Optical Communication Systems

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Oxenløwe, Leif Katsuo

    2005-01-01

    We present investigations on 10 and 40 GHz monolithic mode-locked lasers for applications in optical communications systems. New all-active lasers with one to three quantum wells have been designed, fabricated and characterized.......We present investigations on 10 and 40 GHz monolithic mode-locked lasers for applications in optical communications systems. New all-active lasers with one to three quantum wells have been designed, fabricated and characterized....

  7. A racetrack mode-locked silicon evanescent laser.

    Science.gov (United States)

    Fang, Alexander W; Koch, Brian R; Gan, Kian-Giap; Park, Hyundai; Jones, Richard; Cohen, Oded; Paniccia, Mario J; Blumenthal, Daniel J; Bowers, John E

    2008-01-21

    By utilizing a racetrack resonator topography, an on-chip mode locked silicon evanescent laser (ML-SEL) is realized that is independent of facet polishing. This enables integration with other devices on silicon and precise control of the ML-SEL's repetition rate through lithographic definition of the cavity length. Both passive and hybrid mode-locking have been achieved with transform limited, 7 ps pulses emitted at a repetition rate of 30 GHz. Jitter and locking range are measured under hybrid mode locking with a minimum absolute jitter and maximum locking range of 364 fs, and 50 MHz, respectively.

  8. Phase locking of coupled lasers with many longitudinal modes

    CERN Document Server

    Fridman, Moti; Ronen, Eitan; Friesem, Asher A; Davidson, Nir

    2009-01-01

    Detailed experimental and theoretical investigations on two coupled fiber lasers, each with many longitudinal modes, reveal that the behavior of the longitudinal modes depends on both the coupling strength as well as the detuning between them. For low to moderate coupling strength only longitudinal modes which are common for both lasers phase-lock while those that are not common gradually disappear. For larger coupling strengths, the longitudinal modes that are not common reappear and phase-lock. When the coupling strength approaches unity the coupled lasers behave as a single long cavity with correspondingly denser longitudinal modes. Finally, we show that the gradual increase in phase-locking as a function of the coupling strength results from competition between phase-locked and non phase-locked longitudinal modes.

  9. Theory of Passively Mode-Locked Photonic Crystal Semiconductor Lasers

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Blaaberg, Søren; Mørk, Jesper

    2010-01-01

    We report the first theoretical investigation of passive mode-locking in photonic crystal mode-locked lasers. Related work has investigated coupled-resonator-optical-waveguide structures in the regime of active mode-locking [Opt. Express 13, 4539-4553 (2005)]. An extensive numerical investigation...... of the influence of key parameters of the active sections and the photonic crystal cavity on the laser performance is presented. The results show the possibility of generating stable and high quality pulses in a large parameter region. For optimized dispersion properties of the photonic crystal waveguide cavity......, the pulses have sub picosecond widths and are nearly transform limited....

  10. Vector Dissipative Solitons in Graphene Mode Locked Fiber Lasers

    CERN Document Server

    Zhang, Han; Zhao, Luming; Bao, Qiaoliang; Loh, Kian Ping

    2010-01-01

    Vector soliton operation of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated. Either the polarization rotation or polarization locked vector dissipative solitons were experimentally obtained in a dispersion-managed cavity fiber laser with large net cavity dispersion, while in the anomalous dispersion cavity fiber laser, the phase locked NLSE solitons and induced NLSE soliton were experimentally observed. The vector soliton operation of the fiber lasers unambiguously confirms the polarization insensitive saturable absorption of the atomic layer graphene when the light is incident perpendicular to its 2D atomic layer.

  11. Dual-polarization mode-locked Nd:YAG laser.

    Science.gov (United States)

    Thévenin, J; Vallet, M; Brunel, M

    2012-07-15

    A mode-locked solid-state laser containing a birefringent element is shown to emit synchronously two frequency combs associated to the two polarization eigenstates of the cavity. An analytical model predicts the polarization evolution of the pulse train, which is determined by the adjustable intracavity birefringence. Experiments realized with a Nd:YAG laser passively mode locked by a semiconductor saturable absorber mirror are in perfect agreement with the model. Locking between the two combs arises for particular values of their frequency difference, e.g., half the repetition rate, and the pulse train polarization sequence is then governed by the relative overall phase offset of the two combs.

  12. Single-SectionFabry-Perot Mode-Locked Semiconductor Lasers

    Directory of Open Access Journals (Sweden)

    Weiguo Yang

    2011-01-01

    Full Text Available We present a review of the theoretical models and experimental verification of the single-section Fabry-Perot mode-locked semiconductor lasers based on multiple-spatial-mode (MSM coupling. The mode-locked operation at the repetition rates of 40 GHz and higher and the pulse width of a few picoseconds are confirmed by the intensity autocorrelation, the fast photo detection and RF spectrum, and the optical spectral interference measurement of ultrafast pulse. The spatial mode coupling theory of single-section Fabry-Perot mode-locked semiconductor lasers is also reviewed, and the results are compared with the experimental observations. The small signal modulation response of these lasers, which exhibits high-frequency responses well beyond the relaxation oscillation resonance limit, is also modeled theoretically, and the simulation is verified by the experimental measurements.

  13. Increased reliability of passive mode-locking a multi-atmosphere TE CO2 laser by injection mode-locking

    NARCIS (Netherlands)

    Goor, van F.A.

    1986-01-01

    By injection of manosecond pulses from an AM mode-locked TEA CO2 laser in a passive mode-locked multi-atmosphere TE CO2 laser the shot-to-shot reproducibility of the generated subnanosecond pulses was increased to almost 100%.

  14. Modelling colliding-pulse mode-locked semiconductor lasers

    DEFF Research Database (Denmark)

    Bischoff, Svend

    or to determine the optimum operation conditions. The purpose of this thesis is to elucidate some of the physics of interest in the field of semiconductor laser modelling, semiconductor optics and fiber optics. To be more specific we will investigate: The Colliding-Pulse Mode-Locked (CPM) Quantum Well (QW) laser...

  15. Graphene mode locked, wavelength-tunable, dissipative soliton fiber laser

    CERN Document Server

    Zhang, Han; Knize, R J; Zhao, Luming; Bao, Qiaoliang; Loh, Kian Ping

    2010-01-01

    Atomic layer graphene possesses wavelength-insensitive ultrafast saturable absorption, which can be exploited as a full-band mode locker. Taking advantage of the wide band saturable absorption of the graphene, we demonstrate experimentally that wide range (1570 nm - 1600nm) continuous wavelength tunable dissipative solitons could be formed in an erbium doped fiber laser mode locked with few layer graphene.

  16. Dispersion-managed semiconductor mode-locked ring laser.

    Science.gov (United States)

    Resan, Bojan; Archundia, Luis; Delfyett, Peter J; Alphonse, Gerard

    2003-08-01

    A novel breathing-mode external sigma-ring-cavity semiconductor mode-locked laser is developed. Intracavity pulse compression and stretching produce linearly chirped pulses with an asymmetric exponential temporal profile. External dispersion compensation reduces the pulse duration to 274 fs (within 10% of the bandwidth limit).

  17. Quasi mode-locking of coherent feedback random fiber laser

    Science.gov (United States)

    Ma, R.; Zhang, W. L.; Zeng, X. P.; Yang, Z. J.; Rao, Y. J.; Yao, B. C.; Yu, C. B.; Wu, Y.; Yu, S. F.

    2016-12-01

    Mode-locking is a milestone in the history of lasers that allows the generation of short light pulses and stabilization of lasers. This phenomenon is known to occur only in standard ordered lasers for long time and until recently it is found that it also occurs in disordered random lasers formed by nanoscale particles. Here, we report the realization of a so-called quasi mode-locking of coherent feedback random fiber laser which consists of a partially disordered linear cavity formed between a point reflector and a random distributed fiber Bragg grating array with an inserted graphene saturable absorber. We show that multi-groups of regular light pulses/sub-pulses with different repetition frequencies are generated within the quasi mode-locking regime through the so-called collective resonances phenomenon in such a random fiber laser. This work may provide a platform to study mode locking as well as pulse dynamic regulation of random lasing emission of coherent feedback disordered structures and pave the way to the development of novel multi-frequency pulse fiber lasers with potentially wide frequency tuning range.

  18. Monolithic Hybrid and Passive Mode-Locked 40GHz Quantum Dot Laser Diodes

    DEFF Research Database (Denmark)

    Thompson, M. G.; Larsson, David; Rae, A. R.

    2006-01-01

    For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs.......For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs....

  19. Monolithic Hybrid and Passive Mode-Locked 40GHz Quantum Dot Laser Diodes

    DEFF Research Database (Denmark)

    Thompson, M. G.; Larsson, David; Rae, A. R.;

    2006-01-01

    For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs.......For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs....

  20. Semiconductor Mode-Locked Lasers for Optical Communication Systems

    DEFF Research Database (Denmark)

    Yvind, Kresten

    2003-01-01

    The thesis deals with the design and fabrication of semiconductor mode-locked lasers for use in optical communication systems. The properties of pulse sources and characterization methods are described as well as requirements for application in communication systems. Especially, the importance of......, and ways to reduce high-frequency jitter is discussed. The main result of the thesis is a new design of the epitaxial structure that both enables simplified fabrication and improves the properties of monolithic lasers. 40 GHz monolithic lasers with record low jitter and high power is presented as well...... as the first 10 GHz all-active monolithic laser with both short pulses and low jitter.Results from external cavity mode-locked lasers are also reported along with an investigation of the influence of the operating conditions on the performance of the device. Antireflection coatings are a critical limiting...

  1. Transition state to mode locking in a passively mode-locked erbium-doped fibre ring laser

    Institute of Scientific and Technical Information of China (English)

    Liu Jia-Rui; Xu Wen-Cheng; Luo Zhi-Chao; Luo Ai-Ping; Yin Hai-Sen

    2011-01-01

    The transition state between the continuous wave region and the mode-locked region in a passively mode-locked erbium-doped fibre ring laser has been experimentally observed by utilizing the nonlinear polarization rotation technique. When the pump power reaches the mode-locked threshold, the metastable pulse train with a tunable repetition rate is obtained in the transition from the continuous wave state to the passive mode-locked state via proper adjustment of the polarization controller. A simple model has been established to explain the experimental observation.

  2. Sub-20-Attosecond Timing Jitter Mode-Locked Fiber Lasers

    CERN Document Server

    Kim, Hyoji; Song, Youjian; Yang, Heewon; Shin, Junho; Kim, Chur; Jung, Kwangyun; Wang, Chingyue; Kim, Jungwon

    2014-01-01

    We demonstrate 14.3-attosecond timing jitter [integrated from 10 kHz to 94 MHz offset frequency] optical pulse trains from 188-MHz repetition-rate mode-locked Yb-fiber lasers. In order to minimize the timing jitter, we shorten the non-gain fiber length to shorten the pulsewidth and reduce excessive higher-order nonlinearity and nonlinear chirp in the fiber laser. The measured jitter spectrum is limited by the amplified spontaneous emission limited quantum noise in the 100 kHz - 1 MHz offset frequency range, while it was limited by the relative intensity noise-converted jitter in the lower offset frequency range. This intrinsically low timing jitter enables sub-100-attosecond synchronization between the two mode-locked Yb-fiber lasers over the full Nyquist frequency with a modest 10-kHz locking bandwidth. The demonstrated performance is the lowest timing jitter measured from any free-running mode-locked fiber lasers, comparable to the performance of the lowest-jitter Ti:sapphire solid-state lasers.

  3. Integrated optics dissipative soliton mode-locked laser on glass

    Science.gov (United States)

    Charlet, Bertrand; Bastard, Lionel; Broquin, Jean-Emmanuel

    2011-01-01

    Mode-lock lasers have been studied a lot in the past years for producing pulses as short as possible. These devices have mostly been realized in bulk optics and they are consequently cumbersome and sensitive to vibrations. There are only a few studies on integrated optics mode-lock lasers, though this technology is very promising because of its stability, compactness and the possibility to integrate several functions on a single chip. In this paper, we present an ion-exchange passively mode-locked laser in dissipative soliton operation. One of the key characteristics of this structure is its mechanical stability. Indeed, no bulk optics is needed because the saturable absorber is hybridized on the top of the waveguide in order to interact with the evanescent part of the guided mode. Indeed, the device that has been obtained is composed of an ion-exchanged single mode waveguide realized in a Neodymium doped phosphate glass. The laser feedback is produced by a Fabry-Perot cavity realized with two multilayers dielectric mirrors stuck on the waveguides facets. We implemented a bis(4- dimethylaminodithiobenzil)nickel (BDN) dye included in a cellulose acetate thick film, which presents a saturable absorber behaviour around 1.06 μm. With this structure, pulses with repetition rates of 3.3 GHz and a single mode output have been measured. Moreover, the use of an autocorrelation set-up allowed us measuring picosecond pulse durations.

  4. Pulse properties of external cavity mode locked semiconductor lasers

    DEFF Research Database (Denmark)

    Mulet, Josep; Kroh, Marcel; Mørk, Jesper

    2006-01-01

    The performance of an external-cavity mode-locked semiconductor laser is investigated both theoretically and experimentally. The optimization analysis focuses on the regimes of stable mode locking and the generation of sub-picosecond optical pulses. We demonstrate stable output pulses down to one...... picosecond duration with more than 30 dB trailing pulse suppression. The limiting factors to the device performance are investigated on the basis of a fully-distributed time-domain model.We find that ultrafast gain dynamics effectively reduce the pulse-shaping strength and inhibit the generation...

  5. Chirp of monolithic colliding pulse mode-locked diode lasers

    DEFF Research Database (Denmark)

    Hofmann, M.; Bischoff, S.; Franck, Thorkild

    1997-01-01

    Spectrally resolved streak camera measurements of picosecond pulses emitted by hybridly colliding pulse mode-locked (CPM) laser diodes are presented in this letter. Depending on the modulation frequency both blue-chirped (upchirped) and red-chirped (downchirped) pulses can be observed. The two...... different regimes and the transition between them are characterized experimentally and the behavior is explained on the basis of our model for the CPM laser dynamics. (C) 1997 American Institute of Physics....

  6. Quantum dot mode locked lasers for coherent frequency comb generation

    Science.gov (United States)

    Martinez, A.; Calò, C.; Rosales, R.; Watts, R. T.; Merghem, K.; Accard, A.; Lelarge, F.; Barry, L. P.; Ramdane, A.

    2013-12-01

    Monolithic semiconductor passively mode locked lasers (MLL) are very attractive components for many applications including high bit rate telecommunications, microwave photonics and instrumentation. Owing to the three dimensional confinement of the charge carriers, quantum dot based mode-locked lasers have been the subject of intense investigations because of their improved performance compared to conventional material systems. Indeed, the inhomogeneous gain broadening and the ultrafast absorption recovery dynamics are an asset for short pulse generation. Moreover, the weak coupling of amplified spontaneous emission with the guided modes plus low loss waveguide leads to low timing jitter. Our work concentrates on InAs quantum dash nanostructures grown on InP substrate, intended for applications in the 1.55 μm telecom window. InAs/InP quantum dash based lasers, in particular, have demonstrated efficient mode locking in single section Fabry-Perot configurations. The flat optical spectrum of about 12 nm, combined with the narrow RF beat note linewidth of about 10 kHz make them a promising technology for optical frequency comb generation. Coherence between spectral modes was assessed by means of spectral phase measurements. The parabolic spectral phase profile indicates that short pulses can be obtained provided the intracavity dispersion can be compensated by inserting a single mode fiber.

  7. All-fiber passively mode-locked Ho-laser pumped by ytterbium fiber laser

    Science.gov (United States)

    Filatova, S. A.; Kamynin, V. A.; Zhluktova, I. V.; Trikshev, A. I.; Tsvetkov, V. B.

    2016-11-01

    We report an all-fiber mode-lock holmium-doped ring laser passively mode-locked by nonlinear polarization rotation without dispersion compensation. The laser produced picosecond pulses at 2.057 µm. The average output power was 4.5 mW.

  8. High-Energy Passive Mode-Locking of Fiber Lasers

    Directory of Open Access Journals (Sweden)

    Edwin Ding

    2012-01-01

    Full Text Available Mode-locking refers to the generation of ultrashort optical pulses in laser systems. A comprehensive study of achieving high-energy pulses in a ring cavity fiber laser that is passively mode-locked by a series of waveplates and a polarizer is presented in this paper. Specifically, it is shown that the multipulsing instability can be circumvented in favor of bifurcating to higher-energy single pulses by appropriately adjusting the group velocity dispersion in the fiber and the waveplate/polarizer settings in the saturable absorber. The findings may be used as practical guidelines for designing high-power lasers since the theoretical model relates directly to the experimental settings.

  9. 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.

  10. Environmental stability of actively mode locked fibre lasers

    Science.gov (United States)

    Hill, Calum H.; Lee, Stephen T.; Reid, Derryck T.; Baili, Ghaya; Davies, John

    2016-10-01

    Lasers developed for defence related applications typically encounter issues with reliability and meeting desired specification when taken from the lab to the product line. In particular the harsh environmental conditions a laser has to endure can lead to difficulties. This paper examines a specific class of laser, namely actively mode-locked fibre lasers (AMLFLs), and discusses the impact of environmental perturbations. Theoretical and experimental results have assisted in developing techniques to improve the stability of a mode-locked pulse train for continuous operation. Many of the lessons learned in this research are applicable to a much broader category of lasers. The AMLFL consists of a fibre ring cavity containing a semiconductor optical amplifier (SOA), an isolator, an output coupler, a circulator, a bandpass filter and a modulator. The laser produces a train of 6-ps pulses at 800 nm with a repetition rate in the GHz regime and a low-noise profile. This performance is realisable in a laboratory environment. However, even small changes in temperature on the order of 0.1 °C can cause a collapse of mode-locked dynamics such that the required stability cannot be achieved without suitable feedback. Investigations into the root causes of this failure were performed by changing the temperature of components that constitute the laser resonator and observing their properties. Several different feedback mechanisms have been investigated to improve laser stability in an environment with dynamic temperature changes. Active cavity length control will be discussed along with DC bias control of the Mach-Zehnder modulator (MZM).

  11. Multiwavelength arrays of mode-locked lasers for WDM applications

    Science.gov (United States)

    Davis, Lawrence J.; Young, Martin G.; Dougherty, David J.; Keo, Sam A.; Muller, Richard E.; Maker, Paul D.; Forouhar, Siamak

    1998-08-01

    The continued need for increased bandwidth is driving the pursuit of both increased speed in TDM and more channels in WDM for fiber optic communication systems. Multiwavelength arrays of monolithic mode-locked DBR lasers are an attractive source for future high bit rate (100 - 800 Gb/s) optical communication systems. Monolithic mode-locked lasers in the colliding-pulse mode-locked configuration have been fabricated, with DBR end mirrors for wavelength selection. A continuous gain region has been employed for ease of fabrication and the elimination of multiple reflections within the cavity. Arrays containing up to 9 wavelengths have been fabricated, with all the wavelengths within the erbium-doped fiber amplifier gain bandwidth. An RF signal is applied to the saturable absorber for synchronization to an external clock and reduction of the phase noise. For a 4.6 mm cavity, short (< 10 ps) optical pulses at high (approximately 18 GHz) repetition rates have been achieved. Low single side-band phase noise values (-107 dBc/Hz 100 kHz offset) have been demonstrated, nearly equal to that of the RF source.

  12. Simultaneous Q-switching and mode-locking in the CW Nd:YAG laser

    Science.gov (United States)

    Kuizenga, D. J.; Phillion, D. W.; Siegman, A. E.; Lund, T.

    1973-01-01

    The theory of transient mode-locking for an active modulator in a laser with a homogeneously broadened line is presented. The theory is applied to simultaneously Q-switched and mode-locked Nd:YAG lasers and good agreement between theory and experiment is obtained. The main conclusion is that under usual Q-switched operating conditions the mode-locking process does not have sufficient time to build up to steady-state conditions. We also present a method to overcome this problem by allowing the laser to prelase before the Q-switch is opened. Mode-locked pulses whose width approaches the steady-state value are obtained. The transient mode-locking theory presented here also applies to actively mode-locking TEA CO2 lasers and to other types of simultaneously pulsed and mode-locked lasers.

  13. Multiwavelength mode-locked cylindrical vector beam fiber laser based on mode selective coupler

    Science.gov (United States)

    Huang, Ping; Cai, Yu; Wang, Jie; Wan, Hongdan; Zhang, Zuxing; Zhang, Lin

    2017-10-01

    We propose and demonstrate a multiwavelength mode-locked fiber laser with cylindrical vector beam generation for the first time, to the best of our knowledge. The mode-locking mechanism is based on a nonlinear polarization rotation effect in fiber, and the multiwavelength operation is contributed to by an in-line birefringence fiber filter with periodic multiple passbands, formed by incorporating a section of polarization maintaining fiber into the laser cavity with a fiber polarizer. Furthermore, by using a home-made mode selective coupler, which acts as both a mode converter from fundamental mode to higher-order mode and an output coupler, multiwavelength mode-locked cylindrical vector beams have been obtained. This may have potential applications in mode-division multiplexing optical fiber communication and material processing.

  14. Diode-Pumped Mode-Locked LiSAF Laser

    Energy Technology Data Exchange (ETDEWEB)

    None

    1996-02-01

    Under this contract we have developed Cr{sup 3+}:LiSrAlF{sub 6} (Cr:LiSAF, LiSAF) mode-locked lasers suitable for generation of polarized electrons for CEBAF. As 670 nm is an excellent wavelength for optical pumping of Cr:LiSAF, we have used a LIGHTWAVE developed 670 nm diode pump module that combines the output of ten diode lasers and yields approximately 2 Watts of optical power. By the use of a diffraction limited pump beam however, it is possible to maintain a small mode size through the length of the crystal and hence extract more power from Cr:LiSAF laser. For this purpose we have developed a 1 Watt, red 660nm laser (LIGHTWAVE model 240R) which serves as an ideal pump for Cr:LiSAF and is a potential replacement of costly and less robust krypton laser. This new system is to compliment LIGHTWAVE Series 240, and is currently being considered for commercialization. Partially developed under this contract is LIGHTWAVEs product model 240 which has already been in our production lines for a few months and is commercially available. This laser produces 2 Watts of output at 532 nm using some of the same technology developed for production of the 660nm red system. It is a potential replacement for argon ion lasers and has better current and cooling requirements and is an excellent pump source for Ti:Al{sub 2}O{sub 3}. Also, as a direct result of this contract we now have the capability of commercially developing a mode-locked 100MHz Cr:LiSAF system. Such a laser could be added to our 100 MHz LIGHTWAVE Series 131. The Series 131 lasers provide pico second pulses and were originally developed under another DOE SBIR. Both models of LIGHTWAVE Series 240 lasers, the fiber coupled pump module and the 100MHz LiSAF laser of Series 131 have been partially developed under this contract, and are commercially competitive products.

  15. Material Engineering for Monolithic Semiconductor Mode-Locked Lasers

    DEFF Research Database (Denmark)

    Kulkova, Irina

    This thesis is devoted to the materials engineering for semiconductor monolithic passively mode-locked lasers (MLLs) as a compact energy-efficient source of ultrashort optical pulses. Up to the present day, the achievement of low-noise sub-picosecond pulse generation has remained a challenge....... This work has considered the role of the combined ultrafast gain and absorption dynamics in MLLs as a main factor limiting laser performance. An independent optimization of MLL amplifier and saturable absorber active materials was performed. Two promising approaches were considered: quantum dot (QD...... application in MLLs. Improved QW laser performance was demonstrated using the asymmetric barrier layer approach. The analysis of the gain characteristics showed that the high population inversion beneficial for noise reduction cannot be achieved for 10 GHz QW MLLs and would have required lowering the modal...

  16. WS2 mode-locked ultrafast fiber laser

    Science.gov (United States)

    Mao, Dong; Wang, Yadong; Ma, Chaojie; Han, Lei; Jiang, Biqiang; Gan, Xuetao; Hua, Shijia; Zhang, Wending; Mei, Ting; Zhao, Jianlin

    2015-01-01

    Graphene-like two dimensional materials, such as WS2 and MoS2, are highly anisotropic layered compounds that have attracted growing interest from basic research to practical applications. Similar with MoS2, few-layer WS2 has remarkable physical properties. Here, we demonstrate for the first time that WS2 nanosheets exhibit ultrafast nonlinear saturable absorption property and high optical damage threshold. Soliton mode-locking operations are achieved separately in an erbium-doped fiber laser using two types of WS2-based saturable absorbers, one of which is fabricated by depositing WS2 nanosheets on a D-shaped fiber, while the other is synthesized by mixing WS2 solution with polyvinyl alcohol, and then evaporating them on a substrate. At the maximum pump power of 600 mW, two saturable absorbers can work stably at mode-locking state without damage, indicating that few-layer WS2 is a promising high-power flexible saturable absorber for ultrafast optics. Numerous applications may benefit from the ultrafast nonlinear features of WS2 nanosheets, such as high-power pulsed laser, materials processing, and frequency comb spectroscopy. PMID:25608729

  17. Active mode locking of quantum cascade lasers operating in external ring cavity

    CERN Document Server

    Revin, D G; Wang, Y; Cockburn, J W; Belyanin, A

    2015-01-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode locked operation remains a challenge despite dedicated effort. Here we report the first demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents of a standard commercial laser chip.

  18. Active mode-locking via pump modulation in a Tm-doped fiber laser

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2016-10-01

    Full Text Available We propose and experimentally realize a new class of actively mode-locking technique using pump modulation for rare-earth doped fiber lasers. A Tm-doped fiber laser at 2 μm is mode-locked using the proposed active mode-locking via pump modulation technique. Low-threshold continuous-wave mode-locking is achieved with a transform-limited pulse width of 4.4 ps, a spectral bandwidth of 0.9 nm, and a repetition rate of 12.9 MHz. Second-harmonic mode-locking is also demonstrated by simply driving the pump current at an appropriate frequency. More importantly, we believe that this technique can be applied to mode-lock other rare-earth doped fiber laser systems such as erbium- and ytterbium-doped fiber lasers.

  19. Large energy mode locking of an erbium-doped fiber laser with atomic layer graphene.

    Science.gov (United States)

    Zhang, H; Tang, D Y; Zhao, L M; Bao, Q L; Loh, K P

    2009-09-28

    We report on large energy pulse generation in an erbium-doped fiber laser passively mode-locked with atomic layer graphene. Stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser. Our results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking.

  20. Repetition rate continuously tunable 10-GHz picosecond mode-locked fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Fang Wan; Ziyu Wang

    2006-01-01

    A couple of simple-structure phase modulators were used in active mode-locked fiber laser to implement repetition rate continuous tuning. The laser produces pulse as short as 5.7 ps whose repetition rate tuning can cover the spacing of the adjoining order mode-locking frequencies.

  1. Modeling of mode-locked coupled-resonator optical waveguide lasers

    DEFF Research Database (Denmark)

    Agger, Christian; Skovgård, Troels Suhr; Gregersen, Niels;

    2010-01-01

    Coupled-resonator optical waveguides made from coupled high-Q photonic crystal nanocavities are investigated for use as cavities in mode-locked lasers. Such devices show great potential in slowing down light and can serve to reduce the cavity length of a mode-locked laser. An explicit expression...

  2. Comparison of the noise performance of 10GHz QW and QD mode-locked laser diodes

    DEFF Research Database (Denmark)

    Carpintero, Guillermo; Thompson, Mark G.; Yvind, Kresten

    2010-01-01

    This paper reports the experimental characterization of the noise performance of a quantum dot and a quantum well 10GHz passive mode locked laser diodes.......This paper reports the experimental characterization of the noise performance of a quantum dot and a quantum well 10GHz passive mode locked laser diodes....

  3. Long all-active monolithic mode-locked lasers with surface-etched bragg gratings

    OpenAIRE

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

    2007-01-01

    We have fabricated 4.4-mm-long monolithic InAlGaAsP–InP mode-locked lasers with integrated deeply surface etched distributed Bragg reflector (DBR) mirrors. The lasers produce 3.7-ps transform-limited Gaussian pulses with 10-mW average output power and 250-fs absolute timing jitter. The performance of the DBR lasers is compared to the performance of Fabry–PÉrot mode-locked lasers from the same wafer and to the performance of earlier reported long monolithic DBR mode-locked lasers and is found ...

  4. Long all-active monolithic mode-locked lasers with surface-etched bragg gratings

    DEFF Research Database (Denmark)

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

    2007-01-01

    We have fabricated 4.4-mm-long monolithic InAlGaAsP–InP mode-locked lasers with integrated deeply surface etched distributed Bragg reflector (DBR) mirrors. The lasers produce 3.7-ps transform-limited Gaussian pulses with 10-mW average output power and 250-fs absolute timing jitter. The performance...... of the DBR lasers is compared to the performance of Fabry–PÉrot mode-locked lasers from the same wafer and to the performance of earlier reported long monolithic DBR mode-locked lasers and is found to be better....

  5. Passive harmonic mode locked all-normal-dispersion Yb-doped fibre lasers

    Institute of Scientific and Technical Information of China (English)

    Kong Ling-Jie; Xiao Xiao-Sheng; Yang Chang-Xi

    2011-01-01

    Passive harmonic mode-locking of dissipative solitons is demonstrated in all-normal dispersion Yb-doped fibre lasers. A difference equation model of the mode-locked fibre lasers is adopted to simulate the intra-cavity nonlinear dynamics. Hysteresis phenomena around the mode-locking threshold, and the effect of introducing linear phase bias are discussed. The passive harmonic mode-locking as one kind of multipulsing operations is revealed. Moreover, the simulation shows the bistability between multipulsing and single-pulse or period multiplication.

  6. Properties of InGaAs quantum dot saturable absorbers in monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Thompson, M.G.; Marinelli, C.; Chu, Y.

    Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance.......Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance....

  7. Noise Effects in the Mode-Locked External Cavity Lasers

    Institute of Scientific and Technical Information of China (English)

    Nuran Dogru; M. Sadettin Ozyazici

    2003-01-01

    Effect of high level of spontaneous and carrier noise on mode-locked hybrid soliton pulse source and relative intensity noise is described. Transform limited pulses are not generated over a wide frequency range because of these noises.

  8. Passive mode locking of lasers by crossed-polarization gain modulation.

    Science.gov (United States)

    Javaloyes, Julien; Mulet, Josep; Balle, Salvador

    2006-10-20

    We report on a novel approach for inducing passive mode locking of lasers without using any saturable absorber but exploiting the polarization degree of freedom of light. In our scheme, passive mode locking is achieved by crossed-polarization gain modulation caused by the reinjection of a polarization-rotated replica of the laser output after a time delay. The reinjection time delay defines resonance tongues that correspond to mode-locking operation. Numerical continuation reveals that the cw solution is destabilized through a Hopf bifurcation that defines the onset of multimode operation which evolves sharply into a mode-locked solution. Our approach can be applied to a large variety of laser systems. For vertical-cavity surface-emitting lasers, we demonstrate stable mode-locked pulses at repetition rates in the GHz range and pulse widths of few tens of picoseconds.

  9. A wide bandwidth free-electron laser with mode locking using current modulation.

    Energy Technology Data Exchange (ETDEWEB)

    Kur, E.; Dunning, D. J.; McNeil, B. W. J.; Wurtele, J.; Zholents, A. A. (Accelerator Systems Division (APS)); (Univ. of California at Berkeley); (Univ. of Strathclyde); (STFC Daresbury Lab.); (LBNL)

    2011-01-20

    A new scheme for mode locking a free-electron laser amplifier is proposed based on electron beam current modulation. It is found that certain properties of the original concept, based on the energy modulation of electrons, are improved including the spectral brightness of the source and the purity of the series of short pulses. Numerical comparisons are made between the new and old schemes and between a mode-locked free-electron laser and self-amplified spontaneous emission free-electron laser. Illustrative examples using a hypothetical mode-locked free-electron laser amplifier are provided. The ability to generate intense coherent radiation with a large bandwidth is demonstrated.

  10. Melting and freezing of light pulses and modes in mode-locked lasers.

    Science.gov (United States)

    Gordon, Ariel; Vodonos, Boris; Smulakovski, Vladimir; Fischer, Baruch

    2003-12-15

    We present a first experimental demonstration of melting of light pulses and freezing of lightwave modes by applying external noise which acts like temperature, verifying our recent theoretical prediction (Gordon and Fischer [1]). The experiment was performed in a fiber laser passively mode-locked by nonlinear rotation of polarization. The first order phase transition was observed directly in time domain and also by measurement of the quartic order parameter (RF power).

  11. Phase locking and spectral linewidth of a two-mode terahertz quantum cascade laser

    NARCIS (Netherlands)

    Baryshev, A.; Hovenier, J.N.; Adam, A.J.L.; Kašalynas, I.; Gao, J.R.; Klaassen, T.O.; Williams, B.S.; Kumar, S.; Hu,Q.; Reno, J.L.

    2006-01-01

    We have studied the phase locking and spectral linewidth of an ∼ 2.7 THz quantum cascade laser by mixing its two lateral lasing modes. The beat signal at about 8 GHz is compared with a microwave reference by applying conventional phase lock loop circuitry with feedback to the laser bias current. Pha

  12. Hybrid mode-locked ultrashort-pulse erbium-doped fiber laser

    Science.gov (United States)

    Lazarev, Vladimir A.; Sazonkin, Stanislav S.; Pniov, Alexey B.; Tsapenko, Konstantin P.; Krylov, Alexander A.; Obraztsova, Elena D.

    2014-03-01

    One of the implementations of fs-laser with CNT-film for mode-locking is considered. Scheme of single-pulse, self-starting, stable mode-locked laser generation by appropriate polarization controllers adjustment is suggested. The mechanism of cavity length stabilization for a femtosecond fiber laser based on the pump source modulation is considered. Bandwidth of the feedback frequency stabilization system based on pump source modulation method is defined.

  13. Timing characterization of 100 GHz passively mode-locked discrete mode laser diodes

    CERN Document Server

    Bitauld, David; O'Brien, Stephen

    2011-01-01

    We report on the characterization of the timing stability of passively mode-locked discrete mode diode laser sources. These are edge-emitting devices with a spatially varying refractive index profile for spectral filtering. Two devices with a mode-locking frequency of 100 GHz are characterized. The first device is designed to support a comb of six modes and generates near Fourier limited 1.9 ps pulses. The second supports four primary modes resulting in a sinusoidal modulation of the optical intensity. Using a cross-correlation technique, we measured a 20 fs pulse to pulse timing jitter for the first device, while, for the second device, a mode-beating (RF) linewidth of 1 MHz was measured using heterodyne mixing in a semiconductor optical amplifier. Comparison of these results with those obtained for an equivalent Fabry-Perot laser indicates that the spectral filtering mechanism employed does not adversely affect the timing properties of these passively mode-locked devices.

  14. Independent tunability of the double-mode-locked cw dye laser.

    LENUS (Irish Health Repository)

    Bourkoff, E

    1979-06-01

    We report a new configuration that enables the double-mode-locked cw dye laser to be independently tunable. In addition, the output coupling at each of the two wavelengths can be independently specified. A series of oscillographs shows some interesting features unique to double mode locking and also shows the effects of varying the two cavity lengths with respect to each other.

  15. Dynamic localization and Bloch oscillations in the spectrum of a frequency mode-locked laser.

    Science.gov (United States)

    Longhi, Stefano

    2005-04-01

    It is shown that a frequency mode-locked laser with a sinusoidal sweep of modulation frequency around a mode-locking condition represents an ideal optical system for observing in the spectral domain the phenomena of dynamic localization and Bloch oscillations of electrons in an ideal solid placed in an external ac electric field.

  16. Passive mode locking of a Nd:KGW laser with hot-band diode pumping

    Science.gov (United States)

    Eibna Halim, M. Z.; Talukder, R. C.; Waritanant, T.; Major, A.

    2016-10-01

    Passive mode locking of a Nd:KGW laser with hot-band diode pumping at 910 nm was demonstrated. A semiconductor saturable absorber mirror was used as a mode locking mechanism. The laser generated 2.4 ps pulses at a repetition rate of ~83.8 MHz. An average output power of 87 mW was obtained at 1067 nm. To the best of our knowledge, this is the first report on passive mode locking of a Nd:KGW laser with low quantum defect pumping which holds great promise for further output power scaling.

  17. 70-fs mode-locked erbium-doped fiber laser with topological insulator.

    Science.gov (United States)

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Tian, Wenlong; Chen, Hao; Lei, Ming; Yan, Peiguang; Wei, Zhiyi

    2016-01-27

    Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future.

  18. $CO_{2}$ laser ion source Comparison between mode-locked and free- running laser beams

    CERN Document Server

    Lisi, N; Scrivens, R

    2001-01-01

    The production of highly charged ions in a CO/sub 2/ laser-generated plasma is compared for different laser pulse-time structures. The work was performed at the CERN Laser Ion Source, which has the aim of developing a high current, high charge-state ion source for the Large Hadron Collider (LHC). When an intense laser pulse is focused onto a high-Z metal target, the ions expanding in the plasma plume are suitable for extraction from the plasma and matching into a synchrotron. For the first time, a comparison is made between free- running pulses with randomly fluctuating intensity, and mode-locked pulse trains with a reproducible structure and the same energy. Despite the lower power density with respect to the mode-locked pulse train, the free-running pulse provides higher charge states and higher yield. (10 refs).

  19. Diode-Pumped Soliton and Non-Soliton Mode-Locked Yb:GYSO Lasers

    Institute of Scientific and Technical Information of China (English)

    HE Jin-Ping; LIANG Xiao-Yan; LI Jin-Feng; ZHENG Li-He; SU Liang-Bi; XU Jun

    2011-01-01

    @@ Diode-pumped soliton and non-soliton mode-locked Yb:(Gd1-xYx,)2SiO5 (x=0.5) lasers are demonstrated.Pulsesas short as 1.4 ps are generated for the soliton mode-locked operation, with a pair of SF10 prisms as the negativedispersion elements.The central wavelength is 1056nm and the repetition rate is 48 MHz.For the non-solitonmode locking, the output power could achieve ~1.2W and the pulse width is about 20ps.The critical pulseenergy in the soliton-mode locked operation against the Q-switched mode locking is much lower than the criticalpulse energy in the non-soliton mode-locked operation

  20. Modelling and characterization of colliding-pulse mode-locked (CPM) quantum well lasers. [MPS1

    DEFF Research Database (Denmark)

    Bischoff, Svend; Brorson, S.D.; Franck, T.

    1996-01-01

    A theoretical and experimental study of passive colliding pulse mode-locked quantum well lasers is presented. The theoretical model for the gain dynamics is based on semi-classical density matrixequations. The gain dynamics are characterized exp...

  1. Graphene oxide mode-locked femtosecond erbium-doped fiber lasers

    National Research Council Canada - National Science Library

    Xu, Jia; Liu, Jiang; Wu, Sida; Yang, Quan-Hong; Wang, Pu

    2012-01-01

    We demonstrated the femtosecond erbium-doped all-fiber lasers mode-locked with graphene oxide, which can be conveniently obtained from natural graphite by simple oxidation and ultra-sonication process...

  2. Modelling and characterization of colliding-pulse mode-locked (CPM) quantum well lasers. [MPS1

    DEFF Research Database (Denmark)

    Bischoff, Svend; Brorson, S.D.; Franck, T.;

    1996-01-01

    A theoretical and experimental study of passive colliding pulse mode-locked quantum well lasers is presented. The theoretical model for the gain dynamics is based on semi-classical density matrixequations. The gain dynamics are characterized exp...

  3. Short pulse generation in a passively mode-locked photonic crystal semiconductor laser

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Blaaberg, Søren; Mørk, Jesper

    2010-01-01

    We present a new type of passively mode-locked laser with quantum wells embedded in photonic crystal waveguides operating in the slow light regime, which is capable of emitting sub picosecond pulses with widely controllable properties......We present a new type of passively mode-locked laser with quantum wells embedded in photonic crystal waveguides operating in the slow light regime, which is capable of emitting sub picosecond pulses with widely controllable properties...

  4. Widely tunable Tm-doped mode-locked all-fiber laser

    Science.gov (United States)

    Yan, Zhiyu; Sun, Biao; Li, Xiaohui; Luo, Jiaqi; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2016-06-01

    We demonstrated a widely tunable Tm-doped mode-locked all-fiber laser, with the widest tunable range of 136 nm, from 1842 to 1978 nm. Nonlinear polarization evolution (NPE) technique is employed to enable mode-locking and the wavelength-tunable operation. The widely tunable range attributes to the NPE-induced transmission modulation and bidirectional pumping mechanism. Such kind of tunable mode-locked laser can find various applications in optical communications, spectroscopy, time-resolved measurement, and among others.

  5. Emergence of resonant mode-locking via delayed feedback in quantum dot semiconductor lasers.

    Science.gov (United States)

    Tykalewicz, B; Goulding, D; Hegarty, S P; Huyet, G; Erneux, T; Kelleher, B; Viktorov, E A

    2016-02-22

    With conventional semiconductor lasers undergoing external optical feedback, a chaotic output is typically observed even for moderate levels of the feedback strength. In this paper we examine single mode quantum dot lasers under strong optical feedback conditions and show that an entirely new dynamical regime is found consisting of spontaneous mode-locking via a resonance between the relaxation oscillation frequency and the external cavity repetition rate. Experimental observations are supported by detailed numerical simulations of rate equations appropriate for this laser type. The phenomenon constitutes an entirely new mode-locking mechanism in semiconductor lasers.

  6. Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements.

    Science.gov (United States)

    Olivier, Michel; Gagnon, Marc-Daniel; Habel, Joé

    2016-02-28

    When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

  7. Characterization of a self-starting, passively mode-locked fiber ring laser that exploits nonlinear polarization evolution.

    Science.gov (United States)

    Matsas, V J; Richardson, D J; Newson, T P; Payne, D N

    1993-03-01

    A full characterization of a self-starting, passively mode-locked soliton ring fiber laser in terms of its various modes of mode-locked operation, cavity length, and type of fiber used is presented. Direct evidence, based on state-of-polarization measurements, that nonlinear polarization evolution is the responsible mode-locking mechanism is also given.

  8. Correlation coefficient measurement of the mode-locked laser tones using four-wave mixing.

    Science.gov (United States)

    Anthur, Aravind P; Panapakkam, Vivek; Vujicic, Vidak; Merghem, Kamel; Lelarge, Francois; Ramdane, Abderrahim; Barry, Liam P

    2016-06-01

    We use four-wave mixing to measure the correlation coefficient of comb tones in a quantum-dash mode-locked laser under passive and active locked regimes. We study the uncertainty in the measurement of the correlation coefficient of the proposed method.

  9. High frequency optoelectronic oscillators based on the optical feedback of semiconductor mode-locked laser diodes.

    Science.gov (United States)

    Haji, Mohsin; Hou, Lianping; Kelly, Anthony E; Akbar, Jehan; Marsh, John H; Arnold, John M; Ironside, Charles N

    2012-01-30

    Optical self seeding feedback techniques can be used to improve the noise characteristics of passively mode-locked laser diodes. External cavities such as fiber optic cables can increase the memory of the phase and subsequently improve the timing jitter. In this work, an improved optical feedback architecture is proposed using an optical fiber loop delay as a cavity extension of the mode-locked laser. We investigate the effect of the noise reduction as a function of the loop length and feedback power. The well known composite cavity technique is also implemented for suppressing supermode noise artifacts presented due to harmonic mode locking effects. Using this method, we achieve a record low radio frequency linewidth of 192 Hz for any high frequency (>1 GHz) passively mode-locked laser to date (to the best of the authors' knowledge), making it promising for the development of high frequency optoelectronic oscillators.

  10. Mode-locking external-cavity laser-diode sensor for displacement measurements of technical surfaces

    Science.gov (United States)

    Czarske, Jürgen; Möbius, Jasper; Moldenhauer, Karsten

    2005-09-01

    A novel laser sensor for position measurements of technical solid-state surfaces is proposed. An external Fabry-Perot laser cavity is assembled by use of an antireflection-coated laser diode together with the technical surface. Mode locking results from pumping the laser diode synchronously to the mode spacing of the cavity. The laser cavity length, i.e., the distance to the measurement object, is determined by evaluation of the modulation transfer function of the cavity by means of a phase-locked loop. The mode-locking external-cavity laser sensor incorporates a resonance effect that results in highly resolving position and displacement measurements. More than a factor-of-10 higher resolution than with conventional nonresonant sensing principles is achieved. Results of the displacement measurements of various technical surfaces are reported. Experimental and theoretical investigations are in good agreement.

  11. Polarization dynamic patterns of vector solitons in a graphene mode-locked fiber laser.

    Science.gov (United States)

    Han, Mengmeng; Zhang, Shumin; Li, Xingliang; Zhang, Huaxing; Yang, Hong; Yuan, Ting

    2015-02-09

    Multiple polarization dynamic patterns of vector solitons, including fundamental solitons, bunched solitons, loosely or tightly bound states and harmonic mode locking have been observed experimentally in an erbium-doped fiber ring laser with graphene as a saturable absorber. By carefully adjusting the pump power and the orientation of the intra-cavity polarization controller, either polarization rotation or polarization locked operation have all been achieved for the above vector solitons. This is the first time that high order harmonic mode locking of polarization rotation vector solitons has been achieved. The signal to noise ratio of our system was ~51 dB, which indicates that the laser operated with high stability.

  12. Novel design of low-jitter 10 GHz all-active monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Christiansen, Lotte Jin

    2004-01-01

    Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared.......Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared....

  13. Time Domain Dynamic Analysis of 1550nm Monolithic Two Sections Mode Locked MQW Laser

    OpenAIRE

    DUMAN, Çağlar; ÇAKMAK, Bülent

    2015-01-01

    In this study, time domain dynamic model of a mode locked two sections DBR laser was obtained. Sort duration and high power optical pulse generation from a semiconductor laser was examined by using obtained model. For this aim, while one of the laser sections was thought as reverse biased and so acted as a saturable absorber, other section thought as forward biased with a DC current and so acted as a gain section. A semiconductor laser biased this way can produce mode locked pulses by suitabl...

  14. Generation of the numerator=2 rational harmonic mode-locked pulses in fiber ring lasers

    Institute of Scientific and Technical Information of China (English)

    Pinghe Wang(汪平河); Li Zhan(詹黎); Qinghao Ye(叶庆好); Yuxing Xia(夏宇兴)

    2004-01-01

    In conventional rational harmonic mode-locking, optical pulse trains with the repetition rate of(pn + 1)fc are generated when the modulation frequency of the in-cavity modulator is set at fm=(n + 1/p)fc, where n and p are both integers, fc is the fundamental cavity frequency. In this paper, we report that rational harmonic mode locking phenomenon takes place in the fiber lasers when the modulation frequency is set at fm =(n + 2/p)fc. The pulse generations are experimentally demonstrated when the numerator of the rational corresponds to 2 in 5th and 7th order rational harmonic mode-locking.

  15. Equal-Amplitude Optical Pulse Generation from a Rational Harmonic Mode-Locked Fibre Laser

    Institute of Scientific and Technical Information of China (English)

    FENG Xin-Huan; YUAN Shu-Zhong; LI Yao; LIU Yan-Ge; KAI Gui-Yun; DONG Xiao-Yi

    2004-01-01

    A simple technique for the generation of equal-amplitude high repetition rate pulses from a rational harmonic mode-locked fibre ring laser is demonstrated. The principle is based on the combination of the nonlinear characteristics of the modulator and the effect of rational harmonic mode-locking. The two sources act on each other and the integrated effect eventually leads to the pulse amplitude-equalization. We obtain amplitude-equalized short pulses up to the fifth-order rational harmonic mode-locking with an optimum bias level and modulation depth of the modulator, which demonstrates the efficiency of this method.

  16. Doubly active Q switching and mode locking of an all-fiber laser.

    Science.gov (United States)

    Cuadrado-Laborde, Christian; Díez, Antonio; Cruz, Jose L; Andrés, Miguel V

    2009-09-15

    Simultaneous and independent active Q switching and active mode locking of an erbium-doped fiber laser is demonstrated using all-fiber modulation techniques. A magnetostrictive rod attached to the output fiber Bragg grating modulates the Q factor of the Fabry-Perot cavity, whereas active mode locking is achieved by amplitude modulation with a Bragg-grating-based acousto-optic device. Fully modulated Q-switched mode-locked trains of optical pulses were obtained for a wide range of pump powers and repetition rates. For a Q-switched repetition rate of 500 Hz and a pump power of 100 mW, the laser generates trains of 12-14 mode-locked pulses of about 1 ns each, within an envelope of 550 ns, an overall energy of 0.65 microJ, and a peak power higher than 250 W for the central pulses of the train.

  17. Resonance vector mode locking

    CERN Document Server

    Kolpakov, Stanislav A; Loika, Yuri; Tarasov, Nikita; Kalashnikov, Vladimir; Agrawal, Govind P

    2015-01-01

    A mode locked fibre laser as a source of ultra-stable pulse train has revolutionised a wide range of fundamental and applied research areas by offering high peak powers, high repetition rates, femtosecond range pulse widths and a narrow linewidth. However, further progress in linewidth narrowing seems to be limited by the complexity of the carrier-envelope phase control. Here for the first time we demonstrate experimentally and theoretically a new mechanism of resonance vector self-mode locking where tuning in-cavity birefringence leads to excitation of the longitudinal modes sidebands accompanied by the resonance phase locking of sidebands with the adjacent longitudinal modes. An additional resonance with acoustic phonons provides the repetition rate tunability and linewidth narrowing down to Hz range that drastically reduces the complexity of the carrier-envelope phase control and so will open the way to advance lasers in the context of applications in metrology, spectroscopy, microwave photonics, astronomy...

  18. Trade-off between Linewidth and Slip Rate in a Mode-Locked Laser Model

    CERN Document Server

    Moore, Richard O

    2014-01-01

    We demonstrate a trade-off between linewidth and loss-of-lock frequency in a mode-locked laser employing active feedback to control the carrier-envelope offset phase difference. In frequency metrology applications, the linewidth translates directly to uncertainty in the measured frequency, while the impact of lock loss and recovery on the measured frequency is less well understood. We reduce the dynamics to stochastic differential equations, specifically diffusion processes, and compare the linearized linewidth to the rate of lock loss determined by the mean time to exit calculated from large deviation theory.

  19. Soliton mode locking fiber laser with an all-fiber polarization interference filter.

    Science.gov (United States)

    Yan, Zhijun; Wang, Hushan; Zhou, Kaiming; Wang, Yishan; Li, Cheng; Zhao, Wei; Zhang, Lin

    2012-11-01

    An erbium doped fiber ring laser achieving soliton mode locking by the use of an intra-cavity all-fiber polarization interference filter (AFPIF) has been demonstrated. To incorporate an AFPIF with relative narrow transmission bandwidth, the laser has produced clean soliton pulses of 1.2 ps duration at a repetition rate of 14.98 MHz with a polarization extinction ratio up to 25.7 dB. Moreover, we have demonstrated that the operating wavelength of the mode locking laser can be tuned over 20 nm range from 1545 to 1565 nm by thermally tuning the AFPIF cavity.

  20. Pulse shaping in mode-locked fiber lasers by in-cavity spectral filter.

    Science.gov (United States)

    Boscolo, Sonia; Finot, Christophe; Karakuzu, Huseyin; Petropoulos, Periklis

    2014-02-01

    We numerically show the possibility of pulse shaping in a passively mode-locked fiber laser by inclusion of a spectral filter into the laser cavity. Depending on the amplitude transfer function of the filter, we are able to achieve various regimes of advanced temporal waveform generation, including ones featuring bright and dark parabolic-, flat-top-, triangular- and saw-tooth-profiled pulses. The results demonstrate the strong potential of an in-cavity spectral pulse shaper for controlling the dynamics of mode-locked fiber lasers.

  1. Hierarchy, dimension, attractor and self-organization -- dynamics of mode-locked fiber lasers

    CERN Document Server

    Wei, Huai; Shi, Wei; Zhu, Xiushan; Norwood, Robert A; Peyghambarian, Nasser; Jian, Shuisheng

    2016-01-01

    Mode-locked fiber lasers are one of the most important sources of ultra-short pulses. However, A unified description for the rich variety of states and the driving forces behind the complex and diverse nonlinear behavior of mode-locked fiber lasers have yet to be developed. Here we present a comprehensive theoretical framework based upon complexity science, thereby offering a fundamentally new way of thinking about the behavior of mode-locked fiber lasers. This hierarchically structured frame work provide a model with and changeable variable dimensionality resulting in a simple and elegant view, with which numerous complex states can be described systematically. The existence of a set of new mode-locked fiber laser states is proposed for the first time. Moreover, research into the attractors' basins reveals the origin of stochasticity, hysteresis and multistability in these systems. These findings pave the way for dynamics analysis and new system designs of mode-locked fiber lasers. The paradigm will have a w...

  2. Microwave signal extraction from femtosecond mode-locked lasers with attosecond relative timing drift.

    Science.gov (United States)

    Kim, Jungwon; Kärtner, Franz X

    2010-06-15

    We present a feedback-control method for suppression of excess phase noise in the optical-to-electronic conversion process involved in the extraction of microwave signals from femtosecond mode-locked lasers. A delay-locked loop based on drift-free phase detection with a differentially biased Sagnac loop is employed to eliminate low-frequency (e.g., locked laser with a relative rms timing jitter of 2.4 fs (integrated from 1 mHz to 1 MHz) and a relative rms timing drift of 0.84 fs (integrated over 8 h with 1 Hz bandwidth) between the optical pulse train and the extracted microwave signal.

  3. Mode-locked Pr3+-doped silica fiber laser with an external cavity

    DEFF Research Database (Denmark)

    Shi, Yuan; Poulsen, Christian; Sejka, Milan

    1994-01-01

    We present a Pr3+-doped silica-based fiber laser mode-locked by using a linear external cavity with a vibrating mirror. Stable laser pulses with a FWHM of less than 44 ps, peak power greater than 9 W, and repetition rate up to 100 MHz are obtained. The pulse width versus cavity mismatch ΔL and pump...

  4. Stabilization of an AM mode-locked tea CO2 laser

    NARCIS (Netherlands)

    Goor, van F.A.

    1983-01-01

    An increased shot-to-shot reproducibility has been obtained by injection of radiation from a cw CO2 laser in an amplitude mode-locked TEA CO2 laser without additional pulse broadening. Stable pulses variable from 900 ps up to 4 ns have been generated with this new technique.

  5. Bound soliton pulses in a passively mode-locked fibre ring laser

    Institute of Scientific and Technical Information of China (English)

    Zhang Shu-Min; Lü Fu-Yun; Gong Yan-Dong; Zhou Xiao-Qun; Yang Xiu-Feng; Lü Chao

    2005-01-01

    The bound solitons in a passively mode-locked fibre ring laser are observed and their formation mechanism is summarized in this paper. In order to obtain stable bound solitons, a strong CW laser field at the centre of the soliton spectral is necessary to suppress and synchronize the random soliton phase variations.

  6. Low-jitter and high-power 40 GHz all-active mode-locked lasers

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

    2004-01-01

    A novel design strategy for the epitaxial structure of monolithic mode-locked semiconductor lasers is presented. Using an all-active design, we fabricate 40-GHz lasers generating 2.8-ps almost chirp-free pulses with record low high-frequency jitter and more than 7-mW fiber coupled output power....

  7. An investigation of the spectral content of a mode-locked pulsed CO2 laser

    NARCIS (Netherlands)

    Bormans, B.J.M.; Olbertz, A.H.M.

    1980-01-01

    The frequency width of a pulse train in a pulsed mode-locked CO2 laser has been accurately measured by means of a Fabry-Perot interferometer. We succeeded in resolving the longitudinal mode structure. The results are in excellent agreement with the results of previous measurements of the line width

  8. Efficient graphene Q switching and mode locking of 1.34 μm neodymium lasers.

    Science.gov (United States)

    Xu, Jin-Long; Li, Xian-Lei; He, Jing-Liang; Hao, Xiao-Peng; Yang, Ying; Wu, Yong-Zhong; Liu, Shan-De; Zhang, Bai-Tao

    2012-07-01

    We demonstrate that few-layered graphene sheets used as a saturable absorber can provide efficient Q-switching and mode-locking modulation in 1.34 μm Nd:GdVO(4) bulk lasers. The minimum Q-switched pulses were 450 ns for 260 mW average power, 43 kHz repetition rate, and 2.5 μJ pulse energy. For the mode-locked laser, an average power of 1.29 W was achieved with 11 ps pulse duration and 13 nJ pulse energy. To our knowledge, this average power is the highest yet obtained from a graphene mode-locked laser, and the corresponding optical-optical efficiency of 23% is the best result among 1.3 μm neodymium mode-locked lasers. The quality factor M(2) of the Q-switched beam was 1.4 and 1.6 in the horizontal and longitudinal planes, respectively, and the M(2) of the mode-locked beam reached 1.1 and 1.0. These results clearly indicate the advantages of few-layered graphene as a saturable absorber.

  9. Three types of pulses delivered from a nanotube-mode-locked fiber laser

    Science.gov (United States)

    Yao, X. K.

    2015-07-01

    Three types of pulses are experimentally investigated in a switchable normal-dispersion nanotube-mode-locked fiber laser by adjusting polarizer controller and pump power. They are a standard dissipative-soliton (DS), conventional soliton (CS)-like pulse, and noiselike pulse, which correspond to three mode-locking states. The standard DS with a rectangular spectrum possesses a Gaussian-shape pulse. The CS-like operation has a Lorenz shape, and the spectrum involves several sidebands similar to the CS case. For the noiselike pulse with a bell-shaped spectrum, a 317 fs peak rides upon the 132.5 ps pedestal in the autocorrelation trace. The spectra of these three pulse operations are centered at three close wavelengths. The generation of three such different types of pulses in one identical normal- dispersion laser cavity may find an important application for the future of mode-locked laser research.

  10. Near- infrared, mode-locked waveguide lasers with multi-GHz repetition rates

    Science.gov (United States)

    Choudhary, A.; Lagatsky, A. A.; Zhang, Z. Y.; Zhou, K. J.; Wang, Q.; Hogg, R. A.; Pradeesh, K.; Rafailov, E. U.; Resan, B.; Oehler, A. E. H.; Weingarten, K. J.; Sibbett, W.; Brown, C. T. A.; Shepherd, D. P.

    2014-02-01

    In this work, we discuss mode-locking results obtained with low-loss, ion-exchanged waveguide lasers. With Yb3+-doped phosphate glass waveguide lasers, a repetition rate of up to 15.2 GHz was achieved at a wavelength of 1047 nm with an average power of 27 mW and pulse duration of 811 fs. The gap between the waveguide and the SESAM introduced negative group velocity dispersion via the Gires Tournois Interferometer (GTI) effect which allowed the soliton mode-locking of the device. A novel quantum dot SESAM was used to mode-lock Er3+, Yb3+-doped phosphate glass waveguide lasers around 1500 nm. Picosecond pulses were achieved at a maximum repetition rate of 6.8 GHz and an average output power of 30 mW. The repetition rate was tuned by more than 1 MHz by varying the pump power.

  11. Hybrid mode-locked erbium-doped all-fiber soliton laser with a distributed polarizer.

    Science.gov (United States)

    Chernykh, D S; Krylov, A A; Levchenko, A E; Grebenyukov, V V; Arutunyan, N R; Pozharov, A S; Obraztsova, E D; Dianov, E M

    2014-10-10

    A soliton-type erbium-doped all-fiber ring laser hybrid mode-locked with a co-action of arc-discharge single-walled carbon nanotubes (SWCNTs) and nonlinear polarization evolution (NPE) is demonstrated. For the first time, to the best of our knowledge, boron nitride-doped SWCNTs were used as a saturable absorber for passive mode-locking initiation. Moreover, the NPE was introduced through the implementation of the short-segment polarizing fiber. Owing to the NPE action in the laser cavity, significant pulse length shortening as well as pulse stability improvement were observed as compared with a SWCNTs-only mode-locked laser. The shortest achieved pulse width of near transform-limited solitons was 222 fs at the output average power of 9.1 mW and 45.5 MHz repetition frequency, corresponding to the 0.17 nJ pulse energy.

  12. Attosecond-resolution timing jitter characterization of free-running mode-locked lasers.

    Science.gov (United States)

    Kim, Jungwon; Chen, Jeff; Cox, Jonathan; Kärtner, Franz X

    2007-12-15

    Timing jitter characterization of optical pulse trains from free-running mode-locked lasers with attosecond resolution is demonstrated using balanced optical cross correlation in the timing detector and the timing delay configurations. In the timing detector configuration, the balanced cross correlation between two mode-locked lasers synchronized by a low-bandwidth phase-locked loop is used to measure the timing jitter spectral density outside the locking bandwidth. In addition, the timing delay configuration using a 325 m long timing-stabilized fiber link enables the characterization of timing jitter faster than the delay time. The limitation set by shot noise in this configuration is 2.2 x 10(-8) fs(2)/Hz corresponding to 470 as in 10 MHz bandwidth.

  13. Tunable mode-locked laser with micro-air gap cavity

    Science.gov (United States)

    Ahmad, H.; Aidit, S. N.; Hassan, N. A.; Ooi, S. I.; Tiu, Z. C.

    2017-02-01

    A tunable mode-locked laser with a micro-air gap cavity acting as a high resolution tuning is proposed and demonstrated. The laser utilizes the nonlinear polarization technique in the cavity to obtain a reliable and stable mode locking over the whole tuning range at a resolution of 1 nm. The micro-air gap is constructed by aligning two fiber facets coaxially, and the variation of micro-air gap introduces a tuning mechanism where it changes the gain saturation compensation in the gain medium and thus induces wavelength shifting on the generated solitons.

  14. Comparative study on the temporal contrast of femtosecond mode-locked laser oscillators.

    Science.gov (United States)

    Stuart, Nicholas; Robinson, Timothy; Hillier, David; Hopps, Nick; Parry, Bryn; Musgrave, Ian; Nersisyan, Gagik; Sharba, Ahmed; Zepf, Matthew; Smith, Roland A

    2016-07-15

    We have investigated the temporal intensity contrast characteristics from a broad range of mode-locked short-pulse oscillators used for seeding high-power terawatt and petawatt-class laser systems. Saturable absorber (SESAM), Kerr lens (KLM), nonlinear polarization evolution (NPE) in optical fibers and synchronously pumped optical parametric oscillator (OPO) mode-locked sources have been measured using a third-order autocorrelator with up to 1010 dynamic range. We restricted the temporal characterization to features higher-order dispersion limits the performance of KLM and NPE sources up to the 105 contrast level, while >108 contrast was observed from the SESAM and OPO laser pulse trains.

  15. A Q-switched, mode-locked fiber laser employing subharmonic cavity modulation.

    Science.gov (United States)

    Chang, You Min; Lee, Junsu; Lee, Ju Han

    2011-12-19

    We present a new and simple approach for the generation of Q-switched, mode-locked pulses from a laser cavity. The approach is based on cavity loss modulation that employs a subharmonic frequency of the fundamental intermode frequency spacing. A range of experiments have been carried out using an erbium-doped fiber-based ring cavity laser in order to verify that this simple approach can readily produce high quality Q-switched, mode-locked pulses. An active tuning of the Q-switched envelope repetition rate is also shown to be easily achievable by adjusting the order of the applied subharmonic frequency.

  16. Figure-eight actively-passively mode-locked erbium-doped fiber laser

    Science.gov (United States)

    Wang, Zhaoying; Yu, Zhenhong; Ge, Chunfeng; Zhang, Ruifeng; Jia, Dongfang; Li, Shichen

    2003-03-01

    The advantages of using nonlinear optical loop mirror (NOLM) to compress pulse with slight amplitude fluctuation and reflected energy loss are analyzed in theory. Experimentally the NOLM is placed in an actively mode-locked erbium-doped fiber ring laser to form a figure-eight actively and passively modelocked fiber laser. 12 ps mode-locked pulses centered at 1.543 ?m were obtained with the modulation frequency of 2.498748700 GHz. 3.715 mW output power is achieved with 50 mW pump power.

  17. Graphene oxide mode-locked Yb:GAGG bulk laser operating in the femtosecond regime

    Science.gov (United States)

    Cui, Liang; Lou, Fei; Li, Yan-bin; Hou, Jia; He, Jing-Liang; Jia, Zhi-Tai; Liu, Jing-Quan; Zhang, Bai-Tao; Yang, Ke-Jian; Wang, Zhao-Wei; Tao, Xu-Tang

    2015-04-01

    High-quality graphene oxide saturable absorber (SA) is successfully fabricated with 1-2 layer graphene oxide. By employing this SA, we have demonstrated femtosecond pulse generation from a graphene oxide passively mode locked bulk laser for the first time to our best knowledge. With two Gires-Tournois interferometer mirrors for dispersion compensation, pulses as short as 493 fs with an average power of 500 mW are obtained at the central wavelength of 1035.5 nm. These results presented here indicate the great potential of GO for generating femtosecond mode-locked pulses in the bulk laser.

  18. Pulse-shaping mechanism in colliding-pulse mode-locked laser diodes

    DEFF Research Database (Denmark)

    Bischoff, Svend; Sørensen, Mads Peter; Mørk, J.;

    1995-01-01

    The large signal dynamics of passively colliding pulse mode-locked laser diodes is studied. We derive a model which explains modelocking via the interplay of gain and loss dynamics; no bandwidth limiting element is necessary for pulse formation. It is found necessary to have both fast and slow...... absorber dynamics to achieve mode-locking. Significant chirp is predicted for pulses emitted from long lasers, in agreement with experiment. The pulse width shows a strong dependence on both cavity and saturable absorber length. (C) 1995 American Institute of Physics....

  19. Low jitter and high power all-active mode-locked lasers

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

    2003-01-01

    A novel epitaxial design leading to low loss and low gain saturation improves the properties of 40 GHz mode-locked lasers. We obtain 2.8 ps nearly chirp free pulses with 228 fs jitter and fiber-coupled power of 7 mW.......A novel epitaxial design leading to low loss and low gain saturation improves the properties of 40 GHz mode-locked lasers. We obtain 2.8 ps nearly chirp free pulses with 228 fs jitter and fiber-coupled power of 7 mW....

  20. Low jitter and high power all-active mode-locked lasers

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

    2003-01-01

    A novel epitaxial design leading to low loss and low gain saturation improves the properties of 40 GHz mode-locked lasers. We obtain 2.8 ps nearly chirp free pulses with 228 fs jitter and -coupled power of 7 mW.......A novel epitaxial design leading to low loss and low gain saturation improves the properties of 40 GHz mode-locked lasers. We obtain 2.8 ps nearly chirp free pulses with 228 fs jitter and -coupled power of 7 mW....

  1. A semiconductor-based, frequency-stabilized mode-locked laser using a phase modulator and an intracavity etalon.

    Science.gov (United States)

    Davila-Rodriguez, Josue; Ozdur, Ibrahim; Williams, Charles; Delfyett, Peter J

    2010-12-15

    We report a frequency-stabilized semiconductor-based mode-locked laser that uses a phase modulator and an intracavity Fabry-Perot etalon for both active mode-locking and optical frequency stabilization. A twofold multiplication of the repetition frequency of the laser is inherently obtained in the process. The residual timing jitter of the mode-locked pulse train is 13 fs (1 Hz to 100 MHz), measured after regenerative frequency division of the photodetected pulse train.

  2. Experimental studies of self-starting passive mode locking Er3 + -doped fiber ring soliton laser

    Institute of Scientific and Technical Information of China (English)

    刘东峰; 陈国夫; 王贤华

    1999-01-01

    The mechanism of femtosecond optical pulse generation in a self-starting Er3+-doped fiber ring solitonlaser and experimental research results are discussed. Using the nonlinear polarization rotation effect of the fiber for sat-urable absorbers (and then self-amplitude modulation) which acts as the mode locking mechanism in an Er3+-dopedfiber ring cavity laser, stable self-starting mode locking pulses have been generated. The shortest output pulse is 269 fs,with the central wavelength of 1.531 μm at the repetition rate of 21.37 MHz. The average output powers of the two terminators of the laser are 0.25 mW and 0.08 mW respectively. The threshold pump power which sustains the mode lock-ing is 15 mW. Under high pump power, the laser works in a high order harmonic mode locking state. The mode lockingpulse durations vs different cavity lengths are also studied.

  3. A precise length etalon generator controlled by femtosecond mode-locked laser

    Science.gov (United States)

    Šmid, Radek; Čip, Ondřej; Lazar, Josef

    2007-09-01

    The progress in the field of optical frequency standards is oriented to femtosecond mode-locked lasers stabilized by technique of the optical frequency synthesis. Such a laser produces a supercontinuum light, which is composed of a cluster of coherent frequency components in certain interval of wavelengths. A value of the repetition rate of femtosecond pulses determines (in the frequency domain) spacing of these coherent components. If we control the mode-locked laser by means of i.e. atomic clocks we ensure frequency of these components very stable. With respect to definition of SI unit "one meter" on basis of speed of light the stabilized mode-locked laser can be used for implementation of this definition by non-traditional way. In the work we present our proposal of a system, which converts excellent frequency stability of components generated by the mode-locked laser to a net of discrete absolute lengths represented by a distance of two mirrors of an optical resonator. On basis of theory, the optical resonator with a cavity length has a periodic frequency spectrum Similarly the frequency of i-th comb component could be written as: f i = f ceo + i f rep, where f ceo is the comb offset frequency and f rep is the repetition rate. For the simplicity we presume the offset frequency f ceo equals to zero. If the supercontinuum beam of the mode-locked laser illuminates the resonator and at the same time the cavity length L is adjusted to length L p = c / (2 p f rep ) then both spectra fit. The symbol 'p' is an integer value. It produces intensity maximum in the output of the cavity, which is detected by a photodetector and locked in the servo-loop. For absolute discrete values of cavity lengths L p that well satisfy the condition above we obtain precise etalons of length.

  4. Multi-gigahertz repetition rate ultrafast waveguide lasers mode-locked with graphene saturable absorbers

    Science.gov (United States)

    Obraztsov, P. A.; Okhrimchuk, A. G.; Rybin, M. G.; Obraztsova, E. D.; Garnov, S. V.

    2016-08-01

    We report the development of an approach to build compact waveguide lasers that operate in the stable fundamental mode-locking regime with multigigahertz repetition rates. The approach is based on the use of depressed cladding multi- or single-mode waveguides fabricated directly in the active laser crystal using the femtosecond laser inscription method and a graphene saturable absorber. Using this approach we achieve the stable self-starting mode-locking operation of a diode-pumped waveguide Nd:YAG laser that delivers picosecond pulses at a repetition rate of up to 11.5 GHz with an average power of 12 mW at a central wavelength of 1064 nm. The saturable absorbers are formed through the chemical vapor deposition of single-layer graphene on the output coupler mirror or directly on the end facet of the laser crystal. The stable self-starting mode-locking operation is achieved by controlling the group delay dispersion in the laser cavity with an intracavity interferometer. The method developed for the creation of compact ultrashort pulse laser generators with gigahertz repetition rates can be extended further and applied for the development of compact high-repetition rate lasers that operate at a wide range of IR wavelengths.

  5. Techniques for increasing output power from mode-locked semiconductor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Mar, A.; Vawter, G.A.

    1996-02-01

    Mode-locked semiconductor lasers have drawn considerable attention as compact, reliable, and relatively inexpensive sources of short optical pulses. Advances in the design of such lasers have resulted in vast improvements in pulsewidth and noise performance, at a very wide range of repetition rates. An attractive application for these lasers would be to serve as alternatives for large benchtop laser systems such as dye lasers and solid-state lasers. However, mode-locked semiconductor lasers have not yet approached the performance of such systems in terms of output power. Different techniques for overcoming the problem of low output power from mode-locked semiconductor lasers will be discussed. Flared and arrayed lasers have been used successfully to increase the pulse saturation energy limit by increasing the gain cross section. Further improvements have been achieved by use of the MOPA configuration, which utilizes a flared semiconductor amplifier s amplify pulses to energies of 120 pJ and peak powers of nearly 30W.

  6. Generation of femtosecond optical vortex beams in all-fiber mode-locked fiber laser using mode selective coupler

    CERN Document Server

    Wang, Teng; Shi, Fan; Pang, Fufei; Huang, Sujuan; Wang, Tingyun; Zeng, Xianglong

    2016-01-01

    We experimentally demonstrated a high-order optical vortex pulsed laser based on a mode selective all-fiber fused coupler composed of a single-mode fiber (SMF) and a few-mode fiber (FMF). The fused SMF-FMF coupler inserted in the cavity not only acts as mode converter from LP01 mode to LP11 or LP21 modes with a broadband width over 100 nm, but also directly delivers femtosecond vortex pulses out of the mode locked cavity. To the best of our knowledge, this is the first report on the generation of high-order pulse vortex beams in mode-locked fiber laser. The generated 140 femtosecond vortex beam has a spectral width of 67 nm centered at 1544 nm.

  7. Resonantly pumped continuous-wave mode-locked Ho:YAP laser

    Science.gov (United States)

    Duan, X. M.; Lin, W. M.; Cui, Z.; Yao, B. Q.; Li, H.; Dai, T. Y.

    2016-04-01

    In this paper, we report a continuous-wave mode-locked Ho:YAP laser for the first time to our knowledge. Mode-locked pulse was produced by using an acousto-optic modulator. A 1.91-μm Tm-fiber laser as the pump source, at incident pump power of 25.9 W, the maximum output power of 2.87 W at 2117.8 nm was achieved in continuous-wave mode-locked regime. Pulse as short as 254.8 ps was obtained at repetition frequency of 81.52 MHz. In addition, the beam quality factor M 2 value of 1.6 was obtained.

  8. 10-GHz 1.59-μm quantum dash passively mode-locked two-section lasers

    DEFF Research Database (Denmark)

    Dontabactouny, Madhoussoudhana; Rosenberg, C.; Semenova, Elizaveta

    2010-01-01

    This paper reports the fabrication and the characterisation of a 10 GHz two-section passively mode-locked quantum dash laser emitting at 1.59 μm. The potential of the device's mode-locking is investigated through an analytical model taking into account both the material parameters and the laser g...

  9. High-resolution microwave-photonic applications via precise synchronization between RF and mode-locked laser pulses (Conference Presentation)

    Science.gov (United States)

    Shi, Kebin; Lu, Xing; Lv, Zhiqiang

    2016-10-01

    Precise synchronization between radio frequency and mode-locked laser pulses provides a high resolution capability for detecting either time jitter in laser pulse train or phase noise in radio frequency. In this talk, we will present our recent progresses on radio frequency dissemination and fiber optical sensing based on sub-femtosecond level synchronization between radio frequency and mode-locked pulse train.

  10. Ultrafast pulse generation in a mode-locked Erbium chip waveguide laser

    CERN Document Server

    Khurmi, Champak; Zhang, Wen Qi; V., Shahraam Afshar; Chen, George; Genest, Jérôme; Monro, Tanya M; Lancaster, David G

    2016-01-01

    We report mode-locked ~1550 nm output of transform-limited ~180 fs pulses from a large mode-area (diameter ~ 50 {\\mu}m) guided-wave erbium fluorozirconate glass laser. The passively mode-locked oscillator generates pulses with 25 nm bandwidth at 156 MHz repetition rate and peak-power of 260 W. Scalability to higher repetition rate is demonstrated by transform-limited 410 fs pulse output at 1.3 GHz. To understand the origins of the broad spectral output, the laser cavity is simulated by using a numerical solution to the Ginzburg-Landau equation. This paper reports the widest bandwidth and shortest pulses achieved from an ultra-fast laser inscribed waveguide laser.

  11. Monolithic mode-locked lasers with deeply dry etched Bragg mirror

    DEFF Research Database (Denmark)

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

    Background: Semiconductor mode-locked lasers are attractive as components in futureultra high-speed telecommunication systems (160-640Gb/s); as picosecond pulse sources,clock-recovery devices and for demultiplexing in Optical Time Division Multiplexing(OTDM) systems. We have recently designed, fa...

  12. Tunable mode-locked semiconductor laser with Bragg mirror external cavity

    DEFF Research Database (Denmark)

    Yvind, Kresten; Jørgensen, T.; Birkedal, Dan

    2002-01-01

    We present a simplified design for a wavelength tunable external cavity mode-locked laser by employing a wedged GaAs/AlGaAs Bragg mirror. The device emits 4-6 ps pulses at 10 GHz and is tunable over 15 nm. Although, in the present configuration, tunability is limited to 15 nm, however, we have...

  13. Picosecond pulse generation from a synchronously pumped mode-locked semiconductor laser diode

    Science.gov (United States)

    Auyeung, J. C.; Johnston, A. R.

    1982-01-01

    A semiconductor laser diode was mode locked in an external cavity when synchronously pumped with 90-ps current pulses. Transform-limited optical pulses with a 10-ps pulse width and a peak power of 160 mW were produced. Operating characteristics of such a system are described.

  14. Stable mode-locking in an Yb:YAG laser with a fast SESAM

    Institute of Scientific and Technical Information of China (English)

    Guifang Ju(居桂方); Lu Chai(柴路); Qingyue Wang(王清月); Zhigang Zhang(张志刚); Yonggang Wang(王勇刚); Xiaoyu Ma(马骁宇)

    2003-01-01

    Stable mode-locking in a diode-pumped Yb:YAG laser was obtained with a very fast semiconductor saturable absorber mirror (SESAM). The pulse width was measured to be 4 ps at the central wavelength of 1047 nm. The average power was 200 mW and the repetition rate was 200 MHz.

  15. Performance of external cavity mode-locked semiconductor lasers employing reverse biased saturable absorbers

    DEFF Research Database (Denmark)

    Yvind, Kresten; Skovgaard, P.M.W.; Mørk, Jesper;

    2002-01-01

    We have experimentally investigated the performance of external cavity mode-locked semiconductor lasers employing reverse biased saturable absorbers. We have measured the magnitude of trailing pulses when varying the chip length and studied the pulse quality when changing the driving conditions...

  16. Spectral development of pico second pulses of mode-locked Nd-glass lasers

    Energy Technology Data Exchange (ETDEWEB)

    Penzkofer, A.; Weinhardt, N.

    1983-04-01

    The spectra of single picosecond pulses of mode-locked Nd-glass lasers are investigated along the pulse train. In addition to self-phase modulation, the spectra are modified due to spectral hole burning in the inhomogeneous gain profile of the active medium.

  17. Monolithic Multi-Colour 40 GHz Mode-Locked Laser Array

    OpenAIRE

    Hou, Lianping; Eddie, Iain; Marsh, John

    2016-01-01

    The monolithic integration of four 40 GHz multi-colored mode-locked lasers with a 4×1 MMI, four electroabsorption modulators and an SOA has been demonstrated. The shortest pulse widths are between 2.63 and 2.85 ps.

  18. Quantum beats in forward scattering: subnanosecond studies with a mode-locked dye laser.

    Science.gov (United States)

    Harde, H; Burggraf, H; Mlynek, J; Lange, W

    1981-06-01

    Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D(1) and D(2), lines were resolved. The ground-state splitting could be determined with an accuracy of better than 10(-3).

  19. Quantum beats in forward scattering - Subnanosecond studies with a mode-locked dye laser

    Science.gov (United States)

    Harde, H.; Burggraf, H.; Mlynek, J.; Lange, W.

    1981-06-01

    Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D1 and D2 lines were resolved. The ground-state splitting could be determined with an accuracy of better than 0.001.

  20. Automated mode locking in nonlinear polarization rotation fiber lasers by detection of a discontinuous jump in the polarization state.

    Science.gov (United States)

    Olivier, Michel; Gagnon, Marc-Daniel; Piché, Michel

    2015-03-09

    A strategy to align a mode-locked fiber laser with nonlinear polarization rotation is presented. This strategy is based on measurements of the output polarization state. It is shown that, as the angle of a motorized polarization controller inside the cavity is swept, the laser eventually reaches a mode-locked regime and the values of the Stokes parameters undergo an abrupt change. The sensing of this sudden variation is thus used to detect the mode-locking condition and a feedback mechanism drives the alignment of the polarization controller to force mode locking.

  1. Long-term stable microwave signal extraction from mode-locked lasers

    Science.gov (United States)

    Kim, J.; Ludwig, F.; Felber, M.; Kärtner, F. X.

    2007-07-01

    Long-term synchronization between two 10.225 GHz microwave signals at +10 dBm power level, locked to a 44.26 MHz repetition rate passively mode-locked fiber laser, is demonstrated using balanced optical-microwave phase detectors. The out-of-loop measurement result shows 12.8 fs relative timing jitter integrated from 10 Hz to 10 MHz. Long-term timing drift measurement shows 48 fs maximum deviation over one hour, mainly limited by drift of the out-of-loop characterization setup itself. To the best of our knowledge, this is the first time to demonstrate long-term (>1 hour) 3 mrad-level phase stability of a 10.225 GHz microwave signal extracted from a mode-locked laser.

  2. Experimental investigation of relaxation oscillations resonance in mode-locked Fabry-Perot semiconductor lasers

    CERN Document Server

    Roncin, Vincent; Hayau, Jean-François; Besnard, Pascal; Simon, Jean-Claude; Van Dijk, F; Shen, Alexandre; Duan, Guang-Hua

    2014-01-01

    We propose in this communication an experimental study of the relaxation oscillations behavior in mode-locked lasers. The semiconductor self-pulsating laser diode is composed by two gain sections, without saturable absorber. It is made of bulk structure and designed for optical telecommunication applications. This specific device allows two different regimes of optical modulation: the first one corresponds to the resonance of the relaxation oscillations and the second one, to the mode-locking regime at FSR value. This singular behavior leads us to characterize the self-pulsations which are coexisting in the laser and to describe two regimes of output modulation: the first one appears thanks to the resonance of the oscillation relaxation and the other one corresponds to the FSR of the Fabry-Perot laser at 40 GHz.

  3. Observation of soliton explosions in a passively mode-locked fiber laser

    CERN Document Server

    Runge, Antoine F J; Erkintalo, Miro

    2014-01-01

    Soliton explosions are among the most exotic dissipative phenomena studied in mode-locked lasers. In this regime, a dissipative soliton circulating in the laser cavity experiences an abrupt structural collapse, but within a few roundtrips returns to its original quasi-stable state. In this work we report on the first observation of such events in a fiber laser. Specifically, we identify clear explosion signatures in measurements of shot-to-shot spectra of an Yb-doped mode-locked fiber laser that is operating in a transition regime between stable and noise-like emission. The comparatively long, all-normal-dispersion cavity used in our experiments also permits direct time-domain measurements, and we show that the explosions manifest themselves as abrupt temporal shifts in the output pulse train. Our experimental results are in good agreement with realistic numerical simulations based on an iterative cavity map.

  4. Pulse formation and characteristics of the cw mode-locked titanium-doped sapphire laser

    Science.gov (United States)

    Zschocke, Wolfgang; Stamm, Uwe; Heumann, Ernst; Ledig, Mario; Guenzel, Uwe; Kvapil, Jiri; Koselja, Michael P.; Kubelka, Jiri

    1991-10-01

    We report on measurements of transient and steady-state pulse characteristics of an acousto- optically mode-locked titanium-doped sapphire laser. During the pulse evolution, oscillations in the pulse width and pulse energy are found. A steady state is reached after about 40 to 60 microsecond(s) . The steady-state pulse width is strongly influenced by the mode-locking loss as well as the intracavity bandwidth. Shortest pulses of typically 15 ps are obtained. The experiment is compared with results of a simple computer simulation.

  5. A 12.1-W SESAM mode-locked Yb:YAG thin disk laser

    Science.gov (United States)

    Yingnan, Peng; Zhaohua, Wang; Dehua, Li; Jiangfeng, Zhu; Zhiyi, Wei

    2016-05-01

    Pumped by a 940 nm fiber-coupled diode laser, a passively mode-locked Yb:YAG thin disk oscillator was demonstrated with a semiconductor saturable absorber mirror (SESAM). 12.1 W mode-locked pulses were obtained with pulse duration of 698 fs at the repetition rate of 57.43 MHz. Measurement showed that the beam quality was close to the diffraction limit. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB922402), the National Major Instrument Program of China (Grant No. 2012YQ120047), and the National Natural Science Foundation of China (Grant No. 61210017).

  6. Polarization dynamics in dissipative soliton fiber lasers mode-locked by nonlinear polarization rotation.

    Science.gov (United States)

    Kong, Lingjie; Xiao, Xiaosheng; Yang, Changxi

    2011-09-12

    We numerically studied the polarization dynamics in dissipative soliton lasers mode-locked by nonlinear polarization rotation (NPR). It was found that the polarization states of the intracavity dissipative soliton vary with time across the pulse. Depending on output coupling ratios, the polarization states of the pulse peak before the polarizer can be either nearly circular or nearly linear polarizations. The polarization dependent component in NPR is found to play a role of spectral filter under high and medium output coupling. However, NPR may work as a weak optical limiter under low output coupling, when additional spectral filtering is necessary to maintain steady mode-locking state.

  7. Adjustable high-repetition-rate pulse trains in a passively-mode-locked fiber laser

    Science.gov (United States)

    Si Fodil, Rachid; Amrani, Foued; Yang, Changxi; Kellou, Abdelhamid; Grelu, Ph.

    2016-07-01

    We experimentally investigate multipulse regimes obtained within a passively-mode-locked fiber laser that includes a Mach-Zehnder (MZ) interferometer. By adjusting the time delay imbalance of the MZ, ultrashort pulse trains at multi-GHz repetition rates are generated. We compare the observed dynamics with high-harmonic mode locking, and show that the multi-GHz pulse trains display an inherent instability, which has been overlooked. By using a recirculation loop containing the MZ, we demonstrate a significant improvement of the pulse train stability.

  8. Observation of self-mode-locked noise-like pulses from a net normal dispersion erbium-doped fiber laser

    Science.gov (United States)

    Li, Kexuan; Tian, Jinrong; Guoyu, Heyang; Xu, Runqin; Song, Yanrong

    2017-04-01

    Self-mode-locked noise-like pulses (NLPs) were experimentally investigated from a normal dispersion erbium-doped fiber laser. Different from noise-like pulses with a broadband spectrum, the self-mode-locked NLPs have a narrow optical spectrum of 1-2 nm and hundreds of nanoseconds duration. However, the intra-cavity maximum energy of NLPs is up to 560 nJ without pulse breaking. The higher pulse energy output is promising in the proposed fiber laser. To confirm whether self-mode-locked NLPs are caused by an invisible nonlinear polarization rotation (NPR) mechanism owing to slight residual polarization asymmetry of the fiber and components used, we compared the output characteristics between self-mode-locked NLPs and NPR mode-locked pulses in the same cavity. The experimental results show that the formation mechanism of such self-mode-locked NLPs could be related to a weak NPR effect.

  9. Q-switched mode-locking of an erbium-doped fiber laser using cavity modulation frequency detuning.

    Science.gov (United States)

    Chang, You Min; Lee, Junsu; Jhon, Young Min; Lee, Ju Han

    2012-07-20

    We present the results of an investigation regarding a Q-switched mode-locked fiber laser scheme based on a cavity modulation frequency detuning technique. The approach is based on undamped laser relaxation oscillations occurring due to frequency detuning in the fundamental cavity resonance frequency. Through a range of experiments with an erbium-doped, fiber-based, ring-cavity laser, this approach has been shown to be capable of generating high-quality Q-switched mode-locked pulses from an optical fiber-based laser. The maximum frequency detuning range for a stable Q-switched mode-locking operation has been observed to vary depending on the pump power used. We found that the highest pulse peak power was obtained at the frequency detuning threshold at which the operation changed from the mode-locking to the Q-switched mode-locking regime.

  10. Wavelength and duration tunable soliton generation from a regeneratively mode-locked fiber laser

    Institute of Scientific and Technical Information of China (English)

    Bin Tan(谈斌); Zhiyong Li(李智勇); Zhaoying Wang(王肇颖); Chunfeng Ge(葛春风); Dongfang Jia(贾东方); Wenjun Ni(倪文俊); Shichen Li(李世忱)

    2004-01-01

    A 10-GHz soliton source with pulse duration between 4-8 ps and wavelength continuously tunable from 1530 to 1563 nm is presented. Using regeneratively mode-locking technology, the harmonically modelocked fiber ring laser could work without pulse dropout at room temperature when no cavity length or polarization maintaining mechanism is available. Applying only one 980-nm laser diode pump, the average output power reaches more than 4 mW.

  11. Phase diagram and complexity of mode-locked lasers: from order to disorder

    CERN Document Server

    Leuzzi, L; Folli, V; Angelani, L; Ruocco, G

    2008-01-01

    We investigate mode-locking processes in lasers displaying a variable degree of structural randomness, from standard optical cavities to multiple-scattering media. By employing methods mutuated from spin-glass theory, we analyze the mean-field Hamiltonian and derive a phase-diagram in terms of the pumping rate and the degree of disorder. Three phases are found: i) paramagnetic, corresponding to a noisy continuous wave emission, ii) ferromagnetic, that describes the standard passive mode-locking, and iii) the spin-glass in which the phases of the electromagnetic field are frozen in a exponentially large number of configurations. The way the mode-locking threshold is affected by the amount of disorder is quantified. The results are also relevant for other physical systems displaying a random Hamiltonian, like Bose-Einstein condensates and nonlinear optical beams.

  12. Harmonic Mode-Locked Fiber Laser based on Photonic Crystal Fiber Filled with Topological Insulator Solution

    Directory of Open Access Journals (Sweden)

    Yu-Shan Chen

    2015-04-01

    Full Text Available We reported that the photonic crystal fiber (PCF filled with TI:Bi2Te3 nanosheets solution could act as an effective saturable absorber (SA. Employing this TI-PCF SA device; we constructed an ytterbium-doped all-fiber laser oscillator and achieved the evanescent wave mode-locking operation. Due to the large cavity dispersion; the fundamental mode-locking pulse had the large full width at half maximum (FWHM of 2.33 ns with the repetition rate of ~1.11 MHz; and the radio frequency (RF spectrum with signal-to-noise ratio (SNR of 61 dB. In addition; the transition dynamics from a bunched state of pulses to harmonic mode-locking (HML was also observed; which was up to 26th order.

  13. Electronic control of nonlinear-polarization-rotation mode locking in Yb-doped fiber lasers.

    Science.gov (United States)

    Shen, Xuling; Li, Wenxue; Yan, Ming; Zeng, Heping

    2012-08-15

    We demonstrate a convenient approach to precisely tune the polarization state of a nonlinear-polarization-rotation mode-locked Yb-doped fiber laser by using an electronic polarization controller. It is shown to benefit self-starting of mode-locking states, with precise tuning of the spectral profile, pulse width, and carrier-envelope offset frequency. The pulse width changed linearly by 0.78 ps in the time domain, and the carrier-envelope offset frequency shifted ~77.5 MHz in the frequency domain with a slight change of the driving voltage of 30.7 mV applied on the controller, corresponding to a polarization rotation of 0.0135π. This facilitated precise and automatic regeneration of a particular mode-locking state by setting an accurate voltage at the polarization controller with a programmed microprocessor control unit.

  14. Tunable and switchable dual-wavelength Tm-doped mode-locked fiber laser by nonlinear polarization evolution.

    Science.gov (United States)

    Yan, Zhiyu; Li, Xiaohui; Tang, Yulong; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2015-02-23

    We propose and demonstrate a tunable and switchable dual-wavelength ultra-fast Tm-doped fiber laser. The tunability is based on nonlinear polarization evolution (NPE) technique in a passively mode-locked laser cavity. The NPE effect induces wavelength-dependent loss in the cavity to effectively alleviate mode competition and enables the multiwavelength mode locking. The laser exhibits tunable dual-wavelength mode locking over a wide range from 1852 to 1886 nm. The system has compact structure and both the wavelength tuning and switching capabilities can be realized by controlling the polarization in the fiber ring cavity.

  15. 1700 nm dispersion managed mode-locked bismuth fiber laser

    OpenAIRE

    Teppo Noronen; Sergei Firstov; Evgeny Dianov; Okhotnikov, Oleg G.

    2016-01-01

    We demonstrate the first 1.7 μm bismuth-doped fiber laser generating ultrashort pulses via passive mode-locking. Pulse operation has been achieved for both anomalous and normal dispersion of the laser cavity owing to broadband characteristics of carbon nanotube saturable absorber. The laser delivered 1.65 ps pulses in net anomalous dispersion regime. In normal dispersion regime, the laser delivered 14 ps pulses which could be compressed to 1.2 ps using external fiber compressor.

  16. 1700 nm dispersion managed mode-locked bismuth fiber laser

    Science.gov (United States)

    Noronen, Teppo; Firstov, Sergei; Dianov, Evgeny; Okhotnikov, Oleg G.

    2016-04-01

    We demonstrate the first 1.7 μm bismuth-doped fiber laser generating ultrashort pulses via passive mode-locking. Pulse operation has been achieved for both anomalous and normal dispersion of the laser cavity owing to broadband characteristics of carbon nanotube saturable absorber. The laser delivered 1.65 ps pulses in net anomalous dispersion regime. In normal dispersion regime, the laser delivered 14 ps pulses which could be compressed to 1.2 ps using external fiber compressor.

  17. Hybrid mode-locked fiber ring laser using graphene and charcoal nanoparticles as saturable absorbers

    Science.gov (United States)

    Hu, Hongyu; Zhang, Xiang; Li, Wenbo; Dutta, Niloy K.

    2016-05-01

    A fiber ring laser which implements hybrid mode locking technique has been proposed and experimentally demonstrated to generate pulse train at 20 GHz repetition rate with ultrashort pulse width. Graphene and charcoal nano-particles acting as passive mode lockers are inserted into a rational harmonic mode-locked fiber laser to improve the performance. With graphene saturable absorbers, the pulse duration is shortened from 5.3 ps to 2.8 ps, and with charcoal nano-particles, it is shortened to 3.2 ps. The RF spectra show that supermode noise can be removed in the presence of the saturable absorbers. Numerical simulation of the pulse transmission has also been carried out, which shows good agreement with the experimental results.

  18. Pulse Evolution Characteristics in Self-Similar Mode-locked Fibre Laser

    Institute of Scientific and Technical Information of China (English)

    TU Cheng-Hou; LI Zhen; LEI Ting; LI Yong-Nan; GUO Wen-Gang; WEI Dai; ZHU Hui; ZHANG Shuang-Gen; LU Fu-Yun

    2007-01-01

    A self-similar mode locked fibre laser is studied based on a numerical model. By introducing a dimensionless factor k to characterize the pulse shape, the self-similar pulse evolution, formation and the temporal and spectral shape changes due to the elements in the cavity are investigated throughout the iaser cavity. The results show that in the self-similar mode locked fibre laser, self-similar pulse is first formed in the single-mode fibre, which is then amplified in the gain fibre. Gain bandwidth has a small influence on pulse shape, so high energy self-similar pulse can be obtained after amplification. Because net cavity dispersion directly influences the pulse width as well as peak power after compression by a pair of gratings, which can determine the pulse self-similar evolution, it is very important to control the net cavity dispersion to a certain range to obtain self-similar pulses.

  19. Low threshold diode-pumped picosecond mode-locked Nd:YAG laser with a semiconductor saturable absorber mirror

    Science.gov (United States)

    Eshghi, M. J.; Majdabadi, A.; Koohian, A.

    2017-01-01

    In this paper, a low threshold diode pumped passively mode-locked Nd:YAG laser has been demonstrated by using a semiconductor saturable absorber mirror. The threshold power for continuous-wave mode-locking is relatively low, about 3.2 W. The resonator stability across the pump power has been analytically examined. Moreover, the mode overlap between the pump beam and the laser fundamental mode has been simulated by MATLAB software. Adopting Z-shaped resonator configuration and suitable design of the resonator’s arm lengths, has enabled the author to prepare mode-locking conditions, and obtain 40 ps pulses with 112 MHz pulse repetition rate. The laser output was stable without any Q switched instability. To the best of our knowledge, this is the lowest threshold for CW mode-locking operation of a Nd:YAG laser.

  20. Scheme for independently stabilizing the repetition rate and optical frequency of a laser using a regenerative mode-locking technique.

    Science.gov (United States)

    Nakazawa, Masataka; Yoshida, Masato

    2008-05-15

    We have succeeded in achieving independent control of the repetition rate and optical frequency of a pulse laser by employing a regenerative mode-locking technique. By adopting a voltage-controlled microwave phase shifter or an optical delay line in a regenerative feedback loop we can control the repetition rate of the laser without directly disturbing the optical frequencies. We experimentally show how this independent control can be realized by employing a 40 GHz harmonically and regeneratively mode-locked fiber laser.

  1. Wavelength tunable stretched-pulse mode-locked all-fiber erbium ring laser with single polarization fiber.

    Science.gov (United States)

    Li, Shenping; Chen, Xin; Kuksenkov, Dmitri V; Koh, Joohyun; Li, Ming-Jun; Zenteno, Luis A; Nolan, Daniel A

    2006-06-26

    A wavelength tunable stretched-pulse mode-locked all-fiber ring laser using single polarization fiber (SPF) was demonstrated. In this laser, a segment of SPF was used simultaneously as a polarizer and a tunable filter in the laser cavity. Self-starting mode-locking with femtosecond output pulses was demonstrated. A wavelength tuning of ~20nm was achieved by bending the SPF with different radii.

  2. Optical 40 GHz pulse source module based on a monolithically integrated mode locked DBR laser

    Science.gov (United States)

    Huettl, B.; Kaiser, R.; Kroh, M.; Schubert, C.; Jacumeit, G.; Heidrich, H.

    2005-11-01

    In this paper the performance characteristics of compact optical 40 GHz pulse laser modules consisting of a monolithic mode-locked MQW DBR laser on GaInAsP/InP are reported. The monolithic devices were fabricated as tunable multi-section buried heterostructure lasers. A DBR grating is integrated at the output port of an extended cavity in order to meet the standardized ITU wavelength channels allocated in the spectral window around 1.55 μm in optical high speed communication networks. The fabricated 40 GHz lasers modules not only emit short optical pulses (< 1.5 ps) with very low amplitude noise (<1.5 %) and phase noise levels (timing jitter: 50 fs) but also enable good pulse-to-pulse phase and long-term stability. A wavelength tuning range of 6 nm is possible and large locking bandwidths between 100 ... 260 MHz are observed. All data have been achieved by operating the lasers in a hybrid mode-locking scheme with a required minimum micro-wave power of only 12 dBm for pulse synchronization. Details on laser chip architecture and module performance are summarized and the results of a stable and error free module performance in first 160 Gb/s (4 x 40 Gb/s OTDM) RZ-DPSK transmission experiments are presented.

  3. Systematic investigation of the temperature behavior of InAs/InP quantum nanostructure passively mode-locked lasers

    DEFF Research Database (Denmark)

    Klaime, K.; Piron, R.; Grillot, F.

    2013-01-01

    This paper aims to investigate the effects of the temperature on the mode-locking capability of two section InAs/InP quantum nanostructure (QN) passively mode locked lasers. Devices are made with multi-layers of self-assembled InAs QN either grown on InP(100) (5 quantum dashes (QDashes) layers...

  4. Passively mode-locked fiber laser based on polarization rotation in a multiple-quantum-well waveguide.

    Science.gov (United States)

    Okhotnikov, O G; Salcedo, J R

    1995-01-01

    We give experimental evidence for a new type of mode-locking mechanism for Er-doped fiber lasers based on polarization evolution in an intracavity multiple-quantum-well waveguide. Experiments indicate that anisotropic properties of waveguides can continuously start the mode-locking process.

  5. The generation of femtosecond light pulses from a laser with combined mode locking with new saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, B.V.; Prokhorenko, V.I.; Rodionov, G.D.; Sorokin, V.B.; Slominskii, IU.L.

    1989-01-01

    Combined mode locking was studied experimentally using new 3492-y and 3490-y dyes. In a linear single-stream R6G laser, the 3490-y dye provides for stable mode locking throughout the 576-615 nm tuning range. The pulse duration varies over the tuning range from 180-250 fs, the lasing efficiency amounting to 17 percent. 10 refs.

  6. Mode-locked laser realized by selective area growth for short pulse generation and optical clock recovery in TDM systems

    Science.gov (United States)

    Lach, Eugen; Baums, Dieter; Bouayad-Amine, Jamal; Hache, Claudia; Haisch, Hansjorg; Kuhn, Edgar; Satzke, Klaus; Schilling, Michael; Weber, Juergen; Zielinski, Erich

    1996-04-01

    We report on monolithically integrated active/passive coupled cavity mode locked lasers for 1.55 micrometer realized by selective area growth technology of InGaAs(P) quantum wells. Mode locked FP or DBR lasers are fabricated with an integrated cavity comprising up to three different band gaps. The devices emit short light pulses at around 10 GHz repetition rate with pulse width down to 8.7 ps. A time-bandwidth product of 0.5 is achieved for mode locked DBR lasers. Active/passive integrated mode locked laser is used for generation of optical 10 GHz clock signal from optical 10 Gb/s PRBS RZ data stream injected into the laser cavity.

  7. Polarisation effects in twin-core fibre: Application for mode locking in a fibre laser

    Energy Technology Data Exchange (ETDEWEB)

    Lobach, I A; Kablukov, S I; Podivilov, Evgenii V; Babin, Sergei A; Apolonski, A A

    2012-09-30

    We report the first measurements of the longitudinal power distribution in a twin-core optical fibre at different input light polarisations. Experimental evidence is presented that, because of the difference in birefringence between the cores, the power in them depends on which core the beam is launched into. Experimental data are interpreted in terms of a modified polarisation model for mode coupling in twin-core fibres which takes into account the birefringence of the cores. In addition, we demonstrate for the first time the use of the polarisation properties of a twincore fibre for mode locking in a fibre laser. (optical fibres, lasers and amplifiers. properties and applications)

  8. Modeling of mode-locking in a laser with spatially separate gain media

    CERN Document Server

    Oldenbeuving, R M; van Voorst, P D; Offerhaus, H L; Boller, K -J

    2010-01-01

    We present a novel laser mode-locking scheme and discuss its unusual properties and feasibility using a theoretical model. A large set of single-frequency continuous-wave lasers oscillate by amplification in spatially separated gain media. They are mutually phase-locked by nonlinear feedback from a common saturable absorber. As a result, ultra short pulses are generated. The new scheme offers three significant benefits: the light that is amplified in each medium is continuous wave, thereby avoiding issues related to group velocity dispersion and nonlinear effects that can perturb the pulse shape. The set of frequencies on which the laser oscillates, and therefore the pulse repetition rate, is controlled by the geometry of resonator-internal optical elements, not by the cavity length. Finally, the bandwidth of the laser can be controlled by switching gain modules on and off. This scheme offers a route to mode-locked lasers with high average output power, repetition rates that can be scaled into the THz range, ...

  9. Effects of resonator input power on Kerr lens mode-locked lasers

    Indian Academy of Sciences (India)

    S Kazempour; A Keshavarz; G Honarasa

    2015-07-01

    Using the ABCD matrix method, the common stability region between the sagittal and tangential planes of a four-mirror Kerr lens mode-locked (KLM) laser cavity is obtained for different ranges of input power. In addition, the effect of the input power on the Kerr lens sensitivity is investigated. Optimal input power and position for highest Kerr lens sensitivity in the stability region are presented and self-starting regime has been achieved. Results show that the resonator input power has a great influence on designing the KLM lasers which can be used in fabricating an optimal femtosecond laser.

  10. Ultrashort mode-locked lasers with additional Raman active elements

    Science.gov (United States)

    Trunov, V. I.; Kirpichnikov, A. V.; Pestryakov, Efim V.; Petrov, V. V.; Komarov, A. K.; Komarov, Konstantin P.

    2002-05-01

    Numerical simulation of ultrashort pulse generation in the laser with a composite active medium and additional Raman active element in a cavity has been done. It was created that for some laser parameters the optimization of a Raman gain and a frequency shift values was resulted in additional shortening of pulse duration.

  11. Low-loss flake-graphene saturable absorber mirror for laser mode-locking at sub-200-fs pulse duration

    CERN Document Server

    Cunning, B V; Kielpinski, D

    2011-01-01

    Saturable absorbers are a key component for mode-locking femtosecond lasers. Polymer films containing graphene flakes have recently been used in transmission as laser mode-lockers, but suffer from high nonsaturable loss, limiting their application in low-gain lasers. Here we present a saturable absorber mirror based on a film of pure graphene flakes. The device is used to mode lock an erbium-doped fiber laser, generating pulses with state-of-the-art, sub-200-fs duration. The laser characteristic indicate that the film exhibits low nonsaturable loss (13% per pass) and large absorption modulation depth (45% of low-power absorption).

  12. Fabrication and Characterisation of Low-noise Monolithic Mode-locked Lasers

    DEFF Research Database (Denmark)

    Larsson, David

    2007-01-01

    This thesis deals with the fabrication and characterisation of monolithic semiconductor mode-locked lasers for use in optical communication systems. Other foreseeable applications may be as sources in microwave photonics and optical sampling. The thesis also deals with the design and fabrication...... of intracavity monolithically integrated filters. The common dnominator among the diffrent parts of the thesis is how to achieve and measure the lowest possible noise. Achieving low noise has been pinpointed as one of the most important and difficult challenges for semiconductor mode-locked lasers. The main...... result of this thesis are a fabrication process of a monolithic and deeply etched distributed Bragg reflector and a characterisation system for measurement of quantum limitid timing noise at high repetition rates. The Bragg reflector is a key component in achieving transform limited pulses with low noise...

  13. Magneto-optic Crystal Polarization Controller Assisted Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guang-Zhen; GUI Li-Li; XIAO Xiao-Sheng; YANG Chang-Xi

    2011-01-01

    We report a passively mode-locked erbium-doped fiber laser based on a compact magneto-optic crystal polarization controller. The length of the polarization controller consisting of four magneto-optic crystal rotators and two quarter wave-plates is only 10cm.Adjusting the polarization controller, central wavelength around 1559nm and repetition rate 21.10 MHz mode-locked pulse are obtained. Pulse duration and 3 dB spectrum width are 598.4fs and 6.24nm respectively. Single pulse energy is about 151.7pJ. Because of its small size, low insertion loss,good controllability and negligible dispersion, the magneto-optic crystal polarization controller could be an ideal polarization controller in fiber lasers.

  14. Diode-pumped Yb,Y:CaF2 laser mode-locked by monolayer graphene

    Science.gov (United States)

    Zhu, Hongtong; Liu, Jie; Jiang, Shouzhen; Xu, Shicai; Su, Liangbi; Jiang, Dapeng; Qian, Xiaobo; Xu, Jun

    2015-12-01

    The large-area and high-quality monolayer graphene saturable absorber with a sandwich structure is prepared by the chemical vapor deposition technique. Using graphene saturable absorber, the mode locking operation of a diode-pumped Yb,Y:CaF2 laser is demonstrated. Without extra negative dispersion elements, 4.8 ps pulses are yielded at 1051 nm. The pulse repetition rate is 60 MHz.

  15. Laser-diode pumped self-mode-locked praseodymium visible lasers with multi-gigahertz repetition rate.

    Science.gov (United States)

    Zhang, Yuxia; Yu, Haohai; Zhang, Huaijin; Di Lieto, Alberto; Tonelli, Mauro; Wang, Jiyang

    2016-06-15

    We demonstrate efficient laser-diode pumped multi-gigahertz (GHz) self-mode-locked praseodymium (Pr3+) visible lasers with broadband spectra from green to deep red for the first time to our knowledge. With a Pr3+-doped GdLiF4 crystal, stable self-mode-locked visible pulsed lasers at the wavelengths of 522 nm, 607 nm, 639 nm, and 720 nm have been obtained with the repetition rates of 2.8 GHz, 3.1 GHz, 3.1 GHz, and 3.0 GHz, respectively. The maximum output power was 612 mW with the slope efficiency of 46.9% at 639 nm. The mode-locking mechanism was theoretically analyzed. The stable second-harmonic mode-locking with doubled repetition frequency was also realized based on the Fabry-Perot effect formed in the laser cavity. In addition, we find that the polarization directions were turned with lasing wavelengths. This work may provide a new way for generating efficient ultrafast pulses with high- and changeable-repetition rates in the visible range.

  16. Measuring a Fiber-Optic Delay Line Using a Mode-Locked Laser

    Science.gov (United States)

    Tu, Meirong; McKee, Michael R.; Pak, Kyung S.; Yu, Nan

    2010-01-01

    The figure schematically depicts a laboratory setup for determining the optical length of a fiber-optic delay line at a precision greater than that obtainable by use of optical time-domain reflectometry or of mechanical measurement of length during the delay-line-winding process. In this setup, the delay line becomes part of the resonant optical cavity that governs the frequency of oscillation of a mode-locked laser. The length can then be determined from frequency-domain measurements, as described below. The laboratory setup is basically an all-fiber ring laser in which the delay line constitutes part of the ring. Another part of the ring - the laser gain medium - is an erbium-doped fiber amplifier pumped by a diode laser at a wavelength of 980 nm. The loop also includes an optical isolator, two polarization controllers, and a polarizing beam splitter. The optical isolator enforces unidirectional lasing. The polarization beam splitter allows light in only one polarization mode to pass through the ring; light in the orthogonal polarization mode is rejected from the ring and utilized as a diagnostic output, which is fed to an optical spectrum analyzer and a photodetector. The photodetector output is fed to a radio-frequency spectrum analyzer and an oscilloscope. The fiber ring laser can generate continuous-wave radiation in non-mode-locked operation or ultrashort optical pulses in mode-locked operation. The mode-locked operation exhibited by this ring is said to be passive in the sense that no electro-optical modulator or other active optical component is used to achieve it. Passive mode locking is achieved by exploiting optical nonlinearity of passive components in such a manner as to obtain ultra-short optical pulses. In this setup, the particular nonlinear optical property exploited to achieve passive mode locking is nonlinear polarization rotation. This or any ring laser can support oscillation in multiple modes as long as sufficient gain is present to overcome

  17. Ultrafast erbium-doped fiber laser mode-locked with a black phosphorus saturable absorber

    Science.gov (United States)

    Ahmed, M. H. M.; Latiff, A. A.; Arof, H.; Harun, S. W.

    2016-09-01

    We experimentally demonstrate a passive mode-locked erbium-doped fiber laser (EDFL) using a multi-layer black phosphorus saturable absorber (BPSA). The BPSA is fabricated by mechanically exfoliating a BP crystal and sticking the acquired BP flakes onto scotch tape. A small piece of the tape is then placed between two ferrules and integrated into an EDFL cavity to achieve a self-started soliton mode-locked pulse operation at 1560.7 nm wavelength. The 3 dB bandwidth, pulse width, and repetition rate of the laser are 6.4 nm, 570 fs, and 6.88 MHz, respectively. The average output power is 5.1 mW at pump power of 140 mW and thus, the pulse energy and peak power are estimated at 0.74 nJ and 1.22 kW, respectively. The BPSA was constructed in a simple fabrication process and has a modulation depth of 7% to successfully produce the stable mode-locked fiber laser.

  18. 35 GHz passive mode-locking of InGaAs/GaAs quantum dot lasers at 1.3 μm with Fourier-limited pulses

    DEFF Research Database (Denmark)

    Kuntz, M.; Fiol, G.; Laemmlin, M.;

    2004-01-01

    We report 35 GHz passive mode-locking and 20 GHz hybrid mode-locking of quantum dot (QD) lasers at 1.3 ìm. Our investigations show ultrafast absorber recovery times and for the first time transform-limited mode-locked pulses.......We report 35 GHz passive mode-locking and 20 GHz hybrid mode-locking of quantum dot (QD) lasers at 1.3 ìm. Our investigations show ultrafast absorber recovery times and for the first time transform-limited mode-locked pulses....

  19. RF spectral analysis for characterisation of mode-locked regimes in fibre lasers

    Science.gov (United States)

    Ivanenko, Alexey V.; Kobtsev, Sergey M.; Kokhanovskiy, Alexey; Smirnov, Sergey V.

    2016-10-01

    In this work, we present our results of RF spectral analysis applied to mode-locked lasers and propose a method of qualitative assessment of mode-locked operation, which allows differentiation of individual generation regimes by a parameter calculated from RF spectra of the fundamental and the n-th radiation harmonics. The proposed parameter is derived both from the signal-to-noise ratio and from width and amount of additional noise present in RF spectrum of inter-mode beats at the fundamental pulse repetition frequency and its harmonic. This work presents analysis of energy fluctuations and temporal instability of pulse train period for different regimes of pulse generation in Yb fibre laser mode locked due to nonlinear polarization evolution. The paper shows that energy fluctuations of single-scale ("conventional") pulses is about 1.6%, whereas for double-scale pulses energy fluctuations amount to 11.5%. Temporal instability of double-scale pulse train period is 1.5 times higher in comparison with single-scale pulse train period.

  20. Self-Mode-Locking in a Diode-Pumped Self-Q-Switched Nd3+,Cr4+:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    杨林; 冯宝华; 张治国; Volker Gaebler; 刘百宁; Hans J. Eichler; 张世文

    2002-01-01

    We report for the first time on the observation of self-mode-locking in a diode pumped self-Q-switched (SQS)Nd3+,Cr4+ : YA G laser. This phenomenon results from significant excited state absorption of the Cr4+ ions in theco-doped host during the SQS laser pulses. The self-mode-locking occurs already slightly above the SQS laserthreshold. Experiments using relatively low saturable intensity achieved a modulation depth of more than 40%.

  1. Nonlinear switching in a two-concentric-core chalcogenide glass optical fiber for passively mode-locking a fiber laser.

    Science.gov (United States)

    Nazemosadat, Elham; Mafi, Arash

    2014-08-15

    We propose an all-fiber mode-locking device, which operates based on nonlinear switching in a novel two-concentric-core fiber structure. The design is particularly attractive given the ease of fabrication and coupling to other components in a mode-locked fiber laser cavity. The nonlinear switching in this coupler is studied, and the relative power transmission is obtained. The analysis shows that this nonlinear switch is practical for mode-locking fiber lasers and is forgiving to fabrication errors.

  2. Dynamics of a Dispersion-Managed Passively Mode-Locked Er-Doped Fiber Laser Using Single Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Norihiko Nishizawa

    2015-07-01

    Full Text Available We investigated the dynamics of a dispersion-managed, passively mode-locked, ultrashort-pulse, Er-doped fiber laser using a single-wall carbon nanotube (SWNT device. A numerical model was constructed for analysis of the SWNT fiber laser. The initial process of passive mode-locking, the characteristics of the output pulse, and the dynamics inside the cavity were investigated numerically for soliton, dissipative-soliton, and stretched-pulse mode-locking conditions. The dependencies on the total dispersion and recovery time of the SWNTs were also examined. Numerical results showed similar behavior to experimental results.

  3. Compact and high repetition rate Kerr-lens mode-locked 532 nm Nd:YVO4 laser

    Science.gov (United States)

    Li, Zuohan; Peng, Jiying; Yuan, Ruixia; Wang, Tongtong; Yao, Jianquan; Zheng, Yi

    2015-11-01

    A compact and feasible CW Kerr-lens-induced mode-locked 532 nm Nd:YVO4 laser system was experimentally demonstrated for the first time with theoretical analysis. Kerr-lens mode locking with intracavity second harmonic generation provides a promising method to generate a high-repetition-rate picosecond green laser. With an incident pump power of 6 W, the average output power of mode locking was 258 mW at a high repetition rate of 1.1 GHz.

  4. Theory of the ultrafast mode-locked GaN lasers in a large-signal regime

    CERN Document Server

    Smetanin, Igor V; Boiko, Dmitri L

    2011-01-01

    Analytical theory of the high-power passively mode-locked laser with a slow absorber is developed. In distinguishing from previous treatment, our model is valid at pulse energies well exceeding the saturation energy of absorber. This is achieved by solving the mode-locking master equation in the pulse energy-domain representation. The performances of monolithic sub-picosecond blue-violet GaN mode-locked diode laser in the high-power operation regime are analyzed using the developed approach.

  5. High-Power Hybrid Mode-Locked External Cavity Semiconductor Laser Using Tapered Amplifier with Large Tunability

    Directory of Open Access Journals (Sweden)

    Andreas Schmitt-Sody

    2008-01-01

    Full Text Available We report on hybrid mode-locked laser operation of a tapered semiconductor amplifier in an external ring cavity, generating pulses as short as 0.5 ps at 88.1 MHz with an average power of 60 mW. The mode locking is achieved through a combination of a multiple quantum well saturable absorber (>10% modulation depth and an RF current modulation. This designed laser has 20 nm tuning bandwidth in continuous wave and 10 nm tuning bandwidth in mode locking around 786 nm center wavelength at constant temperature.

  6. Self-stabilized and dispersion-compensated passively mode-locked Yb:Yttrium aluminum garnet laser

    Science.gov (United States)

    Agnesi, A.; Guandalini, A.; Reali, G.

    2005-04-01

    Self-stabilized passive mode-locking of a diode-pumped Yb:yttrium aluminum garnet laser with a semiconductor saturable absorber was achieved using an off-phase-matching second-harmonic crystal. According to the numerical model, such a condition is accomplished by self-defocusing in the nonlinear crystal in the presence of positive intracavity dispersion. Robust mode locking with Fourier-limited 1.0-ps pulses was obtained, whereas mode locking, unassisted by the nonlinear crystal, yielded 2.2-ps pulses, with the laser operating near the edge of the stability region in order to minimize the saturation energy of the semiconductor device.

  7. Flexible pulses from carbon nanotubes mode-locked fiber laser

    Science.gov (United States)

    Yang, Ling-Zhen; Yang, Yi; Wang, Juan-Fen

    2016-12-01

    We demonstrate a flexible erbium-doped pulsed fiber laser which achieves the wavelength and pulse width tuning by adjusting an intracavity filter. The intracavity filter is flexible to achieve any of the different wavelengths and bandwidths in the tuning range. The wavelength and width of pulse can be tuned in a range of ˜ 20 nm and from ˜ 0.8 ps to 87 ps, respectively. The flexible pulsed fiber laser can be accurately controlled, which is insensitive to environmental disturbance. Project supported by the National Natural Science Foundation of China (Grant No. 61575137) and the Program on Social Development by Department of Science and Technology of Shanxi Province, China (Grant No. 20140313023-3).

  8. Terahertz generation and detection using femtosecond mode-locked Yb-doped fiber laser

    Science.gov (United States)

    Kong, Moon Sik; Kim, Ji Su; Han, Sang-Pil; Kim, Namje; Moon, Ki Won; Park, Kyung Hyun; Jeon, Min Yong

    2016-02-01

    We successfully demonstrate a THz generation using an ytterbium (Yb)-doped mode-locked femtosecond fiber laser and a home-made low-temperature grown (LTG) InGaAs Photoconductive antenna (PCA) module for THz Time-domain spectroscopy (TDS) systems. The Yb-doped fiber ring laser consists of a pump laser diode (PLD), a wavelength division multiplexer (WDM) coupler, a single-mode fiber (SMF), a 25 cm-long highly Yb-doped fiber, two collimators, two quarter wave plates (QWPs), a half-wave plate (HWP), a 10 nm broadband band pass filter, an isolator, and a polarizing beam splitter (PBS). In order to achieve the passively mode-locked optical short pulse, the nonlinear polarization rotation (NPR) effect is used. The achieved center wavelength and the 3 dB bandwidth of the modelocked fiber laser are 1.03 μm and ~ 15.6 nm, respectively. It has 175 fs duration after pulse compression with 66.2 MHz repetition rate. The average output power of mode-locked laser has more than 275 mW. The LTG-InGaAs PCA modules are used as the emitter and receiver in order to achieve the THz radiation. The PCA modules comprise a hyper-hemispherical Si lens and a log-spiral antenna-integrated LTG-InGaAs PCA chip electronically contacted on a printed circuit board (PCB). An excitation optical average pumping and probing power were ~ 6.3 mW and 5 mW, respectively. The free-space distance between the emitter and the receiver in the THz-TDS system was 70 mm. The spectrum of the THz radiation is achieved higher than 1.5 THz.

  9. Mode-locked Lasers Applied to Deflecting a Near Earth Object on Collision Course with Earth

    CERN Document Server

    Fork, Richard; Burgess, Luke; Bergstue, Grant

    2013-01-01

    We consider synchronized trains of sub-picosecond pulses generated by mode-locked lasers applied to deflection of near Earth objects (NEO) on collision course with Earth. Our method is designed to avoid a predicted collision of the NEO with Earth by at least the diameter of Earth. We estimate deflecting a 10,000 MT NEO, such as the asteroid which struck Earth near Chelyabinsk, Russia to be feasible within several months using average power in the ten kilowatt range. We see this deflection method as scalable to larger NEO to a degree not possible using continuous laser systems.

  10. Simultaneous picosecond and femtosecond solitons delivered from a nanotube-mode-locked all-fiber laser.

    Science.gov (United States)

    Han, D D; Liu, X M; Cui, Y D; Wang, G X; Zeng, C; Yun, L

    2014-03-15

    We propose a compact nanotube-mode-locked all-fiber laser that can simultaneously generate picosecond and femtosecond solitons at different wavelengths. The pulse durations of picosecond and femtosecond solitons are measured to be ∼10.6  ps and ∼466  fs, respectively. Numerical results agree well with the experimental observations and clearly reveal that the dynamic evolutions of the picosecond and femtosecond solitons are qualitatively distinct in the intracavity. Our study presents a simple, stable, low-cost, and dual-scale ultrafast-pulsed laser source suitable for practical applications in optical communications.

  11. Wide-band residual phase-noise measurements on 40-GHz monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Hvam, Jørn Märcher

    2005-01-01

    We have performed wide-band residual phase-noise measurements on semiconductor 40-GHz mode-locked lasers by employing electrical waveguide components for the radio-frequency circuit. The intrinsic timing jitters of lasers with one, two, and three quantum wells (QW) are compared and our design...... prediction, concerning noise versus number of QWs, for the first time corroborated by experiments. A minimum jitter of 44 fs is found, by extrapolating to the Nyquist frequency, for the one-QW device having nearly transform-limited pulses of 1.2 ps. This jitter is nearly three times lower than for a three...

  12. Cross-phase modulation instability in mode-locked laser based on reduced graphene oxide

    CERN Document Server

    Gaol, Lei; Liu, Min; Huang, Wei

    2014-01-01

    Cross-phase modulation instability (XPMI) is experimentally observed in a fiber ring cavity with net normal dispersion and mode-locked by long fiber taper. The taper is deposited with reduced graphene oxide, which can decrease the threshold of XPMI due to the enhanced nonlinearity realized by 8 mm evanescent field interaction length and strong mode confinement. Experimental results indicate that the phase matching conditions in two polarization directions are different, and sidebands with different intensities are generated. This phase matching condition can be satisfied even the polarization state of the laser varies greatly under different pump strengths.

  13. Polarisation effects in twin-core fibre: Application for mode locking in a fibre laser

    Science.gov (United States)

    Lobach, I. A.; Kablukov, S. I.; Podivilov, Evgenii V.; Babin, Sergei A.; Apolonski, A. A.

    2012-09-01

    We report the first measurements of the longitudinal power distribution in a twin-core optical fibre at different input light polarisations. Experimental evidence is presented that, because of the difference in birefringence between the cores, the power in them depends on which core the beam is launched into. Experimental data are interpreted in terms of a modified polarisation model for mode coupling in twin-core fibres which takes into account the birefringence of the cores. In addition, we demonstrate for the first time the use of the polarisation properties of a twincore fibre for mode locking in a fibre laser.

  14. Mode-locking optimization with a real-time feedback system in a Nd:yttrium lithium fluoride laser cavity

    Science.gov (United States)

    Marengoni, C.; Canova, F.; Batani, D.; Benocci, R.; Librizzi, M.; Narayanan, V.; Gomareschi, M.; Lucchini, G.; Kilpio, A.; Shashkov, E.; Stuchebrukhov, I.; Vovchenko, V.; Chernomyrdin, V.; Krasuyk, I.; Hall, T.; Bittanti, S.

    2007-01-01

    We present a control system, which allows an automatic optimization of the pulse train stability in a mode-locked laser cavity. In order to obtain real-time corrections, we chose a closed loop approach. The control variable is the cavity length, mechanically adjusted by gear system acting on the rear cavity mirror, and the controlled variable is the envelope modulation of the mode-locked pulse train. Such automatic control system maintains the amplitude of the mode-locking pulse train stable within a few percent rms during the working time of the laser. Full implementation of the system on an Nd:yttrium lithium fluoride actively mode-locked laser is presented.

  15. Towards monolithic integration of mode-locked vertical cavity surface emitting laser

    Science.gov (United States)

    Aldaz, Rafael I.

    2007-12-01

    The speed and performance of today's high end computing and communications systems have placed difficult but still feasible demands on off-chip electrical interconnects. However, future interconnect systems may need aggregate bandwidths well into the terahertz range thereby making electrical bandwidth, density, and power targets impossible to meet. Optical interconnects, and specifically compact semiconductor mode-locked lasers, could alleviate this problem by providing short pulses in time at 10s of GHz repetition rates for Optical Time Division Multiplexing (OTDM) and clock distribution applications. Furthermore, the characteristic spectral comb of frequencies of these lasers could also serve as a multi-wavelength source for Wavelength Division Multiplexing (WDM) applications. A fully integrated mode-locked Vertical Cavity Surface Emitting Laser (VCSEL) is proposed as a low-cost high-speed source for these applications. The fundamental laser platform for such a device has been developed and a continuous-wave version of these lasers has been fabricated and demonstrated excellent results. Output powers close to 60mW have been obtained with very high beam quality factor of M2 unassisted ultrafast QD saturable absorbers, without the need to incorporate high concentrations of non radiative recombination centers by either ion-implantation or low temperature growth.

  16. A novel numerical model for passively mode-locked solid-state lasers

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, A.; Aussenegg, F.; Lippitsch, M.; Roschger, E.

    1983-04-01

    Numerical computer models could be of high value in testing ideas for improving passive mode locking. Most of the known models for solid-state lasers lack realistic quantitative results, however. A new model is presented, using a rate-equation approach which has been refined to include interference effects by using field amplitudes and phases instead of energies. Also, the saturable absorber is treated by rate equations. With this model, a rather complete description of the pulse evolution is possible. The influence of various parameters on the mode-locking quality is calculated. The model is also capable of reliably describing processes based mainly on interference effects, like the action of external subresonators.

  17. Simple synchronization technique of a mode-locked laser for Laser-Compton scattering γ-ray source

    Science.gov (United States)

    Mori, Michiaki; Kosuge, Atsushi; Kiriyama, Hiromitsu; Hajima, Ryoichi; Kondo, Kiminori

    2016-06-01

    We propose a simple and effective synchronization technique between a reference electrical oscillator and a mode-locked laser for a narrowband picosecond Laser-Compton scattering γ-ray source by using a commercial-based 1-chip frequency synthesizer, which is widely used in radio communication. The mode-locked laser has been successfully synchronized in time with a jitter of 180 fs RMS for 10 Hz-100 kHz bandwidth. A good stability of 640 μHz at 80 MHz repetition rate for 10 h operation has also been confirmed. We discuss in detail the design and performance of this technique (in terms of timing jitter, stability, and validity).

  18. Fiber Transmission Stabilization by Optical Heterodyning Techniques and Synchronization of Mode-Locked Lasers Using Two Spectral Lines

    CERN Document Server

    Staples, J W

    2005-01-01

    Stabilization of the transit time through a glass fiber using an optical heterodyne technique promises to provide jitter reduction down to the few femtosecond level using inexpensive commodity hardware. An acousto-optical frequency shifter provides the optical frequency offset that is used to downconvert phase shifts at optical frequency to equivalent phase shifts at radio frequency which are used to close a phase-lock loop driving a piezoelectric phase shifter. Using the stabilized fiber transmission medium, two spectral lines of a mode locked laser lock two low-power CW lasers which are transmitted to a receiver which phase locks the same spectral lines of a second mode-locked laser to the first. The optical transmission system operates at low power and is linear, providing excellent signal-to-noise ratio and allows many signals to be transmitted without mutual interference. Experimental results will be presented.

  19. All-fiber widely tunable mode-locked thulium-doped laser using a curvature multimode interference filter

    Science.gov (United States)

    Li, N.; Liu, M. Y.; Gao, X. J.; Zhang, L.; Jia, Z. X.; Feng, Y.; Ohishi, Y.; Qin, G. S.; Qin, W. P.

    2016-07-01

    We demonstrated a widely tunable mode-locked thulium doped fiber laser (TDFL) by using a homemade multimode interference filter (MMIF). The MMIF had a structure of single mode fiber (SMF)—multimode fiber (MMF)—SMF and three main transmission peaks at 1901.2, 1957.2 and 2043.2 nm. By mechanically bending the MMIF, the three main transmission peaks were tuned in the range of 1860-2024 nm due to multimode interference effect. By inserting the MMIF into a passively mode-locked TDFL cavity pumped by a 1570 nm fiber laser, a tunable mode-locked TDFL with a tuning range of 1919.6-2014.9 nm was achieved by adjusting the MMIF. To the best of our knowledge, such a tunable range is the largest among all-fiber tunable mode-locked TDFLs.

  20. Passively Mode-Locked Fiber Laser with a Sub-Megahertz Repetition Rate

    Institute of Scientific and Technical Information of China (English)

    CHEN Jiong; JIA Dong-Fang; WU Yong-Chao; WANG Chang-Le; WANG Zhao-Ying; YANG Tian-Xin

    2011-01-01

    We demonstrate an ultra-long cavity by which an all-fiber erbium-doped fiber laser is passively mode-locked by nonlinear polarization rotation.The length of the resonant cavity amounts to 466m,which can be achieved by incorporating a 420m highly nonlinear fiber.The laser generates stable mode-locked pulses with a 444 kHz fundamental repetition rate.A near transform-limited subpicosecond pulse is obtained without any dispersion compensation.The maximum average power of the output pulses is 5.16 mW,which corresponds to a per-pulse energy of 11.62nJ.A low-repetition-rate optical pulse train is required for many applications such as micromachining,biomedical diagnostics and lidar systems.[1-3] However,the repetition rate of conventional fiber lasers is normally tens of MHz.Pulse pickers such as Pockels cells or acousto-optic modulators are always used to lower the repetition rate,however,reduction in this way introduces significant energy losses,impairs the signal-to-noise ratio (SNR) and increases complexity.Because the pulse repetition rate of a modelocked laser is inversely proportional to its resonator length,longer cavities lead to lower pulse repetition rates and,consequently,to higher pulse energy at the same average power of radiation.%We demonstrate an ultra-long cavity by which an all-fiber erbium-doped fiber laser is passively mode-locked by nonlinear polarization rotation. The length of the resonant cavity amounts to 466 m, which can be achieved by incorporating a 420 m highly nonlinear fiber. The laser generates stable mode-locked pulses with a 444 kHz fundamental repetition rate. A near transform-limited subpicosecond pulse is obtained without any dispersion compensation. The maximum average power of the output pulses is 5.16mW, which corresponds to a per-pulse energy of 11.62 nJ.

  1. Mode-locked InAs/InP quantum-dash-based DBR laser with monolithically integrated SOA

    Science.gov (United States)

    Joshi, Siddharth; Chimot, Nicolas; Barbet, Sophie; Accard, Alain; Lelarge, François

    2014-02-01

    We present the first demonstration of InAs/InP Quantum Dash based single-section frequency comb generator designed for use in photonic integrated circuits. The laser cavity is closed using a specific Bragg reflector without compromising the mode-locking performance of the laser. This enables the integration of single-section mode- locked laser on photonic integrated circuits as on-chip frequency comb source. As a demonstration, we integrate the Fabry Perot laser with a semiconductor optical amplifier. Such a device could be used for amplification or modulation of the frequency generated comb. We thus investigate the device operation to obtain a NRZ modulated comb.

  2. Large net-normal dispersion Er-doped fibre laser mode-locked with a nonlinear amplifying loop mirror

    CERN Document Server

    Bowen, Patrick; Broderick, Neil G R

    2016-01-01

    We report on an environmentally stable, all-PM-fibre, Er-doped, mode-locked laser with a central wavelength of 1550 nm. Significantly, the laser possesses large net-normal dispersion such that its dynamics are comparable to that of an all-normal dispersion fibre laser at 1 {\\mu}m with an analogous architecture. The laser is mode-locked with a nonlinear amplifying loop mirror to produce pulses that are externally compressible to 500 fs. Experimental results are in good agreement with numerical simulations.

  3. Wavelength Spacing Tunable, Multiwavelength Q-switched Fiber Laser Mode-locked by Graphene Oxide

    CERN Document Server

    Gao, Lei

    2014-01-01

    We demonstrate a wavelength spacing tunable, multiwavelength Q-switched mode-locked fiber laser (QML) based on a fiber taper deposited with graphene oxide. The operation of the laser can be understood in terms of the formation of bunches of QMLs which possess small temporal intervals, and multiwavelength spectra are generated due to the Fourier transformation. We find that the temporal spacing of the QMLs is highly sensitive to the pump power, and as a result, the wavelength spacing can be easily tuned by varying the pump power. Our experimental laser provides a wavelength spacing tuning range from ~0.001 nm to 0.145 nm with a pump power variation less than 10 mW. The laser could be developed into a low lost wavelength spacing tunable optical source for a wide range of applications, such as spectroscopy, microwave/terahertz signal generation, optical metrology, optical communications and sensing.

  4. Switchable dual-wavelength all-fiber laser mode-locked by carbon nanotubes

    Science.gov (United States)

    Kong, Y. C.; Yang, H. R.; Li, W. L.; Chen, G. W.

    2015-01-01

    We have proposed a compact dual-wavelength all-fiber pulse laser based on a single-walled carbon nanotube and chirped fiber Bragg gratings (CFBGs). A transmission filter is composed of a circulator and two CFBGs and is capable of controlling the operation of the proposed fiber laser. Mode-locking operations can be switched between 1551.2 and 1548.6 nm with the appropriate adjustment of polarization controller. Our laser delivers the pulses with the spectral bandwidth of about 0.6 nm and the pulse duration of about 7 ps. This work provides a low-cost, stable, and dual-wavelength ultrafast-pulsed laser source suitable for practical applications.

  5. Generation of 170-fs Laser Pulses at 1053 nm by a Passively Mode-Locked Yb:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin-Bin; WEI Zhi-Yi; LI De-Hua; TENG Hao; Bourdet G. L

    2009-01-01

    A novel method is developed to obtain 1.05μm laser operation with a Yb:YAG laser. By using a Yb:YAG crystal with proper length and doping concentration, a femtosecond Yb: YAG laser is realized at the central wavelength of 1053nm. The measured pulse duration and spectral bandwidth (FWHM) are 17ors and 7nm; the repetition rate is 80 MHz. Under a power pump of 2 W, an average mode-locking power of 180mW is achieved.

  6. Mode-locking based on a zero-area pulse formation in a laser with a coherent absorber

    CERN Document Server

    Arkhipov, Mikhail V; Kalinichev, Alexey A; Babuskin, Ihar; Rosanov, Nikolai N; Arkhipov, Rostislav M

    2016-01-01

    We observe experimentally a mode-locking in a continuous narrow-band tunable dye laser with molecular iodine absorber cells, which transitions have large phase relaxation time T2. We show that the mode-locking arises due to coherent interaction of light with the absorbing medium leading to Rabi oscillations, so that zero-area (0{\\pi}-) pulses in the absorber are formed. Such mode-locking regime is different to most typical passive modelocking mechanisms where saturation plays the main role.

  7. Bright-dark rogue wave in mode-locked fibre laser (Conference Presentation)

    Science.gov (United States)

    Kbashi, Hani; Kolpakov, Stanislav; Martinez, Amós; Mou, Chengbo; Sergeyev, Sergey V.

    2017-05-01

    Bright-Dark Rogue Wave in Mode-Locked Fibre Laser Hani Kbashi1*, Amos Martinez1, S. A. Kolpakov1, Chengbo Mou, Alex Rozhin1, Sergey V. Sergeyev1 1Aston Institute of Photonic Technologies, School of Engineering and Applied Science Aston University, Birmingham, B4 7ET, UK kbashihj@aston.ac.uk , 0044 755 3534 388 Keywords: Optical rogue wave, Bright-Dark rogue wave, rogue wave, mode-locked fiber laser, polarization instability. Abstract: Rogue waves (RWs) are statistically rare localized waves with high amplitude that suddenly appear and disappear in oceans, water tanks, and optical systems [1]. The investigation of these events in optics, optical rogue waves, is of interest for both fundamental research and applied science. Recently, we have shown that the adjustment of the in-cavity birefringence and pump polarization leads to emerge optical RW events [2-4]. Here, we report the first experimental observation of vector bright-dark RWs in an erbium-doped stretched pulse mode-locked fiber laser. The change of induced in-cavity birefringence provides an opportunity to observe RW events at pump power is a little higher than the lasing threshold. Polarization instabilities in the laser cavity result in the coupling between two orthogonal linearly polarized components leading to the emergence of bright-dark RWs. The observed clusters belongs to the class of slow optical RWs because their lifetime is of order of a thousand of laser cavity roundtrip periods. References: 1. D. R. Solli, C. Ropers, P. Koonath,and B. Jalali, Optical rogue waves," Nature, 450, 1054-1057, 2007. 2. S. V. Sergeyev, S. A. Kolpakov, C. Mou, G. Jacobsen, S. Popov, and V. Kalashnikov, "Slow deterministic vector rogue waves," Proc. SPIE 9732, 97320K (2016). 3. S. A. Kolpakov, H. Kbashi, and S. V. Sergeyev, "Dynamics of vector rogue waves in a fiber laser with a ring cavity," Optica, 3, 8, 870, (2016). 5. S. Kolpakov, H. Kbashi, and S. Sergeyev, "Slow optical rogue waves in a unidirectional fiber laser

  8. Analysis of timing jitter in external-cavity mode-locked semiconductor lasers

    DEFF Research Database (Denmark)

    Mulet, Josep; Mørk, Jesper

    2006-01-01

    processes, self-phase modulation, and spontaneous emission noise. Fluctuations of the mode-locked pulses are characterized from the fully distributed model using direct integration of noise-skirts in the phase-noise spectrum and the soliton perturbations introduced by Haus. We implement the model in order...... to investigate the performance of a MQW buried heterostructure laser. Results from numerical simulations show that the optimum driving conditions for achieving the shortest pulses with minimum timing jitter occur for large reverse bias in the absorber section at an optimum optical bandwidth limited by Gordon...

  9. Sub-picosecond ultra-low frequency passively mode-locked fiber laser

    Science.gov (United States)

    Cuadrado-Laborde, Christian; Cruz, José L.; Díez, Antonio; Andrés, Miguel V.

    2016-11-01

    We developed a nonlinear polarization rotation all-fiber mode-locked erbium-doped fiber laser, with the purpose to reach a sub-picosecond and sub-megahertz light pulse emission. In the process, we observed three different emission regimes as the net birefringence is changed, namely high-power dissipative soliton resonance, low-power soliton regime, and a mixed combination of both. In the pure solitonic regime, a 0.961 MHz train of chirp-free Gaussian pulses was obtained, with a time width of 0.919 ps at 1564.3 nm.

  10. Supercontinuum generation pumped by a regeneratively mode-locked fiber laser

    Institute of Scientific and Technical Information of China (English)

    JIA Dong-fang; TAN Bin; WANG Zhao-ying; GE Chun-feng; NI Wen-jun; LI Shi-chen

    2005-01-01

    Supercontinuum(SC) generation in a dispersion-shifted fiber(DSF) pumped by a 10 GHz regeneratively mode-locked fiber laser(RMLFL) is presented.Optimization of pump wavelength leads to a 20 dB bandwidth of 58.73 nm,which covers the whole C band and part of L band.Using an angle-tuning thin film filter,multi-wavelength and pico-second pulse trains of low chirp could be chosen from the SC spectrum.Amplified spontaneous emission(ASE) induced degeneration of the achieved pulse trains is observed and discussed.

  11. An ultrafast optics undergraduate advanced laboratory with a mode-locked fiber laser

    Science.gov (United States)

    Schaffer, Andrew; Fredrick, Connor; Hoyt, Chad; Jones, Jason

    2015-05-01

    We describe an ultrafast optics undergraduate advanced laboratory comprising a mode-locked erbium fiber laser, auto-correlation measurements, and an external, free-space parallel grating dispersion compensation apparatus. The simple design of the stretched pulse laser uses nonlinear polarization rotation mode-locking to produce pulses at a repetition rate of 55 MHz and average power of 5.5 mW. Interferometric and intensity auto-correlation measurements are made using a Michelson interferometer that takes advantage of the two-photon nonlinear response of a common silicon photodiode for the second order correlation between 1550 nm laser pulses. After a pre-amplifier and compression, pulse widths as narrow as 108 fs are measured at 17 mW average power. A detailed parts list includes previously owned and common components used by the telecommunications industry, which may decrease the cost of the lab to within reach of many undergraduate and graduate departments. We also describe progress toward a relatively low-cost optical frequency comb advanced laboratory. NSF EIR #1208930.

  12. Kerr Lens Mode-locked Operation of Yb:KYW Laser

    Institute of Scientific and Technical Information of China (English)

    Falihati.Mejiti; V.L.Kalashnikov; I.G.Poloyko; Toran.Vajidi

    2002-01-01

    Using a modified ABCD-matrix approach accounting for nonlinear refraction in active medium,the ranges of cavity parameters that provide a mode-locking of Yb∶KYW-laser in usual z-fold cavity configuration are determined.Taking the cavity parameters that provide a most efficient mode locking and based on fluctuation model,a numerical simulation of laser operation is performed.In the calculations the side-band pump power of 6W at 982 nm is used in 1 cm length KYW crystal with 1 cm×0.005 cm beam cross section.Calculations show that self-starting operation is possible with these parameters and dispersion compensation allows for bandwidth-limited ultrashort pulse generation.The shortest pulse duration was determined to be about 200 fs with self-starting buid-up time of 130 μs.Such a built-up time is comparable and even shorter than that one for the lasers with semiconductor saturable absorbers.The region of negative dispersion provided by prism pair for a stable ultrashort pulse generation was determined to be (-17000~-42000)fs2.

  13. Multiple-Pulse Operation and Bound States of Solitons in Passive Mode-Locked Fiber Lasers

    Directory of Open Access Journals (Sweden)

    A. Komarov

    2012-01-01

    Full Text Available We present results of our research on a multiple-pulse operation of passive mode-locked fiber lasers. The research has been performed on basis of numerical simulation. Multihysteresis dependence of both an intracavity energy and peak intensities of intracavity ultrashort pulses on pump power is found. It is shown that the change of a number of ultrashort pulses in a laser cavity can be realized by hard as well as soft regimes of an excitation and an annihilation of new solitons. Bound steady states of interacting solitons are studied for various mechanisms of nonlinear losses shaping ultrashort pulses. Possibility of coding of information on basis of soliton trains with various bonds between neighboring pulses is discussed. The role of dispersive wave emitted by solitons because of lumped intracavity elements in a formation of powerful soliton wings is analyzed. It is found that such powerful wings result in large bounding energies of interacting solitons in steady states. Various problems of a soliton interaction in passive mode-locked fiber lasers are discussed.

  14. Investigation of Kerr-lens mode locking in lasers with composite active media

    Science.gov (United States)

    Trunov, V. I.; Kirpichnikov, A. V.; Pestryakov, Efim V.; Petrov, V. V.; Komarov, A. K.; Komarov, Konstantin P.

    2001-03-01

    One of the possible methods of realization of active medium with anomalously wide bandwidth has been described. Composite active medium, consisting of several laser active centers with overlapping gainbands in common resonator has been created. In this case gain contour has complex shape with local extremums. Method of numerical simulation of the formation dynamics of ultrashort pulse at passive mode locking in laser with arbitrary spectral gain contour has been performed. The main parameters for the generation of ultrashort pulse in a laser with a composite active medium are obtained and investigated. The conditions of realization of stationary regime in the form of ultrashort pulse generation with duration determined by combined gain bandwidth are calculated.

  15. 152 fs nanotube-mode-locked thulium-doped all-fiber laser

    Science.gov (United States)

    Wang, Jinzhang; Liang, Xiaoyan; Hu, Guohua; Zheng, Zhijian; Lin, Shenghua; Ouyang, Deqin; Wu, Xu; Yan, Peiguang; Ruan, Shuangchen; Sun, Zhipei; Hasan, Tawfique

    2016-07-01

    Ultrafast fiber lasers with broad bandwidth and short pulse duration have a variety of applications, such as ultrafast time-resolved spectroscopy and supercontinuum generation. We report a simple and compact all-fiber thulium-doped femtosecond laser mode-locked by carbon nanotubes. The oscillator operates in slightly normal cavity dispersion at 0.055 ps2, and delivers 152 fs pulses with 52.8 nm bandwidth and 0.19 nJ pulse energy. This is the shortest pulse duration and the widest spectral width demonstrated from Tm-doped all-fiber lasers based on 1 or 2 dimensional nanomaterials, underscoring their growing potential as versatile saturable absorber materials.

  16. Broadband Fourier domain mode-locked laser for optical coherence tomography at 1060 nm

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2012-01-01

    , enable acquisition of densely sampled three-dimensional datasets covering a wide field of view. However, semiconductor optical amplifiers (SOAs)-the typical laser gain media for swept sources-for the 1060nm band could until recently only provide relatively low output power and bandwidth. We have......Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera) due to low absorption in water and deep penetration into the tissue. Rapidly tunable light sources, such as Fourier domain mode-locked (FDML) lasers...... implemented an FDML laser using a new SOA featuring broad gain bandwidth and high output power. The output spectrum coincides with the wavelength range of minimal water absorption, making the light source ideal for OCT imaging of the posterior eye segment. With a moderate SOA current (270 mA) we achieve up...

  17. Mode-Locked CO Laser for Isotope Separation of Uranium Employing Condensation Repression

    Directory of Open Access Journals (Sweden)

    Igor Y. Baranov

    2010-01-01

    Full Text Available In the present work, we have suggested a technical solution of a CO laser facility for industrial separation of uranium used in the production of fuel for nuclear power plants. There has been used a method of laser isotope separation of uranium, employing condensation repression in a free jet. The laser operation with nanosecond pulse irradiation can provide acceptable efficiency in the separating unit and the high effective coefficient of the laser with the wavelength of 5.3 μm. Receiving a uniform RF discharge under medium pressure and high Mach numbers in the gas stream solves the problem of an electron beam and cryogenic cooler of CO lasers. The laser active medium is being cooled while it is expanding in the nozzle; a low-current RF discharge is similar to a non-self-sustained discharge. In the present work, we have developed a calculation model of optimization and have defined the parameters of a mode-locked CO laser with an RF discharge in the supersonic stream. The CO laser average power of 3 kW is sufficient for efficient industrial isotope separation of uranium at one facility.

  18. 177 fs erbium-doped fiber laser mode locked with a cellulose polymer film containing single-wall carbon nanotubes

    Science.gov (United States)

    Tausenev, A. V.; Obraztsova, E. D.; Lobach, A. S.; Chernov, A. I.; Konov, V. I.; Kryukov, P. G.; Konyashchenko, A. V.; Dianov, E. M.

    2008-04-01

    A mode-locked soliton erbium-doped fiber laser generating 177fs pulses is demonstrated. The laser pumped by a 85mW, 980nm laser diode emits 7mW at 1.56μm at a pulse repetition rate of 50MHz. Passive mode locking is achieved with a saturable absorber made of a high-optical quality film based on cellulose derivative with dispersed carbon single-wall nanotubes. The film is prepared with the original technique by using carbon nanotubes synthesized by the arc-discharge method.

  19. Passive mode-locking of fiber ring laser at the 337th harmonic using gigahertz acoustic core resonances.

    Science.gov (United States)

    Kang, M S; Joly, N Y; Russell, P St J

    2013-02-15

    We report the experimental demonstration of a passively mode-locked Er-doped fiber ring laser operating at the 337th harmonic (1.80 GHz) of the cavity. The laser makes use of highly efficient Raman-like optoacoustic interactions between the guided light and gigahertz acoustic resonances trapped in the micron-sized solid glass core of a photonic crystal fiber. At sufficient pump power levels the laser output locks to a repetition rate corresponding to the acoustic frequency. A stable optical pulse train with a side-mode suppression ratio higher than 45 dB was obtained at low pump powers (~60 mW).

  20. Second harmonic pico-second pulse generation with mode-locked 1064nm DBR laser diodes

    Science.gov (United States)

    Klehr, A.; Prziwarka, T.; Jedrzejczyk, D.; Brox, O.; Bugge, F.; Wenzel, H.; Paschke, K.; Erbert, G.; Tränkle, G.

    2014-02-01

    Detailed experimental investigations of the generation of high-energy short infrared and green pulses with a mode-locked multi-section distributed Bragg reflector (DBR) laser in dependence on the lengths of the gain section and the saturableabsorber (SA) section as well the corresponding input currents and reverse voltages, respectively, are presented. The laser under investigation is 3.5 mm long and has a 500 μm long DBR section. The remaining cavity was divided into four 50 μm, four 100 μm, two 200 μm and eight 250 μm long electrically separated segments so that the lengths of the gain and SA sections can be simply varied by bonding. Thus, the dependence of the mode-locking behavior on the lengths of the gain and SA sections can be investigated on the same device. Optimal mode-locking was obtained for absorber lengths between LAbs = 200 μm and 300 μm and absorber voltages between UAbs= -2 V and -3 V. A pulse length of τ ≍ 10 ps, a repetition frequency of 13 GHz and a RF line width of less than 100 kHz were measured. An infrared peak pulse power of 900 mW was reached. The FWHM of the optical spectrum was about 150 pm. With an 11.5 mm long periodically poled MgO doped LiNbO3 crystal having a ridge geometry of 5 μm width and 4 μm height green light pulses were generated. With an infrared pump peak power of 900 mW a green pulse energy of 3.15 pJ was reached. The opto-optical conversion efficiency was about 31%.

  1. Investigations of repetition rate stability of a mode-locked quantum dot semiconductor laser in an auxiliary optical fiber cavity

    DEFF Research Database (Denmark)

    Breuer, Stefan; Elsässer, Wolfgang; McInerney, J.G.

    2010-01-01

    We have investigated experimentally the pulse train (mode beating) stability of a monolithic mode-locked multi-section quantum-dot laser with an added passive auxiliary optical fiber cavity. Addition of the weakly coupled (¿ -24dB) cavity reduces the current-induced shift d¿/dI of the principal...

  2. Diode end-pumped self-Q-switched and mode-locked Nd,Cr:YAG/KTP green laser

    Institute of Scientific and Technical Information of China (English)

    Du Shi-Feng; Wang Su-Mei; Zhang Dong-Xiang; Feng Bao-Hua; Zhang Chun-Yu; Zhang Ling; Zhang Zhi-Guo; Zhang Shi-Wen

    2006-01-01

    We first experimentally demonstrate a laser-diode end-pumped self-Q-switched and mode-locked Nd,Cr:YAG green laser with a KTP crystal as the intra- cavity frequency doubler. The device produces an average output power of 680 mW at 532 nm. The corresponding pulse width of the Q-switched envelope of the green laser is 170 ± 20 ns. The mode-locked pulses have a repetition rate of approximately 183 MHz and the average pulse duration is estimated to be around sub-nanosecond. It is found that the intra-cavity frequency doubling greatly improves the modulation depth and stability of the mode-locked pulses within the Q-switched envelope.

  3. Passive mode locking of ytterbium- and erbium-doped all-fiber lasers using graphene oxide saturable absorbers.

    Science.gov (United States)

    Chen, Hou-Ren; Tsai, Chih-Ya; Cheng, Hsin-Ming; Lin, Kuei-Huei; Hsieh, Wen-Feng

    2014-06-02

    Broadband graphene oxide/PVA films were used as saturable absorbers (SAs) for mode locking erbium-doped fiber laser (EDFL) and ytterbium-doped fiber laser (YDFL) at 1.06 μm and 1.55 μm. They provide modulation depths of 3.15% and 6.2% for EDFL and YDFL, respectively. Stable self-starting mode-locked pulses are obtained for both lasers, confirming that the graphene oxide is cost-effective. We have generated mode-locked pulses with spectral width, repetition rate, and pulse duration of 0.75 nm, 9.5 MHz, and 2.7 ps. This is the shortest pulse duration directly obtained from an all-normal-dispersion YDFL with graphene-oxide saturable absorber.

  4. Microwave emission by nonlinear crystals irradiated with a high-intensity, mode-locked laser

    CERN Document Server

    Borghesani, A F; Guarise, M

    2016-01-01

    We report on the experimental investigation of the efficiency of some nonlinear crystals to generate microwave (RF) radiation as a result of optical rectification (OR) when irradiated with intense pulse trains delivered by a mode-locked laser at $1064\\,$nm. We have investigated lithium triborate (LBO), lithium niobate (LiNbO$_3$), zinc selenide (ZnSe), and also potassium titanyl orthophosphate (KTP) for comparison with previous measurements. The results are in good agreement with the theoretical predictions based on the form of the second-order nonlinear susceptibility tensor. For some crystals we investigated also the second harmonic generation (SHG) to cross check the theoretical model. We confirm the theoretical prediction that OR leads to the production of higher order RF harmonics that are overtones of the laser repetition rate.

  5. Dynamics of soliton explosions in passively mode-locked fiber lasers

    CERN Document Server

    Runge, Antoine F J; Erkintalo, Miro

    2015-01-01

    A soliton explosion is an instability whereby a dissipative soliton undergoes a sudden structural collapse, but remarkably returns back to its original shape after a short transient. We recently reported the first experimental observation of this effect in a fiber laser (A. F. J. Runge et al., Optica 2, 36 (2015)). Here, we expand on our initial work, presenting a more detailed experimental and numerical study of the characteristics and dynamics of soliton explosions in passively mode-locked fiber lasers. Specifically, we explore different cavity configurations and gain levels, observing and characterizing explosion events using spectral and temporal real-time single-shot techniques. Our results highlight that the explosion characteristics observed in experiments depend critically on the position in the cavity where the output coupler is located. Furthermore, we find that the frequency at which explosions occur can be controlled by adjusting the pump power. We also identify a new kind of ``partial'' explosion...

  6. Silicon Photonics WDM Transceiver with SOA and Semiconductor Mode-Locked Laser

    CERN Document Server

    Moscoso-Mártir, Alvaro; Hauck, Johannes; Chimot, Nicolas; Setter, Rony; Badihi, Avner; Rasmussen, Daniel E; Garreau, Alexandre; Nielsen, Mads; Islamova, Elmira; Romero-García, Sebastián; Shen, Bin; Sandomirsky, Anna; Rockman, Sylvie; Li, Chao; Azadeh, Saeed Sharif; Lo, Guo-Qiang; Mentovich, Elad; Merget, Florian; Lelarge, François; Witzens, Jeremy

    2016-01-01

    We demonstrate a complete Silicon Photonics WDM link relying on a single section semiconductor mode-locked laser and a single SOA to support up to 12 multiplexed channels with a bit error rate of 1e-12 at serial data rates of 14 Gbps without channel pre-emphasis, equalization or forward error correction. Individual channels reach error free operation at 25 Gbps and multi-channel operation at 25 Gbps is shown to be compatible with standard 7% overhead hard decision forward error correction. Silicon Photonics transmitter and receiver chips are hybridly integrated with driver and receiver electronics. A detailed link model is derived and verified. Particular emphasis is placed on accurate system level modeling of laser RIN, SOA amplified spontaneous emission noise and receiver noise. The impact of the electrical receiver bandwidth and non-Gaussian statistics on level dependent amplified spontaneous emission noise are investigated in detail. The channel count scalability as limited by SOA saturation is further an...

  7. Femtosecond pulse generation from a Topological Insulator mode-locked fiber laser

    CERN Document Server

    Liu, Hao; Liu, Meng; Zhao, Nian; Luo, Ai-Ping; Luo, Zhi-Chao; Xu, Wen-Cheng; Zhang, Han; Zhao, Chu-Jun; Wen, Shuang-Chun

    2014-01-01

    We reported on the generation of femtosecond pulse in an anomalous-dispersion fiber ring laser by using a polyvinyl alcohol (PVA)-based Topological Insulator (TI), Bi2Se3 saturable absorber (SA). The PVA-TI composite has a low saturable optical intensity of 12 MW/cm2 and a modulation depth of ~3.9%. By incorporating the fabricated PVA-TISA into a fiber laser, mode-locking operation could be achieved at a low pump threshold of 25 mW. After an optimization of the cavity parameters, optical pulse with ~660 fs centered at 1557.5 nm wavelength had been generated. The experimental results demonstrate that the PVA could be an excellent host material for fabricating high-performance TISA, and also indicate that the filmy PVA-TISA is indeed a good candidate for ultrafast saturable absorption device.

  8. Intra-cavity frequency-doubled mode-locked semiconductor disk laser at 325 nm.

    Science.gov (United States)

    Bek, Roman; Baumgärtner, Stefan; Sauter, Fabian; Kahle, Hermann; Schwarzbäck, Thomas; Jetter, Michael; Michler, Peter

    2015-07-27

    We present a passively mode-locked semiconductor disk laser (SDL) emitting at 650nm with intra-cavity second harmonic generation to the ultraviolet (UV) spectral range. Both the gain and the absorber structure contain InP quantum dots (QDs) as active material. In a v-shaped cavity using the semiconductor samples as end mirrors, a beta barium borate (BBO) crystal is placed in front of the semiconductor saturable absorber mirror (SESAM) for pulsed UV laser emission in one of the two outcoupled beams. Autocorrelation (AC) measurements at the fundamental wavelength reveal a FWHM pulse duration of 1.22ps. With a repetition frequency of 836MHz, the average output power is 10mW per beam for the red emission and 0.5mW at 325nm.

  9. Passively harmonic mode-locked fiber laser based on ReS2 saturable absorber

    Science.gov (United States)

    Lu, Feifei

    2017-06-01

    We demonstrate the generation of harmonic mode-locking (HML) in an erbium-doped fiber laser with a microfiber-based rhenium disulfide (ReS2) saturable absorber (SA). Taking advantages of both saturable absorption and large third-order nonlinear effect of ReS2, HML pulse with 318.5 MHz repetition rate can be obtained, corresponding to 168th harmonic of fundamental repetition frequency of 1.896 MHz. When the pump power is increased gradually, the pulse interval remains constant, while the output power increases linearly. At the pump power of 450 mW, the output power is ˜12 mW. The proposed high-repetition-rate pulse lasers would attract considerable attention due to its potential applications in soliton communications and frequency combs.

  10. Graphene oxide mode-locked femtosecond erbium-doped fiber lasers.

    Science.gov (United States)

    Xu, Jia; Liu, Jiang; Wu, Sida; Yang, Quan-Hong; Wang, Pu

    2012-07-02

    We demonstrated the femtosecond erbium-doped all-fiber lasers mode-locked with graphene oxide, which can be conveniently obtained from natural graphite by simple oxidation and ultra-sonication process. With proper dispersion management in an all-fiber ring cavity, the laser directly generated 200 fs pulses at a repetition rate of 22.9 MHz and the average output power was 5.8 mW. With the variation of net cavity dispersion, output pulses with pulse width of 0.2~3 ps were obtained at a repetition rate of 22.9~0.93 MHz. These results are comparable with those of graphene saturable absorbers and the superiority of easy fabrication and hydrophilic property of graphene oxide will facilitate its potential applications for ultrafast photonics.

  11. Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers.

    Science.gov (United States)

    Eigenwillig, Christoph M; Wieser, Wolfgang; Todor, Sebastian; Biedermann, Benjamin R; Klein, Thomas; Jirauschek, Christian; Huber, Robert

    2013-01-01

    Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored optically in the long-fibre delay line and not as population inversion in the laser-gain medium, high-energy pulses can now be generated directly from a low-power, compact semiconductor-based oscillator. Our theory predicts subpicosecond pulses with this new technique in the future.

  12. Isolator-free switchable uni- and bidirectional hybrid mode-locked erbium-doped fiber laser.

    Science.gov (United States)

    Chernysheva, Maria; Araimi, Mohammed Al; Kbashi, Hani; Arif, Raz; Sergeyev, Sergey V; Rozhin, Aleksey

    2016-07-11

    An Erbium-doped fibre ring laser hybrid mode-locked with single-wall carbon nanotubes (SWNT) and nonlinear polarisation evolution (NPE) without an optical isolator has been investigated for various cavity conditions. Precise control of the state of polarisation (SOP) in the cavity ensures different losses for counter-propagating optical fields. As the result, the laser operates in quasi-unidirectional regime in both clockwise (CW) and counter-clockwise (CCW) directions with the emission strengths difference of the directions of 22 dB. Furthermore, by adjusting the net birefringence in the cavity, the laser can operate in a bidirectional generation. In this case, a laser pumped with 75 mW power at 980 nm generates almost identical 790 and 570 fs soliton pulses with an average power of 1.17 and 1.11 mW. The operation stability and pulse quality of the soliton pulses in both unidirectional regimes are highly competitive with those generated in conventional ring fibre lasers with isolator in the cavity. Demonstrated bidirectional laser operation can find vital applications in gyroscopes or precision rotation sensing technologies.

  13. Modeling and analysis of polarization effects in Fourier domain mode-locked lasers.

    Science.gov (United States)

    Jirauschek, Christian; Huber, Robert

    2015-05-15

    We develop a theoretical model for Fourier domain mode-locked (FDML) lasers in a non-polarization-maintaining configuration, which is the most widely used type of FDML source. This theoretical approach is applied to analyze a widely wavelength-swept FDML setup, as used for picosecond pulse generation by temporal compression of the sweeps. We demonstrate that good agreement between simulation and experiment can only be obtained by including polarization effects due to fiber bending birefringence, polarization mode dispersion, and cross-phase modulation into the theoretical model. Notably, the polarization dynamics are shown to have a beneficial effect on the instantaneous linewidth, resulting in improved coherence and thus compressibility of the wavelength-swept FDML output.

  14. Diode-Pumped Self Q-Switched and Mode-Locking Nd3+,Cr4+:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    LI Chun-Yong; LI Ping-Xue; LI De-Hua; FENG Bao-Hua; FU Pan-Ming; ZHANG Zhi-Guo; ZHANG Shi-Wen

    2004-01-01

    @@ Using Nd3+,Cr4+ : YAG as a laser crystal and saturable absorber simultaneously, we obtain a self-Q-switched and mode-locking laser at 1.06 μm with straight cavity structure. Self mode-locking phenomenon was observed at an intracavity intensity of only about 2000 W/cm2. More than 90% modulation depth is achieved at an intracavity intensity of less than 3.0 × 104 W/cm2 for the first time. The Q-switched pulse width and repetition rate are found to be connected with the cavity length and the output power.

  15. Injection locking and mode selection in TEA-CO/sub 2/ laser oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Lachambre, J.L.; Lavigne, P.; Otis, G.; Noel, M.

    1976-12-01

    The injection of a master oscillator signal in a high-power TEA-CO/sub 2/ laser is analyzed and a dynamic model is formulated to represent the interaction. Based on the competition between the injected signal and the spontaneous emission, the model describes the transient evolution of the different field amplitudes and phases together with their effect on the inversion. A study over a wide range of injection levels and detuning frequencies clearly indicates three distinct regions of operation: a spontaneous oscillation zone, a mode-selection zone, and a frequency-locking zone. The main predictions of the model are compared with the results obtained with an experimental injection apparatus that assures adequate control of the TEA laser cavity length and that provides means for measuring the frequency of the output pulse. While the first two zones are directly observed, it is experimentally established that, at injection levels up to 5 W/cm/sup 2/, the frequency-locking zone does not exceed, as predicted, the 3-MHz resolution limit of the apparatus.

  16. Electrical addressing and temporal tweezing of localized pulses in passively-mode-locked semiconductor lasers

    Science.gov (United States)

    Camelin, P.; Javaloyes, J.; Marconi, M.; Giudici, M.

    2016-12-01

    We show that the pumping current is a convenient parameter for manipulating the temporal localized structures (LSs), also called localized pulses, found in passively-mode-locked vertical-cavity surface-emitting lasers. 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 one to control the position and the dynamics of LSs. We show that the localized pulse 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 a finite time scale and breaks the parity invariance along the cavity, thus leading to a different 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.

  17. Ultrafast non-equilibrium carrier dynamics in semiconductor laser mode-locking

    Science.gov (United States)

    Hader, J.; Scheller, M.; Laurain, A.; Kilen, I.; Baker, C.; Moloney, J. V.; Koch, S. W.

    2017-01-01

    Experimental and theoretical results on the mode-locking dynamics in vertical-external-cavity surface-emitting lasers with semiconductor and graphene saturable absorber mirrors are reviewed with an emphasis on the role of nonequilibrium carrier effects. The systems are studied theoretically using a fully microscopic many-body model for the carrier distributions and polarizations, coupled to Maxwell’s equations for the field propagation. Pump-probe measurements are performed with (sub-) 100 fs resolution. The analysis shows that the non-equilibrium carrier dynamics in the gain quantum-wells and saturable absorber medium significantly influences the system’s response and the resulting mode-locked pulses. The microscopic model is used to study the pulse build up from spontaneous emission noise and to determine the dependence of achievable pulse lengths and fluences on the amounts of saturable and non-saturable losses and the optical gain. The change of the group delay dispersion (GDD) on the pump level is examined and the dependence of the pulse lengths on the total amount of GDD is demonstrated experimentally. Theory-experiment comparisons are used to demonstrate the highly quantitative accuracy of the fully microscopic modeling.

  18. Exploring the self-mode-locked dynamics of cryogenic diode-pumped Nd:YLF lasers: switching of orthogonal polarizations

    Science.gov (United States)

    Huang, T. L.; Y Cho, C.; Liang, H. C.; Huang, K. F.; Chen, Y. F.

    2017-08-01

    The self-mode-locked output for cryogenic Nd:YLF laser at the temperature range of 90 K to 290 K is thoroughly investigated. Linearly polarized self-mode-locked lasing at 1047 nm (1053 nm) with a repetition rate up to 1.59 GHz and a pulse width as short as 52 ps can be realized at temperatures above 155 K (below 135 K). Orthogonally polarized self-mode-locked operation can be observed at temperatures near 145 K. During dual-polarization operation, it is found that the polarized component with higher output power is the fundamental transverse mode, whereas the other component with lower output power becomes the high-order transverse mode. The dominant polarized component can be either π- or σ-polarization, depending on the fine adjustment of the cavity.

  19. Contrastive study of two SESAMs for passive mode-locking in Nd:YVO4 laser with low pump power

    Institute of Scientific and Technical Information of China (English)

    Yang Liu; Liqun Sun; Yonggang Wang; Qian Tian; Xiaoyu Ma; Zhigang Zhang

    2005-01-01

    Two semiconductor saturable absorber mirrors (SESAMs), of which one is coated with 50% reflection film on the top and the other is not, were contrastively studied in passively mode-locked solid-state lasers which were pumped by low output power laser diode (LD). Experiments have shown that reducing the modulation depth of SESAM by coating partial reflection film, whose reflectivity is higher than that between SESAM and air interface, is an effective method to get continuous wave (CW) mode-locking instead of Q-switched power LD, in which no water-cooling system was used, could obtain CW mode-locking by the 50% reflector coated SESAM with average output power of ~ 20 mW.

  20. Generation of sub-100 fs pulses from mode-locked Nd,Y:SrF2 laser with enhancing SPM

    Science.gov (United States)

    Zhu, Jiangfeng; Wei, Long; Tian, Wenlong; Liu, Jiaxing; Wang, Zhaohua; Su, Liangbi; Xu, Jun; Wei, Zhiyi

    2016-05-01

    A mode-locked laser using Nd,Y:SrF2 crystal as the gain medium is presented in this letter. By special design of the cavity for enhancing the self-phase modulation effect, femtosecond mode-locking with 97 fs pulse duration and 13.2 nm spectral width centered at 1061 nm is obtained at a repetition rate of 96 MHz. The average output power is 102 mW under 925 mW pump power, corresponding to the optical-to-optical efficiency of 11%. To the best of our knowledge, these are the first sub-100 fs pulses generated from a mode-locked Nd doped crystal laser.

  1. Artificial Neuron Based on Integrated Semiconductor Quantum Dot Mode-Locked Lasers.

    Science.gov (United States)

    Mesaritakis, Charis; Kapsalis, Alexandros; Bogris, Adonis; Syvridis, Dimitris

    2016-12-19

    Neuro-inspired implementations have attracted strong interest as a power efficient and robust alternative to the digital model of computation with a broad range of applications. Especially, neuro-mimetic systems able to produce and process spike-encoding schemes can offer merits like high noise-resiliency and increased computational efficiency. Towards this direction, integrated photonics can be an auspicious platform due to its multi-GHz bandwidth, its high wall-plug efficiency and the strong similarity of its dynamics under excitation with biological spiking neurons. Here, we propose an integrated all-optical neuron based on an InAs/InGaAs semiconductor quantum-dot passively mode-locked laser. The multi-band emission capabilities of these lasers allows, through waveband switching, the emulation of the excitation and inhibition modes of operation. Frequency-response effects, similar to biological neural circuits, are observed just as in a typical two-section excitable laser. The demonstrated optical building block can pave the way for high-speed photonic integrated systems able to address tasks ranging from pattern recognition to cognitive spectrum management and multi-sensory data processing.

  2. Artificial Neuron Based on Integrated Semiconductor Quantum Dot Mode-Locked Lasers

    Science.gov (United States)

    Mesaritakis, Charis; Kapsalis, Alexandros; Bogris, Adonis; Syvridis, Dimitris

    2016-12-01

    Neuro-inspired implementations have attracted strong interest as a power efficient and robust alternative to the digital model of computation with a broad range of applications. Especially, neuro-mimetic systems able to produce and process spike-encoding schemes can offer merits like high noise-resiliency and increased computational efficiency. Towards this direction, integrated photonics can be an auspicious platform due to its multi-GHz bandwidth, its high wall-plug efficiency and the strong similarity of its dynamics under excitation with biological spiking neurons. Here, we propose an integrated all-optical neuron based on an InAs/InGaAs semiconductor quantum-dot passively mode-locked laser. The multi-band emission capabilities of these lasers allows, through waveband switching, the emulation of the excitation and inhibition modes of operation. Frequency-response effects, similar to biological neural circuits, are observed just as in a typical two-section excitable laser. The demonstrated optical building block can pave the way for high-speed photonic integrated systems able to address tasks ranging from pattern recognition to cognitive spectrum management and multi-sensory data processing.

  3. Nanotube-mode-locked linear-cavity fiber laser delivering switchable ultrafast solitons

    Science.gov (United States)

    Han, X. X.

    2015-02-01

    We propose a linear-cavity switchable fiber laser based on a single-wall carbon nanotube mode-locker for the first time to the best of our knowledge. Two chirped fiber Bragg gratings (CFBGs) in series and an optical circulator are employed as end mirrors of the linear cavity. The linear-cavity fiber laser is simple and cost-efficient. By adjusting the polarization controllers, a switchable mode-locking operation is obtained at 1551.3 and 1557.9 nm respectively, corresponding to the central wavelengths of two series-wound CFBGs. The pulse duration and spectral bandwidth of ultrafast solitons are ~4.4 ps and ~0.65 nm for the short wavelength operation at 1551.3 nm and ~3.9 ps and ~0.71 nm for the long wavelength operation at 1557.9 nm, respectively. Our experimental observations are well confirmed by the numerical results. The linear-cavity all-fiber laser reduces the cost and is very attractive for ultrafast optics.

  4. Sub-100 fs mode-locked erbium-doped fiber laser using a 45°-tilted fiber grating.

    Science.gov (United States)

    Zhang, Zuxing; Mou, Chengbo; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin; Turitsyn, Sergei

    2013-11-18

    We demonstrate generation of sub-100 fs pulses at 1.5 µm in a mode-locked erbium-doped fiber laser using a 45°-tilted fiber grating element. The laser features a genuine all-fiber configuration. Based on the unique polarization properties of the 45°-tilted fiber grating, we managed to produce sub-100 fs laser pulses through proper dispersion management. To the best of our knowledge, this is the shortest pulse generated from mode-locked lasers with fiber gratings. The output pulse has an average power of 8 mW, with a repetition rate of 47.8 MHz and pulse energy of 1.68 nJ. The performance of laser also matches well the theoretical simulations.

  5. Diode array pumped, non-linear mirror Q-switched and mode-locked Nd : YVO4 laser – a good tool for powder SHG measurement

    Indian Academy of Sciences (India)

    P K Datta; Chandrajit Basu; S Mukhopadhyay; S K Das; G K Samanta; Antonio Agnesi

    2004-11-01

    A non-linear mirror consisting of a lithium triborate crystal and a dichroic output coupler are used to mode-lock (passively) an Nd : YVO4 laser, pumped by a diode laser array. The laser can operate both in cw mode-locked and simultaneously Q-switched and mode-locked (QML) regime. The peak power of the laser while operating in QML regime is much higher but pulses suffers from poor amplitude stability. The incorporation of an acousto-optic modulator as an active Q-switch enhances the stability of the QML pulse envelope. The second-order non-linearity of powdered crystalline urea is conclusively measured with respect to KDP while the laser is operating in passively Q-switched and passively mode-locked regime as well as in actively Q-switched and passively mode-locked regime.

  6. Compact optical displacement sensing by detection of microwave signals generated from a monolithic passively mode-locked laser under feedback

    Science.gov (United States)

    Simos, Christos; Simos, Hercules; Nikas, Thomas; Syvridis, Dimitris

    2015-05-01

    A monolithic passively mode-locked laser is proposed as a compact optical sensor for displacements and vibrations of a reflecting object. The sensing principle relies on the change of the laser repetition frequency that is induced by optical feedback from the object under measurement. It has been previously observed that, when a semiconductor passively mode locked laser receives a sufficient level of optical feedback from an external reflecting surface it exhibits a repetition frequency that is no more determined by the mode-locking rule of the free-running operation but is imposed by the length of the external cavity. Therefore measurement of the resulting laser repetition frequency under self-injection permits the accurate and straightforward determination of the relative position of the reflecting object. The system has an inherent wireless capability since the repetition rate of the laser can be wirelessly detected by means of a simple antenna which captures the microwave signal generated by the saturable absorber and is emitted through the wiring of the laser. The sensor setup is very simple as it requires few optical components besides the laser itself. Furthermore, the deduction of the relative position of the reflecting object is straightforward and does not require any processing of the detected signal. The proposed sensor has a theoretical sub-wavelength resolution and its performance depends on the RF linewidth of the laser and the resolution of the repetition frequency measurement. Other physical parameters that induce phase changes of the external cavity could also be quantified.

  7. Multi-pass oscillator layout for high-energy mode-locked thin-disk lasers

    CERN Document Server

    Schuhmann, K; Antognini, A

    2016-01-01

    A novel optical layout for a multi-pass resonator is presented paving the way for pulse energy scaling of mode-locked thin-disk lasers. The multi-pass resonator we are proposing consists of a concatenation of nearly identical optical segments. Each segment corresponds to a round-trip in an optically stable cavity containing an active medium exhibiting soft aperture effects. This scheme is apt for energy and power scaling because the stability region of this multi-pass resonator contrarily to the 4f-based schemes does not shrink with the number of passes. We conclude proposing a simple way to double the stability region of the state-of-the-art layouts used in the industry achievable by a minimal rearrangement of the used optical components.

  8. Electrical Addressing and Temporal Tweezing of Localized Pulses in Passively Mode-Locked Semiconductor Lasers

    CERN Document Server

    Camelin, P; Marconi, M; Giudici, M

    2016-01-01

    We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures (LSs), also called localized pulses, found in passively mode-locked Vertical-Cavity Surface-Emitting Lasers. 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. ...

  9. Supercontinuum Generation in DSF Pumped by Actively Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    JIA Dongfang; WANG Zhaoying; LI Shichen

    2005-01-01

    The supercontinuum (SC) generation at the repetition rate of 10 GHz is presented. The SC is generated in a 4.2 km conventional dispersion-shifted fiber ( DSF), which is produced with nonlinear effects and group velocity dispersion. The DSF is pumped by an actively mode-locked Er3+ -doped fiber laser with pulse width of 7.97 ps. A novel SC pulse source with a bandwidth up to 125 nm is obtained, which covers the whole C, L bands and part of S band. The stable, narrow pulses with mean pulse-width of 9.7 ps and time-bandwidth product of 0.48 are filtered out across the whole SC bandwidth. This supercontinuum pulse source is suitable for future high-speed optical communications.

  10. Wavelength-tunable 10 GHz actively harmonic mode-locked fiber laser based on semiconductor optical amplifier

    Science.gov (United States)

    Mao, Yan; Tong, Xinglin; Wang, Zhiqiang; Zhan, Li; Hu, Pan; Chen, Liang

    2015-12-01

    We demonstrate a widely wavelength-tunable actively mode-locked fiber laser based on semiconductor optical amplifier. Beneficiating from the actively mode-locking operation and the wavelength-tunable characteristics of a Fabry-Perot filter, different harmonic mode-locking orders, from the fundamental mode-locking order (18.9 MHz) to the 520th order (9.832 GHz), can be easily achieved. The spectral bandwidth corresponding to the fundamental repetition rate is 0.12 nm with the pulse duration of 9.8 ns, leading to the TBP value of 146, which is about 460 times the transform-limited value for soliton pulse. The highest repetition rate of the mode-locked pulses we obtained is 9.832 GHz, with a signal-to-noise ratio up to 50 dB. The theoretical transform-limited pulse duration is 21 ps. Meanwhile, the central wavelength can be continuously tuned over 43.4 nm range (1522.8-1566.2 nm). The higher repetition rate and the widely tuning wavelength range make the fiber laser to own great potential and promising prospects in areas such as optical communication and photonic analog-to-digital conversion (ADC).

  11. Amplification of short pulses from a mode-locked diode laser in an ytterbium-doped fiber

    NARCIS (Netherlands)

    Hekelaar, M.G.; Adhimoolam, B.; Gross, P.; Lindsay, I.D.; Boller, Klaus J.

    2005-01-01

    We report the first mode-locked diode laser at 1.04 µm with subsequent amplification of the pulses in an ytterbium-doped fiber amplifier. The generated pulses have a pulse duration of 70ps and peak power of 50W.

  12. Rate equation dynamics of passively mode-locked quasi-continuous lasers: pulse stability and dynamic pulse compression

    Energy Technology Data Exchange (ETDEWEB)

    New, G.H.C.; Orkney, K.E.; Nock, M.J.W.

    1976-09-01

    New theoretical results connected with the stability of multiple pulsing in a passively mode-locked quasicontinuous laser in the rate equation approximation are presented. Together with earlier results, these allow the number of pulses per cavity transit to be predicted and a qualitative estimate made of the pulse duration for any combination of parameters. The results are illustrated by computer evolutions.

  13. Q-Switched and Mode Locked Short Pulses from a Diode Pumped, YB-Doped Fiber Laser

    Science.gov (United States)

    2009-03-26

    500fs.pdf. 43. H. Leblond, M. Salhi, A. Hideur, T. Chartier , M. Brunel, F. Sanchez, "Experimental and theoretical study of the passively mode...locked ytterbium-doped double-clad fiber laser", Physical Review A, Vol. 65 063811 (2002) pp 1-9. 44. B. Ortac, A. Hideur, M. Brunel, T. Chartier , M

  14. Structure of picosecond pulses of a Q-switched and mode-locked diode-pumped Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Donin, V I; Yakovin, D V; Gribanov, A V [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2015-12-31

    The pulse duration of a diode-pumped Nd:YAG laser, in which Q-switching with mode-locking (QML regime) is achieved using a spherical mirror and a travelling-wave acousto-optic modulator, is directly measured with a streak camera. It is found that the picosecond pulses can have a non-single-pulse structure, which is explained by excitation of several competing transverse modes in the Q-switching regime with a pulse repetition rate of 1 kHz. In the case of cw mode-locking (without Q-switching), a new (auto-QML) regime is observed, in which the pulse train repetition rate is determined by the frequency of the relaxation oscillations of the laser field while the train contains single picosecond pulses. (control of laser radiation parameters)

  15. CsPbBr3 nanocrystal saturable absorber for mode-locking ytterbium fiber laser

    Science.gov (United States)

    Zhou, Yan; Hu, Zhiping; Li, Yue; Xu, Jianqiu; Tang, Xiaosheng; Tang, Yulong

    2016-06-01

    Cesium lead halide perovskite nanocrystals (CsPbX3, X = Cl, Br, I) have been reported as efficient light-harvesting and light-emitting semiconductor materials, but their nonlinear optical properties have been seldom touched upon. In this paper, we prepare layered CsPbBr3 nanocrystal films and characterize their physical properties. Broadband linear absorption from ˜0.8 to over 2.2 μm and nonlinear optical absorption at the 1-μm wavelength region are measured. The CsPbBr3 saturable absorber (SA), manufactured by drop-casting of colloidal CsPbBr3 liquid solution on a gold mirror, shows modulation depth and saturation intensity of 13.1% and 10.7 MW/cm2, respectively. With this SA, mode-locking operation of a polarization-maintained ytterbium fiber laser produces single pulses with duration of ˜216 ps, maximum average output power of 10.5 mW, and the laser spectrum is centered at ˜1076 nm. This work shows that CsPbBr3 films can be efficient SA candidates for fiber lasers and also have great potential to become broadband linear and nonlinear optical materials for photonics and optoelectronics.

  16. Switchable repetition rate bound solitons passively mode-locked fiber laser

    Science.gov (United States)

    Wang, Xuqin; Yao, Yong

    2016-11-01

    We present a kind of a switchable repetition rate mode-locked of bound-state solitons in a fiber laser based on Bi2Se3 saturable absorber (SA). In the fiber laser, two forms of the bound-state optical spectrum with central wavelength of 1532 nm are observed. The fiber laser is operate at the abnormal group velocity dispersion and the bound state pulses are equally distributed to the temporal domain. The fundamental cavity repetition-rate is 1.11 MHz with a pulse duration of 2.27 ps. The output average power and the pulse peak energy are 1.53 mW and 607 W respectively, which the pump power is 267 mW. The different repetition-rates are also achieved by changing the pump power or adjusting the angle of polarization controller. In the experiment, the repetition-rate is switched from 1.11 MHz to 41.32 MHz (37th-order, the highest repetition-rate).

  17. CsPbBr{sub 3} nanocrystal saturable absorber for mode-locking ytterbium fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yan; Li, Yue; Xu, Jianqiu; Tang, Yulong, E-mail: yulong@sjtu.edu.cn [Key Laboratory for Laser Plasmas (MOE), Department of Physics and Astronomy, Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240 (China); Hu, Zhiping; Tang, Xiaosheng [Key Laboratory of Optoelectronic Technology and Systems of the Education Ministry of China, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2016-06-27

    Cesium lead halide perovskite nanocrystals (CsPbX{sub 3}, X = Cl, Br, I) have been reported as efficient light-harvesting and light-emitting semiconductor materials, but their nonlinear optical properties have been seldom touched upon. In this paper, we prepare layered CsPbBr{sub 3} nanocrystal films and characterize their physical properties. Broadband linear absorption from ∼0.8 to over 2.2 μm and nonlinear optical absorption at the 1-μm wavelength region are measured. The CsPbBr{sub 3} saturable absorber (SA), manufactured by drop-casting of colloidal CsPbBr{sub 3} liquid solution on a gold mirror, shows modulation depth and saturation intensity of 13.1% and 10.7 MW/cm{sup 2}, respectively. With this SA, mode-locking operation of a polarization-maintained ytterbium fiber laser produces single pulses with duration of ∼216 ps, maximum average output power of 10.5 mW, and the laser spectrum is centered at ∼1076 nm. This work shows that CsPbBr{sub 3} films can be efficient SA candidates for fiber lasers and also have great potential to become broadband linear and nonlinear optical materials for photonics and optoelectronics.

  18. Monolithic mode locked DBR laser with multiple-bandgap MQW structure realized by selective area growth

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, M.; Bouayad-Amine, J.; Feeser, T.; Haisch, H.; Kuehn, E.; Lach, E.; Satzke, K.; Weber, J.; Zielinski, E. [Alcatel Telecom, Stuttgart (Germany). Research Div.

    1996-12-31

    The realization of novel monolithically integrated multiple-segment pulse laser sources in InGaAsP MQW technology is reported. The MQW layers for all functional sections of these devices, the modulator, the active (gain) and the passive waveguide, as well as the Bragg section were grown in a single selective area growth (SAG) step by LP-MOVPE on SiO{sub 2} patterned 2 inch InP substrates. Due to a properly selected pattern geometry 3 different bandgap regions with smooth interfaces are thereby formed along the laser cavity. The more than 4 mm long DBR lasers which exhibit a threshold current as low as 30 mA were mode locked by an intra-cavity electroabsorption modulator applying a sinusoidal voltage at around 10 GHz. In this way an optical pulse train with pulse widths < 13 ps (measured with a streak camera) and high extinction ratio was generated. A time-bandwidth product of 0.5 close to the Fourier limit is obtained. This device is very attractive for signal generation in 40 Gb/s OTDM transmission systems at 1.55 {micro}m wavelength.

  19. Developing high energy mode-locked fiber laser at 2 micron

    CERN Document Server

    Huang, C; Shang, W; Tang, Y; Xu, J

    2015-01-01

    While dissipative soliton operation has successfully improved the pulse energy of 1 {\\mu}m and 1.5 {\\mu}m fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy of dissipative solitons at 2 {\\mu}m due to the anomalous dispersion of the gain fiber. Based on theoretical simulation, we analyze intracavity dynamics of dissipative solitons (DSs) and propose that gain fiber should be condensed to short length in order to scale the pulse energy of 2 {\\mu}m DSs. The simulation predicts pulse energy of over 10 nJ for 2 {\\mu}m dissipative solitons, comparable to that achieved in the 1 {\\mu}m and 1.5 {\\mu}m regimes. Experimental operation generates stable 2 {\\mu}m DSs from a linear cavity with pulse energy of 4.9 nJ and dechirped pulse duration of 579 fs. These results advance our understanding of mode-locked fiber laser at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media at 2 {\\mu}m.

  20. The characteristics of Kerr-lens mode-locked self-Raman Nd:YVO4 1176 nm laser

    Science.gov (United States)

    Li, Zuohan; Peng, Jiying; Yao, Jianquan; Han, Ming

    2017-03-01

    In this paper we report on a compact and feasible dual-concave cavity CW Kerr-lens mode-locked self-Raman Nd:YVO4 laser. A self-starting diode-pumped picosecond Nd:YVO4 1176 nm laser is demonstrated without any additional components, where the stimulated Stokes Raman scattering and Kerr-lens-induced mode locking are operated in the same crystal. With an incident pump power of 12 W, the average output power at 1176 nm is up to 643 mW. Meanwhile, the repetition rate and the pulse width of the fundamental laser are measured to be 1.53 GHz and 8.6 ps, respectively. In addition, the yellow laser output at 588 nm is realized by frequency doubling with a LiB3O5 crystal.

  1. Tunable graphene Q-switched erbium-doped fiber laser with suppressed self-mode locking effect.

    Science.gov (United States)

    Zhou, Da-Peng; Wei, Li; Liu, Wing-Ki

    2012-05-10

    Self-mode locking effect in a wideband tunable graphene-based passively Q-switched erbium-doped fiber laser has been observed experimentally. Q-switching is achieved by using graphene as a saturable absorber, while a tunable bandpass filter with a narrow bandwidth is used to obtain wideband tunability. We propose to suppress the modulation on each pulse from self-mode locking by introducing three subring resonators constructed with three 3 dB couplers into the laser ring cavity. Moreover, the laser output characteristics with respect to pump power are studied in detail. A stable Q-switched erbium-doped fiber laser with a tunable range from 1522 nm to 1568 nm is demonstrated experimentally.

  2. Passively mode-locked stretched-pulse erbium-doped fiber ring laser with a regenerative feedback

    Science.gov (United States)

    Roy, Vincent; Lamonde, Martin; Babin, Francois; Piche, Michel

    2003-02-01

    A polarization additive pulse mode-locked stretched-pulse erbium-doped fiber ring laser with a regenerative feedback producing near transform-limited femtosecond pulses is reported. The regenerative feedback makes use of an intensity modulator driven at twice the fundamental repetition rate of the passively mode-locked fiber laser. The laser is self-starting for a limited range of pump power. The de-chirped pulses have a duration of 90 fs (FWHM) and a pulse time-bandwidth product of 0.44. The pulse energy amounts to 0.3 nJ. Pulses with nearly twice that energy could be obtained, though without self-starting capability. The laser RF power spectrum measurement yields an amplitude noise as low as 0.15% (rms) and a pulse timing jitter of 150 fs (rms). In addition, RF spectra show no relaxation oscillation in the self-starting regime.

  3. Q-switched mode-locked diode-pumped Nd:YVO4 laser with a saturable Bragg reflector

    Institute of Scientific and Technical Information of China (English)

    Juan Du(杜鹃); Jingliang He(何京良); Jie Liu(刘杰); Qiuxia Jiang(姜秋霞); Sheng Liu(刘胜); Huitian Wang(王慧田)

    2004-01-01

    We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ~230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ~150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.

  4. Q-switched mode-locked diode-pumped Nd:YVO4 laser with a saturable Bragg reflector

    Institute of Scientific and Technical Information of China (English)

    杜鹃; 何京良; 刘杰; 姜秋霞; 刘胜; 王慧田

    2004-01-01

    We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ~230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ~150kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.

  5. 1.34 µm picosecond self-mode-locked Nd:GdVO4 watt-level laser

    Science.gov (United States)

    Han, Ming; Peng, Jiying; Li, Zuohan; Cao, Qiuyuan; Yuan, Ruixia

    2017-01-01

    With a simple linear configuration, a diode-pumped, self-mode-locked Nd:GdVO4 laser at 1.34 µm is experimentally demonstrated for the first time. Based on the aberrationless theory of self-focusing and thermal lensing effect, through designing and optimizing the resonator, a pulse width as short as 9.1 ps is generated at a repetition rate of 2.0 GHz and the average output power is 2.51 W. The optical conversion efficiency and the slope efficiency for the stable mode-locked operation are approximately 16.7% and 19.2%, respectively.

  6. Mode-locked Yb-doped fiber laser emitting broadband pulses at ultra-low repetition rates

    CERN Document Server

    Bowen, Patrick; Provo, Richard; Harvey, John D; Broderick, Neil G R

    2016-01-01

    We report on an environmentally stable, Yb-doped, all-normal dispersion, mode-locked fibre laser that is capable of creating broadband pulses with ultra-low repetition rates. Specifically, through careful positioning of fibre sections in an all-PM-fibre cavity mode-locked with a nonlinear amplifying loop mirror, we achieve stable pulse trains with repetition rates as low as 506 kHz. The pulses have several nanojules of energy and are compressible down to ultrashort (< 500 fs) durations.

  7. Self-starting mode-locked picosecond Ti:sapphire laser by using of a fast SESAM

    Institute of Scientific and Technical Information of China (English)

    Zhu Jiang-Feng; Tian Jin-Rong; Wang Peng; Ling Wei-Jun; Li De-Hua; Wei Zhi-Yi

    2006-01-01

    A stable continuous wave mode-locked picosecond Ti:sapphire laser by using a fast semiconductor saturable absorber mirror (SESAM) is demonstrated. The laser delivers pulse width of 20 ps at a central wavelength of 813 nm and a repetition rate of 100 MHz. The maximum output power is 1.34 W with pump power of 7 W which corresponds to an optical-optical conversion efficiency of 19.1%.

  8. Monolithic strained-InGaAsP multiple-quantum-well lasers with integrated electroabsorption modulators for active mode locking

    Science.gov (United States)

    Sato, Kenji; Wakita, Koichi; Kotaka, Isamu; Kondo, Yasuhiro; Yamamoto, Mitsuo; Takada, Atsushi

    1994-07-01

    Active mode locking by monolithic lasers with integrated electroabsorption modulators using strained-InGaAsP multiple quantum wells is described. The electroabsorption modulator acts as a short optical gate when a sinusoidal voltage is driven at a deep bias point. Pulse widths as short as 2 ps have been obtained at a repetition rate of 16.3 GHz for a 2.5-mm-long monolithic laser.

  9. Pulse width shaping of passively mode-locked soliton fiber laser via polarization control in carbon nanotube saturable absorber.

    Science.gov (United States)

    Jeong, Hwanseong; Choi, Sun Young; Rotermund, Fabian; Yeom, Dong-Il

    2013-11-04

    We report the continuous control of the pulse width of a passively mode-locked fiber laser via polarization state adjustment in a single-walled carbon nanotube saturable absorber (SWCNT-SA). The SWCNT, coated on the side-polished fiber, was fabricated with optimized conditions and used for stable mode-locking of the fiber laser without Q-switching instabilities for any polarization state of the laser intra-cavity. The 3-dB spectral bandwidth of the mode-locked pulses can be continuously tuned from 1.8 nm to 8.5 nm with the polarization control for a given laser cavity length and applied pump power. A pulse duration varying from 470 fs to 1.6 ps was also observed with a change in the spectral bandwidth. The linear and the nonlinear transmission properties of the SA were analyzed, and found to exhibit different modulation depths depending on the input polarization state in the SA. The largest modulation depth of the SA was observed at the polarization state of the transverse electric mode that delivers shortest pulses at the laser output.

  10. Passive mode locking of a Nd:YAG laser with co-doped Nd, Cr:YAG as saturable absorber

    Institute of Scientific and Technical Information of China (English)

    Yang Lin(杨林); Feng Bao-Hua(冯宝华); Zhang Zhi-Guo(张治国); Gaebler Volker; Liu Bai-Ning(刘百宁); Eichler Hans

    2003-01-01

    We demonstrate the characteristics of relatively low saturation intensity using co-doped Nd, Cr:YAG as saturable absorber for passively mode locking the Nd:YAG laser. The difference of the saturation intensity between Q-switched and mode-locked operation in co-doped Nd, Cr:YAG was only one to two orders of magnitude, while Cr:YAG was generally reported at a difference of five orders of magnitude. More than 80% mode locking modulation depth was achieved at an incident pump power of 4.4W, corresponding to an intracavity intensity of 6 × 104W/cma2, using a 68cm long plano-concave cavity.

  11. Vector soliton fiber laser passively mode locked by few layer black phosphorus-based optical saturable absorber.

    Science.gov (United States)

    Song, Yufeng; Chen, Si; Zhang, Qian; Li, Lei; Zhao, Luming; Zhang, Han; Tang, Dingyuan

    2016-11-14

    We report on the optical saturable absorption of few-layer black phosphorus nanoflakes and demonstrate its application for the generation of vector solitons in an erbium-doped fiber laser. By incorporating the black phosphorus nanoflakes-based saturable absorber (SA) into an all-fiber erbium-doped fiber laser cavity, we are able to obtain passive mode-locking operation with soliton pulses down to ~670 fs. The properties and dynamics of the as-generated vector solitons are experimentally investigated. Our results show that BP nanoflakes could be developed as an effective SA for ultrashort pulse fiber lasers, particularly for the generation of vector soliton pulses in fiber lasers.

  12. Influence of kinetic hole filling on the stability of mode-locked semiconductor disk lasers

    Science.gov (United States)

    Moloney, Jerome V.; Kilen, Isak; Hader, Jorg; Koch, Stephan W.

    2016-03-01

    Microscopic many-body theory is employed to analyze the mode-locking dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror. The quantum-wells are treated microscopically through the semiconductor Bloch equations and the light field using Maxwell's equations. Higher order correlation effects such as polarization dephasing and carrier relaxation at the second Born level are included and also approximated using effective rates fitted to second-Born-Markov evaluations. The theory is evaluated numerically for vertical external cavity surface emitting lasers with resonant periodic gain media. For given gain, the influence of the loss conditions on the very-short pulse generation in the range above 100 fs is analyzed. Optimized operational parameters are identified. Additionally, the fully microscopic theory at the second Born level is used to carrier out a pump-probe study of the carrier recovery in individual critical components of the VECSEL cavity such as the VECSEL chip itself and semiconductor or graphene saturable absorber mirrors.

  13. WS2 as a saturable absorber for ultrafast photonic applications of mode-locked and Q-switched lasers

    CERN Document Server

    Wu, Kan; Wang, Jun; Li, Xing; Chen, Jianping

    2014-01-01

    Two-dimensional (2D) nanomaterials, especially the transition metal sulfide semiconductors, have drawn great interests due to their potential applications in viable photonic and optoelectronic devices, such as saturable absorbers (SAs) and optical switches, etc. In this work, tungsten disulfide (WS2) based SA for ultrafast photonic applications was demonstrated. WS2 nanosheets were prepared using liquid-phase exfoliation method and embedded in polyvinyl alcohol (PVA) thin film for the practical usage. Saturable absorption was observed in the WS2-PVA SA at the telecommunication waveband near 1550 nm. By incorporating WS2-PVA SA into a fiber laser cavity, both stable mode locking operation and Q-switching operation were achieved. In the mode locking operation, the laser obtained femtosecond output pulse width and high spectral purity in the radio frequency spectrum. In the Q-switching operation, the laser had tunable repetition rate and output pulse energy of a few tens of nano joule. Our findings suggest that ...

  14. Narrow bandwidth passively mode locked picosecond Erbium doped fiber laser using a 45° tilted fiber grating device.

    Science.gov (United States)

    Wang, Tianxing; Yan, Zhijun; Mou, Chengbo; Liu, Zuyao; Liu, Yunqi; Zhou, Kaiming; Zhang, Lin

    2017-07-10

    An all-fiber passively picosecond mode locked Erbium doped laser using a 45° tilted fiber grating (45° TFG) and a fiber Bragg grating (FBG) is reported in this work. Due to the strong polarization dependent loss (PDL) of 45° TFG and narrow 3-dB bandwidth of FBG, the Erbium doped fiber laser (EDFL) can generate picosecond mode locked pulse based on the nonlinear polarization rotation (NPR) effect. The laser features a repetition rate of 9.67 MHz, a pulse duration of 33 ps, a signal-to-noise ratio (SNR) of 70 dB, an average output power of 1.2 mW, and a single pulse energy of 124 pJ under the pump power of 102 mW. Besides, the central wavelength of the laser can be continuously adjusted from 1550.65 nm to 1551.44 nm. The technique of using a 45° TFG to generate picosecond pulses can be readily extended to other wavelength such as mid-infrared (mid-IR) where fiber polarizing components are either expensive or not available. To the best of our knowledge, the spectral width is the narrowest among all-fiber passively mode locked Erbium-doped laser based on NPR.

  15. Design and Applications of In-Cavity Pulse Shaping by Spectral Sculpturing in Mode-Locked Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Sonia Boscolo

    2015-11-01

    Full Text Available We review our recent progress on the realisation of pulse shaping in passively-mode-locked fibre lasers by inclusion of an amplitude and/or phase spectral filter into the laser cavity. We numerically show that depending on the amplitude transfer function of the in-cavity filter, various regimes of advanced waveform generation can be achieved, including ones featuring parabolic-, flat-top- and triangular-profiled pulses. An application of this approach using a flat-top spectral filter is shown to achieve the direct generation of high-quality sinc-shaped optical Nyquist pulses with a widely tunable bandwidth from the laser oscillator. We also present the operation of an ultrafast fibre laser in which conventional soliton, dispersion-managed soliton (stretched-pulse and dissipative soliton mode-locking regimes can be selectively and reliably targeted by adaptively changing the dispersion profile and bandwidth programmed on an in-cavity programmable filter. The results demonstrate the strong potential of an in-cavity spectral pulse shaper for achieving a high degree of control over the dynamics and output of mode-locked fibre lasers.

  16. Compact graphene mode-locked wavelength-tunable erbium-doped fiber lasers: from all anomalous dispersion towards all normal dispersion

    CERN Document Server

    Zhang, Han; Zhao, Luming; Bao, Qiaoliang; Loh, Kian Ping; Lin, Bo; Tjin, Swee Chuan

    2010-01-01

    Soliton operation and soliton wavelength tuning of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated under various cavity dispersion conditions. It was shown that not only wide range soliton wavelength tuning but also soltion pulse width variation could be obtained in the fiber lasers. Our results show that the graphene mode locked erbium-doped fiber lasers provide a compact, user friendly and low cost wavelength tunable ultrahsort pulse source.

  17. Pulse bundles and passive harmonic mode-locked pulses in Tm-doped fiber laser based on nonlinear polarization rotation.

    Science.gov (United States)

    Wang, Xiong; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-03-10

    We demonstrate the nanosecond-level pulses in Tm-doped fiber laser generated by passively harmonic mode-locking. Nonlinear polarization rotation performed by two polarization controllers (PCs) is employed to induce the self-starting harmonic mode-locking. The fundamental repetition rate of the laser is 448.8 kHz, decided by the length of the cavity. Bundles of pulses with up to 17 uniform subpulses are generated due to the split of pulse when the pump power increases and the PCs are adjusted. Continuous harmonic mode-locked pulse trains are obtained with 1st to 6th and even more than 15th order when the positions of the PCs are properly fixed and the pump power is scaled up. The widths of all the uniform individual pulses are mostly 3-5 ns, and pulse with width of 304 ns at fundamental repetition rate can also be generated by adjusting the PCs. Hysteresis phenomenon of the passively harmonic mode-locked pulses' repetition frequency versus pump power is observed. The rather wide 3dB spectral bandwidth of the pulse train (25 nm) indicates that they may resemble noise-like pulses.

  18. Suppression of continuous lasing in a carbon nanotube polyimide film mode-locked erbium-doped fiber laser.

    Science.gov (United States)

    Gui, Lili; Yang, Xin; Zhao, Guangzhen; Yang, Xu; Xiao, Xiaosheng; Zhu, Jinsong; Yang, Changxi

    2011-01-01

    We demonstrated an erbium-doped mode-locked fiber laser using a single-walled carbon nanotube-dispersed polyimide (SWNT-PI) film. Different mode-locking operations were compared and analyzed utilizing SWNT-PI films with different concentrations (2, 1, and 0.25 wt.%, respectively). It was found that the continuous single-pulse mode-locking operation was often accompanied by a continuous wave oscillation part for the 1 and 0.25 wt.% SWNT-PI films, whereas the 2 wt.% SWNT-PI film presented the most excellent mode-locking performance, thanks to sufficient modulation depth. Using the 2 wt.% SWNT-PI film, a stable pulse train with a pulse width of 840 fs and a repetition rate of 15.3 MHz was achieved. The average output power was 0.33 mW at the pump power of 155 mW under an output coupling ratio of 10%. Operational performance of the laser cavity when employing the 2 wt.% SWNT-PI film was also demonstrated.

  19. Characterization of timing jitter spectra in free-running mode-locked lasers with 340 dB dynamic range over 10 decades of Fourier frequency

    CERN Document Server

    Jung, Kwangyun

    2014-01-01

    We demonstrate a method that enables accurate timing jitter spectral density characterization of free-running mode-locked laser oscillators over more than 10-decade of Fourier frequency from mHz to tens MHz range. The method is based on analyzing both the input voltage noise to the slave laser and the output voltage noise from the balanced optical cross- correlator (BOC), when two mode-locked lasers are synchronized in repetition rate by the BOC. As a demonstration experiment, timing jitter spectrum of a free-running mode-locked Er-fiber laser with a dynamic range of >340 dB is measured over Fourier frequency ranging from 1 mHz to 38.5 MHz (Nyquist frequency). The demonstrated method can resolve different noise mechanisms that cause specific jitter characteristics in free-running mode-locked laser oscillators for a vast range of time scales from 1000-s.

  20. Mode-locked and Q-switched operation of a diode laser pumped Nd:YAG laser operating at 1.064 µm

    Science.gov (United States)

    Maker, G. T.; Keen, S. J.; Ferguson, A. I.

    1988-10-01

    We describe the performance of a mode-locked and Q-switched Nd:YAG laser operating at 1.064 μm, optically pumped by a 500 mW diode laser. The cw mode-locked system provides bandwidth-limited pulses of 55 ps duration, with a corresponding peak power of 3.3 W. When Q-switched the energy within the 100 ns pulse envelope is 10 μJ giving a peak power in the largest pulse of 7 kW. Preliminary results for operation at 1.32 μm are also reported.

  1. Modeling and Direct Electric-Field Measurements of Passively Mode-Locked Quantum-Dot Lasers (Postprint)

    Science.gov (United States)

    2010-07-01

    H. Li, K. J. Malloy, and L. F. Lester, “Extremely low room-temperature threshold current density diode lasers using InAs dots in In0 .15Ga0 .85As...Fuchs, K. J. Malloy, and L. F. Lester, “Gain and linewidth enhancement factor in InAs quantum-dot laser diodes ,” IEEE Photon. Tech. Lett., vol. 11, no...device physics, and fabrication and characterization of semiconduc- tor quantum-dot light emitters that include mode- locked laser and superluminescent

  2. Picosecond to femtosecond pulses from high power self mode-locked ytterbium rod-type fiber laser

    OpenAIRE

    Deslandes, Pierre; Perrin, Mathias; Saby, Julien; Sangla, Damien; Salin, François; Freysz, Eric

    2013-01-01

    International audience; We have designed an ytterbium rod-type fiber laser oscillator with tunable pulse duration. This system that delivers more than 10 W of average power is self mode-locked. It yields femtosecond to picosecond laser pulses at a repetition rate of 74 MHz. The pulse duration is adjusted by changing the spectral width of a band pass filter that is inserted in the laser cavity. Using volume Bragg gratings of 0.9 nm and 0.07 nm spectrum bandwidth, this oscillator delivers nearl...

  3. Control over the performance characteristics of a passively mode-locked erbium-doped fibre ring laser

    Energy Technology Data Exchange (ETDEWEB)

    Chernysheva, M A; Krylov, A A; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Ogleznev, A A [Perm Research and Production Instrument Company, Perm (Russian Federation); Arutyunyan, N R; Pozharov, A S; Obraztsova, E D [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2013-08-31

    We report an all-fibre ultrashort pulse erbium-doped ring laser passively mode-locked by single-wall carbon nanotubes dispersed in carboxymethylcellulose-based polymer films. Owing to intracavity dispersion management and controlled absorption in the polymer films, the laser is capable of generating both femto- and picosecond pulses of various shapes in the spectral range 1.53 – 1.56 μm. We have demonstrated and investigated the generation of almost transform- limited, inversely modified solitons at a high normal cavity dispersion. (control of laser radiation parameters)

  4. Subharmonic Fourier domain mode locking.

    Science.gov (United States)

    Eigenwillig, Christoph M; Wieser, Wolfgang; Biedermann, Benjamin R; Huber, Robert

    2009-03-15

    We demonstrate a subharmonically Fourier domain mode-locked wavelength-swept laser source with a substantially reduced cavity fiber length. In contrast to a standard Fourier domain mode-locked configuration, light is recirculated repetitively in the delay line with the optical bandpass filter used as switch. The laser has a fundamental optical round trip frequency of 285 kHz and can be operated at integer fractions thereof (subharmonics). Sweep ranges up to 95 nm full width centred at 1317 nm are achieved at the 1/5th subharmonic. A maximum sensitivity of 116 dB and an axial resolution of 12 microm in air are measured at an average sweep power of 12 mW. A sensitivity roll-off of 11 dB over 4 mm and 25 dB over 10 mm is observed and optical coherence tomography imaging is demonstrated. Besides the advantage of a reduced fiber length, subharmonic Fourier domain mode locking (shFDML) enables simple scaling of the sweep speed by extracting light from the delay part of the resonator. A sweep rate of 570 kHz is achieved. Characteristic features of shFDML operation, such as power leakage during fly-back and cw breakthrough, are investigated.

  5. Simple optical frequency comb generation using a passively mode-locked quantum dot laser

    Science.gov (United States)

    Liu, Li; Zhang, Xiupu; Xu, Tiefeng; Dai, Zhenxiang; Liu, Taijun

    2017-08-01

    A simple and quasi-tunable optical frequency comb (OFC) generator is proposed and experimentally demonstrated using a C-band passively Fabry-Pérot quantum dot mode-locked laser and a dual-driven LiNbO3 Mach-Zehnder modulator. A 16-nm bandwidth OFC with 81, 58 and 30 comb lines at frequency interval of 23.3 GHz, 35 GHz and 70 GHz respectively is obtained experimentally. Measured average optical signal to noise ratio of 10-dB bandwidth OFCs is 36.3 dB, 38.5 dB and 40.8 dB at frequency interval of 23.3 GHz, 35 GHz and 70 GHz, respectively. Besides, single-sideband phase noise of the 23.3 GHz and 35 GHz frequency comb is -110 dBc/Hz and -102 dBc/Hz at an offset of 1 kHz, respectively. RF linewidth of the 23.3 GHz and 35 GHz OFC is about from 275 Hz to 289 Hz. This is considered a very simple OFC generator with a broadband and seamless spectrum.

  6. Kerr-Lens Self-Mode-Locked Laser Characteristics of Yb:Lu2SiO5 Crystal

    Institute of Scientific and Technical Information of China (English)

    LIU Jie; YANG Ji-Min; WANG Wei-Wei; ZHENG Li-He; SU Liang-Bi; Xu Jun

    2011-01-01

    A diode-pumped Kerr-lens self-mode-locked laser is achieved by using Yb:Lu2Si05 (Yb:LSO) crystal without additional components.Under the incident pump power of 14.44 W,a self-mode-locked output power of 2.98 W is obtained in the five-mirror cavity,corresponding to an optical-optical efficiency of 20.6%.Pulses as short as 8.2ps are realized at 1059 nm,with the corresponding pulse energy and peak power of 28.9 nJ and 3.5 k W,respectively.A pair of SF10 prisms are inserted into the laser cavity to compensate for the group velocity dispersion. The pulse width is compressed to 2.2 ps with an average output power of 1.25 W.

  7. Black phosphorus mode-locked Er-doped ZBLAN fiber laser at 2.8 um wavelength

    CERN Document Server

    Qin, Zhipeng; Zhao, Chujun; Wen, Shuangchun; Yuan, Peng; Qian, Liejia

    2015-01-01

    Mid-infrared saturable absorber mirror is successfully fabricated by transferring the mechanically exfoliated black phosphorus onto the gold-coated mirror. With the as-prepared black phosphorus saturable absorber mirror, a continuous-wave passively mode-locked Er:ZBLAN fiber laser is demonstrated at the wavelength of 2.8 um, which delivers a maximum average output power of 613 mW, a repetition rate of 24 MHz and a pulse duration of 42 ps. To the best of our knowledge, it is the first time to demonstrate black phosphorus mode-locked laser at 2.8 um wavelength. Our results demonstrate the feasibility of black phosphorus flake as a new two-dimensional material for application in mid-infrared ultrafast photonics.

  8. Passively mode-locking erbium-doped fiber lasers with 0.3 nm single-walled carbon nanotubes.

    Science.gov (United States)

    Xu, Xintong; Zhai, Jianpang; Li, Ling; Chen, Yanping; Yu, Yongqin; Zhang, Min; Ruan, Shuangchen; Tang, Zikang

    2014-10-24

    We demonstrate a passively mode-locked erbium-doped fiber laser (EDFL) by using the smallest single-walled carbon nanotubes (SWNTs) with a diameter of 0.3 nm as the saturable absorber. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of a ZnAPO₄-11 (AEL) single crystal. By placing an AEL crystal into an EDFL cavity pumped by a 980 nm laser diode, stable passive mode-locking is achieved for a threshold pump power of 280 mW, and 73 ps pulses at 1563.2 nm with a repetition rate of 26.79 MHz.

  9. Using graphene nano-particle embedded in photonic crystal fiber for evanescent wave mode-locking of fiber laser.

    Science.gov (United States)

    Lin, Yung-Hsiang; Yang, Chun-Yu; Liou, Jia-Hong; Yu, Chin-Ping; Lin, Gong-Ru

    2013-07-15

    A photonic crystal fiber (PCF) with high-quality graphene nano-particles uniformly dispersed in the hole cladding are demonstrated to passively mode-lock the erbium-doped fiber laser (EDFL) by evanescent-wave interaction. The few-layer graphene nano-particles are obtained by a stabilized electrochemical exfoliation at a threshold bias. These slowly and softly exfoliated graphene nano-particle exhibits an intense 2D band and an almost disappeared D band in the Raman scattering spectrum. The saturable phenomena of the extinction coefficient β in the cladding provides a loss modulation for the intracavity photon intensity by the evanescent-wave interaction. The evanescent-wave mode-locking scheme effectively enlarges the interaction length of saturable absorption with graphene nano-particle to provide an increasing transmittance ΔT of 5% and modulation depth of 13%. By comparing the core-wave and evanescent-wave mode-locking under the same linear transmittance, the transmittance of the graphene nano-particles on the end-face of SMF only enlarges from 0.54 to 0.578 with ΔT = 3.8% and the modulation depth of 10.8%. The evanescent wave interaction is found to be better than the traditional approach which confines the graphene nano-particles at the interface of two SMF patchcords. When enlarging the intra-cavity gain by simultaneously increasing the pumping current of 980-nm and 1480-nm pumping laser diodes (LDs) to 900 mA, the passively mode-locked EDFL shortens its pulsewidth to 650 fs and broadens its spectral linewidth to 3.92 nm. An extremely low carrier amplitude jitter (CAJ) of 1.2-1.6% is observed to confirm the stable EDFL pulse-train with the cladding graphene nano-particle based evanescent-wave mode-locking.

  10. Development prospects and stability limits of mid-IR Kerr-lens mode-locked lasers

    CERN Document Server

    Kalashnikov, V L; Sorokina, I T

    2002-01-01

    The Kerr-lens mode locking stability and the ultrashort pulse characteristics are analyzed numerically for the Cr-doped ZnTe, ZnSe, ZnS active media. The advantages of these materials for the femtosecond lasing within 2 - 3 $\\mu$m spectral range are demonstrated

  11. Up to 400 GHz burst-mode pulse generation from a hybrid harmonic mode-locked Er-doped fibre laser

    Science.gov (United States)

    Wang, Sheng-Min; Lai, Yinchieh

    2017-02-01

    By inserting a birefringence filter with FSR  =  100 GHz inside a hybrid mode-locked Er-doped fibre laser, we successfully generate ps to sub-ps optical burst pulses with the intra-burst pulse rate up to 400 GHz. Multiplication of the intra-burst pulse rate is attributed to a new effect analogous to rational harmonic mode-locking, which occurs due to the relative alignment of the cavity harmonic frequencies, the external phase modulation induced frequencies, and the filter-selected frequencies.

  12. Mode-locked semiconductor laser system with intracavity spatial light modulator for linear and nonlinear dispersion management.

    Science.gov (United States)

    Balzer, Jan C; Döpke, Benjamin; Brenner, Carsten; Klehr, Andreas; Erbert, Götz; Tränkle, Günther; Hofmann, Martin R

    2014-07-28

    We analyze the influence of second and third order intracavity dispersion on a passively mode-locked diode laser by introducing a spatial light modulator (SLM) into the external cavity. The dispersion is optimized for chirped pulses with highest possible spectral bandwidth that can be externally compressed to the sub picosecond range. We demonstrate that the highest spectral bandwidth is achieved for a combination of second and third order dispersion. With subsequent external compression pulses with a duration of 437 fs are generated.

  13. Passive mode locking in a flash-pumped Al sub 2 O sub 3 :Ti(3+) laser

    Energy Technology Data Exchange (ETDEWEB)

    Demchuk, M.I.; Demidovich, A.A.; Zhavoronkov, N.I.; Mikhailov, V.P.; Shkadarevich, A.P. (Belorusskii Gosudarstvennyi Universitet, Minsk (Belorussian SSR))

    1990-02-01

    Passive mode locking was achieved in an Al2O3:Ti(3+) laser pumped by a flashlamp. The Al2O3Ti(3+) crystal used in the experiment (0.1 percent Ti by mass) had been grown by the Czochralski method and measured 7 x 80 mm. The pulse width in the tunable ranges 750-765 and 780-790 nm was 25 picoseconds.

  14. Mid-infrared supercontinuum generation in tapered ZBLAN fiber with a standard Erbium mode-locked fiber laser

    DEFF Research Database (Denmark)

    Kubat, Irnis; Moselund, Peter M.; Bang, Ole

    2013-01-01

    . commercially available), core diameter Dc=7 μm, and ZDW=1.5 μm, is pumped with TFWHM=10 ps and P0=10 kW pulses from an Er mode-locked laser with a 40 MHz repetition rate and 4W average power. The resulting MIR SC seen in Fig. 1(b) is based on Modulation Instability breakup of the pump pulse, which generates...

  15. $\\mathcal{PT}$-symmetric mode-locking

    CERN Document Server

    Longhi, Stefano

    2016-01-01

    Parity-time ($\\mathcal{PT}$) symmetry is one of the most important accomplishments in optics over the past decade. Here the concept of $\\mathcal{PT}$ mode-locking of a laser is introduced, in which active phase locking of cavity axial modes is realized by asymmetric mode coupling in a complex time crystal. $\\mathcal{PT}$ mode-locking shows a transition from single to double pulse emission as the $\\mathcal{PT}$ symmetry breaking point is crossed. The transition can show a turbulent behavior, depending on a dimensionless modulation parameter that plays the same role as the Reynolds number in hydrodynamic flows.

  16. Generation of 30  fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO4 laser.

    Science.gov (United States)

    Ma, Jie; Huang, Haitao; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan

    2016-03-01

    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode-locked 8.43 optical-cycle pulses have a spectral bandwidth of ∼50  nm and a pulse repetition frequency of ∼113.5  MHz. To the best of our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique for directly generating few-cycle optical pulses from a laser oscillator.

  17. Generation of 30 fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO_4 laser

    Science.gov (United States)

    Ma, Jie; Huang, Haitao; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan

    2016-03-01

    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode locked 8.43 optical-cycle pulses have a spectral bandwidth of ~ 50 nm and a pulse repetition frequency of ~ 113.5 MHz. To our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique to generate few-cycle optical pulses directly from a laser oscillator.

  18. Generation of 30-fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO4 laser

    CERN Document Server

    Ma, Jie; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan

    2015-01-01

    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode locked 8.43 optical-cycle pulses have a spectral bandwidth of ~ 50 nm and a pulse repetition frequency of ~ 113.5 MHz. To our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique to generate few-cycle optical pulses directly from a laser oscillator.

  19. Photonic ferromagnetic-like spontaneous mode-locking phase transition with replica symmetry breaking in multimode Nd:YAG laser

    CERN Document Server

    Moura, André L; Raposo, Ernesto P; Gomes, Anderson S L; de Araújo, Cid B

    2016-01-01

    The recent reports of the replica symmetry breaking (RSB) phenomenon in photonic experiments [1-5] boosted the understanding of the role of disorder in multimode lasers, as well as helped to settle enlightening connections [6-13] with the statistical physics of complex systems. RSB manifests when identically-prepared system replicas reach distinct states, yielding different measures of observable quantities [14]. Here we demonstrate the RSB in the spontaneous mode-locking regime of a conventional multimode Nd:YAG laser in a closed cavity. The underlying mechanism is quite distinct from that of the RSB spinglass phase in cavityless random lasers with incoherently-oscillating modes. Here, a specific nonuniform distribution of the gain takes place in each pulse, and frustration is induced since the coherent oscillation of a given subset of longitudinal modes dominates and simultaneously inhibits the others. Nevertheless, when high losses are introduced only the replica-symmetric amplified stimulation emission is...

  20. Characterization of nonlinear saturation and mode-locking potential of ionically-doped colored glass filter for short-pulse fiber lasers.

    Science.gov (United States)

    Zhang, M; Kelleher, E J R; Popov, S V; Taylor, J R

    2013-05-20

    The nonlinear saturable absorption of an ionically-doped colored glass filter is measured directly using a Z-scan technique. For the first time, we demonstrate the potential of this material as a saturable asborber in fiber lasers. We achieve mode-locking of an ytterbium doped system. Mode-locking of cavities with all-positive and net-negative group velocity dispersion are demonstrated, achieving pulse durations of 60 ps and 4.1 ps, respectively. This inexpensive and optically robust material, with the potential for broadband operation, could surplant other saturable absorber devices in affordable mode-locked fiber lasers.

  1. Passively Q-switched and mode-locked erbium doped fiber laser based on N-doped graphene saturable absorber

    Science.gov (United States)

    Ahmad, H.; Aidit, S. N.; Ooi, S. I.; Rezayi, M.; Tiu, Z. C.

    2017-10-01

    A passively Q-switched and mode-locked erbium-doped fiber laser based on a nitrogen-doped graphene saturable absorber is demonstrated. The N-doped graphene based saturable absorber has a modulation depth of 37.88% and a saturation intensity of 0.016 73 MW cm‑2. By integrating the N-doped graphene saturable absorber into the laser cavity, a stable Q-switched operation with a centre wavelength of 1561.1 nm is obtained with a pulse energy of up to 29.0 nJ. As the pump power increases, the Q-switching operation transits into a mode-locking operation. The mode-locking operation is achieved with a centre wavelength of 1560 nm, a pulse width of 0.98 ps, a repetition rate of 28.5 MHz and a signal to noise ratio of up to 40 dB in the RF spectrum.

  2. Multilayer graphene for Q-switched mode-locking operation in an erbium-doped fiber laser

    Science.gov (United States)

    Wang, Zhiteng; Zhu, Shou-En; Chen, Yu; Wu, Man; Zhao, Chujun; Zhang, Han; Janssen, G. C. A. M.; Wen, Shuangchun

    2013-07-01

    We report the laser operation of Q-switched mode-locking (QML) in an erbium-doped fiber laser by using a multilayer graphene saturable absorber (SA), which consists of 22-layer of graphene fabricated by the chemical vapor deposition method. Based on our balanced twin detector measurement, the graphene sample is confirmed to show a saturable intensity of 3.375 MW/cm2 and an absolute modulation depth of 40.27%. It is demonstrated that this graphene SA can readily produce high quality QML pulses. At the pump power of 391.9 mW, the stable mode-locked pulse train with the Q-switched envelope repetition rate of 16.98 kHz and the envelope width of 13.84 μs are achieved. The maximal main pulse peak power can reach up to 35.89 W. This verifies that the multilayer graphene can be still applied as an effective saturable absorber for passively Q-switched mode-locked operation.

  3. Comparative studies of semiconductor saturable absorber mirror mode-locking dynamics in pulsed diode-end-pumped picosecond Nd:GdVO4 and Nd:YAG lasers

    Institute of Scientific and Technical Information of China (English)

    Bingyuan Zhang; Gang Li; Meng Chen; Guoju Wang; Yonggang Wang

    2006-01-01

    Ultrashort pulses were generated in passively mode-locked Nd:YAG and Nd:GdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 10 ps. The evolution of the mode-locked pulse was observed in the experiment and was discussed in detail. Comparing the pulse evolutions of Nd:YAG and Nd:GdVO4 lasers, we found that the buildup time of the steady-state mode-locking with semiconductor saturable absorber mirrors (SESAMs) was relevant to the upper-state lifetime and the emission cross-section of the gain medium.

  4. Sub-femtosecond absolute jitter microwaves generation from free-running mode-locked Er-fiber lasers

    CERN Document Server

    Jung, Kwangyun; Kim, Jungwon

    2013-01-01

    We demonstrate 10-GHz microwave signal generation from a free-running mode-locked Er-fiber laser with 1.5 fs absolute rms timing jitter integrated from 1 kHz to 5 GHz (Nyquist frequency) offset frequency. In the 10 kHz - 10 MHz integration bandwidth typically used for microwave generators, the rms integrated jitter is 0.49 fs. The Er-fiber laser is operated in the stretched-pulse regime at close-to-zero dispersion to minimize the intrinsic phase noise from the laser. In order to mitigate the excess phase noise in the optical-to-electronic conversion process, we synchronize a low-noise voltage-controlled oscillator to the fiber laser using a fiber Sagnac-loop-based optical-microwave phase detector. This result shows that one can generate sub-femtosecond-level jitter microwave signals from free-running mode-locked fiber lasers and commercially available dielectric resonator oscillators without stabilized optical references.

  5. Femtosecond mode-locking of an ytterbium-doped fiber laser using self-assembled gold nanorods

    Science.gov (United States)

    Lee, J.; Koo, J.; Lee, J. H.

    2017-09-01

    We experimentally demonstrate the use of a saturable absorber (SA) based on self-assembled gold nanorods (GNRs) for femtosecond mode-locking of an ytterbium-doped fiber-based 1 µm laser. A novel type of SA was made by implementation of an end-to-end GNRs self-assembly technique through hot-air induced rapid drying of the GNRs in a deionized water suspension, which enabled us to enhance optical absorption in the 1.06 µm wavelength region. By incorporating this novel SA into an ytterbium-doped fiber-based ring cavity under dispersion-managed conditions, we were able to readily generate mode-locked, soliton pulses having a temporal width of 840 fs at 1063.9 nm. To the best of our knowledge, this is the first demonstration of the effectiveness of a GNRs-based SA for the generation of femtosecond soliton pulses operating in the 1 µm range.

  6. Rational harmonic mode-locked laser using a bismuth-oxide-based highly nonlinear erbium-doped fiber

    Science.gov (United States)

    Fukuchi, Yutaka; Hirata, Kouji; Muraguchi, Masahiro; Maeda, Joji

    2017-01-01

    We report a rational harmonic mode-locked fiber laser employing a bismuth-oxide-based highly nonlinear erbium-doped fiber (Bi-HNL-EDF) with a length of 1.5 m. The Bi-HNL-EDF is used as a broadband gain medium and as a noise suppressor based on self-phase modulation. The amplitude of the rational harmonic mode-locked pulses can be regulated by properly tuning the modulation parameters of the intracavity modulator. The cavity length as short as 6 m enables generation of stable and clean short pulses with a repetition frequency up to 40 GHz over the wavelength range covering both the conventional and the longer bands.

  7. Mode-locked Erbium-doped fiber laser generation using hybrid ZnO/GO saturable absorber

    Science.gov (United States)

    Hassan, H.; Ariannejad, M. M.; Safaei, R.; Amiri, I. S.; Ahmad, H.

    2017-06-01

    Mode-locked generation of erbium-doped fiber laser (EDFL) with hybrid zinc oxide/graphene oxide (ZnO/GO) thin film as saturable absorber (SA) is proposed and practically demonstrated. The SA shows the modulation depth of 18.69% and it has been sandwiched between the fiber ferrules. Mode-locked pulse occurred at pump power of 14.8 mW and by varying the pump power to maximum threshold 27.43 mW, the repetition rate of the pulse fixed at 19.98 MHz at 1563 nm of central wavelength. The pulse width is estimated as 0.90 ps, whereas the pulse energy is calculated as 27.0 nJ.

  8. Energy reduction: a technique for seed-injection locking of single-axial-mode Q-switched Nd:YAG laser

    Institute of Scientific and Technical Information of China (English)

    Sui Chen; Wenxiong Lin; Fei Shi; Jianhong Huang; Jinhui Li; Hui Zheng; Jipeng Lin; Canhua Xu

    2007-01-01

    A new technique for seed-injection locking of single-axial-mode (SAM) Q-switched Nd:YAG laser is reported. The technique called energy reduction (ER) is utilized when SAM operation is locked to design its feedback scheme. This method ensures long-term 100% seed-injection locking performance and the pulsed SAM output energy can reach as high as 200 mJ. Both temporal and spatial interferometric experiments have been executed to confirm the SAM oscillation.

  9. Intra-cavity gain shaping of mode-locked Ti:Sapphire laser oscillations

    CERN Document Server

    Yefet, Shai; Pe'er, Avi

    2015-01-01

    The gain properties of an oscillator strongly affect its behavior. When the gain is homogeneous, different modes compete for gain resources in a `winner takes all' manner, whereas with inhomogeneous gain, modes can coexist if they utilize different gain resources. We demonstrate precise control over the mode competition in a mode locked Ti:sapphire oscillator by manipulation and spectral shaping of the gain properties, thus steering the competition towards a desired, otherwise inaccessible, oscillation. Specifically, by adding a small amount of spectrally shaped inhomogeneous gain to the standard homogeneous gain oscillator, we selectively enhance a desired two-color oscillation, which is inherently unstable to mode competition and could not exist in a purely homogeneous gain oscillator. By tuning the parameters of the additional inhomogeneous gain we flexibly control the center wavelengths, relative intensities and widths of the two colors.

  10. Black phosphorus saturable absorber for ultrafast mode-locked pulse laser via evanescent field interaction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kichul; Lee, Young Tack; Choi, Won-Kook; Song, Yong-Won [Center for Opto-electronic Materials and Devices, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Lee, Junsu; Lee, Ju Han [School of Electrical and Computer Engineering, University of Seoul (Korea, Republic of)

    2015-12-15

    Black phosphorus, or BP, has found a lot of applications in recent years including photonics. The most recent studies have shown that the material has an excellent optical nonlinearity useful in many areas, one of which is in saturable absorption for passive mode-locking. A direct interaction scheme for mode-locking, however, has a potential to optically cause permanent damage to the already delicate material. Evanescent field interaction scheme has already been proven to be a useful method to prevent such danger for other 2-dimensional nanomaterials. In this report, we have utilized the evanescent field interaction to demonstrate that the optical nonlinear characteristics of BP is sufficiently strong to use in such an indirect interaction method. The successful demonstration of the passive mode-locking operation has generated pulses with the pulse duration, repetition rate, and time bandwidth product of 2.18 ps, 15.59 MHz, and 0.336, respectively. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser

    CERN Document Server

    Liu, Ya; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

    2016-01-01

    Dual-comb lasers from which asynchronous ultrashort pulses can be simultaneously generated have recently become an interesting research subject. They could be an intriguing alternative to the current dual-laser optical-frequency-comb source with highly sophisticated electronic control systems. If generated through a common light path traveled by all pulses, the common-mode noises between the spectral lines of different pulse trains could be significantly reduced. Therefore, coherent dual-comb generation from a completely common-path, unidirectional lasing cavity would be an interesting territory to explore. In this paper, we demonstrate such a dual-comb lasing scheme based on a nanomaterial saturable absorber with additional pulse narrowing and broadening mechanisms concurrently introduced into a mode-locked fiber laser. The interactions between multiple soliton formation mechanisms result in unusual bifurcation into two-pulse states with quite different characteristics. Simultaneous oscillation of pulses wit...

  12. High-Power and Low-Noise 10-GHz All-Active Monolithic Mode-Locked Lasers with Surface Etched Bragg Grating

    DEFF Research Database (Denmark)

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

    2007-01-01

    We have fabricated 4.4 mm long monolithic InAlGaAsP/InP mode-locked lasers with integrated deeply surface etched DBR-mirrors. The lasers produce 3.7 ps transform-limited Gaussian pulses with 10 mW average power and 250 fs timing jitter.......We have fabricated 4.4 mm long monolithic InAlGaAsP/InP mode-locked lasers with integrated deeply surface etched DBR-mirrors. The lasers produce 3.7 ps transform-limited Gaussian pulses with 10 mW average power and 250 fs timing jitter....

  13. Powerful red-green-blue laser source pumped with a mode-locked thin disk laser.

    Science.gov (United States)

    Brunner, Felix; Innerhofer, Edith; Marchese, Sergio V; Südmeyer, Thomas; Paschotta, Rüdiger; Usami, Takeshi; Ito, Hiromasa; Kurimura, Sunao; Kitamura, Kenji; Arisholm, Gunnar; Keller, Ursula

    2004-08-15

    We present a red-green-blue laser source with average powers of 8 W in the red, 23 W in the green, and 10.1 W in the blue. The entire pump power for the nonlinear conversion stages is provided by a single laser oscillator without any amplifier stages. Our system does not require any synchronized cavities, and all nonlinear crystals except one are critically phase matched at room temperature.

  14. A stable polarization switching laser from a bidirectional passively mode-locked thulium-doped fiber oscillator.

    Science.gov (United States)

    Zhou, Wei; Shen, Deyuan; Wang, Yishan; Ma, Hefeng; Wang, Fei

    2013-04-08

    We report on a novel polarization switching laser from a bidirectional passively mode-locked thulium(Tm)-doped fiber oscillator, which was characterized by the periodical change of polarization state of every pulse. The switching laser was created by combing two orthogonally stable vector solitons, which were found to be wave-breaking-free pulses in the all-anomalous-dispersion regime. The measured repetition rates of switching laser and the corresponding vector solitons were 49.596 MHz, 24.798 MHz, and 24.798MHz. By controlling wave plates, either of the polarized pulse trains can be switched on or off. To our knowledge, this is the first report of polarization switching laser with vector solitons in Tm fiber oscillators.

  15. Wavelength Spacing Tunable, Multiwavelength Q-Switched Mode-Locked Laser Based on Graphene-Oxide-Deposited Tapered Fiber

    CERN Document Server

    Gao, Lei; Zeng, Jing

    2014-01-01

    A wavelength spacing tunable, multiwavelength Q-switched mode-locked (QML) fiber laser in an erbium-doped fiber cavity based on graphene oxide deposited on tapered fiber is proposed by choosing the diameter and length of the taper, graphene oxide thickness and cavity dispersion, in which the wavelength spacing could be tuned by pump power. The evolutions of temporal and spectral with different pump strengths are investigated. Results show that the tunability of the multiwavelength laser can be interpreted by the bound states of QML laser resulting from a mutual interaction of dispersion, nonlinear effect, insertion loss, and pump power. To the best of our knowledge, it is the first experimental observation of bound states of QML, which provides a new mechanism to fabricate tunable multiwavelength laser.

  16. Broadly Tunable SOA-Based Active Mode-Locked Fibre Ring Laser by Forward Injection Optical Pulse

    Institute of Scientific and Technical Information of China (English)

    YAN Shuang-Yi; ZHANG Jian-Guo; ZHAO Wei; LU Hong-Qiang; WANG Wei-Qiang

    2008-01-01

    @@ We present a broadly tunable active mode-locked fibre ring laser based on a semiconductor optical amplifier (SOA), with forward injection optical pulses. The laser can generate pulse sequence with pulsewidth about 12ps and high output power up to 8.56dBm at 2.5 GHz stably. Incorporated with a wavelength-tunable optical bandpass filter, the pulse laser can operate with a broad wavelength tunable span up to 37nm with almost constant pulsewidth. A detailed experimental analysis is also carried out to investigate the relationship between the power of the internal cavity and the pulsewidth of the output pulse sequence. The experimental configuration of the pulse laser is very simple and easy to setup with no polarization-sensitive components.

  17. Ultrafast soliton mode-locked Zirconia-based Erbium-doped fiber laser with carbon nanotubes saturable absorber

    Science.gov (United States)

    Munira Markom, Arni; Wey Sen-Winson, Mah; Paul, Mukul Chandra; Wadi Harun, Sulaiman

    2017-06-01

    Ultrafast soliton mode-locked fiber laser was successfully generated in zirconia-yttria-alumina (Zr-Y-Al) co-doped erbium-doped fiber laser cavity using a single-wall carbon nanotubes (SWCNTs) as saturable absorber. The laser cavity was 11.5 m long with the group delay dispersion of -0.04 ps2. The laser generates soliton pulse train with a center wavelength and 3 dB bandwidth of 1564.2 nm and 3.8 nm, respectively at pump power of 92 mW. Meanwhile, the repetition rate, pulse duration and pulse energy were 17.7 MHz, 770 fs and 51.4 nJ.

  18. Continuous-wave to pulse regimes for a family of passively mode-locked lasers with saturable nonlinearity

    Science.gov (United States)

    Dikandé, Alain M.; Voma Titafan, J.; Essimbi, B. Z.

    2017-10-01

    The transition dynamics from continuous-wave to pulse regimes of operation for a generic model of passively mode-locked lasers with saturable absorbers, characterized by an active medium with non-Kerr nonlinearity, are investigated analytically and numerically. The system is described by a complex Ginzburg–Landau equation with a general m:n saturable nonlinearity (i.e {I}m/{(1+{{Γ }}I)}n, where I is the field intensity and m and n are two positive numbers), coupled to a two-level gain equation. An analysis of stability of continuous waves, following the modulational instability approach, provides a global picture of the self-starting dynamics in the system. The analysis reveals two distinct routes depending on values of the couple (m, n), and on the dispersion regime: in the normal dispersion regime, when m = 2 and n is arbitrary, the self-starting requires positive values of the fast saturable absorber and nonlinearity coefficients, but negative values of these two parameters for the family with m = 0. However, when the spectral filter is negative, the laser can self-start for certain values of the input field and the nonlinearity saturation coefficient Γ. The present work provides a general map for the self-starting mechanisms of rare-earth doped figure-eight fiber lasers, as well as Kerr-lens mode-locked solid-state lasers.

  19. Diode-end-pumped passively mode-locked Nd:GAGG laser at 1.3 μm with SESAM Diode-end-pumped passively mode-locked Nd:GAGG laser

    Science.gov (United States)

    Li, Y. B.; Jia, Z. T.; Yang, Y.; Fu, X. W.; Yuan, D. S.; Zhi, Y. C.; Dong, C. M.; Zhang, B. T.; He, J. L.; Tao, X. T.

    2012-08-01

    The performance of a passively mode-locked Nd:Gd3AlxGa5-xO12 (Nd:GAGG) laser at 1332 nm was experimentally investigated by using a semiconductor saturable absorber mirror (SESAM) for the first time. At the absorbed pump power of 6.7 W, the average output power was obtained to be 293 mW with the pulse duration of 6.3 ps and the repetition rate of 32.2 MHz. The corresponding single pulse energy and the peak power were determined to be 4.55 nJ and 722 W, respectively.

  20. Self-amplitude and self-phase modulation of the charcoal mode-locked erbium-doped fiber lasers.

    Science.gov (United States)

    Lin, Yung-Hsiang; Lo, Jui-Yung; Tseng, Wei-Hsuan; Wu, Chih-I; Lin, Gong-Ru

    2013-10-21

    With the intra-cavity nano-scale charcoal powder based saturable absorber, the 455-fs passive mode-locking of an L-band erbium-doped fiber laser (EDFL) is demonstrated. The size reduction of charcoal nano-particle is implemented with a simple imprinting-exfoliation-wiping method, which assists to increase the transmittance up to 0.91 with corresponding modulation depth of 26%. By detuning the power gain from 17 to 21 dB and cavity dispersion from -0.004 to -0.156 ps² of the EDFL, the shortening of mode-locked pulsewidth from picosecond to sub-picosecond by the transformation of the pulse forming mechanism from self-amplitude modulation (SAM) to the combining effect of self-phase modulation (SPM) and group delay dispersion (GDD) is observed. A narrower spectrum with 3-dB linewidth of 1.83-nm is in the SAM case, whereas the spectral linewidth broadens to 5.86 nm with significant Kelly sideband pair can be observed if the EDFL enters into the SPM regime. The mode-locking mechanism transferred from SAM to SPM/GDD dominates the pulse shortening procedure in the EDFL, whereas the intrinsic defects in charcoal nano-particle only affect the pulse formation at initial stage. The minor role of the saturable absorber played in the EDFL cavity with strongest SPM is observed.

  1. Comparison of the noise performance of 10 GHz repetition rate quantum-dot and quantum well monolithic mode-locked semiconductor lasers

    DEFF Research Database (Denmark)

    Carpintero, G.; Thompson, M. G.; Yvind, Kresten

    2011-01-01

    Mode-locked lasers are commonly used in carrier-wave signal generation systems because of their excellent phase noise performance. Owing to the importance of this key parameter, this study presents a like-for-like comparison of the noise performance of the passive mode-locked regime of two devices...... and the shape of the noise pedestals, both depending on the passive mode-locked bias conditions. Nevertheless, the dominant contribution of the RF linewidth to the phase noise, which is significantly narrower for the QD laser, makes this material more suitable for optical generation of low-noise millimetre...... fabricated with different material gain systems, one quantum well and the other quantum dot (QD), both with a monolithic all-active two-section mode-locked structure. Two important factors are identified as having a significant effect on the noise performance, the RF linewidth of the first harmonic...

  2. Active mode locking at 50 GHz repetition frequency by half-frequency modulation of monolithic semiconductor lasers integrated with electroabsorption modulators

    Science.gov (United States)

    Sato, Kenji; Kotaka, Isamu; Kondo, Yasuhiro; Yamamoto, Mitsuo

    1996-10-01

    Active mode locking achieved at a 50 GHz repetition frequency by modulation at half (25 GHz) the cavity resonance frequency using a monolithic mode-locked InGaAsP laser integrated with an electroabsorption modulator is described. A pulse width of around 3 ps and a high suppression ratio of more than 33 dB of the intensity modulation at the driving frequency are obtained.

  3. Dual-wavelength passive and hybrid mode-locking of 3, 4.5 and 10 GHz InAs/InP(100) quantum dot lasers.

    Science.gov (United States)

    Tahvili, M S; Du, L; Heck, M J R; Nötzel, R; Smit, M K; Bente, E A J M

    2012-03-26

    We present an investigation of passive and hybrid mode-locking in Fabry-Pérot type two-section InAs/InP(100) quantum dot lasers that show dual wavelength operation. Over the whole current and voltage range for mode-locking of these lasers, the optical output spectra show two distinct lobes. The two lobes provide a coherent bandwidth and are verified to lead to two synchronized optical pulses. The generated optical pulses are elongated in time due to a chirp which shows opposite signs over the two spectral lobes. Self-induced mode-locking in the single-section laser shows that the dual-wavelength spectra correspond to emission from ground state. In the hybrid mode-locking regime, a map of locking range is presented by measuring the values of timing jitter for several values of power and frequency of the external electrical modulating signal. An overview of the systematic behavior of InAs/InP(100) quantum dot mode-locked lasers is presented as conclusion.

  4. Tunable GHz pulse repetition rate operation in high-power TEM(00)-mode Nd:YLF lasers at 1047 nm and 1053 nm with self mode locking.

    Science.gov (United States)

    Huang, Y J; Tzeng, Y S; Tang, C Y; Huang, Y P; Chen, Y F

    2012-07-30

    We report on a high-power diode-pumped self-mode-locked Nd:YLF laser with the pulse repetition rate up to several GHz. A novel tactic is developed to efficiently select the output polarization state for achieving the stable TEM(00)-mode self-mode-locked operations at 1053 nm and 1047 nm, respectively. At an incident pump power of 6.93 W and a pulse repetition rate of 2.717 GHz, output powers as high as 2.15 W and 1.35 W are generated for the σ- and π-polarization, respectively. We experimentally find that decreasing the separation between the gain medium and the input mirror not only brings in the pulse shortening thanks to the enhanced effect of the spatial hole burning, but also effectively introduces the effect of the spectral filtering to lead the Nd:YLF laser to be in a second harmonic mode-locked status. Consequently, pulse durations as short as 8 ps and 8.5 ps are obtained at 1053 nm and 1047 nm with a pulse repetition rate of 5.434 GHz.

  5. Multiple Dissipative Solitons in a Long-Cavity Normal-Dispersion Mode-Locked Yb-Doped Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guang-Zhen; XIAO Xiao-Sheng; MEI Jia-Wei; YANG Chang-Xi

    2012-01-01

    Transitional operations of multiple dissipative solitons in a long-cavity normal-dispersion Yb-doped fiber laser are experimentally investigated.Multiple dissipative solitons,including a stable soliton pair and a soliton triplet are observed by increasing the pump power or adjusting the polarization controllers.Two main boundaries of the stable asymmetric soliton and oscillating soliton are found between steady mode-locking.Moreover,multiple dissipative solitons with greater quantities of solitons are observed with pump power increasing.The experimental results agree well with a previous numerical study of multiple dissipative solitons.

  6. Record bandwidth and sub-picosecond pulses from a monolithically integrated mode-locked quantum well ring laser.

    Science.gov (United States)

    Moskalenko, Valentina; Latkowski, Sylwester; Tahvili, Saeed; de Vries, Tjibbe; Smit, Meint; Bente, Erwin

    2014-11-17

    In this paper, we present the detailed characterization of a semiconductor ring passively mode-locked laser with a 20 GHz repetition rate that was realized as an indium phosphide based photonic integrated circuit (PIC). Various dynamical regimes as a function of operating conditions were explored in the spectral and time domain. A record bandwidth of the optical coherent comb from a quantum well based device of 11.5 nm at 3 dB and sub-picosecond pulse generation is demonstrated.

  7. Attosecond timing jitter pulse trains from semiconductor saturable absorber mode-locked Cr:LiSAF lasers

    OpenAIRE

    Sennaroğlu, Alphan; Li, Duo; Demirbaş, Ümit; Benedick, Andrew; Fujimoto, James G.; Kaertner, Franz X.

    2012-01-01

    The timing jitter of optical pulse trains from diode-pumped, semiconductor saturable absorber mode-locked femtosecond Cr:LiSAF lasers is characterized by a single-crystal balanced optical cross-correlator with an equivalent sensitivity in phase noise of -235 dBc/Hz. The RMS timing jitter is 30 attoseconds integrated from 10 kHz to 50 MHz, the Nyquist frequency of the 100 MHz repetition rate oscillator. The AM-to-PM conversion induced excess phase noise is calculated and compared with experime...

  8. Bismuth telluride topological insulator nanosheet saturable absorbers for q-switched mode-locked Tm:ZBLAN waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiantao; Gross, Simon; Withford, Michael J.; Fuerbach, Alexander [Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) and MQ Photonics Research Centre, Dept. of Physics and Astronomy, Macquarie Univ., NSW (Australia); Zhang, Han; Guo, Zhinan [SZU-NUS Collaborative Innovation Centre for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education, College of Optoelectronic Engineering, Shenzhen Univ. (China)

    2016-08-15

    Nanosheets of bismuth telluride (Bi{sub 2}Te{sub 3}), a topological insulator material that exhibits broadband saturable absorption due to its non-trivial Dirac-cone like energy structure, are utilized to generate short pulses from Tm:ZBLAN waveguide lasers. By depositing multiple layers of a carefully prepared Bi{sub 2}Te{sub 3} solution onto a glass substrate, the modulation depth and the saturation intensity of the fabricated devices can be controlled and optimized. This approach enables the realization of saturable absorbers that feature a modulation depth of 13% and a saturation intensity of 997 kW/cm{sup 2}. For the first time to our knowledge, Q-switched mode-locked operation of a linearly polarized mid-IR ZBLAN waveguide chip laser was realized in an extended cavity configuration using the topological insulator Bi{sub 2}Te{sub 3}. The maximum average output power of the laser is 16.3 mW and the Q-switched and mode-locked repetition rates are 44 kHz and 436 MHz, respectively. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Effects of carbon nanotubes and graphene oxide absorbers on the noise of mode-locked fiber lasers

    CERN Document Server

    Li, Xiaohui; Yu, Xuechao; Wang, Yonggang; Wang, Yishan; Meng, Bo; Tang, Yulong; Yu, Xia; Zhang, Ying; Sun, Zhipei; Shum, Perry Ping; Wang, Qi Jie

    2014-01-01

    Phase noise is very important for the ultrafast pulse application in telecommunication, ultrafast diagnose, material science, and biology. In this paper, two types of carbon nano-materials, single-wall carbon nanotube and graphene oxide, are investigated for noise suppression in ultrafast photonics. Various properties of the wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the phase noise of the ultrafast pulses. A reduced-noise femtosecond fiber laser is experimentally demonstrated by optimizing the above parameters of carbon material based SAs. The phase noise reduction more than 10 dB at 10 kHz can be obtained in the experiments. To our knowledge, this is the first time that the relationship between different carbon material based SAs and the phase noise of mode-locked lasers has been investigated. This work will pave the way to get a high-quality ultrashort pulse in passively mode-locked fiber lasers.

  10. Mode-locking and Q-switching in multi-wavelength fiber ring laser using low frequency phase modulation.

    Science.gov (United States)

    Jun, Chang Su; Kim, Byoung Yoon

    2011-03-28

    We describe experimental investigation of pulsed output from a multi-wavelength fiber ring laser incorporating low frequency phase modulation with large modulation amplitude. The Erbium-doped fiber (EDF) ring laser generated more than 8 wavelength channels with the help of a phase modulator operating at 26.2 kHz and a periodic intra-cavity filter. For most cases, the laser output is pulsed in the form of mode-locking at 5.62 MHz and/or Q-switching at harmonic and sub-harmonic of the phase modulation frequency. Chaotic pulse output is also observed. The behavior of the output pulses are described as functions of pump power and phase modulation amplitude. The relative intensity noise (RIN) value of a single wavelength channel is measured to be under -100 dB/Hz (-140 dB/Hz beyond 1.5 GHz).

  11. Picosecond to femtosecond pulses from high power self mode-locked ytterbium rod-type fiber laser.

    Science.gov (United States)

    Deslandes, Pierre; Perrin, Mathias; Saby, Julien; Sangla, Damien; Salin, François; Freysz, Eric

    2013-05-06

    We have designed an ytterbium rod-type fiber laser oscillator with tunable pulse duration. This system that delivers more than 10 W of average power is self mode-locked. It yields femtosecond to picosecond laser pulses at a repetition rate of 74 MHz. The pulse duration is adjusted by changing the spectral width of a band pass filter that is inserted in the laser cavity. Using volume Bragg gratings of 0.9 nm and 0.07 nm spectrum bandwidth, this oscillator delivers nearly Fourier limited 2.8 ps and 18.5 ps pulses, respectively. With a 4 nm interference filter, one obtains picosecond pulses that have been externally dechirped down to 130 fs.

  12. Experimental investigation of harmonic and subharmonic synchronization of 40 GHz mode-locked quantum-dash laser diodes.

    Science.gov (United States)

    Maldonado-Basilio, Ramón; Latkowski, Sylwester; Philippe, Severine; Landais, Pascal

    2011-05-01

    Synchronization of a 40 GHz quantum-dash mode-locked (ML) Fabry-Perot laser diode with optically injected pulse streams is experimentally studied. Injected signals consist of nonmodulated and modulated trains of 1.6 ps pulses at various repetition rates, ranging from 10 to 160 GHz and 10 to 160 Gbps, respectively. Subharmonic, fundamental, and harmonic synchronization of the ML laser allows retrieval of stable 40 GHz clock pulses featuring a width of 1.8 ps. Frequency components at 10 and 20 GHz do not create any amplitude modulation on the recovered 40 GHz clock pulses when injecting signals at 10 and 20 GHz/Gbps. In addition, external synchronization of the laser with pulse streams at 80 and 160 GHz/Gbps is sustained despite the absence of significant components at or below 40 GHz.

  13. Efficient Laser-Diode End-Pumped Passively Q-Switched Mode-Locked Yb:LYSO Laser Based on SESAM

    Institute of Scientific and Technical Information of China (English)

    XU Shi-Xiang; LI Wen-Xue; HAO Qiang; ZHAI Hui; ZENG He-Ping

    2008-01-01

    We report an eddicient Q-switched laser action based on a semiconductor saturable absorber mirrors(SESAMs)as passively Q-switched laser starter and a Yb:LYSO alloyed crystal as gain material pumped directly by 974nm In GaAs laser diodes.The output pulse duration is measured to be about 7μs,while the average power and the repetition rate of the pulse chain are about 0.92 W and 6.2kHz.respectively,under 12.5 W absorbed pumping power.The Q-switched mode-locked pulse train is also observed in this setup.The laser performance shows that Yb:LYSO is a promising laser gain medium for laser-diode pumped compact solid-state lasers.

  14. Titanium Dioxide (TiO2) film as a new saturable absorber for generating mode-locked Thulium-Holmium doped all-fiber laser

    Science.gov (United States)

    Mohd Rusdi, Muhammad Farid; Latiff, Anas Abdul; Paul, Mukul Chandra; Das, Shyamal; Dhar, Anirban; Ahmad, Harith; Harun, Sulaiman Wadi

    2017-03-01

    We report the generation of mode-locked thulium-holmium doped fiber laser (THDFL) at 1979 nm. This is a first demonstration of mode-locked by using Titanium Dioxide (TiO2) film as a saturable absorber (SA). A piece of 1 mm×1 mm TiO2 film was sandwiched in between two fiber ferrule in the cavity. Fabrication process of TiO2 film incorporated a TiO2 and a polyvinyl alcohol (PVA). The stable 9 MHz repetition rate of mode-locked mode operation with 58 dB SNR was generated under pump power of 902-1062 mW. At maximum pump power, the mode-locked THDFL has output power and pulse energy of 15 mW and 1.66 nJ, respectively. Our results demonstrate the TiO2 can be used promisingly in ultrafast photonics applications.

  15. Comparison of different Kerr-lens mode locking laser design techniques

    Science.gov (United States)

    Moreno-Larios, José Agustín.; Rosete-Aguilar, Martha; Garduño-Mejía, Jesús

    2016-04-01

    Three numerical methods for the design of Kerr Lens Mode-Locking (KLML) ultrashort pulse cavities that use a solid state Brewster-cut nonlinear gain medium are compared. The nonlinear medium is modeled first deploying a matrix approximation that considers non-coupled (tangential analysis is independent of sagittal analysis) Kerr and thermal self-focusing; and second with a differential equation that relates the real and imaginary parts of the inverse of the complex Gaussian beam parameter. The third comparison is against a matrix analysis method that considers the coupling between the sagittal and tangential modes inside the nonlinear medium in order to determine the impact of this effect. The three methods search the self-consistency condition for the complex beam parameter and the results are compared.

  16. Long-cavity all-fiber ring laser actively mode locked with an in-fiber bandpass acousto-optic modulator.

    Science.gov (United States)

    Cuadrado-Laborde, C; Bello-Jiménez, M; Díez, A; Cruz, J L; Andrés, M V

    2014-01-01

    We demonstrate low-frequency active mode locking of an erbium-doped all-fiber ring laser. As the mode locker, we used a new in-fiber bandpass acousto-optic modulator showing 74% modulation depth, 3.7 dB power insertion losses, 4.5 nm of optical bandwidth, and 20 dB of nonresonant light suppression. The laser generates 330 ps mode-locked pulses over a 10 ns pedestal, at a 1.538 MHz frequency, with 130 mW of pump power.

  17. Fabrication of 16 W all-normal-dispersion mode-locked Yb-doped rod-type fiber laser with large-mode area

    Institute of Scientific and Technical Information of China (English)

    吕国; 滕浩; 王立娜; 王睿; 王军利; 魏志义

    2015-01-01

    A mode-locked ytterbium-doped rod-type fiber laser with 85 µm core diameter is developed based on the nonlinear polarization evolution in an all-normal-dispersion ring cavity, in which a uniaxial birefringent plate is used as the spectral filter. Average power up to 16 W is obtained at the repetition rate of 58 MHz, and the pulse duration is compressed to 182 fs with a grating-pair compressor. The output laser pulses show very good beam quality and power stability.

  18. Ytterbium-doped fiber laser passively mode locked by few-layer Molybdenum Disulfide (MoS2) saturable absorber functioned with evanescent field interaction

    National Research Council Canada - National Science Library

    Du, Juan; Wang, Qingkai; Jiang, Guobao; Xu, Changwen; Zhao, Chujun; Xiang, Yuanjiang; Chen, Yu; Wen, Shuangchun; Zhang, Han

    2014-01-01

    ... light-matter interaction. This MoS2-taper-fiber device is not only capable of passively mode-locking an all-normal-dispersion ytterbium-doped fiber laser and enduring high power laser excitation (up to 1 W...

  19. Comparison of Monolithic Optical Frequency Comb Generators Based on Passively Mode-Locked Lasers for Continuous Wave mm-Wave and Sub-THz Generation

    DEFF Research Database (Denmark)

    Criado, A. R.; de Dios, C.; Acedo, P.;

    2012-01-01

    In this paper, two different Passive Mode-Locked Laser Diodes (PMLLD) structures, a Fabry–Perot cavity and a ring cavity laser are characterized and evaluated as monolithic Optical Frequency Comb Generators (OFCG) for CW sub-THz generation. An extensive characterization of the devices under study...

  20. High-Power and Low-Noise 10-GHz All-Active Monolithic Mode-Locked Lasers with Surface Etched Bragg Grating

    OpenAIRE

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

    2007-01-01

    We have fabricated 4.4 mm long monolithic InAlGaAsP/InP mode-locked lasers with integrated deeply surface etched DBR-mirrors. The lasers produce 3.7 ps transform-limited Gaussian pulses with 10 mW average power and 250 fs timing jitter.

  1. 10 kHz ps 1342 nm laser generation by an electro-optically cavity-dumped mode-locked Nd:YVO4 laser

    Science.gov (United States)

    Chen, Ying; Liu, Ke; He, Li-jiao; Yang, Jing; Zong, Nan; Yang, Feng; Gao, Hong-wei; Liu, Zhao; Yuan, Lei; Lan, Ying-jie; Bo, Yong; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

    2017-01-01

    We have demonstrated an electro-optically cavity-dumped mode-locked (CDML) picosecond Nd:YVO4 laser at 1342 nm with 880 nm diode-laser direct pumping. At a repetition rate of 10 kHz, an average output power of 0.119 W was achieved, corresponding to a pulse energy of 11.9 μJ. Compared with the continuous wave mode-locking pulse energy of 17.5 nJ, the CDML pulse energy was 680 times higher. The pulse width was measured to be 33.4 ps, resulting in the peak power of 356 kW. Meanwhile, the beam quality was nearly diffraction limited with an average beam quality factor M2 of 1.29.

  2. Periodic adjustment of the position of a laser beam spot on a semiconductor saturable absorber mirror in a passively mode-locked solid-state laser

    Institute of Scientific and Technical Information of China (English)

    Xia Pa-Keti; Yan Ping; Gong Ma-Li

    2011-01-01

    A laser diode end-pumped passively mode-locked Nd:YV04 solid-state laser with a semiconductor saturable absorber mirror (SESAM),in which the intracavity laser beam spot on the SESAM can be adjusted periodically,is investigated. Inserting a rectangular prism (RP) into the laser cavity is a promising approach towards the goal of periodically moving the position of the focus spot of the intracavity pulse on the SESAM surface to avoid the long-time irradiation of the laser beam on the same position,thereby solving a series of problems caused by damage to the SESAM and greatly prolonging its usage life. The adjustment of the rectangular prism in the laser cavity does not break the stable continuous wave (CW) mode-locked condition. The laser generates a stable picosecond pulse sequence at 1064 nm with an output power of 3.6 W and a pulse width of 14 ps. The instabilities of the output power and the pulse width are 1.77% and 4.5%,respectively.

  3. Femtosecond mode-locked erbium-doped fiber laser based on MoS2-PVA saturable absorber

    Science.gov (United States)

    Ahmed, M. H. M.; Latiff, A. A.; Arof, H.; Ahmad, H.; Harun, S. W.

    2016-08-01

    We fabricate a free-standing few-layer molybdenum disulfide (MoS2)-polymer composite by liquid phase exfoliation of chemically pristine MoS2 crystals and use this to demonstrate a soliton mode-locked Erbium-doped fiber laser (EDFL). A stable self-started mode-locked soliton pulse is generated by fine-tuning the rotation of the polarization controller at a low threshold pump power of 25 mW. Its solitonic behavior is verified by the presence of Kelly sidebands in the output spectrum. The central wavelength, pulse width, and repetition rate of the laser are 1573.7 nm, 630 fs, and 27.1 MHz, respectively. The maximum pulse energy is 0.141 nJ with peak power of 210 W at pump power of 170 mW. This result contributes to the growing body of work studying the nonlinear optical properties of transition metal dichalcogenides that present new opportunities for ultrafast photonic applications.

  4. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets.

    Science.gov (United States)

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-03-24

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics.

  5. Towards low timing phase noise operation in fiber lasers mode locked by graphene oxide and carbon nanotubes at 1.5 µm.

    Science.gov (United States)

    Wu, Kan; Li, Xiaohui; Wang, Yonggang; Wang, Qi Jie; Shum, Perry Ping; Chen, Jianping

    2015-01-12

    We investigate the timing phase noise of fiber lasers mode locked by graphene oxide (GO) and carbon nanotubes (CNTs), respectively, integrated in a linear cavity fiber laser in the reflecting operation. Due to the shorter decay time of the GO and CNTs, weaker slow saturable absorber effects are expected and mode-locked lasers based on these two saturable absorbers exhibit low excess timing phase noise coupled from the laser intensity noise. Compared with a reference laser mode locked by semiconductor saturable absorber mirror (SESAM), GO based laser obtains a timing phase noise reduction of 7 dB at 1 kHz and a timing jitter reduction of 45% experimentally whereas CNTs based laser obtains a timing phase noise reduction of 3 dB and a timing jitter reduction of 29%. This finding suggests that saturable absorbers with short decay time have the potential for achieving mode locking operation with low timing phase noise, which is important for applications including frequency metrology, high-precision optical sampling, clock distribution and optical sensing.

  6. 8.5-W mode-locked Yb:Lu$_{1.5}$Y$_{1.5}$Al$_5$O$_{12}$ laser with master oscillator power amplifiers

    CERN Document Server

    Wang, Fuyong; Xie, Guoqiang; Yuan, Peng; Qian, Liejia; Xu, Xiaodong; Xu, Jun

    2014-01-01

    We report on a diode-pumped passively mode-locked Yb:Lu$_{1.5}$Y$_{1.5}$Al$_5$O$_{12}$ (Yb:LuYAG) laser for the first time to our knowledge. With the mixed crystal of Yb:LuYAG as gain medium, the mode-locked laser generated 2.2 W of average output power with a repetition rate of 83.9 MHz and pulse duration of 2.2 ps at the wavelength of 1030 nm. In order to obtain higher output power, the output from the mode-locked oscillator was further amplified to 8.5 W by two-stage single-pass amplifiers. The high-power picosecond laser is very useful for applications such as pumping of mid-infrared optical parametric oscillators, material micro-processing, and UV light generation, etc.

  7. Cross-splicing method for compensating fiber birefringence in polarization-maintaining fiber ring laser mode locked by nonlinear polarization evolution.

    Science.gov (United States)

    Wang, Yunzheng; Zhang, Liqiang; Zhuo, Zhuang; Guo, Songzhen

    2016-07-20

    We propose a cross-splicing method, for the first time to our knowledge, to compensate the effect of fiber birefringence in a polarization-maintaining fiber ring laser mode locked by nonlinear polarization evolution. This method has been investigated numerically and experimentally. The results indicate that stable mode-locking pulses can be obtained in the cavity with this method; otherwise, no mode-locking states are achieved. The design processes of the laser cavity are presented. Pulses with single pulse energy of 2.1 nJ are generated at pump power of 460 mW. The spectral bandwidth and pulse duration are 17.5 nm and 11.7 ps, respectively. The tunability of the laser is also studied. The central wavelength can be tuned from 1023.2 to 1045.9 nm.

  8. Explaining simultaneous dual-band carbon nanotube mode-locking Erbium-doped fiber laser by net gain cross section variation.

    Science.gov (United States)

    Rosa, Henrique G; Steinberg, David; Thoroh de Souza, Eunézio A

    2014-11-17

    In this paper we report the pulse evolution of a simultaneously mode-locked Erbium-doped fiber laser at 1556-nm-band and 1533-nm-band. We explain the dual wavelength laser operation by means of net gain cross section variations caused by the population inversion rate dependence on the pump power. At 1556-nm-band, we observed pulse duration of 370 fs with bandwidth of 8.50 nm and, for pump power higher than 150 mW, we observe the rise of a CW and mode-locked laser, sequentially, at 1533-nm-band. We show that both bands are simultaneously mode-locked and operate at different repetition rates.

  9. Q-switched mode-locked erbium-doped fiber laser based on topological insulator Bi(2)Se(3) deposited fiber taper.

    Science.gov (United States)

    Gao, Lei; Huang, Wei; Zhang, Jing Dong; Zhu, Tao; Zhang, Han; Zhao, Chu Jun; Zhang, Wei; Zhang, Hua

    2014-08-10

    We have demonstrated the passive Q-switching mode-locking operation in an erbium-doped fiber (EDF) laser by using topological insulator Bi(2)Se(3) deposited on fiber taper, whose damage threshold can be further increased by the large evanescent field interacting length. Due to the low saturation intensity, stable Q-switched mode-locked fiber lasers centered at 1562 nm can be generated at a pump power of 10 mW. The temporal and spectral characteristics for different pump strengths have also been investigated. To the best of our knowledge, it is the first time a Q-switched mode-locked EDF laser based on the fiber taper deposited by Bi(2)Se(3) was generated.

  10. Narrow linewidth comb realized with a mode-locked fiber laser using an intra-cavity waveguide electro-optic modulator for high-speed control.

    Science.gov (United States)

    Iwakuni, Kana; Inaba, Hajime; Nakajima, Yoshiaki; Kobayashi, Takumi; Hosaka, Kazumoto; Onae, Atsushi; Hong, Feng-Lei

    2012-06-18

    We have developed an optical frequency comb using a mode-locked fiber ring laser with an intra-cavity waveguide electro-optic modulator controlling the optical length in the laser cavity. The mode-locking is achieved with a simple ring configuration and a nonlinear polarization rotation mechanism. The beat note between the laser and a reference laser and the carrier envelope offset frequency of the comb were simultaneously phase locked with servo bandwidths of 1.3 MHz and 900 kHz, respectively. We observed an out-of-loop beat between two identical combs, and obtained a coherent δ-function peak with a signal to noise ratio of 70 dB/Hz.

  11. Double pass locking and spatial mode locking for gravitational wave detectors

    CERN Document Server

    Cusack, B J; Slagmolen, B; Vine, G D; Gray, M B; McClelland, D E

    2002-01-01

    We present novel techniques for overcoming problems relating to the use of high-power lasers in mode cleaner cavities for second generation laser interferometric gravitational wave detectors. Rearranging the optical components into a double pass locking regime can help to protect locking detectors from damage. Modulator thermal lensing can be avoided by using a modulation-free technique such as tilt locking, or its recently developed cousin, flip locking.

  12. Double pass locking and spatial mode locking for gravitational wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cusack, Benedict J; Shaddock, Daniel A; Slagmolen, Bram J J; Vine, Glenn de; Gray, Malcolm B; McClelland, David E [Department of Physics, Faculty of Science, The Australian National University, ACT 0200 (Australia)

    2002-04-07

    We present novel techniques for overcoming problems relating to the use of high-power lasers in mode cleaner cavities for second generation laser interferometric gravitational wave detectors. Rearranging the optical components into a double pass locking regime can help to protect locking detectors from damage. Modulator thermal lensing can be avoided by using a modulation-free technique such as tilt locking, or its recently developed cousin, flip locking.

  13. Picosecond 1.3{-}\\unicode{956} {\\text{m}} bismuth fibre laser mode-locked by a nonlinear loop mirror

    Science.gov (United States)

    Khegai, A. M.; Afanas'ev, F. V.; Riumkin, K. E.; Firstov, S. V.; Khopin, V. F.; Myasnikov, D. V.; Mel'kumov, M. A.; Dianov, E. M.

    2016-12-01

    The influence of the concentration of bismuth active centres (BACs) in phosphosilicate fibres on their optical parameters, including gain coefficient and non-saturable losses, has been studied. A range of BAC concentrations optimal for designing ultrashort-pulse (USP) lasers was chosen based on the obtained results. The optimised fibre was used to fabricate an all-fibre 1.3-\\unicode{956}{\\text{m}} USP laser mode-locked by a nonlinear loop mirror, which emits 11.3-{\\text{ps}} pulses with an energy of 1.65 {\\text{nJ}} and a repetition rate of 3.6 {\\text{MHz}}. A bismuth fibre amplifier made it possible to increase the pulse energy to 8.3 {\\text{nJ}}. After compression in a diffraction grating compressor, the pulse duration decreased to 530 {\\text{fs}}.

  14. The Study on the Variation of the Cavity Length's Influence on the Output Pulse Train of the Actively Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    LUO Hong-e; TIAN Xiao-jian; GAO Bo

    2005-01-01

    The influence of actively mode-locked Erbium-Doped Fiber Laser(EDFL) cavity length variation on the noises of an optical pulse train is investigated, in theory and in MATLAB simulation. Using a simple model, the noise characteristics of the output pulse train are studied. The results show that the noises of the output pulse train increase with the increasing of the variation of the cavity length. The theory analysis and the simulation results agree well. This result is very significant for us to improve the reliability and the stability of the actively mode-locked fiber laser.

  15. Mode-locking of a high power, 888 nm pumped Nd:YVO4 laser using nonlinear polarization rotation via Type I second harmonic generation.

    Science.gov (United States)

    Schäfer, Christoph; Fries, Christian; Theobald, Christian; L'huillier, Johannes A

    2013-01-15

    Continuous-wave mode-locking of a laser exploiting the nonlinear polarization rotation (NPR) technique via Type I second harmonic generation is demonstrated for the first time. The NPR is generated by a lithium triborate crystal and transformed into nonlinear cavity losses of a 888 nm pumped Nd:YVO4 laser. Self-starting, reliable mode-locking has been achieved at a high average output power of 20.6 W and a pulse duration of 7.3 ps. Furthermore, transform limited pulses down to 2.7 ps have been demonstrated at 9.9 W.

  16. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Jagiello, J.; Lipinska, L. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)

    2015-04-07

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (F{sub rep}) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest F{sub rep} was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  17. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Science.gov (United States)

    Sotor, J.; Sobon, G.; Jagiello, J.; Lipinska, L.; Abramski, K. M.

    2015-04-01

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (Frep) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest Frep was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  18. Theoretical Analysis of Dependence of Nonlinear Effects in Mode-Locked Yb:YAG Lasers with a Highly Nonlinear Intra-Cavity Medium

    Directory of Open Access Journals (Sweden)

    Takeshi Yoshida

    2015-11-01

    Full Text Available Nonlinear ultrashort pulse propagation in a mode-locked Yb:YAG laser with a highly nonlinear intra-cavity medium is analyzed using a nonlinear Schrodinger equation. The output spectra are extended by the increased laser intensity, and spectral bandwidths wider than those of the gain medium are achieved. Moreover, pulse widths are shortened by increased laser intensity to considerably less than those of the gain medium. The simulation results qualitatively agree with the experimental results.

  19. A Bidirectional, Diode-Pumped, Passively Mode-Locked Nd:YVO4 Ring Laser with a Low-Temperature-Grown Semiconductor Saturable Absorber Mirror

    Institute of Scientific and Technical Information of China (English)

    CAI Zhi-Qiang; YAO Jian-Quan; WANG Peng; WANG Yong-Gang; ZHANG Zhi-Gang

    2007-01-01

    We report the operation of a bidirectional picosecond pulsed ring Nd:YVO4 laser based on a low-temperaturegrown semiconductor saturable absorber mirror. Except for the laser crystal, the six-mirror ring laser cavity has no intra-cavity elements such as focusing lens or mirror. The bidirectional mode locked pluses are obtained at the repetition rate of 117.5MHz, pulse duration of Sips, power of 2×200 mW.

  20. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers.

    Science.gov (United States)

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-04-29

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers.

  1. As-grown uniform MoS2/mica saturable absorber for passively Q-switched mode-locked Nd:GdVO4 laser

    Science.gov (United States)

    Xu, Yuanyuan; Yang, Cheng; Ge, Pengguang; Liu, Jie; Jiang, Shouzhen; Li, Chun; Man, Baoyuan

    2016-08-01

    Molybdenum disulfide (MoS2) has recently attracted growing attention due to its distinctive properties and potential applications in optoelectronics and electronics. Here, large-area and high-quality MoS2 film with uniform thickness was obtained by thermally decomposing ammonium thiomolybdate. Besides, it is firstly demonstrated that the as-grown MoS2/mica can be directly inserted into Nd:GdVO4 laser cavity as saturable absorber for the output of diode-pumped passively Q-switched mode-locked pulse trains. Using the MoS2 saturable absorbers, the stable Q-switched mode-locked pulse trains with high modulation depth were realized, suggesting that the broadband MoS2 SA could potentially be employed in mode-locking laser system

  2. On the features of the Optical Rogue Waves observed in the Kerr lens mode locked Ti:Sapphire laser

    CERN Document Server

    Hnilo, Alejandro A; Tredicce, Jorge R

    2014-01-01

    Kerr lens-mode-locked Ti:Sapphire lasers are known to display three coexistent modes of operation, that can be described as: continuous wave (CW), transform limited pulses (P1) and positive chirped pulses (P2). Optical rogue waves, in the form of pulses of high energy appearing much often than expected in a Gaussian distribution, are observed in the chaotic regime of the mode P2, but not of P1. These high energy pulses appear in an unpredictable way, but it is observed that their separation (if measured in number of round trips) can take only some definite values, which received the name of "magic numbers". The existence of optical rogue waves in P2 and not in P1, and also of the magic numbers, are correctly reproduced by a numerical simulation based on a five-variables iterative map. But, a successful numerical simulation provides limited insight on the physical causes of the observed phenomena. We present evidence that optical rogue waves in this laser follow a modulational instability, and that an initial ...

  3. Kerr-Lens Mode-Locked Femtosecond Yb:GdYSiO5 Laser Directly Pumped by a Laser Diode

    Directory of Open Access Journals (Sweden)

    Jiangfeng Zhu

    2015-10-01

    Full Text Available We demonstrate the first Kerr-lens mode-locked operation in a diode-pumped Yb:GdYSiO5 oscillator. Under a diode pump power of 5 W, 141 fs pulses with an average power of 237 mW were obtained at a repetition rate of 118 MHz. The central wavelength was at 1094 nm with a bandwidth of 10.1 nm. Shorter pulses were obtained by adjusting the cavity to operate at a shorter wavelength, resulting in 55 fs pulse duration at the central wavelength of 1054 nm with a bandwidth of 23.5 nm.

  4. Ultrawide broadband photonic source based on a new design of mode-locked erbium-doped fibre laser

    Science.gov (United States)

    Jarabo, S.; Salgado-Remacha, F. J.

    2015-09-01

    Pulses with a spectral width of 134 nm at  -6 dBm nm-1 and 223 nm at  -20 dBm nm-1, covering L-band and U-band and longer wavelengths (even beyond 1700 nm), are achieved by means of a new design of passive mode-locked erbium-doped fibre laser. This source includes a C/L-band filter inside a ring cavity with an L-band erbium-doped fibre amplifier as active medium and its output pulses are amplified by means of a second L-band amplifier. It is demonstrated that output spectra are clearly broadened due to the presence of the C/L band filter.

  5. Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor; Wu, Juhao; /SLAC

    2012-05-10

    We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomic states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).

  6. Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor; Wu, Juhao; /SLAC

    2012-05-10

    We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomic states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).

  7. Integrated Microwave Photonic Isolators: Theory, Experimental Realization and Application in a Unidirectional Ring Mode-Locked Laser Diode

    Directory of Open Access Journals (Sweden)

    Martijn J.R. Heck

    2015-09-01

    Full Text Available A novel integrated microwave photonic isolator is presented. It is based on the timed drive of a pair of optical modulators, which transmit a pulsed or oscillating optical signal with low loss, when driven in phase. A signal in the reverse propagation direction will find the modulators out of phase and, hence, will experience high loss. Optical and microwave isolation ratios were simulated to be in the range up to 10 dB and 20 dB, respectively, using parameters representative for the indium phosphide platform. The experimental realization of this device in the hybrid silicon platform showed microwave isolation in the 9 dB–22 dB range. Furthermore, we present a design study on the use of these isolators inside a ring mode-locked laser cavity. Simulations show that unidirectional operation can be achieved, with a 30–50-dB suppression of the counter propagating mode, at limited driving voltages. The potentially low noise and feedback-insensitive operation of such a laser makes it a very promising candidate for use as on-chip microwave or comb generators.

  8. Low-timing-jitter, stretched-pulse passively mode-locked fiber laser with tunable repetition rate and high operation stability

    Science.gov (United States)

    Liu, Yuanshan; Zhang, Jian-Guo; Chen, Guofu; Zhao, Wei; Bai, Jing

    2010-09-01

    We design a low-timing-jitter, repetition-rate-tunable, stretched-pulse passively mode-locked fiber laser by using a nonlinear amplifying loop mirror (NALM), a semiconductor saturable absorber mirror (SESAM), and a tunable optical delay line in the laser configuration. Low-timing-jitter optical pulses are stably produced when a SESAM and a 0.16 m dispersion compensation fiber are employed in the laser cavity. By inserting a tunable optical delay line between NALM and SESAM, the variable repetition-rate operation of a self-starting, passively mode-locked fiber laser is successfully demonstrated over a range from 49.65 to 50.47 MHz. The experimental results show that the newly designed fiber laser can maintain the mode locking at the pumping power of 160 mW to stably generate periodic optical pulses with width less than 170 fs and timing jitter lower than 75 fs in the 1.55 µm wavelength region, when the fundamental repetition rate of the laser is continuously tuned between 49.65 and 50.47 MHz. Moreover, this fiber laser has a feature of turn-key operation with high repeatability of its fundamental repetition rate in practice.

  9. Mechanically exfoliated black phosphorus as a new saturable absorber for both Q-switching and Mode-locking laser operation.

    Science.gov (United States)

    Chen, Yu; Jiang, Guobao; Chen, Shuqing; Guo, Zhinan; Yu, Xuefeng; Zhao, Chujun; Zhang, Han; Bao, Qiaoliang; Wen, Shuangchun; Tang, Dingyuan; Fan, Dianyuan

    2015-05-18

    Black phosphorus (BP), an emerging narrow direct band-gap two-dimensional (2D) layered material that can fill the gap between the semi-metallic graphene and the wide-bandgap transition metal dichalcogenides (TMDs), had been experimentally found to exhibit the saturation of optical absorption if under strong light illumination. By taking advantage of this saturable absorption property, we could fabricate a new type of optical saturable absorber (SA) based on mechanically exfoliated BPs, and further demonstrate the applications for ultra-fast laser photonics. Based on the balanced synchronous twin-detector measurement method, we have characterized the saturable absorption property of the fabricated BP-SAs at the telecommunication band. By incorporating the BP-based SAs device into the all-fiber Erbium-doped fiber laser cavities, we are able to obtain either the passive Q-switching (with maximum pulse energy of 94.3 nJ) or the passive mode-locking operation (with pulse duration down to 946 fs). Our results show that BP could also be developed as an effective SA for pulsed fiber or solid-state lasers.

  10. Generation of 10 GHz transform-limited pulse train from dual-pump mode-locking erbium-doped fiber laser

    Science.gov (United States)

    He, Li; Yang, Bojun; Zhang, Xiaoguang; Yu, Li

    2006-09-01

    A dual-pump 10 GHz mode-locking erbium-doped fiber laser was demonstrated. With 10-GHz signal modulation of the modulator, less than 12 ps mode-locked pulse at 10 GHz repetition rate with 1.097 mW average output power was obtained. The corresponding spectrum width is 0.277 nm, which is centered at 1561 nm. The corresponding product of time and bandwidth is Δv*Δt which equals 0.433. Gaussian pulse shape is assumed, the output pulse is almost transform limited. Compared with single-pump fiber ring laser, the dual-pump fiber ring laser is helpful for suppression of supermode noise, which make this kind of fiber ring laser more stable.

  11. Gain engineering for all-optical microwave and high speed pulse generation in mode-locked fiber lasers

    Science.gov (United States)

    Li, Fangxin; Helmy, Amr S.

    2014-03-01

    Pulsed sources based on approaches that employ only photonic components and no RF components will be discussed in this talk. Several technologies have been explored to generate actively mode-locked sources using electronically driven fiber ring cavities. However, for these sources the pulse repetition rate is usually limited by the bandwidth of the intracavity modulator. Filtering of highly-stable low repetition rate optical combs utilizing cavities such as Fabry-Perot etalons can be used to overcome this limitation. This scheme is not flexible as it requires highly precise control of ultrahigh finesse etalons which limits the repetition rate to the free spectral range of the filter. Pulsed sources based on semiconductor devices offer many advantages, including large gain bandwidth, rapid tunability, long-term stability. In this work we introduce a novel, simple method to generate optical clock with wavelength tunability using two continuous wave (CW) lasers. The lasers are injected into a conventional SOAs-based fiber ring laser. The beating signal generated by these two lasers causes the modulation of the SOA gain saturation inside the cavity. Thus, the SOA provides gain and functions as the modulator as well as the gain medium. When the lasing mode inside the cavity is amplified, it also results in gain-induced four wave mixing. The proposed technique is particularly versatile, overcoming the bandwidth limitation of other techniques, which require RF sources. Moreover, this technique provides the possibility for hybrid integration as it is comprised of semiconductor chips that can be heterogeneously integrated on a Si platform.

  12. Switchable Dual-Wavelength Mode-Locked Er-Doped Fibre Laser Using a Bragg Grating in Polarization-Maintaining Fibre

    Institute of Scientific and Technical Information of China (English)

    FENG Xin-Huan; LIU Yan-Ge; SUN Lei; XIONG Ling-Yun; LI-Yao; YUAN Shu-Zhong; KAI Gui-Yun; DONG Xiao-Yi

    2004-01-01

    @@ A simple actively mode-locked fibre ring laser is proposed and successfully demonstrated to generate switchable dual-wavelength picosecond pulses using a Bragg grating in a polarization-maintaining fibre. The wavelength spacing specified by the grating is only 0.52nm. The proposed laser can be made to operate in stable dualwavelength or switch between wavelengths at room temperature, only by simple adjustment of a polarization controller.

  13. Mode-locked Nd:YAG laser pumped by LD%LD抽运锁模Nd:YAG激光器研究

    Institute of Scientific and Technical Information of China (English)

    黎章; 袁易君

    2011-01-01

    利用Cr4+:YAG和声光锁模器联合对光纤耦合LD抽运Nd:YAG激光器进行主被动锁模,比较和分析了Cr4+:YAG被动锁模,声光锁模器主动锁模及两者联合主被动锁模三种情况下平均输出功率的特性,结果表明主被动联合锁模克服了主动锁模稳定性差、被动锁模输出功率低、锁模不完全的缺点,得到幅值和能量抖动小于±6%、锁模深度100%、脉宽小于410 ps、输出平均功率290 mW的绿光锁模脉冲.%Using Cr4+:YAG and acousto-optic mode-locker jointly, the fiber coupling LD pumping Nd: YAG laser was actively-passively mode-locked. The output average power of passively mode-locked by Cr4+:YAG only, actively mode-locked by acousto-optic mode-locker only and mode-locked by Cr4+:YAG and acoustooptic jointly are compared and analyzed. The result shows good resolution to the low output energy and stability, and the mode-lock amplitude and energy fluctuation is less than ±6%, with the depth of mode locking of 100%, pulse width less than 410 ps and output average power near 290 mW.

  14. Mode-locking via dissipative Faraday instability

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-08-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  15. Mode-locking via dissipative Faraday instability.

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-08-09

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  16. 6.5 µJ pulses from a compact dissipative soliton resonance mode-locked erbium-ytterbium double clad (DC) laser

    Science.gov (United States)

    Krzempek, K.; Abramski, K.

    2017-01-01

    The feasibility of constructing a compact, all-fiber, dissipative soliton resonance (DSR) mode-locked erbium-ytterbium double clad laser emitting 6.517 µJ pulses directly from the cavity is presented. The laser was built in a figure-8 configuration and mode-locked using a nonlinear optical loop mirror. A DSR regime of operation was enforced in the cavity by large net-anomalous dispersion (-21.431 ps2), obtained by incorporating 1 km of SMF28 fiber in the resonator. The laser operated at a 201 kHz repetition rate, with maximum average output power of 1.31 W at 7.2 W of pump power, yielding an impressive 20% slope efficiency.

  17. Single-section mode-locked 1.55-μm InAs/InP quantum dot lasers grown by MOVPE

    Science.gov (United States)

    Gao, Feng; Luo, Shuai; Ji, Hai-Ming; Liu, Song-Tao; Lu, Dan; Ji, Chen; Yang, Tao

    2016-07-01

    We report on ultra-short pulse single-section mode-locked lasers emitting at 1.55 μm, based on self-assembled InAs/InGaAsP/InP quantum dot active regions grown by metal-organic vapor phase epitaxy (MOVPE). For a 1.5-mm-long Fabry-Perot laser, mode-locking at a repetition rate of 29.8 GHz with pulse duration of 855 fs is obtained without any external pulse compression techniques. The mode-beating exhibits a narrow RF linewidth less than 30 kHz, and a wide frequency tuning range up to 73 MHz can be achieved by simply changing the injection current. Moreover, a higher repetition rate of 55.6 GHz and the transform limited Gaussian-pulse with the 707 fs pulse duration are achieved from a device with a shorter cavity length of 0.8 mm.

  18. 基于氧化石墨烯的锁模激光实验%Experiment of mode-locked laser using graphene oxide

    Institute of Scientific and Technical Information of China (English)

    程晨; 魏加峰; 刘博文; 张建友; 刘杰

    2014-01-01

    设计了低成本全固态锁模超快激光实验系统,使用透射式氧化石墨烯饱和吸收体作为被动锁模元件,直接插入到腔内,可依次观察到激光的不同运转状态.实验采用结构紧凑的谐振腔设计,获得了二极管端面泵浦Nd∶YVO4晶体的1064 nm连续波被动锁模激光输出,重复频率为81 M Hz ,最大平均输出功率为1.23 W ,相应的锁模单脉冲能量为15.2 nJ .%A low cost all solid-state mode-locked ultrashort laser operation based on a graphene oxide saturable absorber was designed .By using graphene oxide saturable absorber (SA ) as mode-locked component ,passively mode-locked 1 064 nm continuous wave laser output of end-diode-pump Nd∶YVO4 crystal was obtained with compact resonator .The maximum average output power of 1 .23 W with a repetition rate of 81 M Hz was obtained ,corresponding to mode-locking single pulse energy of 15 .2 nJ .

  19. Soliton mode-locking in optical microresonators

    CERN Document Server

    Herr, T; Gorodetsky, M L; Kippenberg, T J

    2012-01-01

    The discovery of mode-locking via saturable absorbers has led to optical femto-second pulses with applications ranging from eye-surgery to the analysis of chemical reactions on ultra-short timescales. In the frequency domain a train of such optical pulses corresponds to a frequency comb (equidistant optical laser lines spaced by the pulse repetition rate), which find use in precision spectroscopy and optical frequency metrology. Not relying on mode-locking, frequency combs can also be generated in continuously driven high-Q Kerr-nonlinear optical microresonators via cascaded four-wave mixing. Over the past years these Kerr-combs have been demonstrated in a variety of microresonator geometries. Applying a pulse-shaping mode locking mechanism, could enable compact femto-second pulse generators. However, conventional saturable absorbers are challenging to apply to microresonators, as they affect the high-quality-factor. Here, we report on passive mode-locking in microresonators without saturable absorber. This m...

  20. Coupled optical resonance laser locking.

    Science.gov (United States)

    Burd, S C; du Toit, P J W; Uys, H

    2014-10-20

    We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for locking the different lasers are obtained by modulating each laser at a different frequency and using lock-in detection of a single photodiode signal. Experimentally, we simultaneously lock a 369 nm and a 935 nm laser to the (2)S(1/2) → (2)(P(1/2) and (2)D(3/2) → (3)D([3/2]1/2) transitions, respectively, of Yb(+) ions generated in a hollow cathode discharge lamp. Stabilized lasers at these frequencies are required for cooling and trapping Yb(+) ions, used in quantum information and in high precision metrology experiments. This technique should be readily applicable to other ion and neutral atom systems requiring multiple stabilized lasers.

  1. Frequency locking of single-mode 3.5-THz quantum cascade lasers using a gas cell

    NARCIS (Netherlands)

    Ren, Y.; Hovenier, J.N.; Cui, M.; Hayton, D.J.; Gao, J.R.; Klapwijk, T.M.; Shi, S.C.; Kao, T.Y.; Hu, Q.; Reno, J.L.

    2012-01-01

    We report frequency locking of two 3.5-THz third-order distributed feedback (DFB) quantum cascade lasers (QCLs) by using methanol molecular absorption lines, a proportional-integral-derivative controller, and a NbN bolometer. We show that the free-running linewidths of the QCLs are dependent on the

  2. Self-Starting Passively Mode-Locking All-Solid-State Laser with GaAs Absorber Grown at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    JIA Yu-Lei; LING Wei-Jun; WEI Zhi-Yi; WANG Yong-Gang; MA Xiao-Yu

    2005-01-01

    @@ We realize a stable self-starting passively mode-locking all-solid-state laser by using novel GaAs mirrors as the absorber and output coupler. The GaAs mirror is grown by the technology of metal organic chemical vapour deposition at low temperature. With such an absorber as the output coupler in the laser resonator, laser pulses with duration of 42ps were generated at a repetition rate of 400MHz, corresponding to the average power of 590mW.

  3. Mode-locked femtosecond all polarization-maintaining erbium-doped dispersion managed fiber laser based on a nonlinear amplifying loop mirror

    Science.gov (United States)

    Wu, Wenjue; Zhou, Yue; Sun, Ji; Dai, Yitang; Yin, Feifei; Dai, Jian; Xu, Kun

    2016-11-01

    We proposed a mode-locked all-polarization-maintaining erbium-doped fiber laser base on a nonlinear amplifying loop mirror (NALM). The laser can generate 1.6 ps pulses at 1550 nm with the energy of 1 nJ that can be compressed down to 100 fs with the compressor outside the cavity. The repetition rate of the output pulse is 12MHz. Such configuration of laser is easier controlled and self starting long term operation, and is highly desirable for industrial applications, such as micro-machining.

  4. Dissipative soliton mode-locked all-fiber laser with a broad spectral bandwidth

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seolwon; Yeom, Dongil [Ajou University, Suwon (Korea, Republic of)

    2014-12-15

    We demonstrate an all-fiber dissipative soliton fiber laser (DSFL) with a very broad spectral bandwidth by optimizing the cavity design of the fiber laser. Two different cavity schemes of the DSFL with simple cavity structures were built by employing a hybrid component, and their properties were investigated while varying the net cavity dispersion of the laser. By optimizing the cavity dispersion of the fiber laser, we achieved a DSFL that stably deliver linear chirped pulses with a pulse duration of 912.5 fs at a repetition rate of 52.2 MHz without additional pulse compression. The measured spectral bandwidth of the laser was 68 nm, which is the largest value ever reported for Er-doped DSFL oscillators.

  5. Multi-Format Wavelength Conversion Using Quantum Dash Mode-Locked Laser Pumps

    Directory of Open Access Journals (Sweden)

    Yousra Ben M’Sallem

    2015-05-01

    Full Text Available We investigate and compare the performance of wavelength conversion for two different non-return-to-zero (NRZ modulation formats at 40 Gb/s: on off keying (OOK and differential phase-shift keying (DPSK. To achieve wide wavelength coverage and integrability, we use a dual pump scheme exploiting four-wave mixing in semiconductor optical amplifiers. For phase stability, we use a quantum-dash mode-locked laser (QD-MLL as a multi-wavelength source for the dual pumps, with tunability provided by the output filter. The significant sidelobes of the DPSK spectrum (relative to OOK require the balancing of the pump proximity to the original signal (facilitating high conversion efficiency with the signal degradation from the pump spectrum overlapping the converted DPSK signal. We achieve a conversion efficiency near –3.6 dB for OOK and –5.4 dB for DPSK across a 12 nm tuning range with low input powers (1 dBm. We measure bit error rate (BER and obtain error free transmission (BER < 10−9 with a power penalty less than 2 dB for OOK and 3 dB for DPSK.

  6. Hybrid mode-locking in pulsed ytterbium fiber laser with carbon nanotube saturable absorber

    Science.gov (United States)

    Khudyakov, Dmitry V.; Borodkin, Andrey A.; Lobach, Anatoly S.; Vartapetov, Sergey K.

    2015-10-01

    Ultrafast pulse generation in all-normal dispersion Yb-doped fiber laser on 1.04 μm have been reported. Stable self-starting pulse generation in output of the ring fiber laser have been investigated where nonlinear polarization rotation interacted with contribution from the single walled carbon nanotube saturable absorber. Laser pulses with 0.7 nJ pulse energy and 1.7 ps pulse width at 35.6 MHz repetition rate were achieved. The output pulse could be externally compressed to width of 180 fs by pair of gratings.

  7. Generation of high energy square-wave pulses in all anomalous dispersion Er:Yb passive mode locked fiber ring laser.

    Science.gov (United States)

    Semaan, Georges; Ben Braham, Fatma; Salhi, Mohamed; Meng, Yichang; Bahloul, Faouzi; Sanchez, François

    2016-04-18

    We have experimentally demonstrated square pulses emission from a co-doped Er:Yb double-clad fiber laser operating in anomalous dispersion DSR regime using the nonlinear polarization evolution technique. Stable mode-locked pulses have a repetition rate of 373 kHz with 2.27 µJ energy per pulse under a pumping power of 30 W in cavity. With the increase of pump power, both the duration and the energy of the output square pulses broaden. The experimental results demonstrate that the passively mode-locked fiber laser operating in the anomalous regime can also realize a high-energy pulse, which is different from the conventional low-energy soliton pulse.

  8. Passively mode-locking erbium-doped fiber lasers with 0.3 nm Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Xu, Xintong; Zhai, Jianpang; Li, Ling; Chen, Yanping; Yu, Yongqin; Zhang, Min; Ruan, Shuangchen; Tang, Zikang

    2014-01-01

    We demonstrate a passively mode-locked erbium-doped fiber laser (EDFL) by using the smallest single-walled carbon nanotubes (SWNTs) with a diameter of 0.3 nm as the saturable absorber. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of a ZnAPO4-11 (AEL) single crystal. By placing an AEL crystal into an EDFL cavity pumped by a 980 nm laser diode, stable passive mode-locking is achieved for a threshold pump power of 280 mW, and 73 ps pulses at 1563.2 nm with a repetition rate of 26.79 MHz. PMID:25342292

  9. Ultrafast erbium-doped fiber laser mode-locked by a CVD-grown molybdenum disulfide (MoS2) saturable absorber.

    Science.gov (United States)

    Xia, Handing; Li, Heping; Lan, Changyong; Li, Chun; Zhang, Xiaoxia; Zhang, Shangjian; Liu, Yong

    2014-07-14

    We demonstrate an erbium-doped fiber laser passively mode-locked by a multilayer molybdenum disulfide (MoS(2)) saturable absorber (SA). The multilayer MoS(2) is prepared by the chemical vapor deposition (CVD) method and transferred onto the end-face of a fiber connector. Taking advantage of the excellent saturable absorption of the fabricated MoS(2)-based SA, stable mode locking is obtained at a pump threshold of 31 mW. Resultant output soliton pulses have central wavelength, spectral width, pulse duration, and repetition rate of 1568.9 nm, 2.6 nm, 1.28 ps, and 8.288 MHz, respectively. The experimental results show that multilayer MoS(2) is a promising material for ultrafast laser systems.

  10. Experimental demonstration of change of dynamical properties of a passively mode-locked semiconductor laser subject to dual optical feedback by dual full delay-range tuning.

    Science.gov (United States)

    Nikiforov, O; Jaurigue, L; Drzewietzki, L; Lüdge, K; Breuer, S

    2016-06-27

    In this contribution we experimentally demonstrate the change and improvement of dynamical properties of a passively mode-locked semiconductor laser subject to optical feedback from two external cavities by coupling the feedback pulses back into the gain segment. Hereby, we tune the full delay-phase of the pulse-to-pulse period of both external cavities separately and demonstrate the change of the repetition rate, timing jitter, multi-pulse formation and side-band suppression for the first time for such a dual feedback configuration. In addition, we thereby confirm modeling predictions by achieving both a good qualitative and quantitative agreement of experimental and simulated results. Our findings suggest a path towards the realization of side-band free all-optical photonic oscillators based on mode-locked lasers.

  11. Effective generation of optical quadruple frequency millimeter-wave based on fiber laser using injection rational harmonic mode-locked technique

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Xue Feng; Fei Huang; Xiaoming Liu

    2009-01-01

    A method to generate the optical quadruple frequency millimeter-wave with high power efficiency is pro-posed and demonstrated based on the combination of the injection 2nd-order rational harmonic mode-locked fiber ring laser technique and the fiber grating notch filter. In this approach, the fiber Bragg grating notch filter is inserted into the laser cavity to prevent the undesired optical carrier, so that the pump power can be converted to 2nd-order harmonic wave more efficiently. In our experiment, the power efficiency of optical quadruple frequency millimeter-wave (40 GHz) generation is ten folds of that of our previous method based only on the rational harmonic mode-locked technique.

  12. A Passively Mode-Locked Diode-End-Pumped Nd:YAG Laser with a Semiconductor Saturable Absorber Mirror Grown by Metal Organic Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    王勇刚; 马骁宇; 李春勇; 张治国; 张丙元; 张志刚

    2003-01-01

    We report the experimental results of a mode-locked diode-end-pumped Nd:YAG laser with a semiconductor saturable absorber mirror(SESAM)from which we achieved a 10ps pulse duration at 150MHz repetition rate.The SESAM was grown by metal organic chemical vapour deposition at low temperature.The recovery time was measured to be 0.5 ps,indicating the potential pulse compression to sub-picoseconds.

  13. 220 fs Er-Yb:glass laser mode-locked by a broadband low-loss Si/Ge saturable absorber

    CERN Document Server

    Grawert, F J; Ilday, F O; Liu, J; Gopinath, J T; Shen, H M; Wada, K; Ippen, E P; Kimerling, L C; Kaertner, Franz X

    2004-01-01

    We demonstrate femtosecond performance of an ultra-broadband high-index-contrast saturable Bragg reflector consisting of a silicon/silicon-dioxide/germanium structure that is fully compatible with CMOS processing. This device offers a reflectivity bandwidth of over 700 nm and sub-picosecond recovery time of the saturable loss. It is used to achieve mode-locking of an Er-Yb:glass laser centered at 1540 nm, generating 220 fs pulses, with the broadest output spectrum to date.

  14. Large area growth of monolayer MoS2 film on quartz and its use as a saturable absorber in laser mode-locking

    Science.gov (United States)

    Zhao, Wei-fang; Yu, Hua; Liao, Meng-zhou; Zhang, Ling; Zou, Shu-zhen; Yu, Hai-juan; He, Chao-jian; Zhang, Jing-yuan; Zhang, Guang-yu; Lin, Xue-chun

    2017-02-01

    Monolayer MoS2 film on quartz was fabricated by a home-made three-temperature zone chemical vapor deposition method. The photo, AFM image, Raman spectroscopy and HRTEM image showed that high quality as-grown MoS2 film completely covered the whole quartz substrate of a few cm2. A Nd:YVO4 laser with mode-locking operation was obtained by using the monolayer MoS2 on quartz as the saturable absorber (SA). To the best of our knowledge, this is the first report on large-area growth of high quality monolayer MoS2 film on transparent quartz substrate, and the first time that the CVD MoS2 SA was used in mode-locked solid state lasers. Because of the large area, high transmission, low non-saturable loss and high optical damage threshold of this material, it is very suitable for application in mode-locked solid state lasers.

  15. Numerical modeling of mode-locked fiber lasers with a fiber-based saturable-absorber

    Science.gov (United States)

    Wang, Long; Chong, Andy; Haus, Joseph W.

    2017-01-01

    We report fiber laser simulations with a fiber compatible, self-focusing, saturable absorber (SA) device. The SA device consists of two tapered fiber ends separated by a bulk, nonlinear medium. An optical beam transmitted from one tapered fiber end, propagate through the nonlinear medium (chalcogenide glass As40 S e60) and couples back into the other tapered fiber end. Pulse propagation in the fiber laser cavity is performed using the Split Step Method. Stable pulses are generated with energies around 0.3 nJ and a transform limited pulse width around 200 fs.

  16. Broadband Spectroscopy of CO_2 Bands Near 2 μm Using a Femtosecond Mode-Locked Laser

    Science.gov (United States)

    Klose, Andrew; Maser, Daniel L.; Ycas, Gabriel; Diddams, Scott; Newbury, Nathan R.; Coddington, Ian

    2014-06-01

    The optical frequency comb provided in the output of a femtosecond, mode-locked laser has been employed for many applications, including broadband spectroscopic measurements of trace gases using a variety of detection techniques. One environmentally significant trace gas is CO_2, which has characteristic absorption bands near 1.6 μm and 2.0 μm. Continuous wave (cw) lasers have typically been used to measure CO_2 at atmospheric-level concentrations. However, a broadband frequency comb source can provide rapid, simultaneous and accurate measurements of multiple transitions without the need for mechanical scanning or frequency tuning. Previously, precision broadband spectroscopy was performed on CO_2 bands near 1.6 μm. However, the CO_2 absorption bands near 2 μm have nearly a ten-fold increase in line strength compared to the bands near 1.6 μm, making the 2 μm bands attractive candidates for precision measurements of CO_2 with improved signal-to-noise and reduced uncertainty. Here, broadband quantitative spectroscopy of CO_2 bands near 2 μm is pursued. The source that was developed consists of an Er:fiber oscillator, Er:doped fiber amplifier, and highly nonlinear optical fiber, which generates a broadband spectrum spanning from 1 to 2.2 μm with an average power of 270 mW. Over 70 mW of the optical power is contained in the 1.8-2.2 μm region relevant to the CO_2 measurement. After generation, the laser light is passed through laboratory gas cells or open air where the absorption features from the sample gas are imprinted onto the laser light. Initial detection efforts involve a virtually imaged phased array- (VIPA-)based spectrometer whose output is subsequently imaged on a InSb array detector. The bandwidth of the measured spectrum is 50 nm, limited by the size of the detector array. The characteristics of the spectrometer, including the detection limits and temporal resolution, will be presented. In addition, the progress towards the use of the present

  17. Enhanced efficiency of a continuous-wave mode-locked Nd:YAG laser by compensation of the thermally induced, polarization-dependent bifocal lens.

    Science.gov (United States)

    Wetter, N U; Maldonado, E P; Vieira, N D

    1993-09-20

    Measurements of the bifocal, thermally induced lenses of a cw Nd:YAG laser were obtained. We observed four different focal lengths that are polarization and direction dependent. The focal lengths were used to design stable resonators with large fundamental mode filling in the laser gain medium. The beam is totally polarized in the desired direction even without an intracavity Brewster window. We developed a general approach for the optimization of single-lamp, cw-pumped Nd:YAG lasers. Up to 22 W of cw output power in the vertically polarized TEM(00) mode and 15 W in the horizontal polarization are obtained for moderate lamp currents. Also, we demonstrate mode locking with 56-ps pulse duration at 33 A of lamp current and up to 13 W of average output power.

  18. Graphene mode-locked multipass-cavity femtosecond Cr4+: forsterite laser

    OpenAIRE

    Baylam, Işınsu; Çizmeciyan, Melisa Natali; Sennaroğlu, Alphan; Ozharar, Sarper; Balcı, Osman; Pince, Ercag; Kocabaş, Coşkun

    2013-01-01

    We report, for the first time to our knowledge, the use of graphene as a saturable absorber in an energy-scaled femtosecond Cr4+: forsterite laser. By incorporating a multipass cavity, the repetition rate of the original short resonator was reduced to 4.51 MHz, which resulted in the generation of 100 fs, nearly transform-limited pulses at 1252 nm with a peak power of 53 kW. To the best of our knowledge, this is the highest peak power obtained from a room-temperature, femtosecond Cr4+: forster...

  19. Monolithic mode-locked lasers with deeply dry etched Bragg mirror

    DEFF Research Database (Denmark)

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

    gasmixture, gas flow, chamber pressure and the power supplied to the plasma2.Figure 1: SEM micrograph of a deeply etched 2nd order grating and waveguidein InP. 1K. yvind et al, Phot. Technology Letters 16, 975-977 (2004)2Y. Feurprier et al., J. Vac. Sci. A 16(3), 1552-1559 (1998)...... section, such as self-phase modulation. The solution to this problem is to integratethe laser with a wavelength selective Bragg grating. Another advantage of the gratingshould be lower noise. Deep Reactive Ion Etching (RIE) of the grating is a key for lowcostmass production of these lasers, making...... and high index regions (etched andunetched), is 240 nm for a 1st order grating and 480 nm for the 2nd order.Fabrication: The mask for the grating is formed by a combination of E-beam writing andUV-lithography. The resist pattern is transferred to a 100 nm SiO2-film, with a CHF3(Freon) based dry etch...

  20. Sub-picosecond Graphene-based Harmonically Mode-Locked Fiber Laser With Repetition Rates up to 2.22 GHz

    Directory of Open Access Journals (Sweden)

    Abramski K.M.

    2013-03-01

    Full Text Available Passive harmonic-mode locking (PHML of erbium-doped fiber laser with multilayer graphene is presented. The laser could operate at several harmonics (from 2nd to 21st of the fundamental repetition frequency of the ring resonator (106 MHz. The highest achieved repetition rate was 2.22 GHz (which corresponds to the 21st harmonic with 900 fs pulse duration and 50 dB of the supermode noise suppression. The saturable absorber was formed by multilayer graphene, mechanically exfoliated from pure graphite block through Scotch-tape and deposited on the fiber ferrule.

  1. High power dissipative soliton in an Erbium-doped fiber laser mode-locked with a high modulation depth saturable absorber mirror.

    Science.gov (United States)

    Cabasse, A; Martel, G; Oudar, J L

    2009-06-08

    We report on a passively mode-locked erbium-doped fiber laser, using a high nonlinear modulation depth saturable absorber mirror, in a Fabry-Perot cavity. A segment of dispersion compensation fiber is added inside the cavity in order to build a high-positive dispersion regime. The setup produced highly chirped pulses with an energy of 1.8 nJ at a repetition rate of 33.5 MHz. Numerical simulations accurately reflect our experimental results and show that pulse-shaping in this laser could be interpreted as producing 'dissipative solitons'.

  2. Generation of ultrashort pulses with minimum duration of 90\\ {\\text{fs}} in a hybrid mode-locked erbium-doped all-fibre ring laser

    Science.gov (United States)

    Dvoretskiy, D. A.; Sazonkin, S. G.; Voropaev, V. S.; Negin, M. A.; Leonov, S. O.; Pnev, A. B.; Karasik, V. E.; Denisov, L. K.; Krylov, A. A.; Davydov, V. A.; Obraztsova, E. D.

    2016-11-01

    Regimes of ultrashort pulse generation in an erbium-doped all-fibre ring laser with hybrid mode locking based on single-wall carbon - boron nitride nanotubes and the nonlinear Kerr effect in fibre waveguides are studied. Stable dechirped ultrashort pulses are obtained with a duration of ˜ 90 {\\text{fs}}, a repetition rate of ˜ 42.2 {\\text{MHz}}, and an average output power of ˜ 16.7 {\\text{mW}}, which corresponds to a pulse energy of ˜ 0.4 {\\text{nJ}} and a peak laser power of ˜ 4.4 {\\text{kW}}.

  3. Supercontinuum generation based on all-normal-dispersion Yb-doped fiber laser mode-locked by nonlinear polarization rotation: Influence of seed's output port

    Science.gov (United States)

    Xiao, Xiaosheng; Hua, Yi

    2016-10-01

    All-normal-dispersion (ANDi) mode-locked Yb-doped fiber laser is a promising seed source for supercontinuum (SC) generation, due to its compact structure and broadband output. The influences of output ports of the ANDi laser mode-locked by nonlinear polarization rotation (NPR), on the generated SC are investigated. Two output ports of ANDi laser are considered, one of which is the conventional nonlinear polarization rotation (NPR) port and the other is extracted from a coupler after the NPR port. It is found that, the SC originated from the coupler port is much broader than that from the NPR port, which is validated by lots of experiments with different output parameters. Furthermore, the conclusion is verified and generalized to general ANDi lasers by numerical simulations, because the output pulse from coupler port could be cleaner than that from NPR port. Besides, there are no significant differences in the phase coherence and temporal stability between the SCs generated from both ports. Hence for the SC generation based on ANDi laser, it is preferred to use the pulse of coupler port (i.e. pulse after NPR port) serving as the seed source.

  4. Efficient OPSL-pumped mode-locked Yb:Lu2O3 laser with 67% optical-to-optical efficiency

    Science.gov (United States)

    Heuer, Alexander M.; Saraceno, Clara J.; Beil, Kolja; Huber, Günter; Kränkel, Christian

    2016-01-01

    We present a mode-locked Yb:Lu2O3 laser with up to 67% of optical-to-optical efficiency. By utilizing a high brightness optically pumped semiconductor laser (OPSL) as a pump source and using a semiconductor saturable absorber mirror (SESAM) we obtained self-starting mode locking. A pulse duration of 571 fs at 4.73 W of average output power with an optical-to-optical efficiency of 67% was achieved. In a slightly different cavity configuration the pulse duration was reduced to 313 fs at 2.16 W of average output power. In both cases the pulse duration was longer than the Fourier limit and the spectrum supports significantly shorter pulse durations. The laser wavelength is centered at 1034 nm and the repetition rate is 100.76 MHz in both cases. In continuous wave fundamental mode operation the optical-to-optical efficiency was as high as 78% with output powers exceeding 5 W.

  5. Reduction of timing jitter and intensity noise in normal-dispersion passively mode-locked fiber lasers by narrow band-pass filtering.

    Science.gov (United States)

    Qin, Peng; Song, Youjian; Kim, Hyoji; Shin, Junho; Kwon, Dohyeon; Hu, Minglie; Wang, Chingyue; Kim, Jungwon

    2014-11-17

    Fiber lasers mode-locked with normal cavity dispersion have recently attracted great attention due to large output pulse energy and femtosecond pulse duration. Here we accurately characterized the timing jitter of normal-dispersion fiber lasers using a balanced cross-correlation method. The timing jitter characterization experiments show that the timing jitter of normal-dispersion mode-locked fiber lasers can be significantly reduced by using narrow band-pass filtering (e.g., 7-nm bandwidth filtering in this work). We further identify that the timing jitter of the fiber laser is confined in a limited range, which is almost independent of cavity dispersion map due to the amplifier-similariton formation by insertion of the narrow bandpass filter. The lowest observed timing jitter reaches 0.57 fs (rms) integrated from 10 kHz to 10 MHz Fourier frequency. The rms relative intensity noise (RIN) is also reduced from 0.37% to 0.02% (integrated from 1 kHz to 5 MHz Fourier frequency) by the insertion of narrow band-pass filter.

  6. Piezoelectric-transducer-based optoelectronic frequency synchronizer for control of pulse delay in a femtosecond passively mode-locked Ti:sapphire laser.

    Science.gov (United States)

    Un, Gong-Ru; Chang, Yung-Cheng; Liu, Tze-An; Pan, Ci-Ling

    2003-05-20

    We propose a piezoelectric transducer-(PZT-) based optoelectronic frequency synchronizer to control simultaneously change in the repetition rate, the relative pulse delay, and the phase noise of a passively mode-locked femtosecond Ti:sapphire laser with an intracavity saturable Bragg reflector absorber with respect to an electronic frequency reference. An optoelectronic phase-locked-loop-based PZT feedback controller with a proportional, integral, and differential (PID) circuit and a tunable voltage regulator is designed to achieve frequency synchronization, phase-noise suppression, and delay-time tuning. When the controlling voltage is tuned from -2.6 to 2.6 V, the maximum pulse-delay range, tuning slope, and tuning resolution of the laser pulse-train are 11.3 ns, 2.3 ps/mV, and 1.2 ps, respectively. Setting the gain constant of the PID circuit at 10 or larger causes the delay-time tuning function to be linearly proportional to the controlling voltage. In the delay-time tuning mode the uncorrelated single-side-band phase-noise density of the frequency-synchronized laser is approximately -120 dBc/Hz at an offset frequency of 5 kHz, which is only 7 dBc/Hz higher than that of the electrical frequency reference. The proposed system also supports linear,continuous switching,and programmable control of the delay time of Ti:sapphire laser pulses when they are frequency synchronized to external reference clocks.

  7. Generation of soliton and bound soliton pulses in mode-locked erbium-doped fiber laser using graphene film as saturable absorber

    Science.gov (United States)

    Haris, H.; Harun, S. W.; Anyi, C. L.; Muhammad, A. R.; Ahmad, F.; Tan, S. J.; Nor, R. M.; Zulkepely, N. R.; Ali, N. M.; Arof, H.

    2016-04-01

    We report an observation of soliton and bound-state soliton in passive mode-locked fibre laser employing graphene film as a passive saturable absorber (SA). The SA was fabricated from the graphene flakes, which were obtained from electrochemical exfoliation process. The graphene flakes was mixed with polyethylene oxide solution to form a polymer composite, which was then dried at room temperature to produce a film. The film was then integrated in a laser cavity by attaching it to the end of a fibre ferrule with the aid of index matching gel. The fibre laser generated soliton pulses with a 20.7 MHz repetition rate, 0.88 ps pulse width, 0.0158 mW average output power, 0.175 pJ pulse energy and 18.72 W peak power at the wavelength of 1564 nm. A bound soliton with pulse duration of ~1.04 ps was also obtained at the pump power of 110.85 mW by carefully adjusting the polarization of the oscillating laser. The formation of bound soliton is due to the direct pulse to pulse interaction. The results show that the proposed graphene-based SA offers a simple and cost efficient approach of generating soliton and bound soliton in mode-locked EDFL set-up.

  8. Pulse-Width Saturation and Kelly-Sideband Shift in a Graphene-Nanosheet Mode-Locked Fiber Laser with Weak Negative Dispersion

    Science.gov (United States)

    Yang, Chun-Yu; Lin, Yung-Hsiang; Chi, Yu-Chieh; Wu, Chung-Lun; Lo, Jui-Yung; Lin, Gong-Ru

    2015-04-01

    The optimized soliton mode locking of the erbium-doped fiber laser (EDFL) and its pulse-shortening dynamic with the graphene nanosheet is demonstrated by precisely detuning the weakly negative group-delay dispersion (GDD) and maintaining strong self-phase-modulation (SPM), to obtain the shortest pulse width of 449 fs with a spectral linewidth of 6.02 nm. The pulse evolution with the mode-locking mechanism changing from the self-amplitude-modulation of the saturable absorber, to the soliton compression caused by the GDD and SPM is experimentally and numerically investigated in detail. Under high pumping powers, the enlarged up-chirp inside the EDFL cavity can induce a significant Kelly-sideband shift of up to 0.5 nm. The passively-mode-locked EDFL pulse width is controllable by detuning the GDD and SPM parameters, so that the pulse width can be compressed from 642 to 449 fs while reducing the negative GDD from -0.354 to -0.154 ps2 . The compression ratio can be also improved by strengthening the SPM at this stage.

  9. Carbon nanotubes for mode-locking: polarization study

    Science.gov (United States)

    Afkhamiardakani, Hanieh; Kamer, Brian; Diels, Jean-Claude; Arissian, Ladan

    2016-03-01

    Mode-locked fiber lasers are the most promising lasers for intracavity phase interferometry,1 because they offer the possibility to have two orthogonally polarized pulses circulating independently in the cavity. The saturable absorbers based on polarization maintaining tapered fiber coated with carbon nanotubes are developed and analyzed for minimum coupling between the slow and fast axis of the fiber.

  10. Diode-pumped, Cr:YAG passively Q-switched and mode-locked Nd:YVO4/KTP green laser

    Institute of Scientific and Technical Information of China (English)

    Junying Wang(王军营); Quan Zheng(郑权); Qinghua Xue(薛庆华); Huiming Tan(檀慧明)

    2003-01-01

    The phenomena of simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4/Cr:YAG/KTP green laser are reported and discussed in this paper. With 5.3-W pump power, by using a nearlyhemispherical cavity (the cavity length is only 97 mm), the results of modulation depth of 70% and theperiod of 0.6 ns are obtained, the output power and the repetitive frequency of Q-switched pulse are 90mW and 12 kHz, respectively.

  11. Efficiency of non-linear frequency conversion of double-scale pico-femtosecond pulses of passively mode-locked fiber laser.

    Science.gov (United States)

    Smirnov, Sergey V; Kobtsev, Sergey M; Kukarin, Sergey V

    2014-01-13

    For the first time we report the results of both numerical simulation and experimental observation of second-harmonic generation as an example of non-linear frequency conversion of pulses generated by passively mode-locked fiber master oscillator in different regimes including conventional (stable) and double-scale (partially coherent and noise-like) ones. We show that non-linear frequency conversion efficiency of double-scale pulses is slightly higher than that of conventional picosecond laser pulses with the same energy and duration despite strong phase fluctuations of double-scale pulses.

  12. Clock recovery from NRZ data at 10 Gb/s using SOA loop mirror and mode-locked fiber ring laser based on SOA

    Institute of Scientific and Technical Information of China (English)

    Lina Yin; Guoming Liu; Jian Wu; Jintong Lin

    2006-01-01

    @@ All-optical clock recovery from non-return-to-zero (NRZ) data using an semiconductor optical amplifier(SOA) loop mirror and a mode-locked SOA fiber laser is firstly schematically explained and experimentally demonstrated at 10 Gb/s. Furthermore, the pulse quality of the recovered clock is effectively improved by using a continuous-wave (CW) assist light in the gain region of SOA, through which the amplitude modulation is reduced from 57.2% to 8.47%. This scheme is a promising method for clock recovery from NRZ data in the future all-optical communication networks.

  13. Passively synchronized Q-switched and mode-locked dual-band Tm3+:ZBLAN fiber lasers using a common graphene saturable absorber

    Science.gov (United States)

    Jia, Chenglai; Shastri, Bhavin J.; Abdukerim, Nurmemet; Rochette, Martin; Prucnal, Paul R.; Saad, Mohammed; Chen, Lawrence R.

    2016-11-01

    Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm3+:ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm. Q-switched operation at 1480 nm and 1840 nm is achieved with a synchronized repetition rate from 20 kHz to 40.5 kHz. For synchronous mode-locked operation, pulses with full-width at half maximum durations of 610 fs and 1.68 ps at wavelengths of 1480 nm and 1845 nm, respectively, are obtained at a repetition rate of 12.3 MHz. These dual-band pulsed sources with an ultra-broadband wavelength separation of ~360 nm will add new capabilities in applications including optical sensing, spectroscopy, and communications.

  14. Passively synchronized Q-switched and mode-locked dual-band Tm(3+):ZBLAN fiber lasers using a common graphene saturable absorber.

    Science.gov (United States)

    Jia, Chenglai; Shastri, Bhavin J; Abdukerim, Nurmemet; Rochette, Martin; Prucnal, Paul R; Saad, Mohammed; Chen, Lawrence R

    2016-11-02

    Dual-band fiber lasers are emerging as a promising technology to penetrate new industrial and medical applications from their dual-band properties, in addition to providing compactness and environmental robustness from the waveguide structure. Here, we demonstrate the use of a common graphene saturable absorber and a single gain medium (Tm(3+):ZBLAN fiber) to implement (1) a dual-band fiber ring laser with synchronized Q-switched pulses at wavelengths of 1480 nm and 1840 nm, and (2) a dual-band fiber linear laser with synchronized mode-locked pulses at wavelengths of 1480 nm and 1845 nm. Q-switched operation at 1480 nm and 1840 nm is achieved with a synchronized repetition rate from 20 kHz to 40.5 kHz. For synchronous mode-locked operation, pulses with full-width at half maximum durations of 610 fs and 1.68 ps at wavelengths of 1480 nm and 1845 nm, respectively, are obtained at a repetition rate of 12.3 MHz. These dual-band pulsed sources with an ultra-broadband wavelength separation of ~360 nm will add new capabilities in applications including optical sensing, spectroscopy, and communications.

  15. Generation regimes of bidirectional hybridly mode-locked ultrashort pulse erbium-doped all-fiber ring laser with a distributed polarizer.

    Science.gov (United States)

    Krylov, Alexander A; Chernykh, Dmitriy S; Arutyunyan, Natalia R; Grebenyukov, Vyacheslav V; Pozharov, Anatoly S; Obraztsova, Elena D

    2016-05-20

    We report on the stable picosecond and femtosecond pulse generation from the bidirectional erbium-doped all-fiber ring laser hybridly mode-locked with a coaction of a single-walled carbon nanotube-based saturable absorber and nonlinear polarization evolution that was introduced through the insertion of the short-segment polarizing fiber. Depending on the total intracavity dispersion value, the laser emits conservative solitons, transform-limited Gaussian pulses, or highly chirped stretched pulses with almost 20 nm wide parabolic spectrum in both clockwise (CW) and counterclockwise (CCW) directions of the ring. Owing to the polarizing action in the cavity, we have demonstrated for the first time, to the best of our knowledge, an efficient tuning of soliton pulse characteristics for both CW and CCW channels via an appropriate polarization control. We believe that the bidirectional laser presented may be highly promising for gyroscopic and other dual-channel applications.

  16. Stable mode-locked operation of a low repetition rate diode-pumped Nd:GdVO4 laser by combining quadratic polarisation switching and a semiconductor saturable absorber mirror.

    Science.gov (United States)

    Gerhard, Christoph; Druon, Frédéric; Georges, Patrick; Couderc, Vincent; Leproux, Philippe

    2006-08-07

    In this paper, we present the mode-locked operation of an ultra-robustly stabilised Nd:GdVO(4) laser with low repetition rate by combining quadratic polarisation switching and a semiconductor saturable absorber mirror (SESAM). In addition, similar experiment was also done with Nd:YVO(4). For Nd:GdVO(4), 16-ps pulses at 1063 nm with a repetition rate of 3.95 MHz have been obtained for a laser average output power of 1.4 W. For Nd:YVO(4), the performance was 2.5 W of average power for 15-ps pulses at 1064 nm. Moreover, we demonstrate experimentally the advantage of combining these two passive mode locking techniques in terms of stability ranges. We show how the dual mode-locking technique is crucial to obtain a stable and long-term mode-locked regime in our case of a diode-pumped Nd:GdVO(4) laser operating at low repetition rate and more generally how this dual mode-locking technique improves the stability range of the mode-locked operation giving more flexibility on different parameters.

  17. Research of actively-passively mode-locked Nd:YAG laser pumped by pulse xenon lamp%主被动锁模脉冲氙灯抽运Nd:YAG激光器的研究

    Institute of Scientific and Technical Information of China (English)

    袁易君

    2011-01-01

    为了克服主动锁模脉冲能量低、被动调Q锁模稳定性差、锁模不完全的缺点,采用Cr:YAG和声光锁模器进行主被动联合锁模脉冲氙灯抽运的Nd:YAG激光器,实验验证和分析了Cr:YAG被动锁模,声光锁模器主动锁模及两者联合主被动锁模3种情况下输出脉冲的特性.结果表明,主被动联合锁模可得到200mJ输出能量、输出幅值和能量抖动小于±5%、锁模深度100%、脉宽小于450ps的1064nm锁模脉冲输出,腔外增加KTP倍频晶体,可得到约41%的转换效率的532nm稳定锁模脉冲输出.这一结果验证了主被动锁模技术的可行性,有利于锁模技术的进一步发展.%In order to resolve the low output energy of active mode-locked laser and instability of passive mode-locked laser,Cr4+ :YAG passive mode-locker and acousto-optic active mode-locker were used jointly for Nd:YAG laser mode-locking.The output characteristics of passively mode-locked by Cr4+ :YAG only, actively mode-locked by anousto-optic mode-locker only and mode-locked by Cr+ :YAG and acousto-optic jointly were analyzed and compared through experiments.Results showed that the joint mode-locking method gave good resolution to the low output energy and stability, and the mode-lock amplitude and energy fluctuation were less than ± 5%, with the depth of mode locking of 100%, pulse width less than 450ps and output energy near 200mJ at 1064nm wavelength.Adding KTP crystal out of the cavity, the output conversion efficiency was about 41% at 532nm wavelength.The results show the possibility of actively-passively mode-locked technology and it is helpful for the development of mode-locking technology.

  18. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Science.gov (United States)

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  19. 1030-nm diode-laser-based light source delivering pulses with nanojoule energies and picosecond duration adjustable by mode locking or pulse gating operation

    Science.gov (United States)

    Klehr, A.; Liero, A.; Wenzel, H.; Bugge, F.; Brox, O.; Fricke, J.; Ressel, P.; Knigge, A.; Heinrich, W.; Tränkle, G.

    2017-02-01

    A new compact 1030 nm picosecond light source which can be switched between pulse gating and mode locking operation is presented. It consists of a multi-section distributed Bragg reflector (DBR) laser, an ultrafast multisection optical gate and a flared power amplifier (PA), mounted together with high frequency electronics and optical elements on a 5×4 cm micro bench. The master oscillator (MO) is a 10 mm long ridge wave-guide (RW) laser consisting of 200 μm long saturable absorber, 1500 μm long gain, 8000 μm long cavity, 200 μm long DBR and 100 μm long monitor sections. The 2 mm long optical gate consisting of several RW sections is monolithically integrated with the 4 mm long gain-guided tapered amplifier on a single chip. The light source can be switched between pulse gating and passive mode locking operation. For pulse gating all sections of the MO (except of the DBR and monitor sections) are forward biased and driven by a constant current. By injecting electrical pulses into one section of the optical gate the CW beam emitted by the MO is converted into a train of optical pulses with adjustable widths between 250 ps and 1000 ps. Peak powers of 20 W and spectral linewidths in the MHz range are achieved. Shorter pulses with widths between 4 ps and 15 ps and peak powers up to 50 W but larger spectral widths of about 300 pm are generated by mode locking where the saturable absorber section of the MO is reversed biased. The repetition rate of 4.2 GHz of the pulse train emitted by the MO can be reduced to values between 1 kHz and 100 MHz by utilizing the optical gate as pulse picker. The pulse-to-pulse distance can be controlled by an external trigger source.

  20. Correlations between locked modes and impurity influxes

    Energy Technology Data Exchange (ETDEWEB)

    Fishpool, G.M. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Lawson, K.D. [UKAEA Culham Lab., Abingdon (United Kingdom)

    1994-07-01

    An analysis of pulses that were disturbed by medium Z impurity influxes (Cl, Cr, Fe and Ni) recorded during the 91/92 JET operations, has demonstrated that such influxes can result in MHD modes which subsequently ``lock``. A correlation is found between the power radiated by the influx and the time difference between the start of the influx and the beginning of the locked mode. The growth in the amplitude of the locked mode itself can lead to further impurity influxes. A correlation is noted between intense influxes (superior to 10 MW) and the mode ``unlocking``. (authors). 4 refs., 4 figs.

  1. Mid-infrared ultra-short mode-locked fiber laser utilizing topological insulator Bi2Te3 nano-sheets as the saturable absorber

    CERN Document Server

    Yin, Ke; Zheng, Xin; Yu, Hao; Cheng, Xiangai; Hou, Jing

    2015-01-01

    The newly-emergent two-dimensional topological insulators (TIs) have shown their unique electronic and optical properties, such as good thermal management, high nonlinear refraction index and ultrafast relaxation time. Their narrow energy band gaps predict their optical absorption ability further into the mid-infrared region and their possibility to be very broadband light modulators ranging from the visible to the mid-infrared region. In this paper, a mid-infrared mode-locked fluoride fiber laser with TI Bi2Te3 nano-sheets as the saturable absorber is presented. Continuous wave lasing, Q-switched and continuous-wave mode-locking (CW-ML) operations of the laser are observed sequentially by increasing the pump power. The observed CW-ML pulse train has a pulse repetition rate of 10.4 MHz, a pulse width of ~6 ps, and a center wavelength of 2830 nm. The maximum achievable pulse energy is 8.6 nJ with average power up to 90 mW. This work forcefully demonstrates the promising applications of two-dimensional TIs for ...

  2. Diode-pumped passively Q-switched and mode-locked Nd:YLF laser with Cr4+:YAG saturable absorber

    Institute of Scientific and Technical Information of China (English)

    Shudi Pan; Kezhen Han; Hongmei Wang; Xiuwei Fan; Jingliang He

    2006-01-01

    @@ A diode-pumped passively Q-switched Nd:YLF laser was demonstrated by using saturable absorber of Cr4+:YAG. At the incident power of 7.74 W, pure passively Q-switched laser with per pulse energy of 210 Μj and pulse width of 19.6 ns at repetition rate of 1.78 kHz was obtained by using Cr4+:YAG with initial transmission of 80%. At the incident power of 8.70 W, a Q-switched mode-locking with average output power of 650 Mw was achieved, the overall slop efficiency was 16%, corresponding to the initial transmission of 85% of Cr4+ :YAG.

  3. Self-organization of the Q-switched mode-locked regime in a diode-pumped Nd:YAG laser

    Science.gov (United States)

    Donin, V. I.; Yakovin, D. V.; Gribanov, A. V.

    2015-06-01

    A new Q-switched mode-locked generation regime of a solid-state laser, in which a Q-switch is "spontaneously" formed at the frequency of relaxation oscillations, has been observed for the first time. The new generation has been implemented by means of the previously proposed method of an acoustic modulator of a traveling wave in combination with a spherical mirror of a cavity. Stable pulse trains with a repetition frequency of ~30 kHz and a duration of ~2 µs have been observed in the diode-pump Nd:YAG laser with an average output power of ~3 W. Each train contains about 200 equispaced single pulses with a duration of ~45 ps.

  4. Handheld nonlinear microscope system comprising a 2 MHz repetition rate, mode-locked Yb-fiber laser for in vivo biomedical imaging.

    Science.gov (United States)

    Krolopp, Ádám; Csákányi, Attila; Haluszka, Dóra; Csáti, Dániel; Vass, Lajos; Kolonics, Attila; Wikonkál, Norbert; Szipőcs, Róbert

    2016-09-01

    A novel, Yb-fiber laser based, handheld 2PEF/SHG microscope imaging system is introduced. It is suitable for in vivo imaging of murine skin at an average power level as low as 5 mW at 200 kHz sampling rate. Amplified and compressed laser pulses having a spectral bandwidth of 8 to 12 nm at around 1030 nm excite the biological samples at a ~1.89 MHz repetition rate, which explains how the high quality two-photon excitation fluorescence (2PEF) and second harmonic generation (SHG) images are obtained at the average power level of a laser pointer. The scanning, imaging and detection head, which comprises a conventional microscope objective for beam focusing, has a physical length of ~180 mm owing to the custom designed imaging telescope system between the laser scanner mirrors and the entrance aperture of the microscope objective. Operation of the all-fiber, all-normal dispersion Yb-fiber ring laser oscillator is electronically controlled by a two-channel polarization controller for Q-switching free mode-locked operation. The whole nonlinear microscope imaging system has the main advantages of the low price of the fs laser applied, fiber optics flexibility, a relatively small, light-weight scanning and detection head, and a very low risk of thermal or photochemical damage of the skin samples.

  5. Gigahertz repetition rate, sub-femtosecond timing jitter optical pulse train directly generated from a mode-locked Yb:KYW laser

    CERN Document Server

    Yang, Heewon; Shin, Junho; Kim, Chur; Choi, Sun Young; Kim, Guang-Hoon; Rotermund, Fabian; Kim, Jungwon

    2014-01-01

    We show that a 1.13-GHz repetition rate optical pulse train with 0.70 fs high-frequency timing jitter (integration bandwidth of 17.5 kHz - 10 MHz, where the measurement instrument-limited noise floor contributes 0.41 fs in 10 MHz bandwidth) can be directly generated from a free-running, single-mode diode-pumped Yb:KYW laser mode-locked by single-walled carbon nanotube (SWCNT)-coated mirrors. To our knowledge, this is the lowest timing jitter optical pulse train with the GHz repetition rate ever measured. If this pulse train is used for direct sampling of 565-MHz signals (Nyquist frequency of the pulse train), the demonstrated jitter level corresponds to the projected effective-number-of-bit (ENOB) of 17.8, which is much higher than the thermal noise limit of 50-ohm load resistance (~14 bits).

  6. 4.5 W mid-infrared supercontinuum generation in a ZBLAN fiber pumped by a Q-switched mode-locked Tm3+- doped fiber laser

    Science.gov (United States)

    Kneis, C.; Donelan, B.; Berrou, A.; Manek-Hönninger, I.; Cadier, B.; Robin, T.; Poulain, M.; Joulain, F.; Eichhorn, M.; Kieleck, C.

    2015-02-01

    The generation of mid-infrared (mid-IR) supercontinuum (SC) radiation, ranging from 2 - 5 μm, is subject of intense research due to its wide range of applications. A very popular host media for mid-IR SC generation are soft glass fibers owing to their low-loss transmission in the mid-IR wavelength regime, particularly fluoride fibers are very attractive for high-power operation. In this research study, a diode-pumped Q-switched mode-locked (QML) thulium (Tm3+)-doped double-clad silica fiber laser is used to pump a ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber for mid-IR SC generation. The QML regime of the fiber laser is actively generated by two acousto-optic modulators. The Tm3+-fiber laser provided up to 23.5 W (26 W) of average output power in QML (continuous wave) regime with a slope efficiency of 36 % (32 %). The measured beam quality has been close to the diffraction-limit in QML regime. The system delivered mode-locked pulses with a duration of 7.5 ps, measured with a commercial autocorrelator system, at a repetition rate of 46 MHz. The Q-switched envelopes had a width between 50 and 150 ns depending on the output power level and the adjustable repetition rate. Mid-IR SC with an average output power in all spectral bands of 4.5 W have been achieved with more than 3 W/ 1.7 W/ 1 W/ 0.36 W after a long-wave-pass filter with a 3 dB-edge at 2.15 μm/ 2.65 μm/ 3.1 μm/ 3.5 μm.

  7. Experimental characterization of an all-optical wavelength converter of OFDM signals using two-mode injection-locking in a Fabry-Pérot laser.

    Science.gov (United States)

    Dang, Juntao; Yi, Xingwen; Zhang, Jing; Ye, Taiping; Xu, Bo; Qiu, Kun

    2016-07-25

    While optical OFDM has been demonstrated for superior transmission performance, its analogue waveform in the time domain challenges many conventional all-optical wavelength converters (AOWC) that are needed for future flexible optical networks. There only exist a few reports on AOWC of OFDM signals, which are mainly based on the low-efficient four-wave mixing. In this paper, we propose an AOWC for OFDM signals by using two-mode injection-locking in a low-cost Fabry-Pérot laser. The control signal and the probe signal at a milliwatt power level are combined and injected into the FP laser. By a proper control, they can be injection-locked to two longitudinal modes in the FP laser and subsequently, the transmission of the probe signal is conditioned by the control signal. We conduct an experimental study on various aspects of this AOWC. Despite a vendor-specified electrical-to-optical (E/O) modulation bandwidth of 2.5 GHz, we find that the optical-to-optical (O/O) modulation bandwidth of AOWC is free from this limit and can be much wider. We examine the linear transfer curve of the AOWC by simply using the OFDM waveforms as the stimulus. The performance tolerance to the wavelength detuning and injected power ratio is also measured. The proposed AOWC can provide a linear transfer function from the control signal to the probe signal to support the random-fluctuated OFDM waveform. We also investigate the maximum capacity of the AOWC by using the adaptive bit-loading OFDM. Finally, we measure the power penalty after the AOWC at two different bit rates to show the tradeoff between the penalty and capacity.

  8. Active Stabilization of a Diode Laser Injection Lock

    OpenAIRE

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

    2016-01-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudde...

  9. Active Stabilization of a Diode Laser Injection Lock

    OpenAIRE

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

    2016-01-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudde...

  10. Active Stabilization of a Diode Laser Injection Lock

    CERN Document Server

    Saxberg, Brendan; Gupta, Subhadeep

    2016-01-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.

  11. Active stabilization of a diode laser injection lock

    Science.gov (United States)

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

    2016-06-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.

  12. Self-mode-locking in erbium-doped fibre lasers with saturable polymer film absorbers containing single-wall carbon nanotubes synthesised by the arc discharge method

    Science.gov (United States)

    Tausenev, Anton V.; Obraztsova, Elena D.; Lobach, A. S.; Chernov, A. I.; Konov, Vitalii I.; Konyashchenko, Aleksandr V.; Kryukov, P. G.; Dianov, Evgenii M.

    2007-03-01

    We studied the ring and linear schemes of erbium-doped fibre lasers in which passive mode locking was achieved with the help of saturable absorbers made of high-optical quality films based on cellulose derivatives with dispersed single-wall carbon nanotubes. The films were prepared by the original method with the use of nanotubes synthesised by the arc discharge method. The films exhibit nonlinear absorption at a wavelength of 1.5 μm. Pulses in the form of optical solitons of duration 1.17 ps at a avelength of 1.56 μm were generated in the ring scheme of the erbium laser. The average output power was 1.1 mW at a pulse repetition rate of 20.5 MHz upon pumping by the 980-nm, 25-mW radiation from a laser diode. The pulse duration in the linear scheme was reduced to 466 fs for the output power up to 4 mW and a pulse repetition rate of 28.5 MHz. The specific feature of these lasers is a low pump threshold in the regime of generation of ultrashort pulses.

  13. Dual-central-wavelength passively mode-locked diffusion-bonded Nd:YVO4/Nd:GdVO4 laser with a semiconductor saturable absorber mirror

    Science.gov (United States)

    Chang, F. L.; Sung, C. L.; Huang, T. L.; Wu, T. W.; Cho, H. H.; Liang, H. C.; Chen, Y. F.

    2017-08-01

    A dual-central-wavelength passively mode-locked laser with full modulation in the 0.31 THz optical beating is achieved by using a diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal and a semiconductor saturable absorber mirror. The output power of the dual-band emission is well balanced by tuning the focal position of the pump waist. At a pump power of 13 W, the total output power is up to 2.7 W with a repetition rate of 297.9 MHz. The autocorrelation traces clearly reveal the synchronization of the dual-band emission. Moreover, an analytical model is developed to manifest the multi-pulse structure caused by the etalon effect of the gain medium. More important, we experimentally verify that the etalon effect can be completely eliminated by using the wedge-cut diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal.

  14. Ultrafast and widely tuneable vertical-external-cavity surface-emitting laser, mode-locked by a graphene-integrated distributed Bragg reflector.

    Science.gov (United States)

    Zaugg, C A; Sun, Z; Wittwer, V J; Popa, D; Milana, S; Kulmala, T S; Sundaram, R S; Mangold, M; Sieber, O D; Golling, M; Lee, Y; Ahn, J H; Ferrari, A C; Keller, U

    2013-12-16

    We report a versatile way of controlling the unsaturated loss, modulation depth and saturation fluence of graphene-based saturable absorbers (GSAs), by changing the thickness of a spacer between a single layer graphene (SLG) and a high-reflection mirror. This allows us to modulate the electric field intensity enhancement at the GSA from 0 up to 400%, due to the interference of incident and reflected light at the mirror. The unsaturated loss of the SLG-mirror-assembly can be reduced to ∼0. We use this to mode-lock a vertical-external-cavity surface-emitting laser (VECSEL) from 935 to 981 nm. This approach can be applied to integrate SLG into various optical components, such as output coupler mirrors, dispersive mirrors or dielectric coatings on gain materials. Conversely, it can also be used to increase the absorption (up to 10%) in various graphene based photonics and optoelectronics devices, such as photodetectors.

  15. Passively mode-locked fiber laser based on a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution.

    Science.gov (United States)

    Liu, Zhi-Bo; He, Xiaoying; Wang, D N

    2011-08-15

    We demonstrate a nanosecond-pulse erbium-doped fiber laser that is passively mode locked by a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution. Owing to the good solution processing capability of few-layered graphene oxide, which can be filled into the core of a hollow-core photonic crystal fiber through a selective hole filling process, a graphene saturable absorber can be successfully fabricated. The output pulses obtained have a center wavelength, pulse width, and repetition rate of 1561.2 nm, 4.85 ns, and 7.68 MHz, respectively. This method provides a simple and efficient approach to integrate the graphene into the optical fiber system.

  16. Nanosecond soliton pulse generation by mode-locked erbium-doped fiber laser using single-walled carbon-nanotube-based saturable absorber.

    Science.gov (United States)

    Ismail, Mohd Afiq; Harun, Sulaiman Wadi; Zulkepely, Nurul Rozullyah; Nor, Roslan Md; Ahmad, Fauzan; Ahmad, Harith

    2012-12-20

    We demonstrate a simple and low cost mode-locked erbium-doped fiber laser (EDFL) operating in the nanosecond region using a single-walled carbon nanotube (SWCNT)-based saturable absorber (SA). A droplet of SWCNT solution is applied on the end of a fiber ferrule, which is then mated to another clean connector ferrule to construct an SA. Then the SA is integrated into a ring EDFL cavity for nanosecond pulse generation. The EDFL operates at around 1570.4 nm, with a soliton-like spectrum with small Kelly sidebands, which confirms the attainment of the anomalous dispersion. It produces a soliton pulse train with a 332 ns width, repetition rate of 909.1 kHz, an average output power of 0.31 mW, and energy of 0.34 nJ at the maximum pump power of 130.8 mW.

  17. 200-fs mode-locked Erbium-doped fiber laser by using mechanically exfoliated MoS2 saturable absorber onto D-shaped optical fiber.

    Science.gov (United States)

    Aiub, Eduardo J; Steinberg, David; Thoroh de Souza, Eunézio A; Saito, Lúcia A M

    2017-05-01

    For the first time, we demonstrated the fabrication of mechanically exfoliated molybdenum disulfide (MoS2) samples deposited onto a D-shaped optical fiber. The MoS2 exfoliated flakes were deposited onto a stacked of 1.2 µm PVA (polyvinyl alcohol) and 300 nm PMMA (polymethyl methacrylate) layers and then transferred directly onto a side polished surface of D-shaped optical fiber with polishing length of 17 mm and no distance from the fiber core. The sample exhibited a high polarization performance as a polarizer with relative polarization extinction ratio of 97.5%. By incorporating the sample as a saturable absorber in the Erbium-doped fiber laser (EDFL), bandwidth of 20.5 nm and pulse duration of 200 fs were generated, which corresponded to the best mode-locking results obtained for all-fiber MoS2 saturable absorber at 1.5 µm wavelength.

  18. Observation of phase noise reduction in photonically synthesized sub-THz signals using a passively mode-locked laser diode and highly selective optical filtering

    DEFF Research Database (Denmark)

    Criado, A. R.; Acedo, P.; Carpintero, G.

    2012-01-01

    A Continuous Wave (CW) sub-THz photonic synthesis setup based on a single Passively Mode-Locked Laser Diode (PMLLD) acting as a monolithic Optical Frequency Comb Generator (OFCG) and highly selective optical filtering has been implemented to evaluate the phase noise performance of the generated sub......-THz signals. The analysis of the synthesized sub-THz signals up to 120 GHz gives as a result an effective reduction of the electrical linewidth when compared to direct harmonic generation that begins at 50 GHz and becomes greater as the frequency increases. The phase noise reduction offered by the setup......, along with its integration potential, cost and bandwidth, make it a promising candidate to the development of an integrated and high performance low phase noise local oscillator in the sub-THz range....

  19. A 31 mW, 280 fs passively mode-locked fiber soliton laser using a high heat-resistant SWNT/P3HT saturable absorber coated with siloxane.

    Science.gov (United States)

    Ono, Takato; Hori, Yuichiro; Yoshida, Masato; Hirooka, Toshihiko; Nakazawa, Masataka; Mata, Junji; Tsukamoto, Jun

    2012-10-08

    We report a substantial increase in the heat resistance in a connector-type single-wall carbon nanotube (SWNT) saturable absorber by sealing SWNT/P3HT composite with siloxane. By applying the saturable absorber to a passively mode-locked Er fiber laser, we successfully demonstrated 280 fs, 31 mW pulse generation with a fivefold improvement in heat resistance.

  20. Cavity spatial mode-locking and high controllability of radial output coupling for circular/square plasmonic nano-resonator lasers.

    Science.gov (United States)

    Chen, Xi; Huang, Yingyan; Ho, Seng-Tiong

    2015-02-01

    We proposed and investigated a novel output coupling scheme for a circular and a square plasmonic nano-ring laser based on a T-shaped radial coupler that is easier to realize than a tangential coupler. The amount of coupling efficiency is shown to be highly controllable from a few percent to tens of percents. This is due to the fact that the standing-wave lasing mode pattern will rotate to give the minimal cavity loss at the T-coupler's location, making the amount of output coupling surprisingly low and hence, controllable. For a non-circular cavity, other symmetry-breaking and geometry-induced scattering could result in separate mode-pattern locking. These give a few main ways to control and optimize the coupling efficiency: via widening/narrowing or rotating the T-coupler's waveguide, or, for the case of a non-circular cavity, via shifting the location of the T-coupler. We observed increased unidirectional lasing induced by either rotating the waveguide or shifting it (for non-circular cases). We simulated the coupling using Maxwell's equations based on the multi-level multi-electron FDTD (MLME-FDTD) method to realistically model the lasing and output coupling behaviors of such plasmonic semiconductor lasers.

  1. Mode-locked erbium-doped fiber laser based on evanescent field interaction with Sb{sub 2}Te{sub 3} topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Grodecki, K. [Faculty of Physics, University of Warsaw, Hoza 69, 00-681 Warsaw (Poland); Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)

    2014-06-23

    In this Letter, we demonstrate a mode-locked Er-doped fiber laser incorporating antimony telluride (Sb{sub 2}Te{sub 3}) topological insulator (TI) as a saturable absorber (SA). The laser was capable of generating 270 fs-short soliton pulses at 1560 nm wavelength, which are the shortest solitons generated with a TI-based saturable absorber so far. In order to form a saturable absorber, a bulk piece of Sb{sub 2}Te{sub 3} was deposited on a side-polished single-mode fiber with the presence of a low refractive index polymer. Such saturable absorber exhibits modulation depth at the level of 6% with less than 3 dB of non-saturable losses. Our study shows that TI-based saturable absorbers with evanescent field interaction might compete with SAs based on carbon nanomaterials, like graphene or nanotubes. Additionally, thanks to the interaction with the evanescent field, the material is not exposed to high optical power, which allows to avoid optical or thermal damage.

  2. High-quality and Large-size Topological Insulator Bi2Te3-Gold Saturable Absorber Mirror for Mode-Locking Fiber Laser

    Science.gov (United States)

    Chen, Hou-Ren; Tsai, Chih-Ya; Cheng, Hsin-Ming; Lin, Kuei-Huei; Yen, Po-Hsiu; Chen, Chyong-Hua; Hsieh, Wen-Feng

    2016-12-01

    A novel high-quality, large-size, reflection-type topological insulator Bi2Te3-Gold (BG) film-based nonlinear optical modulator has been successfully fabricated as a two-dimensional saturable absorber mirror (SAM) by pulsed laser deposition (PLD). This BG-SAM possesses saturation fluence of 108.3 μJ/cm2, modulation depth (ΔR) of 6.5%, non-saturable loss of 38.4%, high damage threshold above 1.354 mJ/cm2 and excellent uniformity providing for the generation of passive mode-locked (ML) pulses for erbium-doped fiber lasers (EDFLs) on a large sample area. Under 124 mW 976 nm pumping, We obtained 452-fs continuous-wave ML pulses with pulse energy of 91 pJ and full width at half-maximum (FWHM) of 6.72-nm from this EDFL. The results clearly evidence that the PLD is an efficient method for fabricating BG-SAM that is suitable for a compact ultrafast ML fiber laser system.

  3. Self-induced transparency mode-locking, and area theorem

    CERN Document Server

    Arkhipov, R M; Babushkin, I

    2015-01-01

    Self-induced transparency mode-locking (or coherent mode-locking, CML) which is based on intracavity self-induced transparency soliton dynamics, allows potentially to achieve nearly single cycle intracavity pulse durations, much below the phase relaxation time $T_2$ in a laser, which, despite of great promise, has not yet been realized experimentally. We develop a diagram technique which allows to predict the main features of CML regimes in a generic two-section laser. We show that CML can arise directly at the first laser threshold if the phase relaxation time is large enough. Furthermore, CML regimes can be unconditionally stable. We also predict the existence of ``super-CML regimes``, with a pulse coupled to several Rabi oscillations in the nonlinear medium.

  4. A technique for suppressing the super-mode noise of actively mode-locked fiber lasers%一种主动锁模光纤激光器超模噪声的抑制方法

    Institute of Scientific and Technical Information of China (English)

    薛天明; 朱广浩

    2015-01-01

    We introduce a technique to suppress the super-mode noise of actively mode-locked fiber lasers.This is achieved by driving the intra-cavity modulator with a RF signal and a feedback signal that is derived from the laser’s output.Using numerical simulations,we examine the effects of feedback loop gain,loop bandwidth,and loop delay on the extent of laser super-mode noise suppressions.Our results show that with proper choices of the loop parameters, the supper-mode noises of actively mode-locked fiber lasers can be suppressed by as much as 60 dB.%本文介绍了一种抑制主动锁模光纤激光器超模噪声的新方法.该方法采用基于光强信号的负反馈技术对激光器腔内的光脉冲能量进行动态调整,从而抑制激光脉冲的幅度抖动.通过仿真,讨论了负反馈回路的增益、带宽、和脉冲时延对激光器噪声抑制效果的影响.仿真结果表明通过合理地设置参数,本方法可以使激光器超模噪声的抑制比达到60 dB.

  5. Effect of beam expansion loss in a carbon nanotube-doped PVA film on passively mode-locked erbium-doped fiber lasers with different feedback ratios

    Science.gov (United States)

    Cheng, Kuang-Nan; Chi, Yu-Chieh; Cheng, Chih-Hsien; Lin, Yung-Hsiang; Lo, Jui-Yung; Lin, Gong-Ru

    2014-10-01

    The effect of beam expansion induced divergent loss in a single-wall carbon nanotube (SWCNT) doped polyvinyl alcohol (PVA) based ultrafast saturable absorber (SA) film thickness on the passive mode-locking (PML) performances of erbium-doped fiber lasers are demonstrated. The variation on the PML pulsewidth of the EDFL is discussed by changing the SWCNT-PVA SA film thicknesses, together with adjusting the pumping power and the intra-cavity feedback ratio. An almost 6 dB increment of divergent loss when enlarging the SWCNT-PVA based SA film thickness from 30-130 µm is observed. When shrinking the SA thickness to 30 µm at the largest pumping power of 52.5 mW, the optical spectrum red-shifts to 1558.8 nm with its 3 dB spectral linewidth broadening up to 2.7 nm, while the pulse has already entered the soliton regime with multi-order Kelly sidebands aside the spectral shoulder. The soliton pulsewidth is as short as 790 fs, which is much shorter than those obtained with other thicker SWCNT doped PVA polymer film based SAs; therefore, the peak power from the output of the PML-EDFL is significantly enlarged accompanied by a completely suppressed residual continuous-wave level to achieve the largest on/off extinction ratio. The main mechanism of pulse shortening with reducing thickness of SWCNT doped PVA polymer film based SA is attributed to the limited beam expansion as well as the enlarged modulation depth, which results in shortened soliton pulsewidth with a clean dc background, and broadened spectrum with enriched Kelly sidebands. The increase of total SWCNT amount in the thicker SA inevitably causes a higher linear absorption; hence, the mode-locking threshold also rises accordingly. By enlarging pumping power from 38.5-52.5 mW, the highest ascent on pulse extinction of up to 32 dB is observed among all kinds of feedback conditions. Nevertheless, the enlargement on the extinction slightly decays with increasing the feedback ratio from 30-90%, as

  6. Green Output of 1.5 W from a Diode-Pumped Intracavity Frequency-Doubled Self-Q-Switched and Mode-Locked Cr,Nd:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    DU Shi-Feng; WANG Su-Mei; ZHANG Dong-Xiang; LI De-Hua; ZHANG Zhi-Guo; FENG Bao-Hua; ZHANG Shi-Wen

    2007-01-01

    We report a diode-pumped intracavity frequency-doubled self-Q-switched and mode-locked Cr,Nd:YAG/KTP green laser with a Z-type cavity, which produces 1.5 W of average power at 532 nm with incident pump power 14.2 W. The individual mode-locked green pulse duration is about 560ps with 149MHz repetition rate. Almost 100% modulation depth of the mode-locked green pulses is achieved at an incident pump power of 4.13 W. The maximum energy of Q-switched green pulse is 19.8 fiJ. The experimental results of pulse duration and pulse energy of Q-switched green pulse agree well with the theoretical calculations.

  7. Observation of high-order polarization-locked vector solitons in a fiber laser.

    Science.gov (United States)

    Tang, D Y; Zhang, H; Zhao, L M; Wu, X

    2008-10-10

    We report on the experimental observation of a new type of polarization-locked vector soliton in a passively mode-locked fiber laser. The vector soliton is characterized by the fact that not only are the two orthogonally polarized soliton components phase-locked, but also one of the components has a double-humped intensity profile. Multiple phase-locked high-order vector solitons with identical soliton parameters and harmonic mode locking of the vector solitons were also obtained in the laser. Numerical simulations confirmed the existence of stable high-order vector solitons in the fiber laser.

  8. Dual-band wavelength tunable nonlinear polarization rotation mode-locked Erbium-doped fiber lasers induced by birefringence variation and gain curvature alteration.

    Science.gov (United States)

    Lin, Sheng-Fong; Lin, Gong-Ru

    2014-09-08

    With the combining effects of the fiber birefringence induced round-trip phase variation and the gain profile reshaping induced spectral filtering in the Erbium-doped fiber laser (EDFL) cavity, the mechanism corresponding to the central wavelength tunability of the EDFL passively mode-locked by nonlinear polarization rotation is explored. Bending the intracavity fiber induces the refractive index difference between orthogonal axes, which enables the dual-band central wavelength shift of 2.9 nm at 1570 nm region and up to 10.2 nm at 1600 nm region. The difference between the wavelength shifts at two bands is attributed to the gain dispersion decided by the gain spectral curvature of the EDFA, and the spacing between two switchable bands is provided by the birefringence induced variation on phase delay which causes transmittance variation. In addition, the central wavelength shift can also be controlled by varying the pumping geometry. At 1570 nm regime, an offset of up to 5.9 nm between the central wavelengths obtained under solely forward or backward pumping condition is observed, whereas the bidirectional pumping scheme effectively compensates the gain spectral reshaping effects to minimize the central wavelength shift. In contrast, the wavelength offset shrinks to only 1.1 nm when mode-locking at 1600 nm under single-sided pumping, as the gain profile strongly depends on the spatial distribution of the excited erbium ions under different pumping schemes. Except the birefringence variation and the gain spectral filtering phenomena, the gain-saturation mechanism induced refractive index change and its influence to the dual-band central wavelength tunability are also observed and analyzed.

  9. Intelligent Systems for Stabilizing Mode-Locked Lasers and Frequency Combs: Machine Learning and Equation-Free Control Paradigms for Self-Tuning Optics

    Directory of Open Access Journals (Sweden)

    Kutz J. Nathan

    2015-12-01

    Full Text Available We demonstrate that a software architecture using innovations in machine learning and adaptive control provides an ideal integration platform for self-tuning optics. For mode-locked lasers, commercially available optical telecom components can be integrated with servocontrollers to enact a training and execution software module capable of self-tuning the laser cavity even in the presence of mechanical and/or environmental perturbations, thus potentially stabilizing a frequency comb. The algorithm training stage uses an exhaustive search of parameter space to discover best regions of performance for one or more objective functions of interest. The execution stage first uses a sparse sensing procedure to recognize the parameter space before quickly moving to the near optimal solution and maintaining it using the extremum seeking control protocol. The method is robust and equationfree, thus requiring no detailed or quantitatively accurate model of the physics. It can also be executed on a broad range of problems provided only that suitable objective functions can be found and experimentally measured.

  10. Ultrashort Generation Regimes in the All-Fiber Kerr Mode-Locked Erbium-Doped Fiber Ring Laser for Terahertz Pulsed Spectroscopy

    Directory of Open Access Journals (Sweden)

    V. S. Voropaev

    2015-01-01

    Full Text Available Many femtosecond engineering applications require for a stable generation of ultrashort pulses. Thus, in the terahertz pulsed spectroscopy a measurement error in the refractive index is strongly dependent on the pulse duration stability with allowable variation of few femtoseconds. The aim of this work is to study the ultrashort pulses (USP regimes stability in the all – fiber erbium doped ring laser with Kerr mode-locking. The study was conducted at several different values of the total resonator intra-cavity dispersion. Three laser schemes with the intra-cavity dispersion values from -1.232 ps2 to +0.008 ps2 have been studied. In the experiment there were two regimes of generation observed: the stretched pulse generation and ordinary soliton generation. Main attention is focused on the stability of regimes under study. The most stable regime was that of the stretched pulse generation with a spectrum form of sech2 , possible pulse duration of 490 fs at least, repetition rate of 2.9 MHz, and average output power of 17 mW. It is worth noting, that obtained regimes had characteristics suitable for the successful use in the terahertz pulsed spectroscopy. The results may be useful in the following areas of science and technology: a high-precision spectroscopy, optical frequency standards, super-continuum generation, and terahertz pulsed spectroscopy. The future system development is expected to stabilize duration and repetition rate of the obtained regime of ultra-short pulse generation.

  11. Dissolution-and-reduction CVD synthesis of few-layer graphene on ultra-thin nickel film lifted off for mode-locking fiber lasers

    Science.gov (United States)

    Peng, Kaung-Jay; Lin, Yung-Hsiang; Wu, Chung-Lun; Lin, Sheng-Fong; Yang, Chun-Yu; Lin, Shih-Meng; Tsai, Din-Ping; Lin, Gong-Ru

    2015-01-01

    The in-situ dissolution-and-reduction CVD synthesized few-layer graphene on ultra-thin nickel catalyst film is demonstrated at temperature as low as 550 °C, which can be employed to form transmission-type or reflection-type saturable absorber (SA) for mode-locking the erbium-doped fiber lasers (EDFLs). With transmission-type graphene SA, the EDFL shortens its pulsewidth from 483 to 441 fs and broadens its spectral linewidth from 4.2 to 6.1 nm with enlarging the pumping current from 200 to 900 mA. In contrast, the reflection-type SA only compresses the pulsewidth from 875 to 796 fs with corresponding spectral linewidth broadened from 2.2 to 3.3 nm. The reflection-type graphene mode-locker increases twice of its equivalent layer number to cause more insertion loss than the transmission-type one. Nevertheless, the reflection-type based saturable absorber system can generate stabilized soliton-like pulse easier than that of transmission-type system, because the nonlinearity induced self-amplitude modulation depth is simultaneously enlarged when passing through the graphene twice under the retro-reflector design. PMID:26328535

  12. Dissolution-and-reduction CVD synthesis of few-layer graphene on ultra-thin nickel film lifted off for mode-locking fiber lasers

    Science.gov (United States)

    Peng, Kaung-Jay; Lin, Yung-Hsiang; Wu, Chung-Lun; Lin, Sheng-Fong; Yang, Chun-Yu; Lin, Shih-Meng; Tsai, Din-Ping; Lin, Gong-Ru

    2015-09-01

    The in-situ dissolution-and-reduction CVD synthesized few-layer graphene on ultra-thin nickel catalyst film is demonstrated at temperature as low as 550 °C, which can be employed to form transmission-type or reflection-type saturable absorber (SA) for mode-locking the erbium-doped fiber lasers (EDFLs). With transmission-type graphene SA, the EDFL shortens its pulsewidth from 483 to 441 fs and broadens its spectral linewidth from 4.2 to 6.1 nm with enlarging the pumping current from 200 to 900 mA. In contrast, the reflection-type SA only compresses the pulsewidth from 875 to 796 fs with corresponding spectral linewidth broadened from 2.2 to 3.3 nm. The reflection-type graphene mode-locker increases twice of its equivalent layer number to cause more insertion loss than the transmission-type one. Nevertheless, the reflection-type based saturable absorber system can generate stabilized soliton-like pulse easier than that of transmission-type system, because the nonlinearity induced self-amplitude modulation depth is simultaneously enlarged when passing through the graphene twice under the retro-reflector design.

  13. Synchronization of Fourier-Synthesized Optical Pulses to a Mode-Locked Optical Clock

    Institute of Scientific and Technical Information of China (English)

    Masaharu; Hyodo; Kazi; Sarwal; Abedin; Noriaki; Onodera; Masayoshi; Watanabe

    2003-01-01

    A Fourier-synthesized 40-GHz optical pulse train was successfully synchronized to an 8-GHz optical clock generated from a mode-locked fiber ring laser. The measured timing jitter of the synchronization was 0.43 ps.

  14. All-optical NOR gate based on injection-locking effect in a semiconductor laser

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A scheme for all-optical NOR logic gate is proposed based on injection-locking effect in a semiconductor laser. In this scheme, signal light injection into the laser will cause frequency shift of laser modes, as a result, the probe light into the laser can be switched between injection-locked and unlocked status, and its output power will be modulated. Theoretical analysis for this scheme is carried out by using a model to describe the dynamics of the injection-locked laser. By numerical simulation, the influence of laser bias current, laser length, injected signal power and signal frequency on the output performance of NOR logic gate is quantitatively analyzed.

  15. 41 GHz and 10.6 GHz low threshold and low noise InAs/InP quantum dash two-section mode-locked lasers in L band

    DEFF Research Database (Denmark)

    Dontabactouny, M.; Piron, R.; Klaime, K.

    2012-01-01

    This paper reports recent results on InAs/InP quantum dash-based, two-section, passively mode-locked lasers pulsing at 41 GHz and 10.6 GHz and emitting at 1.59 mu m at 20 degrees C. The 41-GHz device (1 mm long) starts lasing at 25 mA under uniform injection and the 10.6 GHz (4 mm long) at 71 mA....

  16. Stable Similariton Generation in an All-Fiber Hybrid Mode-Locked Ring Laser for Frequency Metrology.

    Science.gov (United States)

    Lazarev, Vladimir; Krylov, Alexander; Dvoretskiy, Dmitriy; Sazonkin, Stanislav; Pnev, Alexey; Leonov, Stanislav; Shelestov, Dmitriy; Tarabrin, Mikhail; Karasik, Valeriy; Kireev, Alexey; Gubin, Mikhail

    2016-07-01

    Ultrashort pulse lasers constitute an important tool in the emerging field of optical frequency metrology and are enabling unprecedented measurement capabilities and new applications in a wide range of fields, including precision spectroscopy, atomic clocks, ultracold gases, and molecular fingerprinting. We demonstrate the generation of stable 127-fs self-similar pulses at a central wavelength of 1560 nm with 7.14-mW average output power. Similariton lasers have a low repetition rate deviation in the averaging time interval [Formula: see text], a low relative intensity noise [Formula: see text] (30 Hz to 10 kHz), a narrow single comb line width of 32 kHz, and high reliability. Thus, such lasers are highly promising for further development of the stabilized combs and open up a robust and substantially simplified route to synthesizing low-noise microwaves.

  17. Nonlinear High-Energy Pulse Propagation in Graded-Index Multimode Optical Fibers for Mode-Locked Fiber Lasers

    Science.gov (United States)

    2014-12-23

    bels or specify how to translate the μ index into the p;m index pair. jAμzj2 represents the optical power in the LGpm mode. Fig. 1. GIMF of...crystal fiber,” Opt. Lett. 31, 1480–1482 (2006). 19. T. F. S. Büttner, D. D. Hudson, E. C. Mägi, A. Casas Bedoya, T. Taunay, and B. J. Eggleton

  18. Pulse generation and propagation in dispersion-managed ultralong erbium-doped fiber lasers mode-locked by carbon nanotubes.

    Science.gov (United States)

    Rosa, H G; Thoroh de Souza, E A

    2012-12-15

    We present a study of pulse generation and propagation in erbium-doped fiber lasers with cavity length varying from 8 m to 3.5 km. We demonstrate that soliton effect determines the pulse stabilization in ultralong cavities, measuring pulses with an average 7.0 ps pulsewidth for cavity lengths between 2.25 and 3.5 km. We also demonstrate that, by filling fundamental soliton requirements, pulsewidth can be determined by length and total dispersion cavity parameters.

  19. High power coherent polarization locked laser diode.

    Science.gov (United States)

    Purnawirman; Phua, P B

    2011-03-14

    We have coherently combined a broad area laser diode array to obtain high power single-lobed output by using coherent polarization locking. The single-lobed coherent beam is achieved by spatially combining four diode emitters using walk-off crystals and waveplates while their phases are passively locked via polarization discrimination. While our previous work focused on coherent polarization locking of diode in Gaussian beams, we demonstrate in this paper, the feasibility of the same polarization discrimination for locking multimode beams from broad area diode lasers. The resonator is designed to mitigate the loss from smile effect by using retro-reflection feedback in the cavity. In a 980 nm diode array, we produced 7.2 W coherent output with M2 of 1.5x11.5. The brightness of the diode is improved by more than an order of magnitude.

  20. Locked modes and magnetic field errors in MST

    Energy Technology Data Exchange (ETDEWEB)

    Almagri, A.F.; Assadi, S.; Prager, S.C.; Sarff, J.S.; Kerst, D.W.

    1992-06-01

    In the MST reversed field pinch magnetic oscillations become stationary (locked) in the lab frame as a result of a process involving interactions between the modes, sawteeth, and field errors. Several helical modes become phase locked to each other to form a rotating localized disturbance, the disturbance locks to an impulsive field error generated at a sawtooth crash, the error fields grow monotonically after locking (perhaps due to an unstable interaction between the modes and field error), and over the tens of milliseconds of growth confinement degrades and the discharge eventually terminates. Field error control has been partially successful in eliminating locking.

  1. Sub-nanometer tuning of mode-locked pulse by mechanical strain on tapered fiber

    Science.gov (United States)

    Ahmad, Harith; Faruki, Md Jahid; Tiu, Zian Cheak; Thambiratnam, K.

    2017-03-01

    A tunable mode-locked fiber laser based on the non-linear polarization rotation (NPR) technique is proposed and demonstrated. A passively generated mode-locked output is obtained with a repetition rate of about 70 ns and an average output power of 0.7 mW, as well as a laser efficiency of 0.53%. The mode-locked pulses can be tuned over a span of 4.4 nm, from 1560.6 nm to 1556.2, corresponding to a stretching of the tapered fiber from 0 to 100 μm in 10 μm increments. The pulses have an average signal-to-noise ratio of about 41 dB in the frequency domain, indicating a highly stable mode-locked output. The system can repeat and reverse the generation of these pulses, a crucial criterion of many communications and sensing applications.

  2. Kerr-lens Mode Locking Without Nonlinear Astigmatism

    CERN Document Server

    Yefet, Shi; Pe'er, Avi

    2013-01-01

    We demonstrate a Kerr-lens mode locked folded cavity using a planar (non-Brewster) Ti:sapphire crystal as a gain and Kerr medium, thus cancelling the nonlinear astigmatism caused by a Brewster cut Kerr medium. Our method uses a novel cavity folding in which the intra-cavity laser beam propagates in two perpendicular planes such that the astigmatism of one mirror is compensated by the other mirror, enabling the introduction of an astigmatic free, planar-cut gain medium. We demonstrate that this configuration is inherently free of nonlinear astigmatism, which in standard cavity folding needs a special power specific compensation.

  3. Phase locking of lasers with intracavity polarization elements.

    Science.gov (United States)

    Ronen, E; Fridman, M; Nixon, M; Friesem, A A; Davidson, N

    2008-10-15

    New configurations for phase locking several laser beams with intracavity polarization elements are presented. With this configuration we demonstrated efficient phase lock of up to 24 ND:YAG laser beams with only two polarization beam displacers.

  4. 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...

  5. Real-time Detection of Locked Modes

    Science.gov (United States)

    Angelini, S.; Granetz, R. S.; Wolfe, S. M.

    2007-11-01

    Disruptions are one of the largest problems facing tokamaks. In a large-scale experiment such as ITER, disruptions would cause crippling damage and severe setbacks in experimentation. One method for disruption mitigation involves the use of a gas jet which has been tested on both normally running plasmas and vertical displacement events (VDEs) on Alcator C-Mod. In both cases, the jet was successful in mitigating disruption effects. The gas jet has not yet been tested on other types of disruptions. Locked-mode major disruptions are easily created in C-Mod and could be used to test the effectiveness of the gas jet as a mitigation method if the jet could be fired early enough. It has been empirically observed that the electron cyclotron emissions (ECE) signal displays a flattening of the normally-present sawteeth before the current quench occurs in certain locked-mode major disruptions. A procedure is being written which will detect the ECE flattening by reading changes in the standard deviation of the signal. This procedure will be programmed into the digital plasma control system (DPCS) for real-time testing.

  6. Mode-locking in nonlinear rotordynamics

    Science.gov (United States)

    van der Heijden, G. H. M.

    1995-05-01

    We present a computer-assisted study of the dynamics of two nonlinearly coupled driven oscillators with rotational symmetry which arise in rotordynamics (the nonlinearity coming from bearing clearance). The nonlinearity causes a splitting of the twofold degenerate natural frequency of the associated linear model, leading to three interacting frequencies in the system. Partial mode-locking then yields a biinfinite series of attracting invariant 2-tori carrying (quasi-) periodic motion. Due to the resonance nature, the (quasi-) periodic solutions become periodic in a corotating coordinate system. They can be viewed as entrainments of periodic solutions of the associated linear problem. One presumably infinite family is generated by (scaled) driving frequencies ω = 1+2/ n, n = 1,2,3,...; another one is generated by frequencies ω = m, m = 4,5,6,... Both integers n and m can be related to discrete symmetry properties of the particular periodic solutions. Under a perturbation that breaks the rotational symmetry, more complicated behavior is possible. In particular, a second rational relation between the frequencies can be established, resulting in fully mode-locked periodic motion.

  7. Can one passively phase lock 25 fiber lasers?

    CERN Document Server

    Fridman, Moti; Davidson, Nir; Friesem, Asher A

    2010-01-01

    Yes, it is possible to phase lock 25 fiber lasers but only for a short time. Our experiments on passively phase locking two-dimensional arrays of coupled fiber lasers reveal that the average phase locking level of 25 lasers is low ($20%-30%$) but can exceed 90% on rare instantaneous events. The average phase locking level was found to decrease for larger number of lasers in the array and increase with the connectivity of the array.

  8. Anapole nanolasers for mode-locking and ultrafast pulse generation

    KAUST Repository

    Gongora, Juan S. Totero

    2017-05-31

    Nanophotonics is a rapidly developing field of research with many suggestions for a design of nanoantennas, sensors and miniature metadevices. Despite many proposals for passive nanophotonic devices, the efficient coupling of light to nanoscale optical structures remains a major challenge. In this article, we propose a nanoscale laser based on a tightly confined anapole mode. By harnessing the non-radiating nature of the anapole state, we show how to engineer nanolasers based on InGaAs nanodisks as on-chip sources with unique optical properties. Leveraging on the near-field character of anapole modes, we demonstrate a spontaneously polarized nanolaser able to couple light into waveguide channels with four orders of magnitude intensity than classical nanolasers, as well as the generation of ultrafast (of 100 fs) pulses via spontaneous mode locking of several anapoles. Anapole nanolasers offer an attractive platform for monolithically integrated, silicon photonics sources for advanced and efficient nanoscale circuitry.

  9. Picosecond pulses of variable duration from a high-power passively mode-locked Nd:YVO(4) laser free of spatial hole burning.

    Science.gov (United States)

    Nadeau, Marie-Christine; Petit, Stéphane; Balcou, Philippe; Czarny, Romain; Montant, Sébastien; Simon-Boisson, Christophe

    2010-05-15

    We report on a high-power passively mode-locked TEM(00)Nd:YVO(4) oscillator, 888 nm diode-pumped, with pulse durations adjustable between 46 ps and 12 ps. The duration tunability was obtained by varying the output coupler (OC) transmission while avoiding resorting to spatial hole burning (SHB) for pulse shortening. At a repetition rate of 91 MHz and for an output power ranging from 15 Wto45 W, we produced SHB-free 12-ps-to32-ps-long pulses. Within this range of power, these are the shortest pulse durations obtained directly from Nd:YVO(4) oscillators.

  10. 50-GHz repetition-rate, 280-fs pulse generation at 100-mW average power from a mode-locked laser diode externally compressed in a pedestal-free pulse compressor

    Science.gov (United States)

    Tamura, Kohichi R.; Sato, Kenji

    2002-07-01

    280-fs pedestal-free pulses are generated at average output powers exceeding 100 mW at a repetition rate of 50 GHz by compression of the output of a mode-locked laser diode (MLLD) by use of a pedestal-free pulse compressor (PFPC). The MLLD consists of a monolithically integrated chirped distributed Bragg reflector, a gain section, and an electroabsorption modulator. The PFPC is composed of a dispersion-flattened dispersion-decreasing fiber and a dispersion-flattened dispersion-imbalanced nonlinear optical loop mirror. Frequency modulation for linewidth broadening is used to overcome the power limitation imposed by stimulated Brillouin scattering.

  11. Exploring transverse pattern formation in a dual-polarization self-mode-locked monolithic Yb: KGW laser and generating a 25-GHz sub-picosecond vortex beam via gain competition.

    Science.gov (United States)

    Chang, M T; Liang, H C; Su, K W; Chen, Y F

    2016-04-18

    Formation of transverse modes in a dual-polarization self-mode-locked monolithic Yb: KGW laser under high-power pumping is thoroughly explored. It is experimentally observed that the polarization-resolved transverse patterns are considerably affected by the pump location in the transverse plane of the gain medium. In contrast, the longitudinal self-mode-locking is nearly undisturbed by the pump position, even under the high-power pumping. Under central pumping, a vortex beam of the Laguerre-Gaussian LGp,l mode with p = 1 and l = 1 can be efficiently generated through the process of the gain competition with a sub-picosecond pulse train at 25.3 GHz and the output power can be up to 1.45 W at a pump power of 10.0 W. Under off-center pumping, the symmetry breaking causes the transverse patterns to be dominated by the high-order Hermite-Gaussian modes. Numerical analyses are further performed to manifest the symmetry breaking induced by the off-center pumping.

  12. Development and commercialization of mode-locked VECSELs

    Science.gov (United States)

    Hempler, Nils; Bialkowski, Bartlomiej; Hamilton, Craig J.; Maker, Gareth T.; Malcolm, Graeme P. A.

    2015-03-01

    This paper will describe the current state-of-the-art in commercial mode-locked Vertical External Cavity Surface Emitting Lasers (VECSEL) and demonstrate their efficacy in key applications. Based on indium gallium arsenide quantum well gain structures, our systems operate between 920 nm - 1050 nm with >1 W output powers, 200 MHz pulse repetition rate and duration. Crucially, the development issues that have been overcome to bring this promising technology to market will be discussed. These include: thermal management challenges, electronic control system development and robust mechanical design requirements. Having the potential to replace more conventional titanium sapphire laser technology where wavelength flexibility can be traded off against a significantly lower cost point and form factor, we will discuss the use of VECSELs in key applications such as nonlinear microscopy.

  13. Group velocity locked vector dissipative solitons in a high repetition rate fiber laser

    CERN Document Server

    Luo, Yiyang; Li, Lei; Sun, Qizhen; Wu, Zhichao; Xu, Zhilin; Fu, Songnian; Zhao, Luming

    2016-01-01

    Vectorial nature of dissipative solitons (DSs) with high repetition rates is studied for the first time in a normal-dispersion fiber laser. Despite the fact that the formed DSs are strongly chirped and the repetition rate is greater than 100 MHz, polarization locked and polarization rotating group velocity locked vector DSs can be formed under 129.3 MHz fundamental mode-locking and 258.6 MHz harmonic mode-locking of the fiber laser, respectively. The two orthogonally polarized components of these vector DSs possess distinctly different central wavelengths and travel together at the same group velocity in the laser cavity, resulting in a gradual spectral edge and small steps on the optical spectra, which can be considered as an auxiliary indicator of the group velocity locked vector DSs.

  14. Ultrashort Pulse Generation at Quasi-40-GHz by Using a Two-Section Passively Mode-Locked InGaAsP-InP Tensile Strained Quantum-Well Laser

    Institute of Scientific and Technical Information of China (English)

    KONG Duan-Hua; ZHU Hong-Liang; LIANG Song; QIU Ji-Fang; ZHAO Ling-Juan

    2012-01-01

    A 1.56 μm passively mode-locked laser diode with a two-section tensile strained multi-quantum-well structure is fabricated.Without any external pulse compression,a Lorentz pulse train with a pulse width of 1.03 ps and a repetition rate of 35.6 GHz is obtained,which is one of the best results that have been reported on similar devices.The optical pulse has a 300 kHz line width and a 50dB peak over the noise floor in the photodetected radio-frequency electrical spectrum.%A 1.56μm passively mode-locked laser diode with a two-section tensile strained multi-quantum-well structure is fabricated. Without any external pulse compression, a Lorentz pulse train with a pulse width of 1.03ps and a repetition rate of 35.6 GHz is obtained, which is one of the best results that have been reported on similar devices. The optical pulse has a 300 kHz line width and a 50 dB peak over the noise floor in the photodetected radio-frequency electrical spectrum.

  15. Tolerances for Phase Locking of Semiconductor Laser Arrays.

    Science.gov (United States)

    1988-04-18

    laser fabrication . This means that the starting material is critically important to tne success of locked laser arrays. F. TOLERANCE REQUIREMENTS ON...typically r , 0.1. Because Eq. (7) represents a small frequency deviation, and implies A - 0.5 4, this report will look into the tolerances on laser ... fabrication and operation to ensure that the free-running laser frequencies remain within this locking range. D. COMPARISON OF LOCKING CONDITION WITH

  16. High peak-power picosecond pulse generation at 1.26 µm using a quantum-dot-based external-cavity mode-locked laser and tapered optical amplifier.

    Science.gov (United States)

    Ding, Y; Aviles-Espinosa, R; Cataluna, M A; Nikitichev, D; Ruiz, M; Tran, M; Robert, Y; Kapsalis, A; Simos, H; Mesaritakis, C; Xu, T; Bardella, P; Rossetti, M; Krestnikov, I; Livshits, D; Montrosset, Ivo; Syvridis, D; Krakowski, M; Loza-Alvarez, P; Rafailov, E

    2012-06-18

    In this paper, we present the generation of high peak-power picosecond optical pulses in the 1.26 μm spectral band from a repetition-rate-tunable quantum-dot external-cavity passively mode-locked laser (QD-ECMLL), amplified by a tapered quantum-dot semiconductor optical amplifier (QD-SOA). The laser emission wavelength was controlled through a chirped volume Bragg grating which was used as an external cavity output coupler. An average power of 208.2 mW, pulse energy of 321 pJ, and peak power of 30.3 W were achieved. Preliminary nonlinear imaging investigations indicate that this system is promising as a high peak-power pulsed light source for nonlinear bio-imaging applications across the 1.0 μm - 1.3 μm spectral range.

  17. Watt-level, all-fiber, ultrafast Er/Yb-codoped double-clad fiber laser mode-locked by reduced graphene oxide interacting with a weak evanescent field

    CERN Document Server

    Gao, Lei; Li, Yujia

    2015-01-01

    We propose a Watt-level, all-fiber, ultrafast Er/Yb-codoped double-clad fiber laser passively mode-locked by reduced graphene oxide (rGO) interacting with a weak evanescent field of photonic crystal fiber (PCF). The rGO solution is filled into the cladding holes of the PCF based on total reflection, and after evaporation, the rGO flakes bear only 1/107 of the total energy in laser system, which enhances the thermal damage threshold and decreases the accumulated nonlinearity. By incorporating the saturable absorber into an Er/Yb-codoped fiber ring cavity, stable conventional soliton with a duration of 573 fs is generated, and a average output power up to 1.14 W is obtained.

  18. Power Enhancement Cavity for Burst-Mode Laser Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yun [ORNL

    2015-01-01

    We demonstrate a novel optical cavity scheme and locking method that can realize the power enhancement of picosecond UV laser pulses operating at a burst mode with arbitrary burst (macropulse) lengths and repetition rates.

  19. Fast Offset Laser Phase-Locking System

    Science.gov (United States)

    Shaddock, Daniel; Ware, Brent

    2008-01-01

    Figure 1 shows a simplified block diagram of an improved optoelectronic system for locking the phase of one laser to that of another laser with an adjustable offset frequency specified by the user. In comparison with prior systems, this system exhibits higher performance (including higher stability) and is much easier to use. The system is based on a field-programmable gate array (FPGA) and operates almost entirely digitally; hence, it is easily adaptable to many different systems. The system achieves phase stability of less than a microcycle. It was developed to satisfy the phase-stability requirement for a planned spaceborne gravitational-wave-detecting heterodyne laser interferometer (LISA). The system has potential terrestrial utility in communications, lidar, and other applications. The present system includes a fast phasemeter that is a companion to the microcycle-accurate one described in High-Accuracy, High-Dynamic-Range Phase-Measurement System (NPO-41927), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 22. In the present system (as in the previously reported one), beams from the two lasers (here denoted the master and slave lasers) interfere on a photodiode. The heterodyne photodiode output is digitized and fed to the fast phasemeter, which produces suitably conditioned, low-latency analog control signals which lock the phase of the slave laser to that of the master laser. These control signals are used to drive a thermal and a piezoelectric transducer that adjust the frequency and phase of the slave-laser output. The output of the photodiode is a heterodyne signal at the difference between the frequencies of the two lasers. (The difference is currently required to be less than 20 MHz due to the Nyquist limit of the current sampling rate. We foresee few problems in doubling this limit using current equipment.) Within the phasemeter, the photodiode-output signal is digitized to 15 bits at a sampling frequency of 40 MHz by use of the same analog

  20. Generation of Stable Picosecond Chirp-Free Pulses at 10 GHz from a Nonpolarization Maintaining Regeneratively Mode-Locked Fibre Laser

    Institute of Scientific and Technical Information of China (English)

    TAN Bin; LI Zhi-Yong; WANG Zhao-Ying; GE Chun-Feng; JIA Dong-Fang; NI Wen-Jun; LI Shi-Chen

    2004-01-01

    @@ A 10 GHz regeneratively mode-lockedfibre laser (RMLFL) at 1550nm constructed with commercially available radio frequency components is presented. Chirp-free hyperbolic secant pulses with duration from 4.4ps to 8ps and output reaching 3.6 mW are acquired. Without any cavity length or polarization maintaining mechanism,the error-free operation of this RMLFL can be carried out in room temperature.

  1. Laser Metrology Heterodyne Phase-Locked Loop

    Science.gov (United States)

    Loya, Frank; Halverson, Peter

    2009-01-01

    A method reduces sensitivity to noise in a signal from a laser heterodyne interferometer. The phase-locked loop (PLL) removes glitches that occur in a zero-crossing detector s output [that can happen if the signal-to-noise ratio (SNR) of the heterodyne signal is low] by the use of an internal oscillator that produces a square-wave signal at a frequency that is inherently close to the heterodyne frequency. It also contains phase-locking circuits that lock the phase of the oscillator to the output of the zero-crossing detector. Because the PLL output is an oscillator signal, it is glitch-free. This enables the ability to make accurate phase measurements in spite of low SNR, creates an immunity to phase error caused by shifts in the heterodyne frequency (i.e. if the target moves causing Doppler shift), and maintains a valid phase even when the signal drops out for brief periods of time, such as when the laser is blocked by a stray object.

  2. Frequency locking of an erbium-doped fiber ring laser to an external fiber Fabry-Perot resonator

    OpenAIRE

    Park, Namkyoo; Dawson, Jay W.; Vahala, Kerry J.

    1993-01-01

    An all-fiber, single-frequency, erbium-doped ring laser has been frequency locked to a resonance peak of an external fiber Fabry-Perot resonator by the Pound-Drever technique. In addition, feedback to the mode selection filter in the laser resonator eliminates occasional mode hopping completely, resulting in frequency-locked, stable, single-frequency operation of the laser for periods of several hours.

  3. 采用不同可饱和吸收体的Nd:YAG激光器的锁模运转%Mode-locked operation of a Nd:YAG laser with the different saturable absorber

    Institute of Scientific and Technical Information of China (English)

    王加贤; 张文珍

    2001-01-01

    In this paper,we report that the mode-locked operation of a flashlamp-pumped Nd:YAG laser was realized and a single pulse train was obtained,using the pentamethine cyanine,Cr4+:YAG and LiF:F-2 as saturable absorber respectively.We also separately analyse the mode-locked mechanism and progress resulted from the excited-state saturable absorption of Cr4+:YAG and the self-focus effect of Nd:YAG with LiF:F-2 as Q-switch.The theoretical analysis accords with experimental results.%本文报道采用五甲川染料、Cr4+:YAG和LiF:F-2分别作为可饱和吸收体实现闪光灯泵浦的Nd:YAG激光器的锁模运转,得到稳定的单脉冲序列。着重分析了Cr4+:YAG激发态吸收饱和导致的被动锁模以及在LiF:F-2调Q下Nd:YAG的自聚焦引起的锁模运转机制和锁模过程,理论分析与实验结果一致。

  4. Single-frequency, single-polarization ytterbium-doped fiber laser by self-injection locking

    Institute of Scientific and Technical Information of China (English)

    Anting Wang(王安廷); Hai Ming(明海); Feng Li(李锋); Lixin Xu(许立新); Liang Lü(吕亮); Huaqiao Gui(桂华侨); Jing Huang(黄晶); Jianping Xie(谢建平)

    2004-01-01

    We demonstrated a stable single-frequency, single-polarization operation of ytterbium-doped fiber laser. As a novel practical method to realize single-polarization operation of fiber distributed Bragg reflector (DBR)laser, we proposed self-injection locking (SIL) with an active fiber ring feedback cavity. The laser has high output power exceeding 15 mW, wavelength of 1053.20 nm, and side-mode suppression ratio greater than 60 dB. The SIL fiber laser shows the improvements in output power and side-mode suppression compared with the fiber DBR laser. No mode-hopping is observed within 2 hours.

  5. External laser locking using a pressure-tunable microbubble resonator

    CERN Document Server

    Madugani, Ramgopal; Le, Vu H; Ward, Jonathan M; Chormaic, Síle Nic

    2015-01-01

    The tunability of an optical cavity is an essential requirement for many areas of research especially for the rapidly progressing field of photonics. In particular, low-cost laser tuning methods and miniaturization of the optical components are desirable. By applying aerostatic pressure to the interior surface of a microbubble resonator, optical mode shift rates of around $58$ GHz/MPa are achieved. The micobubble can measure pressure with a limit of detection of $2\\times 10^{-4}$ MPa. Here we use the Pound-Drever-Hall technique, whereby a laser is locked to a whispering gallery mode (WGM) of the microbubble resonator, to show that linear tuning of the WGM and the corresponding locked laser display almost zero hysteresis. The long-term frequency stability of this tuning method for different input pressures is measured. The frequency noise of the WGM, measured over 10 minutes, with a maximum input pressure of 0.5 MPa has a standard deviation of 36 MHz.

  6. Effects of flake size on mode-locking behavior for flake-graphene saturable absorber mirrors

    CERN Document Server

    Hussain, M I; Booth, L S; Petrasiunas, M J; Brown, C L; Kielpinski, D

    2016-01-01

    After advent of graphene as a saturable absorber many experiments have been conducted to produce short pulse duration pulses. Here, we have measured the properties of flake-graphene saturable absorber mirrors of various flake sizes dependent on fabrication technique. These mirrors enabled us to obtain a large mode-locking bandwidth of 16nm in an erbium-doped fiber laser. Mirrors with large flake size and multi-layered thickness induce strong pulse shaping and reflect mode-locked train of pulses with very large bandwidths.

  7. A comparative study on dual colour soft aperture cascaded second-order mode-locking with different nonlinear optical crystals

    Indian Academy of Sciences (India)

    Shyamal Mondal; Satya Pratap Singh; Sourabh Mukhopadhyay; Aditya Date; Kamal Hussain; Shouvik Mukherjee; Prasanta Kumar Datta

    2014-02-01

    A comparative study in terms of optimized output power and stability is made on cascaded second-order nonlinear optical mode-locking with KTP, BBO and LBO crystals for both 1064 nm and 532 nm. Large nonlinear optical phase shift achieved in a non-phase-matched second harmonic generating crystal, is transformed into amplitude modulation through soft aperturing the nonlinear cavity mode variation at the laser gain medium to mode-lock a Nd:YVO4 laser. The laser delivers stable dual wavelength cw mode-locked pulse train with pulse duration 10.3 ps and average power of 1.84 W and 255 mW at 1064 nm and 532 nm respectively for the optimum performance in type-II KTP crystal. The exceptional stability achieved with KTP is accounted by simulating the mode-size variation with phase mismatch.

  8. Experiment Study on Active-passive Mode-locking Using Cr4+∶YAG as Saturable Absorber

    Institute of Scientific and Technical Information of China (English)

    LENG Yuxin; LU Haihe; LIN Lihuang; XU Zhizhan

    2002-01-01

    Cr4+∶YAG crystal was used as a saturable absorber in an active-passive mode-locked Nd∶YAG laser. The stable and complete mode-locked pulse train was achieved at 1064 nm. The duration of ~0.8 ns to 2.4 ns for a single pulse was obtained by using Cr4+∶YAG crystals with the different initial transmissions, and there was a shortest pulse width. The mode-locking dynamic process of Cr4+∶YAG crystal was discussed to explain the experimental result, and the effect of excited-state absorption was considered.

  9. High-power 200 fs Kerr-lens mode-locked Yb:YAG thin-disk oscillator.

    Science.gov (United States)

    Pronin, O; Brons, J; Grasse, C; Pervak, V; Boehm, G; Amann, M-C; Kalashnikov, V L; Apolonski, A; Krausz, F

    2011-12-15

    We demonstrate a power-scalable Kerr-lens mode-locked Yb:YAG thin-disk oscillator. It delivers 200 fs pulses at an average power of 17 W and a repetition rate of 40 MHz. At an increased (180 W) pump power level, the laser produces 270 fs 1.1 μJ pulses at an average power of 45 W (optical-to-optical efficiency of 25%). Semiconductor-saturable-absorber-mirror-assisted Kerr-lens mode locking (KLM) and pure KLM with a hard aperture show similar performance. To our knowledge, these are the shortest pulses achieved from a mode-locked Yb:YAG disk oscillator and this is the first demonstration of a Kerr-lens mode-locked thin-disk laser.

  10. Phase-locking-level statistics of coupled random fiber lasers.

    Science.gov (United States)

    Fridman, Moti; Pugatch, Rami; Nixon, Micha; Friesem, Asher A; Davidson, Nir

    2012-10-01

    We measure the statistics of phase locking levels of coupled fiber lasers with fluctuating cavity lengths. We found that the measured distribution of the phase locking level of such coupled lasers can be described by the generalized extreme value distribution. For large number of lasers the distribution of the phase locking level can be approximated by a Gumbel distribution. We present a simple model, based on the spectral response of coupled lasers, and the calculated results are in good agreement with the experimental results.

  11. Q-switched and Mode-locked Characteristics of Cr4+:YAG Crystal

    Institute of Scientific and Technical Information of China (English)

    TIAN Wen-miao; YANG Feng; GAO Li-yan; WANG Guang-gang; LIU Shi-hua; LIU Jie

    2006-01-01

    The passively Q-switched and mode-locked(QML) characteristics in a diode-pumped Nd:GdVO4 laser with Cr4+:YAG saturable absorbers have been demonstrated. A maximum average output power of 710 mW has been obtained in the QML laser. The maximum energy of a single Q-switched pulse is 52.5 μJ,with the corresponding pulse width of 30 ns and the peak power of 1.75 kW,at the incident pump power of 7.75 W. The repetition rates of the Q-switched envelope and the mode-locked laser pulse are 16.7 kHz and 680 MHz,respectively.

  12. 基于锁模脉冲泵浦的全光纤化超连续谱光源%All-fiber supercontinuum laser source pumped by mode-locked pulse

    Institute of Scientific and Technical Information of China (English)

    王雄飞; 李尧; 朱辰; 张昆; 张利明; 张浩斌; 郝金坪; 张大勇; 赵鸿

    2016-01-01

    采用基于半导体可饱和吸收镜(SESAM)的被动锁模方案,通过三级主振荡功率放大(MOPA)结构,构建了平均输出功率39.2 W 的全光纤皮秒脉冲光纤激光器。输出激光脉冲宽度10.7 ps,重复频率68 MHz。利用该皮秒光纤激光器泵浦一段4.5 m 长的国产光子晶体光纤(PCF),实现了平均功率20.1 W 的全光纤化结构超连续谱(SC)光纤激光输出。光谱宽度超出所用光谱仪600~1700 nm 的观测范围,在观测范围内具有10 dB 的光谱平坦度。%All fiber picosecond ytterbium doped fiber laser with average output power of 39.2 W is constructed with a passively mode -locked seed laser based on semiconductor saturable absorber mirror and triple -stage master oscilla-tor power amplifier (MOPA)configuration.When pumped power is 65.1 W,pulse width of output laser is 10.7 ps and repetition frequency is 68 MHz.This picoseconds fiber laser is used to pump a 4.5 m long photonic crystal fiber, and all -fiber supercontinuum laser source with average power 20.1 W is realized.The supercontinuum covers the whole spectral range from 600 to 1700 nm of the optical spectrum analyzer.The spectral flatness is 10 dB in the de-tected spectral range.

  13. Effect of light backscattering on high-speed modulation performance in strongly injection-locked unidirectional semiconductor ring lasers

    Science.gov (United States)

    Smolyakov, Gennady A.; Osinski, Marek

    2014-03-01

    Greatly enhanced high-speed modulation performance has been recently predicted in numerical calculations for a novel injection-locking scheme involving a DBR or DFB master laser monolithically integrated with a unidirectional semiconductor microring laser. In this work, we investigate the effect of light backscattering between the two counterpropagating modes on high-speed modulation performance of strongly injection-locked unidirectional semiconductor microring lasers.

  14. Compact, Low-Cost, Frequency-Locked Semiconductor Laser for Injection Seeding High Power Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA Small Business Innovative Research Phase II project will develop a compact, low-cost, wavelength locked seed laser for injection locking high powered...

  15. A stable, power scaling, graphene-mode-locked all-fiber oscillator

    Science.gov (United States)

    Popa, D.; Jiang, Z.; Bonacchini, G. E.; Zhao, Z.; Lombardi, L.; Torrisi, F.; Ott, A. K.; Lidorikis, E.; Ferrari, A. C.

    2017-06-01

    We report power tunability in a fiber laser mode-locked with a solution-processed filtered graphene film on a fiber connector. ˜370 fs pulses are generated with output power continuously tunable from ˜4 up to ˜52 mW. This is a simple, low-cost, compact, portable, all-fiber ultrafast source for applications requiring environmentally stable, portable sources, such as imaging.

  16. Spectral and picosecond temporal properties of flared guide Y-coupled phase-locked laser arrays

    Science.gov (United States)

    Defreez, R. K.; Bossert, D. J.; Yu, N.; Hartnett, K.; Elliott, R. A.

    1988-01-01

    Spatiospectral and spatiotemporal characteristics of flared waveguide Y-coupled laser arrays are studied for the cases of both CW and pulsed operation. Regular sustained self-pulsations were observed for both operation modes. It is suggested that the pulsations are due to the destabilization of phase locking which is caused by amplitude phase coupling.

  17. Dual-frequency injection-locked continuous-wave near-infrared laser

    CERN Document Server

    Gavara, Trivikramarao; Sasaki, Yusuke; Kawashima, Takuya; Hamano, Hiroaki; Yoshizaki, Ryo; Fujimura, Yuki; Yoshii, Kazumichi; Ohae, Chiaki; Katsuragawa, Masayuki

    2016-01-01

    We report a dual-frequency injection-locked continuous-wave near-infrared laser. The entire system consists of a Ti:sapphire ring laser as a power oscillator, two independent diode-lasers employed as seed lasers, and a master cavity providing a frequency reference. Stable dual-frequency injection-locked oscillation is achieved with a maximum output power of 2.8 W. As fundamental performance features of this laser system, we show its single longitudinal/transverse mode characteristics and practical power stability. Furthermore, as advanced features, we demonstrate arbitrary selectivity of the two frequencies and flexible control of their relative powers by simply manipulating the seed lasers.

  18. Regrowth-free integration of injection locked slotted laser with an electroabsorption modulator.

    Science.gov (United States)

    Kelly, Niall P; Caro, Ludovic; Dernaika, Mohamad; Peters, Frank H

    2017-02-20

    Optical injection locking was used to red shift an integrated semiconductor laser up to 30 nm away from the main free running lasing mode. This injection locking of the laser beyond its band edge enabled its integration with an electroabsorption modulator to produce a 2.5 Gb/s eye diagram. The electroabsorption modulator was shown to have a 3 dB bandwidth of 5.5 GHz, which was limited by the contact capacitance. This paper demonstrates that such devices could be applied in a regrowth free, monolithic coherent wavelength division multiplexing transmitter.

  19. Femtosecond laser pumped by high-brightness coherent polarization locked diodes.

    Science.gov (United States)

    Purnawirman; Phua, P B

    2011-08-01

    We demonstrate, for the first time to our knowledge, the use of a coherent polarization locked diode as the high-brightness pump source for a femtosecond laser. Four diode emitters are coherently locked to produce more than 5 W linearly polarized, narrow linewidth, and single-lobed pump beam. This gives >10× brightness improvement over the conventional diode array. The diode beam is then used to pump a Yb:KYW laser to obtain 2 W output with 57% slope efficiency in cw laser operation. By using a saturable absorber mirror, we achieved cw mode-locking operation with a 177 fs pulse width at an average power of 0.55 W.

  20. Magnetic Control of Locked Modes in Present Devices and ITER

    Science.gov (United States)

    Volpe, F. A.; Sabbagh, S.; Sweeney, R.; Hender, T.; Kirk, A.; La Haye, R. J.; Strait, E. J.; Ding, Y. H.; Rao, B.; Fietz, S.; Maraschek, M.; Frassinetti, L.; in, Y.; Jeon, Y.; Sakakihara, S.

    2014-10-01

    The toroidal phase of non-rotating (``locked'') neoclassical tearing modes was controlled in several devices by means of applied magnetic perturbations. Evidence is presented from various tokamaks (ASDEX Upgrade, DIII-D, JET, J-TEXT, KSTAR), spherical tori (MAST, NSTX) and a reversed field pinch (EXTRAP-T2R). Furthermore, the phase of interchange modes was controlled in the LHD helical device. These results share a common interpretation in terms of torques acting on the mode. Based on this interpretation, it is predicted that control-coil currents will be sufficient to control the phase of locking in ITER. This will be possible both with the internal coils and with the external error-field-correction coils, and might have promising consequences for disruption avoidance (by aiding the electron cyclotron current drive stabilization of locked modes), as well as for spatially distributing heat loads during disruptions. This work was supported in part by the US Department of Energy under DE-SC0008520, DE-FC-02-04ER54698 and DE-AC02-09CH11466.

  1. Phase Space of Tristability in Dual Injection-Locked Fabry-Perot Laser Diodes

    Directory of Open Access Journals (Sweden)

    R. V. Pajković

    2015-06-01

    Full Text Available We investigate theoretically the case of dual injection-locking, in which the two light signals are simultaneously externally injected into the cavity of a slave Fabry-Perot laser diode. We show that dual injection-locking leads to formation of new stationary points, and potentially to optical tristability of the slave laser. We show that a region in which the slave laser exhibits three stable steady-states occurs only for sufficiently different frequency detunings of the two injection signals. Moreover, the slave laser tunability depends on the choice of injection modes, and strongly depends on the slave laser bias current, with an optimal value around 2 times threshold current.

  2. Mode-locked pulse oscillation of a self-resonating enhancement optical cavity

    CERN Document Server

    Hosaka, Yuji; Kosuge, Atsushi; Omori, Tsunehiko; Sakaue, Kazuyuki; Takahashi, Tohru; Uesugi, Yuuki; Urakawa, Junji; Washio, Masakazu

    2016-01-01

    A power enhancement optical cavity is a compelling means of realizing a pulsed laser with a high peak power and a high repetition frequency, which is not feasible by using a simple amplifier scheme. However, a precise feedback system is necessary for maintaining the narrow resonance condition of the optical cavity, and has become a major technical issue in developing such cavities. We developed a new approach that does not require any active feedback system, by placing the cavity in the outer loop of a laser amplifier. We report on the first demonstration of a mode-locked pulse oscillation using the new system.

  3. Statistical Analysis of Locked Modes and their Disruptivity at DIII-D

    Science.gov (United States)

    Sweeney, R.; Choi, W.; Olofsson, K. E. J.; Volpe, F. A.

    2014-10-01

    A database has been developed to study locking and disruptivity of neoclassical tearing modes with poloidal and toroidal mode numbers m = 2 and n = 1. Approximately 30,000 DIII-D discharges are studied providing statistics on the fraction of disruptions containing locked modes (LMs) and the ratio of disruptive LMs to all LMs. Other quantities analyzed include the time-scales between mode-formation and locking, and between locking and disruption, the amplitude of the mode upon locking and disruption, the existence or lack of a rotating precursor, and the toroidal phase of locking. Correlations are examined between locking and disruptivity and parameters such as plasma beta and neutral beam torque. Simple interpretations are provided in terms of island size and torques acting on the island, and implications for an automatic locked mode controller are discussed. This work was supported by the US Department of Energy under DE-SC0008520.

  4. Laser induced phase locking of hydrogen plasma striations

    Energy Technology Data Exchange (ETDEWEB)

    Glab, W.; Nayfeh, M.H.

    1982-04-01

    Laser induced transient striations of a hydrogen discharge plasma are studied as a function of the ''detuning'' of the discharge parameters from the steady-state oscillatory response conditions. We observed laser induced phase locking of the steady-state striations.

  5. Nonlinear high-order mode locking in stochastic sensory neurons

    Science.gov (United States)

    Rowe, Michael; Afghan, Muhammad; Neiman, Alexander

    2004-03-01

    Excitable systems demonstrate various mode locking regimes when driven by periodic external signals. With noise taken into account, such regimes represent complex nonlinear responses which depend crucially on the frequency and amplitude of the periodic drive as well as on the noise intensity. We study this using a computational model of a stochastic Hodgkin-Huxley neuron in combination with the turtle vestibular sensory system as an experimental model. A bifurcation analysis of the model is performed. Extracellular recordings from primary vestibular afferent neurons with two types of stimuli are used in the experimental study. First, mechanical stimuli applied to the labyrinth allow us to study the responses of the entire system, including transduction by the hair cells and spike generation in the primary afferents. Second, a galvanic stimuli applied directly to an afferent are used to study the responses of afferent spike generator directly. The responses to galvanic stimuli reveal multiple high-order mode locking regimes which are well reproduced in numerical simulation. Responses to mechanical stimulation are characterized by larger variability so that fewer mode-locking regimes can be observed.

  6. Smooth and selective photo-electrochemical etching of heavily doped GaN:Si using a mode-locked 355 nm microchip laser

    Science.gov (United States)

    Lee, SeungGeun; Mishkat-Ul-Masabih, Saadat; Leonard, John T.; Feezell, Daniel F.; Cohen, Daniel A.; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.

    2017-01-01

    We investigate the photo-electrochemical (PEC) etching of Si-doped GaN samples grown on nonpolar GaN substrates, using a KOH/K2S2O8 solution and illuminated by a Xe arc lamp or a Q-switched 355 nm laser. The etch rate with the arc lamp decreased as the doping concentration increased, and the etching stopped for concentrations above 7.7 × 1018 cm-3. The high peak intensity of the Q-switched laser extended the etchable concentration to 2.4 × 1019 cm-3, with an etch rate of 14 nm/min. Compositionally selective etching was demonstrated, with an RMS surface roughness of 1.6 nm after etching down to an n-Al0.20Ga0.80N etch stop layer.

  7. Supercontinuum generation in nonlinear fibers using high-energy figure-of-eight mode-locked fiber laser for SD-OCT application

    Science.gov (United States)

    Xu, Bo; Nagata, Tsubasa; Yamashita, Shinji

    2014-05-01

    Generation of flat and broadband supercontinum is demonstrated in an all fiber system using the high-energy noise-like pulses from a stable figure-of-eight fiber laser and nonlinear fibers. This SC source is successfully applied to the spectral domain optical coherence tomography (SD-OCT). The axial resolution is significantly improved compared with the case of the superluminescent diode source. SD-OCT imaging is also demonstrated.

  8. Mode locking and spatiotemporal chaos in periodically driven Gunn diodes

    DEFF Research Database (Denmark)

    Mosekilde, Erik; Feldberg, Rasmus; Knudsen, Carsten;

    1990-01-01

    Numerical simulation is applied to study the highly nonlinear-dynamic phenomena that can arise in Gunn diodes by interaction between the internally generated domain mode and an external microwave signal. By adjusting the time of domain formation and the speed of propagation, the internal...... oscillation entrains with the external signal. This produces a devil’s staircase of frequency-locked solutions. At higher microwave amplitudes, period doubling and other forms of mode-converting bifurcations can be seen. In this interval the diode also exhibits spatiotemporal chaos. At still higher microwave...

  9. Harmonic mode locking in a high-Q whispering gallery mode microcavity

    Science.gov (United States)

    Tanabe, Takasumi; Kato, Takumi; Kobatake, Tomoya; Suzuki, Ryo; Chen-Jinnai, Akitoshi

    2016-03-01

    We present a numerical and experimental study of the generation of harmonic mode locking in a silica toroid microcavity. We use a generalized mean-field Lugiato-Lefever equation and solve it with the split-step Fourier method. We found that a stable harmonic mode-locking regime can be accessed when we reduce the input power after strong pumping even if we do not carefully adjust the wavelength detuning. This is due to the bistable nature of the nonlinear cavity system. The experiment agrees well with the numerical analysis, where we obtain a low-noise Kerr comb spectrum with a narrow longitudinal mode spacing by gradually reducing the input pump power after strong pumping. This finding clarifies the procedure for generating harmonic mode locking in such high-Q microcavity systems.

  10. Phase-locked laser coherent interference

    Institute of Scientific and Technical Information of China (English)

    Jingjing Wang; Xiaobo Wang; Bo He; Liantuan Mao; Suotang Jia

    2011-01-01

    A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated. It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system. After phase locking using the phase modulating and lock-in technique, the drift of the relative phase is focalized around ±0.0016 rad and the fringe visibility is restricted to 2×l0-4.%@@ A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated.It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system.After phase locking using the vhase modulating and lock-in technique.the drift of the relative phase is focalized around±0.0016 rad and the fringe visibility is restricted to 2×10-4.

  11. Diffraction coupled phase-locked arrays of quantum cascade lasers with monolithically integrated Talbot cavities

    CERN Document Server

    Wang, Lei; Jia, Zhi-Wei; Zhao, Yue; Liu, Chuan-Wei; Liu, Ying-Hui; Zhai, Shen-Qiang; Zhuo, Ning; Liu, Feng-Qi; Xu, Xian-Gang

    2016-01-01

    Diffraction coupled arrays of quantum cascade laser are presented. The phase-locked behavior is achieved through monolithic integration of a Talbot cavity at one side of the laser array. The principle is based on fractional Talbot effect. By controlling length of Talbot cavity to be a quarter of Talbot distance (Zt/4), in-phase mode operation is selected. Measured far-field radiation patterns reflect stable in-phase mode operation under different injection currents, from threshold current to full power current. Diffraction-limited performance is shown from the lateral far-field, where three peaks can be obtained and main peak and side peak interval is 10.5{\\deg}. The phase-locked arrays with in-phase mode operation may be a feasible solution to get higher output power and maintain well beam quality meanwhile.

  12. Ultrafast nonlinear optical properties of thin-solid DNA film and their application as a saturable absorber in femtosecond mode-locked fiber laser

    Science.gov (United States)

    Khazaeinezhad, Reza; Hosseinzadeh Kassani, Sahar; Paulson, Bjorn; Jeong, Hwanseong; Gwak, Jiyoon; Rotermund, Fabian; Yeom, Dong-Il; Oh, Kyunghwan

    2017-01-01

    A new extraordinary application of deoxyribonucleic acid (DNA) thin-solid-film was experimentally explored in the field of ultrafast nonlinear photonics. Optical transmission was investigated in both linear and nonlinear regimes for two types of DNA thin-solid-films made from DNA in aqueous solution and DNA-cetyltrimethylammonium chloride (CTMA) in an organic solvent. Z-scan measurements revealed a high third-order nonlinearity with n2 exceeding 10-9 at a wavelength of 1570 nm, for a nonlinarity about five orders of magnitude larger than that of silica. We also demonstrated ultrafast saturable absorption (SA) with a modulation depth of 0.43%. DNA thin solid films were successfully deposited on a side-polished optical fiber, providing an efficient evanescent wave interaction. We built an organic-inorganic hybrid all-fiber ring laser using DNA film as an ultrafast SA and using Erbium-doped fiber as an efficient optical gain medium. Stable transform-limited femtosecond soliton pulses were generated with full width half maxima of 417 fs for DNA and 323 fs for DNA-CTMA thin-solid-film SAs. The average output power was 4.20 mW for DNA and 5.46 mW for DNA-CTMA. Detailed conditions for DNA solid film preparation, dispersion control in the laser cavity and subsequent characteristics of soliton pulses are discussed, to confirm unique nonlinear optical applications of DNA thin-solid-film.

  13. Optical phase locking of two infrared CW lasers separated by 100 THz

    CERN Document Server

    Chiodo, Nicola; Hrabina, Jan; Lours, Michel; Chea, Erick; Acef, Ouali

    2014-01-01

    We report on phase-locking of two continuous wave infrared laser sources separated by 100 THz emitting around 1029 nm and 1544 nm respectively. Our approach uses three independent harmonic generation processes of the IR laser frequencies in periodically poled MgO: LiNbO3 crystals to generate second and third harmonic of that two IR sources. The beat note between the two independent green radiations generated around 515 nm is used to phase-lock one IR laser to the other, with tunable radio frequency offset. In this way, the whole setup operates as a mini frequency comb (MFC) emitting four intense optical radiations (1544 nm, 1029 nm, 772 nm and 515 nm), with output powers at least 3 orders of magnitude higher than the available power from each mode emitted by femtosecond lasers.

  14. Laser frequency locking based on Rydberg electromagnetically induced transparency

    Science.gov (United States)

    Yuechun, Jiao; Jingkui, Li; Limei, Wang; Hao, Zhang; Linjie, Zhang; Jianming, Zhao; Suotang, Jia

    2016-05-01

    We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency (EIT) spectra in a room-temperature cesium vapor cell. Cesium levels 6S1/2, 6P3/2, and the nD5/2 state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ˜0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10-11. This kind of locking method can be used to stabilize the laser frequency to the excited transition. Project supported by the National Basic Research Program of China (Grant No. 2012CB921603), the National Natural Science Foundation of China (Grants Nos. 11274209, 61475090, 61378039, and 61378013), and the Research Project Supported by Shanxi Scholarship Council of China (Grant No. 2014-009).

  15. Optical Phase Locking of Modelocked Lasers for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Plettner, T.; Sinha, S.; Wisdom, J.; /Stanford U., Phys. Dept.; Colby, E.R.; /SLAC

    2006-02-17

    Particle accelerators require precise phase control of the electric field through the entire accelerator structure. Thus a future laser driven particle accelerator will require optical synchronism between the high-peak power laser sources that power the accelerator. The precise laser architecture for a laser driven particle accelerator is not determined yet, however it is clear that the ability to phase-lock independent modelocked oscillators will be of crucial importance. We report the present status on our work to demonstrate long term phaselocking between two modelocked lasers to within one degree of optical phase and describe the optical synchronization techniques that we employ.

  16. Note: Digital laser frequency auto-locking for inter-satellite laser ranging.

    Science.gov (United States)

    Luo, Yingxin; Li, Hongyin; Yeh, Hsien-Chi

    2016-05-01

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  17. Low-timing-jitter high-power mode-locked 1063 nm Nd:GdVO₄ master oscillator power amplifier.

    Science.gov (United States)

    Wang, Zhi-min; Zhang, Feng-feng; Zuo, Jun-wei; Yang, Jing; Yuan, Lei; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

    2015-10-01

    A low-timing-jitter high-power semiconductor saturable absorber mirror mode-locked picosecond (ps) 1063 nm Nd:GdVO4 master oscillator power amplifier is presented. Using a single-pass Nd:GdVO4 amplifier, an amplified laser with 21.5 W output power and 8.3 ps pulsewidth was achieved at 250 MHz repetition rate. Employing a servo control, an average RMS timing jitter of ∼222  fs was realized. This laser can be used as a drive laser for photocathode injectors in free-electron lasers.

  18. Fourier domain mode-locked swept source at 1050 nm based on a tapered amplifier

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang;

    2010-01-01

    While swept source optical coherence tomography (OCT) in the 1050 nm range is promising for retinal imaging, there are certain challenges. Conventional semiconductor gain media have limited output power, and the performance of high-speed Fourier domain mode-locked (FDML) lasers suffers from...... achieved stable FDML operation, exploiting the full bandwidth of the tapered amplifier despite high dispersion. The light source operates at a repetition rate of 116 kHz with an effective average output power in excess of 30 mW. With a total sweep range of 70 nm, we achieved an axial resolution of 15 μm...

  19. Evanescent-wave coupled right angled buried waveguide: Applications in carbon nanotube mode-locking

    Energy Technology Data Exchange (ETDEWEB)

    Mary, R.; Thomson, R. R.; Kar, A. K., E-mail: a.k.kar@hw.ac.uk [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Brown, G. [Optoscribe Ltd, 0/14 Alba Innovation Centre, Alba Campus, Livingston EH54 7GA (United Kingdom); Beecher, S. J. [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Popa, D.; Sun, Z.; Torrisi, F.; Hasan, T.; Milana, S.; Bonaccorso, F.; Ferrari, A. C. [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2013-11-25

    We present an evanescent-field device based on a right-angled waveguide. This consists of orthogonal waveguides, with their points of intersection lying along an angled facet of the chip. Light guided along one waveguide is incident at the angled dielectric-air facet at an angle exceeding the critical angle, so that the totally internally reflected light is coupled into the second waveguide. By depositing a nanotube film on the angled surface, the chip is then used to mode-lock an Erbium doped fiber ring laser with a repetition rate of 26 MHz, and pulse duration of 800 fs.

  20. Mode-locked 1.5 micrometers semiconductor optical amplifier fiber ring

    OpenAIRE

    Pedersen, Niels V.; Jakobsen, Kaj Bjarne; Vaa, Michael

    1996-01-01

    The dynamics of a mode-locked SOA fiber ring are investigated experimentally and numerically. Generation of near transform-limited (time-bandwidth product=0.7) 1.5 μm 54 ps FWHM pulses with a peak power of 2.8 mW at a repetition rate of 960 MHz is demonstrated experimentally. The experimental results agree well with the simulation results obtained using a transmission line laser model (TLLM) model, Both experiments and numerical simulations show how the RF power and the detuning affect the pu...