WorldWideScience

Sample records for broadband all-optical ultrasound

  1. Broadband unidirectional ultrasound propagation

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Dipen N.; Pantea, Cristian

    2017-12-12

    A passive, linear arrangement of a sonic crystal-based apparatus and method including a 1D sonic crystal, a nonlinear medium, and an acoustic low-pass filter, for permitting unidirectional broadband ultrasound propagation as a collimated beam for underwater, air or other fluid communication, are described. The signal to be transmitted is first used to modulate a high-frequency ultrasonic carrier wave which is directed into the sonic crystal side of the apparatus. The apparatus processes the modulated signal, whereby the original low-frequency signal exits the apparatus as a collimated beam on the side of the apparatus opposite the sonic crystal. The sonic crystal provides a bandpass acoustic filter through which the modulated high-frequency ultrasonic signal passes, and the nonlinear medium demodulates the modulated signal and recovers the low-frequency sound beam. The low-pass filter removes remaining high-frequency components, and contributes to the unidirectional property of the apparatus.

  2. Ultrafast defect dynamics: A new approach to all optical broadband switching employing amorphous selenium thin films

    Directory of Open Access Journals (Sweden)

    Rituraj Sharma

    2015-07-01

    Full Text Available Optical switches offer higher switching speeds than electronics, however, in most cases utilizing the interband transitions of the active medium for switching. As a result, the signal suffers heavy losses. In this article, we demonstrate a simple and yet efficient ultrafast broadband all-optical switching on ps timescale in the sub-bandgap region of the a-Se thin film, where the intrinsic absorption is very weak. The optical switching is attributed to short-lived transient defects that form localized states in the bandgap and possess a large electron-phonon coupling. We model these processes through first principles simulation that are in agreement with the experiments.

  3. Review of Laser-Generated Ultrasound Transmitters and Their Applications to All-Optical Ultrasound Transducers and Imaging

    Directory of Open Access Journals (Sweden)

    Sung-Liang Chen

    2016-12-01

    Full Text Available Medical ultrasound is an imaging technique that utilizes ultrasonic signals as information carriers, and has wide applications such as seeing internal body structures, finding a source of a disease, and examining pregnant women. The most commonly used ultrasonic transducer today is based on piezoelectricity. The piezoelectric transducer, however, may have a limited bandwidth and insufficient sensitivity for reduced element size. Laser-generated ultrasound (LGUS technique is an effective way to resolve these issues. The LGUS approach based on photoacoustic effect is able to greatly enhance the bandwidth of ultrasound signals and has the potential for high-resolution imaging. High-amplitude LGUS could also be used for therapy to accomplish high precision surgery without an incision. Furthermore, LGUS in conjunction with optical detection of ultrasound allows all-optical ultrasound imaging (i.e., ultrasound is generated and received optically. The all-optical platform offers unique advantages in providing high-resolution information and in facilitating the construction of miniature probes for endoscopic ultrasound. In this article, a detailed review of the recent development of various LGUS transmitters is presented. In addition, a recent research interest in all-optical ultrasound imaging, as well as its applications, is also discussed.

  4. All-optical Photoacoustic and laser-ultrasound imaging of fixed arterial tissue (Conference Presentation)

    Science.gov (United States)

    Johnson, Jami L.; van Wijk, Kasper; Merrilees, Mervyn

    2017-03-01

    Arterial tissue imaging and characterization is important for disease diagnosis, treatment planning and monitoring, and research into disease processes. The high optical contrast of photoacoustic imaging can distinguish molecules with unique optical spectra from surrounding arterial tissue, while ultrasound is sensitive to variations in acoustic properties. Combining photoacoustics with ultrasonics provides more comprehensive diagnostic information by extracting molecular information from photoacoustics and structural information from ultrasound. Furthermore, ultrasound may be able to distinguish molecules with indistinct optical spectra but strong acoustic properties, such as calcification. In this work we will present our results applying our recently developed all-optical, multi-channel photoacoustic and laser-ultrasound imaging techniques to arterial tissue ex-vivo. We first apply redatuming techniques to remove reverberation artifacts, and subsequently image with time-reversal.

  5. All-optical scanhead for ultrasound and photoacoustic imaging-Imaging mode switching by dichroic filtering.

    Science.gov (United States)

    Hsieh, Bao-Yu; Chen, Sung-Liang; Ling, Tao; Guo, L Jay; Li, Pai-Chi

    2014-03-01

    Ultrasound (US) and photoacoustic (PA) multimodality imaging has the advantage of combining good acoustic resolution with high optical contrast. The use of an all-optical scanhead for both imaging modalities can simplify integration of the two systems and miniaturize the imaging scanhead. Herein we propose and demonstrate an all-optical US/PA scanhead using a thin plate for optoacoustic generation in US imaging, a polymer microring resonator for acoustic detection, and a dichroic filter to switch between the two imaging modes by changing the laser wavelength. A synthetic-aperture focusing technique is used to improve the resolution and contrast. Phantom images demonstrate the feasibility of this design, and show that axial and lateral resolutions of 125 μm and 2.52°, respectively, are possible.

  6. Ultrasound imaging using all-optical power and signal transfer in catheters (Conference Presentation)

    Science.gov (United States)

    Pekar, Martin; van der Mark, Martin B.

    2017-02-01

    Smart medical catheters face a connectivity challenge. An example is found in ultrasound imaging where the supply of power at the distal end and the signal transmission requires many thin and fragile wires in order to keep the catheter thin and flexible and this leads to a relatively high cost of production. We have built a fully functional benchtop demonstrator that is immediately scalable to catheter dimensions, in which all electrical wires are replaced by just two optical fibers. We show signal transfer of synthetic aperture ultrasound images as well as photovoltaic conversion to supply all electronics. The absence of conductors provides excellent galvanic isolation as well as RF and MRI compatibility and the simple design utilizing off the shelf components holds a promise of cost effectiveness all of which may help translation of these advanced devices into the clinic. We show photovoltaic conversion of 405 nm light to 45 V and 1.8 V by two blue LEDs as well as 200 MHz broad-band signal transfer using modulated 850 nm VCSEL light. Synthetic aperture ultrasound images are acquired at a frequency of 12 MHz with a collapse-mode capacitive-micromachined ultrasonic transducer. Bandwidth, noise level and dynamic range are nearly identical as shown in comparison of the images acquired with the optical link and its electrical equivalent. In conclusion, we have successfully demonstrated low-cost and scalable optical signal and power transmission for an ultrasound imaging system enjoying intrinsic RF / MRI compatibility and galvanic isolation.

  7. Broadband Acoustic Cloak for Ultrasound Waves

    Science.gov (United States)

    Zhang, Shu; Xia, Chunguang; Fang, Nicholas

    2011-01-01

    Invisibility devices based on coordinate transformation have opened up a new field of considerable interest. We present here the first practical realization of a low-loss and broadband acoustic cloak for underwater ultrasound. This metamaterial cloak is constructed with a network of acoustic circuit elements, namely, serial inductors and shunt capacitors. Our experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow. Because of the nonresonant nature of the building elements, this low-loss (˜6dB/m) cylindrical cloak exhibits invisibility over a broad frequency range from 52 to 64 kHz. Furthermore, our experimental study indicates that this design approach should be scalable to different acoustic frequencies and offers the possibility for a variety of devices based on coordinate transformation.

  8. Performance improvement of an all-optical Fabry Perot ultrasound detector

    Science.gov (United States)

    Thathachary, Supriya V.; Ashkenazi, Shai

    2017-02-01

    A highly sensitive Fiber-Optic Fabry Perot Ultrasound sensor with a self-written waveguide is presented in this work. A simulated device using Gold mirrors showed periodic resonance with Q-factor 1900 for 45 μm thick devices. Including a waveguide to limit lateral power losses resulted in improvement of Q-factor to 3200. Simulations also indicated greater improvement in Q-factor upon the introduction of waveguide with larger device thicknesses. Subsequently, a prototype was fabricated on a single mode optical fiber. Benzocyclobutene was chosen as the cavity medium as it undergoes a refractive index change upon exposure to UV. The refractive index change in BCB upon UV exposure was studied using a phase grating. Upon confirming that 2-hour exposure produced a change of 0.004, a self-aligned waveguide was written into the cavity. A consequent increase in Q-factor from 2500 to 5200 was seen for an 80 μm thick device. Simulation studies indicate further improvement when incorporating dielectric Bragg mirrors instead of Gold, with Q-factors of 6400 and 10200 with and without the waveguide. Therefore, the proposed design includes Dielectric Bragg mirrors as well as a self-aligned waveguide. The fabrication techniques being fairly controlled and automated, this device is highly suitable for mass-manufacturing, making is possible to produce as an inexpensive, disposable device. A potential application is to integrate it within a commercial guidewire to create a smart guidewire capable of detecting vascular vessel walls in order to guide interventions for Chronic Total Occlusions, reducing risk of wall perforation, which is currently an unmet clinical need.

  9. All optical wavelength broadcast based on simultaneous Type I QPM broadband SFG and SHG in MgO:PPLN.

    Science.gov (United States)

    Gong, Mingjun; Chen, Yuping; Lu, Feng; Chen, Xianfeng

    2010-08-15

    We experimentally demonstrate wavelength broadcast based on simultaneous Type I quasi-phase-matched (QPM) broadband sum-frequency generation (SFG) and second-harmonic generation (SHG) in 5 mol.% MgO-doped periodically poled lithium niobate (MgO:PPLN). One signal has been synchronously converted into seven different wavelengths using two pumps at a 1.5 microm band via quadratic cascaded nonlinear wavelength conversion. By selecting different pump regions, i.e., selecting different cascaded chi((2)):chi((2)) interactions, the flexible wavelength conversions with shifting from one signal to single, double, and triple channels were also demonstrated.

  10. Conformal Coating of a Phase Change Material on Ordered Plasmonic Nanorod Arrays for Broadband All-Optical Switching.

    Science.gov (United States)

    Guo, Peijun; Weimer, Matthew S; Emery, Jonathan D; Diroll, Benjamin T; Chen, Xinqi; Hock, Adam S; Chang, Robert P H; Martinson, Alex B F; Schaller, Richard D

    2017-01-24

    Actively tunable optical transmission through artificial metamaterials holds great promise for next-generation nanophotonic devices and metasurfaces. Plasmonic nanostructures and phase change materials have been extensively studied to this end due to their respective strong interactions with light and tunable dielectric constants under external stimuli. Seamlessly integrating plasmonic components with phase change materials, as demonstrated in the present work, can facilitate phase change by plasmonically enabled light confinement and meanwhile make use of the high sensitivity of plasmon resonances to the variation of dielectric constant associated with the phase change. The hybrid platform here is composed of plasmonic indium-tin-oxide nanorod arrays (ITO-NRAs) conformally coated with an ultrathin layer of a prototypical phase change material, vanadium dioxide (VO2), which enables all-optical modulation of the infrared as well as the visible spectral ranges. The interplay between the intrinsic plasmonic nonlinearity of ITO-NRAs and the phase transition induced permittivity change of VO2 gives rise to spectral and temporal responses that cannot be achieved with individual material components alone.

  11. Conformal Coating of a Phase Change Material on Ordered Plasmonic Nanorod Arrays for Broadband All-Optical Switching

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Peijun; Weimer, Matthew S. [Department; Emery, Jonathan D.; Diroll, Benjamin T.; Chen, Xinqi; Hock, Adam S. [Department; Chang, Robert P. H.; Martinson, Alex B. F.; Schaller, Richard D.

    2016-12-19

    Actively tunable optical transmission through artificial metamaterials holds great promise for next-generation nanophotonic devices and metasurfaces. Plasmonic nanostructures and phase change materials have been extensively studied to this end due to their respective strong interactions with light and tunable dielectric constants under external stimuli. Seamlessly integrating plasmonic components with phase change materials, as demonstrated in the present work, can facilitate phase change by plasmonically enabled light confinement and meanwhile make use of the high sensitivity of plasmon resonances to the variation of dielectric constant associated with the phase change. The hybrid platform here is composed of plasmonic indium tin-oxide nanorod arrays (ITO-NRAs) conformally coated with an ultrathin layer of a prototypical phase change material, vanadium dioxide (VO2), which enables all-optical modulation of the infrared as well as the visible spectral ranges. The interplay between the intrinsic plasmonic nonlinearity of ITO-NRAs and the phase transition induced permittivity change of VO2 gives rise to spectral and temporal responses that cannot be achieved with individual material components alone.

  12. Broadband minimum variance beamforming for ultrasound imaging.

    Science.gov (United States)

    Holfort, Iben Kraglund; Gran, Fredrik; Jensen, Jørgen Arendt

    2009-02-01

    A minimum variance (MV) approach for near-field beamforming of broadband data is proposed. The approach is implemented in the frequency domain, and it provides a set of adapted, complex apodization weights for each frequency subband. The performance of the proposed MV beamformer is tested on simulated data obtained using Field II. The method is validated using synthetic aperture data and data obtained from a plane wave emission. Data for 13 point targets and a circular cyst with a radius of 5 mm are simulated. The performance of the MV beamformer is compared with delay-and-sum (DS) using boxcar weights and Hanning weights and is quantified by the full width at half maximum (FWHM) and the peak-side-lobe level (PSL). Single emission {DS boxcar, DS Hanning, MV} provide a PSL of {-16, -36, -49} dB and a FWHM of {0.79, 1.33, 0.08} mm. Using all 128 emissions, {DS boxcar, DS Hanning, MV} provides a PSL of {-32, -49, -65} dB, and a FWHM of {0.63, 0.97, 0.08} mm. The contrast of the beamformed single emission responses of the circular cyst was calculated as {-18, -37, -40} dB. The simulations have shown that the frequency subband MV beamformer provides a significant increase in lateral resolution compared with DS, even when using considerably fewer emissions. An increase in resolution is seen when using only one single emission. Furthermore, the effect of steering vector errors is investigated. The steering vector errors are investigated by applying an error of the sound speed estimate to the ultrasound data. As the error increases, it is seen that the MV beamformer is not as robust compared with the DS beamformer with boxcar and Hanning weights. Nevertheless, it is noted that the DS does not outperform the MV beamformer. For errors of 2% and 4% of the correct value, the FWHM are {0.81, 1.25, 0.34} mm and {0.89, 1.44, 0.46} mm, respectively.

  13. Broadband Minimum Variance Beamforming for Ultrasound Imaging

    DEFF Research Database (Denmark)

    Holfort, Iben Kraglund; Gran, Fredrik; Jensen, Jørgen Arendt

    2009-01-01

    A minimum variance (MV) approach for near-field beamforming of broadband data is proposed. The approach is implemented in the frequency domain, and it provides a set of adapted, complex apodization weights for each frequency subband. The performance of the proposed MV beamformer is tested on simu...

  14. Broadband ultrasound attenuation imaging: a new imaging method in osteoporosis.

    Science.gov (United States)

    Roux, C; Fournier, B; Laugier, P; Chappard, C; Kolta, S; Dougados, M; Berger, G

    1996-08-01

    The purpose of this study was to evaluate the usefulness in osteoporosis of a new ultrasound imaging device able to create a parametric image of broadband ultrasound attenuation (BUA) at the os calcis. Three regions of interest were located in the great tuberosity of the os calcis. Precision was evaluated in 37 patients. Calcaneal bone mineral density (BMD) and BUA were compared in 33 patients. In 236 patients (including 77 with osteoporotic fractures), BUA and lumbar and femoral BMD measurements were performed. The measurements were compared using correlation coefficients. Their clinical value was estimated by comparisons of the results between patients with fractures and age-matched controls, using comparisons of the means, areas under the ROC curves, and logistic regression. Precision was in a 1.4-3.3% range. Local BUA and BMD were highly correlated (r = 0.88). Significant correlations were found between BUA and lumbar (r = 0.56) and femur (r = 0.66) BMD. In multiple regression, years since menopause and weight were significant predictors of BUA. Patients with fractures had lower BUA and BMD than age-matched controls. BUA showed the largest difference between the two populations (13-16%). Areas under the ROC curves were similar for BUA and BMD. Logistic regression after adjustment for confounding factors showed that BUA discriminated between fracture and nonfracture subjects. Broadband ultrasound attenuation imaging improves the reproducibility of ultrasound measurements. It may be useful in osteoporosis, due to its good discriminating value.

  15. All-optical photoacoustic microscopy

    Directory of Open Access Journals (Sweden)

    Sung-Liang Chen

    2015-12-01

    Full Text Available Three-dimensional photoacoustic microscopy (PAM has gained considerable attention within the biomedical imaging community during the past decade. Detecting laser-induced photoacoustic waves by optical sensing techniques facilitates the idea of all-optical PAM (AOPAM, which is of particular interest as it provides unique advantages for achieving high spatial resolution using miniaturized embodiments of the imaging system. The review presents the technology aspects of optical-sensing techniques for ultrasound detection, such as those based on optical resonators, as well as system developments of all-optical photoacoustic systems including PAM, photoacoustic endoscopy, and multi-modality microscopy. The progress of different AOPAM systems and their representative applications are summarized.

  16. Ultrasound velocity and broadband attenuation as predictors of load-bearing capacities of human calcanei.

    Science.gov (United States)

    Han, S; Medige, J; Davis, J; Fishkin, Z; Mihalko, W; Ziv, I

    1997-01-01

    The main purpose of this study was to determine whether calcaneal ultrasound parameters, measured in the mediolateral direction, reflect load-bearing capacities of human calcanei. Broadband ultrasound attenuation (BUA) and ultrasound velocity (UV) were measured in 20 cadaveric calcanei with a mean age of 74.1 (SD 8.8). Normalized BUA (nBUA) was determined by dividing BUA by the calcaneal thickness obtained using a pulse-echo technique. The bone mineral density (BMD) of each calcaneus was measured by quantitative computed tomography. The calcanei were embedded in PMMA to simulate the midstance physiologic orientation during compressive testing in the load-bearing direction. The failure load, stiffness, and energy absorption were determined for each calcaneus. It was shown that BMD was well correlated with all ultrasound parameters (P 0.5).

  17. Fractal dimension of bone texture in radiographs correlates to ultrasound broadband attenuation T-score.

    Science.gov (United States)

    Bianciardi, Giorgio; Bisogno, Stefania; Bertoldi, Ilaria; Laurini, Lorella; Coviello, Giuseppe; Frediani, Bruno

    2013-01-01

    We aimed to measure the fractal dimension on x-ray images and ultrasonographic parameters of the os calcis of bone from 4 districts in osteoporotic patients and in control subjects, in order to test the hypothesis that ultrasonographic parameters correlate to the fractal dimension obtained on x-ray images. Fractal analysis on radiological images from 4 bone districts (proximal femur, calcaneus, metacarpus and 3rd phalanx) was performed in a study comparing ultrasonographic evaluation of the os calcis in severe osteoporotic patients and in control cases. We studied 86 x-ray-views from patients with severe reduction of ultrasound Stiffness Index and in healthy women. Ultrasound measurements of left os calcis were performed using the Lunar Achilles-Plus instrument. Fractal analysis was performed using the box-counting method. In healthy subjects, fractal dimension, D, measure of structural complexity, resulted close to the topological dimension (no fractal structure), TD, in femur (1.99±0.03)and phalanx (1.96±0.03), D differed significantly from TD in calcaneus (D=1.90±0.02; pfractal dimension and ultrasound broadband attenuation T-score correlated significantly in calcaneus and metacarpus (pfractal analysis on radiographic images may add useful structural information regarding the patients' skeleton using non invasive procedures.

  18. All-optical pressure sensor

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to an all-optical pressure sensor comprising a waveguide accommodating a distributed Bragg reflector. Pressure sensing can then be provided by utilizing effective index modulation of the waveguide and detection of a wavelength shift of light reflected from the Bragg...... reflector. Sound sensing may also be provided thereby having an all-optical microphone. One embodiment of the invention relates to an optical pressure sensor comprising at least one outer membrane and a waveguide, the waveguide comprising at least one core for confining and guiding light,at least one...... distributed Bragg reflector located in said at least one core, and at least one inner deflecting element forming at least a part of the core,wherein the pressure sensor is configured such that the geometry and/or dimension of the at least one core is changed when the at least one outer membrane is submitted...

  19. All optical regeneration using semiconductor devices

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Tromborg, Bjarne

    All-optical regeneration is a key functionality for implementing all-optical networks. We present a simple theory for the bit-error-rate in links employing all-optical regenerators, which elucidates the interplay between the noise and and nonlinearity of the regenerator. A novel device structure ...... is analyzed, emphasizing general aspects of active semiconductor waveguides....

  20. Broadband ultrasound attenuation in the calcaneal region: a comparative study of single-position versus scanning systems.

    Science.gov (United States)

    Maia, Joaquim A; Costa, Eduardo T; Neto, João F Marques; Button, Vera L S N

    2008-01-01

    This work describes a system developed to measure the broadband ultrasound attenuation (BUA) in the calcaneal region. The patient's calcanei were inspected using a microcomputer-controlled X-Y axis displacement unit with two 500-kHz, central-frequency, ultrasound transducers. The transducers facing each other are submerged in a small water tank with a support for the patient's foot between them. The system allows data to be collected from a single position or by scanning the calcaneal region to obtain a BUA map. Tests were carried out on 201 patients (110 using the single-position method, and 91 using the scanning method). The results were compared with those of densitometry tests performed using the dual energy X-ray absorptiometry (DEXA) technique (single position: r=0.50; Pposition method is more susceptible to errors due to the difficulty in positioning the transducers relative to the calcaneus. The scanning method provides better results and can be used to screen patients before referring them for DEXA.

  1. Semiconductor devices for all-optical regeneration

    DEFF Research Database (Denmark)

    Öhman, Filip; Bischoff, Svend; Tromborg, Bjarne

    2003-01-01

    We review different implementations of semiconductor devices for all-optical regeneration. A general model will be presented for all-optical regeneration in fiber links, taking into consideration the trade-off between non-linearity and noise. Furthermore we discuss a novel regenerator type, based...

  2. Control of broadband optically generated ultrasound pulses using binary amplitude holograms.

    Science.gov (United States)

    Brown, Michael D; Jaros, Jiri; Cox, Ben T; Treeby, Bradley E

    2016-04-01

    In this work, the use of binary amplitude holography is investigated as a mechanism to focus broadband acoustic pulses generated by high peak-power pulsed lasers. Two algorithms are described for the calculation of the binary holograms; one using ray-tracing, and one using an optimization based on direct binary search. It is shown using numerical simulations that when a binary amplitude hologram is excited by a train of laser pulses at its design frequency, the acoustic field can be focused at a pre-determined distribution of points, including single and multiple focal points, and line and square foci. The numerical results are validated by acoustic field measurements from binary amplitude holograms, excited by a high peak-power laser.

  3. Assessment of the relationship between broadband ultrasound attenuation and bone mineral density at the calcaneus using BUA imaging and DXA.

    Science.gov (United States)

    Chappard, C; Laugier, P; Fournier, B; Roux, C; Berger, G

    1997-01-01

    The purposes of this study was to determine the relationship between broadband ultrasound attenuation (BUA) and bone mineral density (BMD) measured at different regions of the calcaneus with identical site-matched regions of interest (ROIs). Dual-energy X-ray absorptiometry (DXA) measurements of the calcaneus and BUA imaging were performed in 30 women (15 premenopausal and 15 postmenopausal). Four square ROIs were located in the great tuberosity and one square ROI in the foramen calcaneus. A ROI adapted to the shape and size of the whole calcaneus was also considered. All ROIs were analyzed three times with both techniques to minimize intra-observer variability. The correlation coefficient between attenuation and frequency was used as an index of BUA measurement error. Before accepting a measurement of BUA in inhomogeneous material, it could be useful to map the spatial variations of the measurement error. In all ROIs we found the BUA and BMD were strongly related (r = 0.78-0.91, p < 0.001). The correlation between BUA and BMD was slightly higher in the inferior part of the posterior tuberosity than in the superior part and in the foramen calcaneus. The very high correlation between attenuation and frequency found in all ROIs (r = 0.99) suggests that measurement errors of propagation were probably not significant. Ultrasound imaging yields the opportunity for studying the spatial acoustic properties in the calcaneus and their relation to bone mass or structural parameters provided by independent imaging techniques. BUA measured with current transmission techniques reflects mainly bone mass, and microarchitecture to a smaller extent.

  4. All-optical optoacoustic microscope based on wideband pulse interferometry.

    Science.gov (United States)

    Wissmeyer, Georg; Soliman, Dominik; Shnaiderman, Rami; Rosenthal, Amir; Ntziachristos, Vasilis

    2016-05-01

    Optical and optoacoustic (photoacoustic) microscopy have been recently joined in hybrid implementations that resolve extended tissue contrast compared to each modality alone. Nevertheless, the application of the hybrid technique is limited by the requirement to combine an optical objective with ultrasound detection collecting signal from the same micro-volume. We present an all-optical optoacoustic microscope based on a pi-phase-shifted fiber Bragg grating (π-FBG) with coherence-restored pulsed interferometry (CRPI) used as the interrogation method. The sensor offers an ultra-small footprint and achieved higher sensitivity over piezoelectric transducers of similar size. We characterize the spectral bandwidth of the ultrasound detector and interrogate the imaging performance on phantoms and tissues. We show the first optoacoustic images of biological specimen recorded with π-FBG sensors. We discuss the potential uses of π-FBG sensors based on CRPI.

  5. Micro-fabricated all optical pressure sensors

    DEFF Research Database (Denmark)

    Havreland, Andreas Spandet; Petersen, Søren Dahl; Østergaard, Christian

    2017-01-01

    Optical pressure sensors can operate in certain harsh application areas where the electrical pressure sensors cannot. However, the sensitivity is often not as good for the optical sensors. This work presents an all optical pressure sensor, which is fabricated by micro fabrication techniques, where...... the sensitivity can be tuned in the fabrication process. The developed sensor design, simplifies the fabrication process leading to a lower fabrication cost, which can make the all optical pressure sensors more competitive towards their electrical counterpart. The sensor has shown promising results and a linear...

  6. All-optical tunable photonic crystal cavity

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    We demonstrate an ultra-small photonic crystal cavity with two resonant modes. An all-optical tuning operation based on the free-carrier plasma effect is, for the first time, realized utilizing a continuous wave light source. The termo-optical effect is minimized by isoproponal infiltration...... of the photonic crystal structure....

  7. Tunable all-optical negative multitap microwave filters based on uniform fiber Bragg gratings.

    Science.gov (United States)

    Mora, J; Andrés, M V; Cruz, J L; Ortega, B; Capmany, J; Pastor, D; Sales, S

    2003-08-01

    We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gratings.

  8. FLAMINGO: A Packet-switched IP-over-WDM All-optical MAN

    NARCIS (Netherlands)

    Dey, D.; van Bochove, A.C.; Koonen, A.M.J.; Geuzebroek, D.H.; Salvador, M.R.; Verbeek, B.H.; prof.dr.ir. Demeester, P.

    2001-01-01

    FLAMINGO (flexible multiwavelength optical local access network supporting multimedia broadband services) is a research project supported by the Dutch Technology Foundation, STW. We describe the architecture for the all-optical wavelength-and-time-slotted MAN. Key aspects of this architecture

  9. Design of all Optical Packet Switching Networks

    Directory of Open Access Journals (Sweden)

    Hussein T. Mouftah

    2002-06-01

    Full Text Available Optical switches and wavelength converters are recognized as two of the most important DWDM system components in future all-optical networks. Optical switches perform the key functions of flexible routing, reconfigurable optical cross-connect (OXC, network protection and restoration, etc. in optical networks. Wavelength Converters are used to shift one incoming wavelength to another outgoing wavelength when this needs to be done.  Always residing in optical switches, they can effectively alleviate the blocking probability and help solve contention happening at the output port of switches. The deployment of wavelength converters within optical switches provides robust routing, switching and network management in optical layer, which is critical to the emerging all-optical Internet. However, the high cost of wavelength converters at current stage of manufacturing technology has to be taken into consideration when we design node architectures for an optical network. Our research explores the efficiency of wavelength converters in a long-haul optical network at different degrees of traffic load by running a simulation. Then, we propose a new cost-effective way to optimally design wavelength-convertible switch so as to achieve higher network performance while still keeping the total network cost down. Meanwhile, the routing and wavelength assignment (RWA algorithm used in the research is designed to be a generic one for both large-scale and small-scale traffic. Removing the constraint on the traffic load makes the RWA more adaptive and robust. When this new RWA works in conjunction with a newly introduced concept of wavelength-convertible switches, we shall explore the impact of large-scale traffic on the role of wavelength converter so as to determine the method towards optimal use of wavelength convertible switches for all-optical networks.

  10. All-optical nanomechanical heat engine.

    Science.gov (United States)

    Dechant, Andreas; Kiesel, Nikolai; Lutz, Eric

    2015-05-08

    We propose and theoretically investigate a nanomechanical heat engine. We show how a levitated nanoparticle in an optical trap inside a cavity can be used to realize a Stirling cycle in the underdamped regime. The all-optical approach enables fast and flexible control of all thermodynamical parameters and the efficient optimization of the performance of the engine. We develop a systematic optimization procedure to determine optimal driving protocols. Further, we perform numerical simulations with realistic parameters and evaluate the maximum power and the corresponding efficiency.

  11. All-optical signal processing and regeneration

    DEFF Research Database (Denmark)

    Wolfson, David

    2001-01-01

    of a detailed large-signal model. An important parameter for SOA-based gates is the input power dynamic range (IPDR) as it determines the cascadability of the devices. Guidelines on how to maximise the IPDR are therefore established. Important trends are that short SOAs with low confinement factors and a low...... to conventional wavelength conversion since conversion of an optical clock signal is used instead of CW light. An investigation of these advantages is carried out and the feasibility of the scheme is demonstrated at 20 Gbit/s. A description of interferometric wavelength converters (IWCs) is also given. The high...... attractive for all-optical regeneration. Experiments carried out at 40 Gbit/s demonstrate excellent performance for 2R regeneration, which is emphasised by a clear improvement of the optical signal-to-noise ratio and a noise suppression capability. 3R regeneration is also illustrated at 40 Gbit/s, where...

  12. All-Optical Stern-Gerlach Effect

    Science.gov (United States)

    Karnieli, Aviv; Arie, Ady

    2018-01-01

    We introduce a novel formalism in which the paraxial coupled wave equations of the nonlinear optical sum-frequency generation process are shown to be equivalent to the Pauli equation describing the dynamics of a spin-1 /2 particle in a spatially varying magnetic field. This interpretation gives rise to a new classical state of paraxial light, described by a mutual beam comprising of two frequencies. As a straightforward application, we propose the existence of an all-optical Stern-Gerlach effect, where an idler beam is deflected by a gradient in the nonlinear coupling, into two mutual beams of the idler and signal waves (equivalent to oppositely oriented spinors), propagating in two discrete directions. The Stern-Gerlach deflection angle and the intensity pattern in the far field are then obtained analytically, in terms of the parameters of the original optical system, laying the grounds for future experimental realizations.

  13. Ultrasound

    Science.gov (United States)

    Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and ... liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound ...

  14. Photonic encryption using all optical logic.

    Energy Technology Data Exchange (ETDEWEB)

    Blansett, Ethan L.; Schroeppel, Richard Crabtree; Tang, Jason D.; Robertson, Perry J.; Vawter, Gregory Allen; Tarman, Thomas David; Pierson, Lyndon George

    2003-12-01

    With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines two classes of all optical logic (SEED, gain competition) and how each discrete logic element can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of the SEED and gain competition devices in an optical circuit were modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model of the SEED or gain competition device takes certain parameters (reflectance, intensity, input response), and models the optical ripple and time delay characteristics. These 'black box' models are interconnected and

  15. All-optical devices for ultrafast packet switching

    DEFF Research Database (Denmark)

    Dorren, H.J.S.; HerreraDorren, J.; Raz, O.

    2007-01-01

    We discuss integrated devices for all-optical packet switching. We focus on monolithically integrated all-optical flip-flops, ultra-fast semiconductor based wavelength converters and explain the operation principles. Finally, a 160 Gb/s all-optical packet switching experiment over 110 km of field...

  16. Characterisation of hybrid integrated all-optical flip-flop

    DEFF Research Database (Denmark)

    Liu, Y.; McDougall, R.; Seoane, Jorge

    2006-01-01

    We present a fully-packaged, hybrid-integrated all-optical flip-flop with separate optical set and reset operation. The flip-flop can control a wavelength converter to route 40 Gb/s data packets all-optically. The experimental results are given.......We present a fully-packaged, hybrid-integrated all-optical flip-flop with separate optical set and reset operation. The flip-flop can control a wavelength converter to route 40 Gb/s data packets all-optically. The experimental results are given....

  17. Technologies for all-optical wavelength conversion in DWDM networks

    DEFF Research Database (Denmark)

    Wolfson, David; Fjelde, Tina; Kloch, Allan

    2001-01-01

    Different techniques for all-optical wavelength conversion are reviewed and the advantages and disadvantages seen from a system perspective are highlighted. All-optical wavelength conversion will play a major role in making cost-effective network nodes in future high-speed WDM networks, where fun...

  18. Ultrasound

    Science.gov (United States)

    ... reflect off body structures. A computer receives the waves and uses them to create a picture. Unlike with an x-ray or CT scan, this test does not use ionizing radiation. The test is done in the ultrasound ...

  19. Dynamics of an all-optical atomic spin gyroscope.

    Science.gov (United States)

    Fang, Jiancheng; Wan, Shuangai; Yuan, Heng

    2013-10-20

    We present the transfer function of an all-optical atomic spin gyroscope through a series of differential equations and validate the transfer function by experimental test. A transfer function is the basis for further control system design. We build the differential equations based on a complete set of Bloch equations describing the all-optical atomic spin gyroscope, and obtain the transfer function through application of the Laplace transformation to these differential equations. Moreover, we experimentally validate the transfer function in an all-optical Cs-Xe129 atomic spin gyroscope through a series of step responses. This transfer function is convenient for analysis of the form of control system required. Furthermore, it is available for the design of the control system specifically to improve the performance of all-optical atomic spin gyroscopes.

  20. Advanced Optoelectronic Components for All-Optical Networks

    National Research Council Canada - National Science Library

    Shapiro, Jeffrey H

    2002-01-01

    Under APOSR Grant F49620-96-1-0126, 'Advanced Optoelectronic Components for All-Optical Networks', we have worked to develop key technologies and components to substantially improve the performance...

  1. 100GHz Integrated All-Optical Switch Enabled by ALD

    CERN Document Server

    Moille, Gregory; Morgenroth, Laurence; Lehoucq, Gaëlle; Neuilly, François; Hu, Bowen; Decoster, Didier; de Rossi, Alfredo

    2015-01-01

    The carrier lifetime of a photonic crystal all-optical switch is optimized by controlling the surface of GaAs by Atomic Layer Deposition. We demonstrate an all optical modulation capability up to 100GHz at Telecom wavelengths, with a contrast as high as 7dB. Wavelength conversion has also been demonstrated at a repetition rate of 2.5GHz with average pump power of about 0.5mW

  2. All optical logic for optical pattern recognition and networking applications

    Science.gov (United States)

    Khoury, Jed

    2017-05-01

    In this paper, we propose architectures for the implementation 16 Boolean optical gates from two inputs using externally pumped phase- conjugate Michelson interferometer. Depending on the gate to be implemented, some require single stage interferometer and others require two stages interferometer. The proposed optical gates can be used in several applications in optical networks including, but not limited to, all-optical packet routers switching, and all-optical error detection. The optical logic gates can also be used in recognition of noiseless rotation and scale invariant objects such as finger prints for home land security applications.

  3. All-optical Demultiplexing Using an Electroabsorption Modulator

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    1999-01-01

    In the last decade, the electroabsorption modulator (EAM) (essentially a reverse biased semiconductor optical amplifier) has found an increasingly wider range of applications within optical communications, although mostly at the research level. Recently, all-optical signal-processing such as wave......In the last decade, the electroabsorption modulator (EAM) (essentially a reverse biased semiconductor optical amplifier) has found an increasingly wider range of applications within optical communications, although mostly at the research level. Recently, all-optical signal...... the channel to be demultiplexed, and the other OTDM channels is shown to saturate at a value which increases with the signal input power....

  4. OPTICAL BURST SWITCHING PROTOCOLS IN ALL-OPTICAL NETWORKS

    OpenAIRE

    KIRCI, Pınar; ZAİM, A.Halim

    2012-01-01

    In this paper, all optical network's  general structure  is briefly described  and all optical network's optical switching methods is concantrated on. All  optical network's  classification is presented according to switching methods  and burst switching methods studied carefully.The protocols which are defined for burst switching are studied. One of these protocols JET (Just-Enough-Time) which is mostly studied, is introduced. And the other protocol JIT (Just-In-Time) is prese...

  5. High-resolution all-optical photoacoustic imaging system for remote interrogation of biological specimens

    Science.gov (United States)

    Sampathkumar, Ashwin

    2014-05-01

    Conventional photoacoustic imaging (PAI) employs light pulses to produce a photoacoustic (PA) effect and detects the resulting acoustic waves using an ultrasound transducer acoustically coupled to the target tissue. The resolution of conventional PAI is limited by the sensitivity and bandwidth of the ultrasound transducer. We have developed an all-optical versatile PAI system for characterizing ex vivo and in vivo biological specimens. The system employs noncontact interferometric detection of the acoustic signals that overcomes limitations of conventional PAI. A 532-nm pump laser with a pulse duration of 5 ns excited the PA effect in tissue. Resulting acoustic waves produced surface displacements that were sensed using a 532-nm continuous-wave (CW) probe laser in a Michelson interferometer with a GHz bandwidth. The pump and probe beams were coaxially focused using a 50X objective giving a diffraction-limited spot size of 0.48 μm. The phase-encoded probe beam was demodulated using a homodyne interferometer. The detected time-domain signal was time reversed using k-space wave-propagation methods to produce a spatial distribution of PA sources in the target tissue. Performance was assessed using PA images of ex vivo rabbit lymph node specimens and human tooth samples. A minimum peak surface displacement sensitivity of 0.19 pm was measured. The all-optical PAI (AOPAI) system is well suited for assessment of retinal diseases, caries lesion detection, skin burns, section less histology and pressure or friction ulcers.

  6. All-optical signal processing in quadratic nonlinear materials

    DEFF Research Database (Denmark)

    Johansen, Steffen Kjær

    2002-01-01

    The focal point of the research presented here is all-optical signal processing via nonlinearities. The objective has been to investigate the interaction between optical signals via nonlinearities and how these nonlinearities can be engineered to serve specific purposes. The nonlinear response...

  7. Phase-coherent all-optical frequency division by three

    NARCIS (Netherlands)

    Lee, Dong-Hoon; Klein, M.E.; Meyn, Jan-Peter; Wallenstein, Richard; Gross, P.; Boller, Klaus J.

    2003-01-01

    The properties of all-optical phase-coherent frequency division by 3, based on a self-phase-locked continuous-wave (cw) optical parametric oscillator (OPO), are investigated theoretically and experimentally. The frequency to be divided is provided by a diode laser master-oscillator power-amplifier

  8. All-Optical Signal Processing using Silicon Devices

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Pu, Minhao; Ding, Yunhong

    2014-01-01

    This paper presents an overview of recent wo rk on the use of silicon waveguides for processing optical data signals. We will describe ultra-fast, ultra-broadband, polarisation-insensitive and phase-sensitive applications including processing of spectrally-efficient data formats and optical phase...

  9. All-optical noninvasive control of semiconductor lasers

    Science.gov (United States)

    Schikora, Sylvia; Wünsche, Hans-Jürgen; Henneberger, Fritz

    2008-02-01

    All-optical noninvasive control of a multi-section semiconductor laser by means of time-delayed feedback from an external Fabry-Perot cavity is realized experimentally. The role of the optical phase as a specific new control parameter of this type of delayed-feedback control is stressed. Using phase-dependent feedback from a resonant plane Fabry-Perot interferometer, the stabilization of unstable steady states and unstable self-pulsations is achieved, including experimental demonstration of all-optical chaos control. In the latter experiment, optical chaos is transformed into a regular 12.9 GHz self-pulsation. This result is the fastest realization of chaos control ever reported. The control is noninvasive, only less than one per mille feedback keeps the stabilized states stable.

  10. A nonlinear plasmonic waveguide based all-optical bidirectional switching

    Science.gov (United States)

    Bana, Xiaoqiang; Pang, Xingxing; Li, Xiaohui; Hu, Bin; Guo, Yixuan; Zheng, Hairong

    2018-01-01

    In this paper, an all-optical switching with a nanometer coupled ring resonator is demonstrated based on the nonlinear material. By adjusting the light intensity, we implement the resonance wavelength from 880 nm to 940 nm in the nonlinear material structure monocyclic. In the bidirectional switch structure, the center wavelength (i.e. 880 nm) is fixed. By changing the light intensity from I = 0 to I = 53 . 1 MW /cm2, the function of optical switching can be obtained. The results demonstrate that both the single-ring cavity and the T-shaped double-ring structure can realize the optical switching effect. This work takes advantage of the simple structure. The single-ring cavity plasmonic switches have many advantages, such as nanoscale size, low pumping light intensity, ultrafast response time (femtosecond level), etc. It is expected that the proposed all-optical integrated devices can be potentially applied in optical communication, signal processing, and signal sensing, etc.

  11. Polarization-Independent All-Optical Regenerator for DPSK Data

    Directory of Open Access Journals (Sweden)

    Valeria Vercesi

    2014-05-01

    Full Text Available We demonstrate polarization-independent simultaneous all-optical phase-preserving amplitude regeneration and wavelength conversion of NRZ differential phase shift keying (DPSK data by four-wave mixing (FWM in a semiconductor optical amplifier (SOA. The dependence upon polarization state of the signals is eliminated by using a co-polarized dual-pump architecture. Investigation on the regenerative capability vs. pumps detuning shows significant BER threshold margin improvement over 6 nm conversion range.

  12. Optical RRH working in an all-optical fronthaul network

    Science.gov (United States)

    Zakrzewski, Zbigniew

    2017-12-01

    The paper presents an example of an optical RRH (Remote Radio Head) design, which is equipped with photonic components for direct connection to an all-optical network. The features that can be fulfilled by an all-optical network are indicated to support future 5G mobile networks. The demand for optical bandwidth in fronthaul/midhaul distribution network links, working in D-RoF and A-RoF formats was performed. The increase in demand is due to the very large traffic generated by the Optical Massive-MIMO RRH/RRU will work in format of an Active-Distributed Antenna System (A-DAS). An exemplary next-generation mobile network that will utilize O-RRH and an all-optical backbone is presented. All components of presented network will work in the Centralized/Cloud Radio Access Network (C-RAN) architecture, which is achievable by control with the use of the OpenFlow (OF).

  13. All-optical framing photography based on hyperspectral imaging method

    Science.gov (United States)

    Liu, Shouxian; Li, Yu; Li, Zeren; Chen, Guanghua; Peng, Qixian; Lei, Jiangbo; Liu, Jun; Yuan, Shuyun

    2017-02-01

    We propose and experimentally demonstrate a new all optical-framing photography that uses hyperspectral imaging methods to record a chirped pulse's temporal-spatial information. This proposed method consists of three parts: (1) a chirped laser pulse encodes temporal phenomena onto wavelengths; (2) a lenslet array generates a series of integral pupil images;(3) a dispersive device disperses the integral images at void space of image sensor. Compared with Ultrafast All-Optical Framing Technology(Daniel Frayer,2013,2014) and Sequentially Time All-Optical Mapping Photography( Nakagawa 2014, 2015), our method is convenient to adjust the temporal resolution and to flexibly increase the numbers of frames. Theoretically, the temporal resolution of our scheme is limited by the amount of dispersion that is added to a Fourier transform limited femtosecond laser pulse. Correspondingly, the optimal number of frames is decided by the ratio of the observational time window to the temporal resolution, and the effective pixels of each frame are mostly limited by the dimensions M×N of the lenslet array. For example, if a 40fs Fourier transform limited femtosecond pulse is stretched to 10ps, a CCD camera with 2048×3072 pixels can record 15 framing images with temporal resolution of 650fs and image size of 100×100 pixels. As spectrometer structure, our recording part has another advantage that not only amplitude images but also frequency domain interferograms can be imaged. Therefore, it is comparatively easy to capture fast dynamics in the refractive index change of materials. A further dynamic experiment is being conducted.

  14. All-optical nonlinear switching cell made of photonic crystal.

    Science.gov (United States)

    Wirth Lima, A; da Silva, Marcio G; Ferreira, A C; Sombra, A S B

    2009-07-01

    We analyze and propose a directional optical coupler embedded in photonic crystal, which is driven by an external command signal. Therefore, this switching cell can work in an all-optical switch. The switching method uses a low-power external command signal, inserted in the central coupling region, which acts as another waveguide. The switching process is based on the change from the bar state to the cross state due to the external command signal. In our simulations we used the plane wave expansion method, finite-difference time-domain method, and our own binary propagation method.

  15. All-optical photonic band control in a quantum metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    Felbacq, D.; Rousseau, E. [University of Montpellier, Laboratory Charles Coulomb UMR CNRS-UM 5221, Montpellier (France)

    2017-09-15

    Metamaterials made of periodic collections of dielectric nanorods are considered theoretically. When quantum resonators are embedded within the nanorods, one obtains a quantum metamaterial, whose electromagnetic properties depend upon the state of the quantum resonators. The theoretical model predicts that when the resonators are pumped and reach the inversion regime, the quantum metamaterial exhibits an all-optical switchable conduction band. The phenomenon can be described by considering the pole stucture of the scattering matrix of the metamaterial. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. All-Optical Switching in Photonic Crystal Cavities

    DEFF Research Database (Denmark)

    Heuck, Mikkel

    exhibiting Fano resonances. These devices were predicted to be superior to structures with the more well-known Lorentzian line shape in terms of energy consumption and switching contrast. Finally, the mathematical framework of optimal control theory was employed as a general setting, in which the optical......All-Optical switching in photonic crystal waveguide-cavity structures is studied predominantly theoretically and numerically, but also from an experimental point of view. We have calculated the first order perturbations to the resonance frequency and decay rate of cavity modes, using a mathematical...

  17. Realization of an all optical exciton-polariton router

    Energy Technology Data Exchange (ETDEWEB)

    Marsault, Félix; Nguyen, Hai Son; Tanese, Dimitrii; Lemaître, Aristide; Galopin, Elisabeth; Sagnes, Isabelle; Amo, Alberto [Laboratoire de Photonique et de Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis (France); Bloch, Jacqueline, E-mail: jacqueline.bloch@lpn.cnrs.fr [Laboratoire de Photonique et de Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis (France); Physics Department, Ecole Polytechnique, F-91128 Palaiseau Cedex (France)

    2015-11-16

    We report on the experimental realization of an all optical router for exciton-polaritons. This device is based on the design proposed by Flayac and Savenko [Appl. Phys. Lett. 103, 201105 (2013)], in which a zero-dimensional island is connected through tunnel barriers to two periodically modulated wires of different periods. Selective transmission of polaritons injected in the island, into either of the two wires, is achieved by tuning the energy of the island state across the band structure of the modulated wires. We demonstrate routing of ps polariton pulses using an optical control beam which controls the energy of the island quantum states, thanks to polariton-exciton interactions.

  18. Advanced all-optical logic gates on a spectral bus.

    Science.gov (United States)

    Hedekvist, P O; Bhardwaj, A; Vahala, K; Andersson, H

    2001-04-10

    We present experimental results on a new method for ultrafast all-optical logic, which utilizes four-wave mixing on polarization-modulated signals. The technique allows advanced operations such as exclusive-or and three-bit addition with carry bit. Furthermore, we show that on-the-fly error-correction encoding and decoding of a simple Hamming code is achieved when these gates are used on the bits of a spectrally structured word. These gates may be suitable for logic operations in an optoelectronic front end, which moves some of the necessary computation of data to the optical domain, before detection.

  19. Ultrasound pregnancy

    Science.gov (United States)

    ... sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; Placenta previa - ultrasound; Multiple pregnancy - ...

  20. All-optical noninvasive delayed feedback control of semiconductor lasers

    CERN Document Server

    Schikora, Sylvia

    2013-01-01

    The stabilization of unstable states hidden in the dynamics of a system, in particular the control of chaos, has received much attention in the last years. Sylvia Schikora for the first time applies a well-known control method called delayed feedback control entirely in the all-optical domain. A multisection semiconductor laser receives optical feedback from an external Fabry-Perot interferometer. The control signal is a phase-tunable superposition of the laser signal and provokes the laser to operate in an otherwise unstable periodic state with a period equal to the time delay. The control is noninvasive, because the reflected signal tends to zero when the target state is reached.   The work has been awarded the Carl-Ramsauer-Prize 2012.   Contents ·         All-Optical Control Setup ·         Stable States with Resonant Fabry-Perot Feedback ·         Control of an Unstable Stationary State and of Unstable Selfpulsations ·         Controlling Chaos ·         Con...

  1. Power requirements reducing of FBG based all-optical switching

    Science.gov (United States)

    Scholtz, Ľubomír.; Solanská, Michaela; Ladányi, Libor; Müllerová, Jarmila

    2017-12-01

    Although Fiber Bragg gratings (FBGs) are well known devices, their using as all-optical switching elements has been still examined. Current research is focused on optimization of their properties for their using in future all-optical networks. The main problem are high switching intensities needed for achieving the changes of the transmission state. Over several years switching intensities have been reduced from hundreds of GW/cm2 to tens of MW/cm2 by selecting appropriate gratings and signal parameters or using suitable materials. Two principal nonlinear effects with similar power requirements can result in the bistable transmission/reflection of an input optical pulse. In the self-phase modulation (SPM) regime switching is achieved by the intense probe pulse itself. Using cross-phase modulation (XPM) a strong pump alters the FBG refractive index experienced by a weak probe pulse. As a result of this the detuning of the probe pulse from the center of the photonic band gap occurs. Using of XPM the effect of modulation instability is reduced. Modulation instability which is the main SPM degradation mechanism. We focused on nonlinear FBGs based on chalcogenide glasses which are very often used in various applications. Thanks to high nonlinear parameters chalcogenide glasses are suitable candidates for reducing switching intensities of nonlinear FBGs.

  2. All-Optical Reconstruction of Crystal Band Structure.

    Science.gov (United States)

    Vampa, G; Hammond, T J; Thiré, N; Schmidt, B E; Légaré, F; McDonald, C R; Brabec, T; Klug, D D; Corkum, P B

    2015-11-06

    The band structure of matter determines its properties. In solids, it is typically mapped with angle-resolved photoemission spectroscopy, in which the momentum and the energy of incoherent electrons are independently measured. Sometimes, however, photoelectrons are difficult or impossible to detect. Here we demonstrate an all-optical technique to reconstruct momentum-dependent band gaps by exploiting the coherent motion of electron-hole pairs driven by intense midinfrared femtosecond laser pulses. Applying the method to experimental data for a semiconductor ZnO crystal, we identify the split-off valence band as making the greatest contribution to tunneling to the conduction band. Our new band structure measurement technique is intrinsically bulk sensitive, does not require a vacuum, and has high temporal resolution, making it suitable to study reactions at ambient conditions, matter under extreme pressures, and ultrafast transient modifications to band structures.

  3. All optical OFDM transmission for passive optical networks

    Science.gov (United States)

    Kachare, Nitin; Ashik T., J.; Bai, K. Kalyani; Kumar, D. Sriram

    2017-06-01

    This paper demonstrates the idea of data transmission at a very higher rate (Tbits/s) through optical fibers in a passive optical network using the most efficient data transmission technique widely used in wireless communication that is orthogonal frequency division multiplexing. With an increase in internet users, data traffic has also increased significantly and the current dense wavelength division multiplexing (DWDM) systems may not support the next generation passive optical networks (PONs) requirements. The approach discussed in this paper allows to increase the downstream data rate per user and extend the standard single-mode fiber reach for future long-haul applications. All-optical OFDM is a promising solution for terabit per second capable single wavelength transmission, with high spectral efficiency and high tolerance to chromatic dispersion.

  4. Optimised Design and Analysis of All-Optical Networks

    DEFF Research Database (Denmark)

    Glenstrup, Arne John

    2002-01-01

    -connects should be drastically cheaper if they are to compete on the cost with ring networks. An MPXS (multi-protocol wavelength switching) simulator is constructed, focusing especially on the timing in the setup phase to asess the blocking probability effect of node and link delays as well as wavelength...... is developed, based on shortest-path algorithms and a comparatively new metaheuristic called simulated allocation. It is able to handle design of all-optical mesh networks with optical cross-connects, considers duct as well as fibre and node costs, and can also design protected networks. The method is assessed...... level is presented. The method uses an unorthodox routing strategy focusing on common subpaths rather than individual connections, and strives to minimise switch port count as well as fibre usage. It is shown to produce cheaper network designs than previous methods when fibre costs are comparatively...

  5. All-optical coaxial framing photography using parallel coherence shutters.

    Science.gov (United States)

    Guanghua, Chen; Jianfeng, Li; Qixian, Peng; Shouxian, Liu; Jun, Liu

    2017-02-01

    An all-optical framing camera has been developed to obtain serial images of high temporal and spatial resolution with identical spatial benchmark, identical temporal benchmark, and identical chromatic benchmark in a single shot. A train of laser probe pulses with identical wavelength coaxially illuminate the target and form sequentially timed images by means of parallel coherence shutters. A coherence shutter only selects one of the probe pulses to form a nonmultiplexing hologram. The other probe pulses superpose incoherently on the hologram as the background. By this method, each hologram is entirely separated from the others both in spatial and temporal domains. Two kinds of ultrafast physical process experiments, including laser driving air and laser driving aluminum foil, were performed to verify the feasibility of the parallel coherence shutters.

  6. Broadband radiometer

    Science.gov (United States)

    Cannon, T.W.

    1994-07-26

    A broadband radiometer is disclosed including (a) an optical integrating sphere having generally spherical integrating chamber and an entry port for receiving light (e.g., having visible and ultraviolet fractions), (b) a first optical radiation detector for receiving light from the sphere and producing an electrical output signal corresponding to broadband radiation, (c) a second optical radiation detector for receiving light from the sphere and producing an electrical output signal corresponding to a predetermined wavelength fraction of the broadband radiation, and (d) an output for producing an electrical signal which is proportional to the difference between the two electrical output signals. The radiometer is very useful, for example, in measuring the absolute amount of ultraviolet light present in a given light sample. 8 figs.

  7. All-optical Compton gamma-ray source

    CERN Document Server

    Phuoc, K Ta; Thaury, C; Malka, V; Tafzi, A; Goddet, J P; Shah, R C; Sebban, S; Rousse, A; 10.1038/nphoton.2012.82

    2013-01-01

    One of the major goals of research for laser-plasma accelerators is the realization of compact sources of femtosecond X-rays. In particular, using the modest electron energies obtained with existing laser systems, Compton scattering a photon beam off a relativistic electron bunch has been proposed as a source of high-energy and high-brightness photons. However, laser-plasma based approaches to Compton scattering have not, to date, produced X-rays above 1 keV. Here, we present a simple and compact scheme for a Compton source based on the combination of a laser-plasma accelerator and a plasma mirror. This approach is used to produce a broadband spectrum of X-rays extending up to hundreds of keV and with a 10,000-fold increase in brightness over Compton X-ray sources based on conventional accelerators. We anticipate that this technique will lead to compact, high-repetition-rate sources of ultrafast (femtosecond), tunable (X- through gamma-ray) and low-divergence (~1 degree) photons from source sizes on the order...

  8. Photonic encryption : modeling and functional analysis of all optical logic.

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jason D.; Schroeppel, Richard Crabtree; Robertson, Perry J.

    2004-10-01

    With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple

  9. All-optical non-mechanical fiber-coupled sensor for liquid- and airborne sound detection.

    Science.gov (United States)

    Rohringer, Wolfgang; Preißer, Stefan; Fischer, Balthasar

    2017-04-01

    Most fiber-optic devices for pressure, strain or temperature measurements are based on measuring the mechanical deformation of the optical fiber by various techniques. While excellently suited for detecting strain, pressure or structure-borne sound, their sensitivity to liquid- and airborne sound is so far not comparable with conventional capacitive microphones or piezoelectric hydrophones. Here, we present an all-optical acoustic sensor which relies on the detection of pressure-induced changes of the optical refractive index inside a rigid, millimeter-sized, fiber-coupled Fabry-Pérot interferometer (FPI). No mechanically movable or deformable parts take part in the signal transduction chain. Therefore, due to the absence of mechanical resonances, this sensing principle allows for high sensitivity as well as a flat frequency response over an extraordinary measurement bandwidth. As a fiber-coupled device, it can be integrated easily into already available distributed fiber-optic networks for geophysical sensing. We present characterization measurements demonstrating the sensitivity, frequency response and directivity of the device for sound and ultrasound detection in air and water. We show that low-frequency temperature and pressure drifts can be recorded in addition to acoustic sensing. Finally, selected application tests of the laser-based hydrophone and microphone implementation are presented.

  10. Ultrasonic guided waves in composite plates: A study of interface bond condition and material properties determination with broadband focussed air coupled ultrasounds

    Science.gov (United States)

    Teles, Sorin Vasile

    This work is focused on two important aspects of the study of the composite materials: characterization of interface bonding in layered composites and evaluation of elastic material properties in air-coupled experiments. The characterization of interface condition in a layered composite is critical to understand the behavior of the material under various stress situations. A closed disbond, alternatively known as zero-volume disbond or " kissing-disbond" (KSD) is difficult to detection by conventional normal-incidence ultrasonic nondestructive evaluation (NDE) methods. Such undetected defect may be dangerous because it can produce a significant decrease in structural integrity or lead to a catastrophic failure under certain loading conditions. We have successfully demonstrated a new technique for KSD detection in carried-to-completion experiments involving various artificially created defects. The dependence of the modes of the propagating wave in a plate on the elastic material properties has motivated us to develop a method suitable for rapid non-contact reconstruction of the guided waves spectra. To overcome the weak and inefficient generation of ultrasonic waves in air of conventional transducers and to achieve the desired wide angular spread of the acoustic beam in air, we employed capacitive foil transducers and designed focusing devices. Measurements of the acoustic pressure profile of the transducers have been performed in both planar and focused configurations and compared with our computationally efficient received voltage model. We exploited our custom broadband focused air-coupled system and a synthetic aperture scan technique to produce, in one line scan with only one incident angle, an almost complete spectrum of the Rayleigh-Lamb waves of various engineering materials subject to a 700-kHz frequency and 16° angular bandwidth limitation of the transducers. A pulse-compression method along with a fast data acquisition and processing capability allowed

  11. Duplex ultrasound

    Science.gov (United States)

    Vascular ultrasound; Peripheral vascular ultrasound ... A duplex ultrasound combines: Traditional ultrasound: This uses sound waves that bounce off blood vessels to create pictures. Doppler ultrasound: This ...

  12. All-optical photoacoustic imaging and detection of early-stage dental caries

    Science.gov (United States)

    Sampathkumar, Ashwin; Hughes, David A.; Longbottom, Chris; Kirk, Katherine J.

    2015-02-01

    Dental caries remain one of the most common oral diseases in the world. Current detection methods, such as dental explorer and X-ray radiography, suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease because of the small size (caries. Ex-vivo teeth exhibiting early-stage, white-spot lesions were imaged using AOPAI. Experimental scans targeted each early-stage lesion and a reference healthy enamel region. Photoacoustic (PA) signals were generated in the tooth using a 532-nm pulsed laser and the light-induced broadband ultrasound signal was detected at the surface of the tooth with an optical path-stabilized Michelson interferometer operating at 532 nm. The measured time-domain signal was spatially resolved and back-projected to form 2D and 3D maps of the lesion using k-wave reconstruction methods. Experimental data collected from areas of healthy and diseased enamel indicate that the lesion generated a larger PA response compared to healthy enamel. The PA-signal amplitude alone was able to detect a lesion on the surface of the tooth. However, time- reversal reconstructions of the PA scans also quantitatively depicted the depth of the lesion. 3D PA reconstruction of the diseased tooth indicated a sub-surface lesion at a depth of 0.6 mm, in addition to the surface lesion. These results suggest that our AOPAI system is well suited for rapid clinical assessment of early-stage dental caries. An overview of the AOPAI system, fine-resolution PA and histology results of diseased and healthy teeth will be presented.

  13. Adoption of Broadband Services

    DEFF Research Database (Denmark)

    Falch, Morten

    2008-01-01

    Broadband is seen as a key infrastructure for developing the information society. For this reason many Governments are actively engaged in stimulating investments in broadband infrastructures and use of broadband services. This chapter compares a wide range of broadband strategies in the most...... successful markets for broadband. This is done through analysis of national policies in three European countries-Denmark, Sweden, and Germany-and the U.S., Japan, and South Korea. We concluded that successful implementation of broadband depends on the kind of policy measures to be taken at the national level...

  14. 40-Gb/s all-optical processing systems using hybrid photonic integration technology

    DEFF Research Database (Denmark)

    Kehayas, E.; Tsiokos, D.I.; Bakopoulos, P.

    2006-01-01

    This paper presents an experimental performance characterization of all-optical subsystems at 40 Gb/s using interconnected hybrid integrated all-optical semiconductor optical amplifier (SOA) Mach-Zehnder interferometer (MZI) gates and flip-flop prototypes. It was shown that optical gates can...

  15. All-optical signal processing at 10 GHz using a photonic crystal molecule

    Energy Technology Data Exchange (ETDEWEB)

    Combrié, Sylvain; Lehoucq, Gaëlle; Junay, Alexandra; De Rossi, Alfredo, E-mail: alfredo.derossi@thalesgroup.com [Thales Research and Technology, 1 Avenue A. Fresnel, 91767 Palaiseau (France); Malaguti, Stefania; Bellanca, Gaetano; Trillo, Stefano [Department of Engineering, Università di Ferrara, v. Saragat 1, 44122 Ferrara (Italy); Ménager, Loic [Thales Systèmes Aeroportés, 2 Av. Gay Lussac, 78851 Elancourt (France); Peter Reithmaier, Johann [Institute of Nanostructure Technologies and Analytics, CINSaT, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel (Germany)

    2013-11-04

    We report on 10 GHz operation of an all-optical gate based on an Indium Phosphide Photonic Crystal Molecule. Wavelength conversion and all-optical mixing of microwave signals are demonstrated using the 2 mW output of a mode locked diode laser. The spectral separation of the optical pump and signal is crucial in suppressing optical cross-talk.

  16. 160 Gb/s all-optical packet switching field experiment

    DEFF Research Database (Denmark)

    Dorren, H.J.S.; Herrera, J.; Raz, O.

    2007-01-01

    We discus an all-optical packet switching experiment over 110 km of field installed optical fiber. The switching node is controlled by solely photonic control circuits.......We discus an all-optical packet switching experiment over 110 km of field installed optical fiber. The switching node is controlled by solely photonic control circuits....

  17. PAPR Reduction in All-optical OFDM Systems Based on Phase Pre-emphasis

    Energy Technology Data Exchange (ETDEWEB)

    He Zhou; Li, Wei; Shao Jing; Liang Xiaojun; Huang Dexiu [Wuhan National Lab for Optoelectronics, Department of Optoelectronics Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Tao Zhiyong [State Key Laboratory of Optical Communication Technologies and Networks, Wuhan Research Institute of Posts and Telecommunications, Wuhan 430074 (China); Deng Zhuanhua, E-mail: hezhou@wri.com.cn, E-mail: weilee@mail.hust.edu.cn [School of Computer Science and Technology, Hubei University of Economics, Wuhan 430205 (China)

    2011-02-01

    This paper investigates the peak-to-average power ratio (PAPR) theory in all-optical orthogonal frequency division multiplexing (OFDM) optical fibre communication systems. We find out that phase pre-emphasis could effectively reduce PAPR in all-optical OFDM communication systems which employ intensity modulation-direct detection (IM-DD) method. An equation is developed and proposed to calculate suitable phasing values for pre-emphasis. Furthermore, we find out that phase pre-emphasis cannot reduce PAPR effectively in all-optical OFDM systems that employ Phase Shift Keying (PSK) or Quadracture Amplitude Modulation (QAM) method.

  18. High-speed optical transmission technology using all-optical signal processing

    Science.gov (United States)

    Kawanishi, Satoki

    2006-09-01

    This paper reviews recent progress on high-speed technologies for optical transmission systems in the IP and FTTH era. First, we describe our latest research results of 160 Gbit/s optical time-division multiplexing and demultiplexing experiments. The all-optical time-division multiplexer is realized as a hybrid integrated device consisting of planar lightwave circuits (PLC's) and highly-nonlinear periodically-poled lithium niobate (PPLN) waveguides while the demultiplexer is realized as a hybrid integrated device consisting of PLC's and semiconductor optical amplifiers. A new type of all-optical switch that uses a photonic crystal nanocavity and an all-optical flip-flop circuit that is composed of two-port resonant-tunneling filters based on a two dimensional photonic crystal slab with triangular air-hole lattice are shown. Finally, the possibility of over 100 Gbit/s all-optical signal processing is discussed for high-speed optical transmission systems.

  19. Semiconductor optical amplifier-based all-optical gates for high-speed optical processing

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2000-01-01

    Semiconductor optical amplifiers are useful building blocks for all-optical gates as wavelength converters and OTDM demultiplexers. The paper reviews the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using cross-phase modulatio....... These gates are very efficient for high-speed signal processing and open up interesting new areas, such as all-optical regeneration and high-speed all-optical logic functions......Semiconductor optical amplifiers are useful building blocks for all-optical gates as wavelength converters and OTDM demultiplexers. The paper reviews the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using cross-phase modulation...

  20. High bandwidth all-optical 3×3 switch based on multimode interference structures

    Science.gov (United States)

    Le, Duy-Tien; Truong, Cao-Dung; Le, Trung-Thanh

    2017-03-01

    A high bandwidth all-optical 3×3 switch based on general interference multimode interference (GI-MMI) structure is proposed in this study. Two 3×3 multimode interference couplers are cascaded to realize an all-optical switch operating at both wavelengths of 1550 nm and 1310 nm. Two nonlinear directional couplers at two outer-arms of the structure are used as all-optical phase shifters to achieve all switching states and to control the switching states. Analytical expressions for switching operation using the transfer matrix method are presented. The beam propagation method (BPM) is used to design and optimize the whole structure. The optimal design of the all-optical phase shifters and 3×3 MMI couplers are carried out to reduce the switching power and loss.

  1. Integrated all-optical logic discriminators based on plasmonic bandgap engineering.

    Science.gov (United States)

    Lu, Cuicui; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2013-09-27

    Optical computing uses photons as information carriers, opening up the possibility for ultrahigh-speed and ultrawide-band information processing. Integrated all-optical logic devices are indispensible core components of optical computing systems. However, up to now, little experimental progress has been made in nanoscale all-optical logic discriminators, which have the function of discriminating and encoding incident light signals according to wavelength. Here, we report a strategy to realize a nanoscale all-optical logic discriminator based on plasmonic bandgap engineering in a planar plasmonic microstructure. Light signals falling within different operating wavelength ranges are differentiated and endowed with different logic state encodings. Compared with values previously reported, the operating bandwidth is enlarged by one order of magnitude. Also the SPP light source is integrated with the logic device while retaining its ultracompact size. This opens up a way to construct on-chip all-optical information processors and artificial intelligence systems.

  2. Integrated all-optical logic discriminators based on plasmonic bandgap engineering

    Science.gov (United States)

    Lu, Cuicui; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2013-01-01

    Optical computing uses photons as information carriers, opening up the possibility for ultrahigh-speed and ultrawide-band information processing. Integrated all-optical logic devices are indispensible core components of optical computing systems. However, up to now, little experimental progress has been made in nanoscale all-optical logic discriminators, which have the function of discriminating and encoding incident light signals according to wavelength. Here, we report a strategy to realize a nanoscale all-optical logic discriminator based on plasmonic bandgap engineering in a planar plasmonic microstructure. Light signals falling within different operating wavelength ranges are differentiated and endowed with different logic state encodings. Compared with values previously reported, the operating bandwidth is enlarged by one order of magnitude. Also the SPP light source is integrated with the logic device while retaining its ultracompact size. This opens up a way to construct on-chip all-optical information processors and artificial intelligence systems. PMID:24071647

  3. All-Optical Regeneration System for Optical Wavelength Division Multiplexed Communication Systems

    DEFF Research Database (Denmark)

    2014-01-01

    an input WDM data signal comprising multiple wavelength channels into an input OTDM data signal comprising multiple time multiplexed time channels. The system further comprises an all-optical regenerator unit being configured for regenerating the input OTDM data signal into an output OTDM data signal....... The system additionally comprises an OTDM-to-WDM converter for converting the output OTDM data signal to an output WDM data signal. An input of the all-optical regenerator unit is in optical communication with an output of the WDM-to-OTDM converter, and an output of the all-optical regenerator unit...... is in optical communication with an input of the OTDM-to-WDM converter. The invention further relates to a method for all-optical regeneration of WDM data signals....

  4. All-Optical Terahertz Optical Asymmetric Demultiplexer (toad) Based Binary Comparator:. a Proposal

    Science.gov (United States)

    Chattopadhyay, Tanay

    Comparator determines whether a number is greater than, equals to or less than another number. It plays a significant role in fast central processing unit in all-optical scheme. In all-optical scheme here 1-bit binary comparator is proposed and described by Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch. Simulation result by Mathcad-7 is also given. Cascading technique of building up the n-bit binary comparator with this 1-bit comparator block is also proposed here.

  5. The cascaded amplifier and saturable absorber (CASA) all-optical switch

    DEFF Research Database (Denmark)

    Hilliger, E.; Berger, J.; Weber, H. G.

    2001-01-01

    The cascaded amplifier and saturable absorber is presented as a new all-optical switching scheme for optical signal processing applications. First demultiplexing experiments demonstrate the principle of operation of this scheme.......The cascaded amplifier and saturable absorber is presented as a new all-optical switching scheme for optical signal processing applications. First demultiplexing experiments demonstrate the principle of operation of this scheme....

  6. Ultracompact all-optical logic gates based on nonlinear plasmonic nanocavities

    OpenAIRE

    Yang Xiaoyu; Hu Xiaoyong; Yang Hong; Gong Qihuang

    2016-01-01

    In this study, nanoscale integrated all-optical XNOR, XOR, and NAND logic gates were realized based on all-optical tunable on-chip plasmon-induced transparency in plasmonic circuits. A large nonlinear enhancement was achieved with an organic composite cover layer based on the resonant excitation-enhancing nonlinearity effect, slow light effect, and field confinement effect provided by the plasmonic nanocavity mode, which ensured a low excitation power of 200 μW that is three orders of magnitu...

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound - Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer ...

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  9. All optical wavelength conversion and parametric amplification in Ti:PPLN channel waveguides for telecommunication applications

    Energy Technology Data Exchange (ETDEWEB)

    Nouroozi, Rahman

    2010-10-19

    Efficient ultra-fast integrated all-optical wavelength converters and parametric amplifiers transparent to the polarization, phase, and modulation-level and -format are investigated. The devices take advantage of the optical nonlinearity of Ti:PPLN waveguides exploiting difference frequency generation (DFG). In a DFG, the signal ({lambda}{sub s}) is mixed with a pump ({lambda}{sub p}) to generate a wavelength shifted idler (1/{lambda}{sub i}=1/{lambda}{sub p}-1/{lambda}{sub s}). Efficient generation of the pump in Ti:PPLN channel guides is investigated using different approaches. In the waveguide resonators, first a resonance of the fundamental wave alone is considered. It is shown that the maximum power enhancement of the fundamental wave, and therefore the maximum second-harmonic generation (SHG) efficiency, can be achieved with low loss matched resonators. By this way, SHG efficiency of {proportional_to}10300%/W (10.3 %/mW) has been achieved in a 65 mm long waveguide resonator. Its operation for cSHG/DFG requires narrowband reflector for fundamental wave only. Thus, the SH (pump) wave resonator is investigated. The SH-wave resonator enhances the intracavity SH power only. Based on this scheme, an improvement of {proportional_to}10 dB for cSHG/DFG based wavelength conversion efficiency has been achieved with 50 mW of coupled fundamental power in a 30 mm long Ti:PPLN. However, operation was limited to relatively small fundamental power levels (<50 mW) due to the onset of photorefractive instabilities destroying the cavity stabilization. The cSHG/DFG efficiency can be considerably improved by using a double-pass configuration in which all the interacting waves were reflected by a broadband dielectric mirror deposited on the one endface of the waveguide. Three different approaches are investigated and up to 9 dB improvement of the wavelength conversion efficiency in comparison with the single-pass configuration is achieved. Polarization-insensitive wavelength

  10. Broadband acoustic properties of a murine skull

    Science.gov (United States)

    Estrada, Héctor; Rebling, Johannes; Turner, Jake; Razansky, Daniel

    2016-03-01

    It has been well recognized that the presence of a skull imposes harsh restrictions on the use of ultrasound and optoacoustic techniques in the study, treatment and modulation of the brain function. We propose a rigorous modeling and experimental methodology for estimating the insertion loss and the elastic constants of the skull over a wide range of frequencies and incidence angles. A point-source-like excitation of ultrawideband acoustic radiation was induced via the absorption of nanosecond duration laser pulses by a 20 μm diameter microsphere. The acoustic waves transmitted through the skull are recorded by a broadband, spherically focused ultrasound transducer. A coregistered pulse-echo ultrasound scan is subsequently performed to provide accurate skull geometry to be fed into an acoustic transmission model represented in an angular spectrum domain. The modeling predictions were validated by measurements taken from a glass cover-slip and ex vivo adult mouse skulls. The flexible semi-analytical formulation of the model allows for seamless extension to other transducer geometries and diverse experimental scenarios involving broadband acoustic transmission through locally flat solid structures. It is anticipated that accurate quantification and modeling of the skull transmission effects would ultimately allow for skull aberration correction in a broad variety of applications employing transcranial detection or transmission of high frequency ultrasound.

  11. Prostate Ultrasound

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves ... the limitations of Prostate Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound ... limitations of Pelvic Ultrasound Imaging? What is Pelvic Ultrasound Imaging? Ultrasound is safe and painless, and produces ...

  13. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to ... Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces pictures ...

  14. All-Optical Signal processing using Highly Nonlinear Photonic Crystal Fiber

    DEFF Research Database (Denmark)

    Andersen, Peter Andreas

    2006-01-01

    The use of HNL-PCF in optical communication systems has been investigated in this thesis. The investigation has been done with respect to the future of telecommunications in an all-optical system. The PCFs used have all been used for all-optical signal processing as part of an optical component......-regeneration experiments have been reported [40] for high speed signals. An extensive investigation into using HNL-PCF as part of an alloptical wavelength converter has been performed in chapter 5. Especially FWM has been used in order to perform wavelength conversion since FWM is a transparent process. Using a HNL...... measurement results from various PCFs. The dispersion of a PCF was measured over 1100 nm and a zero dispersion wavelength at 1064 nm was found. The results obtained in the work presented in this thesis show that PCF technology and especially HNL-PCF can be used in an all-optical system for signal processing....

  15. Security Situation Assessment of All-Optical Network Based on Evidential Reasoning Rule

    Directory of Open Access Journals (Sweden)

    Zhong-Nan Zhao

    2016-01-01

    Full Text Available It is important to determine the security situations of the all-optical network (AON, which is more vulnerable to hacker attacks and faults than other networks in some cases. A new approach of the security situation assessment to the all-optical network is developed in this paper. In the new assessment approach, the evidential reasoning (ER rule is used to integrate various evidences of the security factors including the optical faults and the special attacks in the AON. Furthermore, a new quantification method of the security situation is also proposed. A case study of an all-optical network is conducted to demonstrate the effectiveness and the practicability of the new proposed approach.

  16. All-optical WDM Regeneration of DPSK Signals using Optical Fourier Transformation and Phase Sensitive Amplification

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Kjøller, Niels-Kristian

    2015-01-01

    We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time.......We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time....

  17. All-optical ultra-high-speed OFDM to Nyquist-WDM conversion

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

    2015-01-01

    We propose an all-optical ultra-high-speed OFDM to Nyquist-WDM conversion scheme based on complete OFT. An 8-subcarrier 640 Gbit/s DPSK OFDM super-channel is converted to eight 80-Gbit/s Nyquist-WDM channels with BER <10−9 performance for all channels.......We propose an all-optical ultra-high-speed OFDM to Nyquist-WDM conversion scheme based on complete OFT. An 8-subcarrier 640 Gbit/s DPSK OFDM super-channel is converted to eight 80-Gbit/s Nyquist-WDM channels with BER

  18. Experimental demonstration of cyclic prefix insertion for all-optical fractional OFDM

    Science.gov (United States)

    Nagashima, T.; Cincotti, G.; Murakawa, T.; Shimizu, S.; Hasegawa, M.; Hattori, K.; Okuno, M.; Mino, S.; Himeno, A.; Wada, N.; Uenohara, H.; Konishi, T.

    2017-08-01

    We verified the insertion effect of a cyclic prefix (CP) in an all-optical fractional orthogonal frequency division multiplexing (FrOFDM) system. CP is an essential technique for reducing inter-channel interference in conventional OFDM. Because a FrOFDM signal is generated by a fractional Fourier transform, which is a generalization of the Fourier transform, a CP is also effective for a FrOFDM signal. The measured bit error rate of a 4×10 Gbit/s DBPSK all-optical FrOFDM system showed that the CP improves the signal quality even if the performance of the time gate is insufficient.

  19. All-optical combination of DPSK and OOK to 160 Gbit/s DQPSK data signals

    DEFF Research Database (Denmark)

    Galili, Michael; Huettl, B.; Schmidt-Langhorst, C.

    2007-01-01

    All-optical combination of a DPSK and an OOK data signal to 160 Gbit/s DQPSK is proposed and demonstrated using highly nonlinear fiber. Error-free operation of the combiner is shown mid-span in a 320 km transmission link.......All-optical combination of a DPSK and an OOK data signal to 160 Gbit/s DQPSK is proposed and demonstrated using highly nonlinear fiber. Error-free operation of the combiner is shown mid-span in a 320 km transmission link....

  20. BER estimation for all-optical regenerators influenced by pattern effects

    DEFF Research Database (Denmark)

    Bischoff, Svend; Lading, B.; Mørk, Jesper

    2002-01-01

    An efficient method is presented for the estimation of the bit-error rate (BER) of a system employing all-optical regenerators influenced by pattern effects. We theoretically study noise accumulation and noise redistribution in long distance transmission systems employing a delayed interference...... signal wavelength converter for all-optical regeneration. The BER is studied for return-to-zero signals at bit rates of 2.5 Gb/s (no patterning) up to 40 Gb/s (strong patterning). The calculation of the BER is based on pattern dependent transfer functions, which may be obtained numerically or measured....

  1. Cascaded all-optical operations in a hybrid integrated 80-Gb/s logic circuit.

    Science.gov (United States)

    LeGrange, J D; Dinu, M; Sochor, T; Bollond, P; Kasper, A; Cabot, S; Johnson, G S; Kang, I; Grant, A; Kay, J; Jaques, J

    2014-06-02

    We demonstrate logic functionalities in a high-speed all-optical logic circuit based on differential Mach-Zehnder interferometers with semiconductor optical amplifiers as the nonlinear optical elements. The circuit, implemented by hybrid integration of the semiconductor optical amplifiers on a planar lightwave circuit platform fabricated in silica glass, can be flexibly configured to realize a variety of Boolean logic gates. We present both simulations and experimental demonstrations of cascaded all-optical operations for 80-Gb/s on-off keyed data.

  2. Analytical expression for the bit error rate of cascaded all-optical regenerators

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Bischoff, S.

    2003-01-01

    We derive an approximate analytical expression for the bit error rate of cascaded fiber links containing all-optical 2R-regenerators. A general analysis of the interplay between noise due to amplification and the degree of reshaping (nonlinearity) of the regenerator is performed....

  3. On-Chip All-Optical Switching and Memory by Silicon Photonic Crystal Nanocavities

    Directory of Open Access Journals (Sweden)

    Masaya Notomi

    2008-01-01

    Full Text Available We review our recent studies on all-optical switching and memory operations based on thermo-optic and carrier-plasma nonlinearities both induced by two-photon absorption in silicon photonic crystal nanocavities. Owing to high-Q and small volume of these photonic crystal cavities, we have demonstrated that the switching power can be largely reduced. In addition, we demonstrate that the switching time is also reduced in nanocavity devices because of their short diffusion time. These features are important for all-optical nonlinear processing in silicon photonics technologies, since silicon is not an efficient optical nonlinear material. We discuss the effect of the carrier diffusion process in our devices, and demonstrate improvement in terms of the response speed by employing ion-implantation process. Finally, we show that coupled bistable devices lead to all-optical logic, such as flip-flop operation. These results indicate that a nanocavity-based photonic crystal platform on a silicon chip may be a promising candidate for future on-chip all-optical information processing in a largely integrated fashion.

  4. Linear all-optical signal processing using silicon micro-ring resonators

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Xu, Jing

    2016-01-01

    Silicon micro-ring resonators (MRRs) are compact and versatile devices whose periodic frequency response can be exploited for a wide range of applications. In this paper, we review our recent work on linear all-optical signal processing applications using silicon MRRs as passive filters. We focus...

  5. Improving the All-Optical Response of SOAs Using a Modulated Holding Signal

    DEFF Research Database (Denmark)

    Bischoff, Svend; Nielsen, Mads Lønstrup; Mørk, Jesper

    2004-01-01

    A method for increasing the all-optical modulation bandwidth of semiconductor optical amplifiers (SOAs) by use of a cross-gain-modulated (XGM) holding signal is suggested and analyzed. The bandwidth improvement is numerically demonstrated by studying wavelength conversion in an SOA-based Mach...

  6. Efficient ultra-fast all-optical wavelength converters with Ti:PPLN waveguides

    DEFF Research Database (Denmark)

    Nouroozi, Rahman; Suche, Hubertus; Hu, Hao

    2014-01-01

    Applications of packaged and pigtailed (tunable) integrated all-optical Ti:PPLN wavelength converters (AOWC) with different modulation formats (RZ-DQPSK, 16-ary QAM) are reported. The devices take advantage of cascaded second order nonlinear interactions allowing tuning with either one or two...

  7. All-optical octave-broad ultrafast switching of Si woodpile photonic band gap crystals

    NARCIS (Netherlands)

    Euser, T.G.; Molenaar, Adriaan J.; Fleming, J.G.; Gralak, Boris; Polman, Albert; Vos, Willem L.

    2008-01-01

    We present ultrafast all-optical switching measurements of Si woodpile photonic band gap crystals. The crystals are spatially homogeneously excited and probed by measuring reflectivity over an octave in frequency (including the telecommunication range) as a function of time. After 300 fs, the

  8. Ultrafast coherent dynamics of a photonic crystal all-optical switch

    DEFF Research Database (Denmark)

    Colman, Pierre; Hansen, Per Lunnemann; Yu, Yi

    2016-01-01

    We present pump-probe measurements of an all-optical photonic crystal switch based on a nanocavity, resolving fast coherent temporal dynamics. The measurements demonstrate the importance of coherent effects typically neglected when considering nanocavity dynamics. In particular, we report...

  9. Ultrafast low-energy all-optical switching using a photonic-crystal asymmetric Fano structure

    DEFF Research Database (Denmark)

    Yu, Yi; Hu, Hao; Oxenløwe, Leif Katsuo

    2015-01-01

    We experimentally demonstrate 20 Gbit/s all-optical switching with low-energy consumption using a simple and ultra-compact InP photonic-crystal structure by employing a well-engineered Fano resonance in combination with broken mirror symmetry....

  10. Ultrafast dynamics in semiconductor optical amplifiers and all-optical processing: Bulk versus quantum dot devices

    DEFF Research Database (Denmark)

    Mørk, Jesper; Berg, Tommy Winther; Magnúsdóttir, Ingibjörg

    2003-01-01

    We discuss the dynamical properties of semiconductor optical amplifiers and the importance for all-optical signal processing. In particular, the dynamics of quantum dot amplifiers is considered and it is suggested that these may be operated at very high bit-rates without significant patterning...

  11. All-optical wavelength conversion by picosecond burst absorption in colloidal PbS quantum dots

    NARCIS (Netherlands)

    Geiregat, P.A.; Houtepen, A.J.; Van Thourhout, Dries; Hens, Zeger

    2016-01-01

    All-optical approaches to change the wavelength of a data signal are considered more energy-and cost-effective than current wavelength conversion schemes that rely on back and forth switching between the electrical and optical domains. However, the lack of cost-effective materials with

  12. All-optical clock recovery of NRZ-DPSK signals using optical resonator-type filters

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Seoane, Jorge; Ji, Hua

    2009-01-01

    It is shown how introducing a limited rise time to the driving signal enables all-optical clock recovery of NRZ-DPSK signals generated using a phase modulator. A Fabry-Perot filter is used to generate the optical clock....

  13. All-Optical Frequency Modulated High Pressure MEMS Sensor for Remote and Distributed Sensing

    DEFF Research Database (Denmark)

    Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

    2011-01-01

    We present the design, fabrication and characterization of a new all-optical frequency modulated pressure sensor. Using the tangential strain in a circular membrane, a waveguide with an integrated nanoscale Bragg grating is strained longitudinally proportional to the applied pressure causing a sh...

  14. Characterisation of a MQW electroabsorption modulator as an all-optical demultiplexer

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Romstad, Francis Pascal; Tersigni, Andrea

    2001-01-01

    A detailed experimental investigation of the all-optical switching properties of an InGaAsP MQW electroabsorption modulator has been performed. Using high pump pulse energies and high reverse bias settings, switching windows were demonstrated with extinction ratios up to 25 dB and widths down to 10...

  15. A study on Optical Labelling Techniques for All-Optical Networks

    DEFF Research Database (Denmark)

    Holm-Nielsen, Pablo Villanueva

    2005-01-01

    Optical switching has been proposed as an effective solution to overcoming the potential electronic bottleneck in all-optical network nodes carrying IP over WDM. The solution builds on the use of optical labelling as a mean to route packets or bursts of packets through the network. In addition to...

  16. Few-layer antimonene decorated microfiber: ultra-short pulse generation and all-optical thresholding with enhanced long term stability

    Science.gov (United States)

    Song, Yufeng; Liang, Zhiming; Jiang, Xiantao; Chen, Yunxiang; Li, Zhongjun; Lu, Lu; Ge, Yanqi; Wang, Ke; Zheng, Jilin; Lu, Shunbin; Ji, Jianhua; Zhang, Han

    2017-12-01

    Antimonene, a new type of mono/few-layer two-dimensional (2D) mono-elemental material purely consisting of antimony similar as graphene and phosphorene, has been theoretically predicted with excellent optical response and enhanced stability. Herein, we experimentally investigated the broadband nonlinear optical response of highly stable few-layer antimonene (FLA) by performing an open-aperture Z-scan laser measurement. Thanks to the direct bandgap and resonant absorption at the telecommunication band, we demonstrated the feasibility of FLA-decorated microfiber not only as an optical saturable absorber for ultrafast photonics operation, but also as a stable all-optical pulse thresholder that can effectively suppress the transmission noise, boost the signal-to-noise ratio (SNR), and reshape the deteriorated input signal. Our findings, as the first prototypic device of absorption of antimonene, might facilitate the development of antimonene-based optical communication technologies towards high stability and practical applications in the future.

  17. Routing and wavelength assignment based on normalized resource and constraints for all-optical network

    Science.gov (United States)

    Joo, Seong-Soon; Nam, Hyun-Soon; Lim, Chang-Kyu

    2003-08-01

    With the rapid growth of the Optical Internet, high capacity pipes is finally destined to support end-to-end IP on the WDM optical network. Newly launched 2D MEMS optical switching module in the market supports that expectations of upcoming a transparent optical cross-connect in the network have encouraged the field applicable research on establishing real all-optical transparent network. To open up a customer-driven bandwidth services, design of the optical transport network becomes more challenging task in terms of optimal network resource usage. This paper presents a practical approach to finding a route and wavelength assignment for wavelength routed all-optical network, which has λ-plane OXC switches and wavelength converters, and supports that optical paths are randomly set up and released by dynamic wavelength provisioning to create bandwidth between end users with timescales on the order of seconds or milliseconds. We suggest three constraints to make the RWA problem become more practical one on deployment for wavelength routed all-optical network in network view: limitation on maximum hop of a route within bearable optical network impairments, limitation on minimum hops to travel before converting a wavelength, and limitation on calculation time to find all routes for connections requested at once. We design the NRCD (Normalized Resource and Constraints for All-Optical Network RWA Design) algorithm for the Tera OXC: network resource for a route is calculated by the number of internal switching paths established in each OXC nodes on the route, and is normalized by ratio of number of paths established and number of paths equipped in a node. We show that it fits for the RWA algorithm of the wavelength routed all-optical network through real experiments on the distributed objects platform.

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, also called transrectal ultrasound, provides ...

  19. All-optical logic gates based on nanoscale plasmonic slot waveguides.

    Science.gov (United States)

    Fu, Yulan; Hu, Xiaoyong; Lu, Cuicui; Yue, Song; Yang, Hong; Gong, Qihuang

    2012-11-14

    We report realizations of nanoscale integrated all-optical XNOR, XOR, NOT, and OR logic gates using plasmonic slot waveguides based on linear interference between surface plasmon polariton modes. The miniature device size with lateral dimensions smaller than 5 μm, precisely controlled optical phase difference, and quasi-monochromatic surface plasmon polariton modes excited by a continuous wave 830 nm laser beam ensure a high intensity contrast ratio of 24 dB between the output logic states "1" and "0". Compared with previous reported results, the intensity contrast ratio is enhanced 4-fold, whereas the lateral dimension is reduced 4-fold. These compact logic devices are stable, robust, free from environmental impact, and much suitable for practical on-chip applications. These also provide a means to construct all-optical logic devices and nanophotonic processors.

  20. Ultrafast all-optical clock recovery based on phase-only linear optical filtering

    DEFF Research Database (Denmark)

    Maram, Reza; Kong, Deming; Galili, Michael

    2014-01-01

    We report on a novel, efficient technique for all-optical clock recovery from RZ-OOK data signals based on spectral phase-only (all-pass) optical filtering. This technique significantly enhances both the recovered optical clock quality and energy efficiency in comparison with conventional amplitu...... optical filtering approaches using a Fabry-Perot filter. The proposed concept is validated through recovery of the optical clock from a 640 Gbit/s RZ-OOK data signal using a commercial linear optical waveshaper. (C) 2014 Optical Society of America......We report on a novel, efficient technique for all-optical clock recovery from RZ-OOK data signals based on spectral phase-only (all-pass) optical filtering. This technique significantly enhances both the recovered optical clock quality and energy efficiency in comparison with conventional amplitude...

  1. All-optical code routing in interconnected optical CDMA and WDM ring networks.

    Science.gov (United States)

    Deng, Yanhua; Fok, Mable P; Prucnal, Paul R; Wang, Ting

    2010-11-01

    We propose an all-optical hybrid network composed of optical code division multiple access (CDMA) rings interconnecting through a reconfigurable wavelength division multiplexing (WDM) metro area ring. This network retains the advantages of both the optical CDMA and WDM techniques, including asynchronous access and differentiated quality of service, while removing the hard limit on the number of subscribers and increasing network flexibility. The all-optical network is enabled by using nonlinear optical loop mirrors in an add/drop router (ADR) that performs code conversion, dropping, and switching asynchronously. We experimentally demonstrate the functionalities of the ADR in the proposed scheme asynchronously and obtain error-free performance. The bit-error rate measurements show acceptable power penalties for different code routes.

  2. All-optically integrated photoacoustic and optical coherence tomography: A review

    Directory of Open Access Journals (Sweden)

    Wei Qiao

    2017-07-01

    Full Text Available All-optically integrated photoacoustic (PA and optical coherence tomography (OCT dual-mode imaging technology that could offer comprehensive pathological information for accurate diagnosis in clinic has gradually become a promising imaging technology in the aspect of biomedical imaging during the recent years. This review refers to the technology aspects of all-optical PA detection and system evolution of optically integrated PA and OCT, including Michelson interferometer dual-mode imaging system, Fabry–Perot (FP interferometer dual-mode imaging system and Mach–Zehnder interferometer dual-mode imaging system. It is believed that the optically integrated PA and OCT has great potential applications in biomedical imaging.

  3. Fast holonomic quantum computation based on solid-state spins with all-optical control

    Science.gov (United States)

    Zhou, Jian; Liu, BaoJie; Hong, ZhuoPing; Xue, ZhengYuan

    2018-01-01

    Holonomic quantum computation is a quantum computation strategy that promises some built-in noise-resilience features. Here, we propose a scheme for nonadiabatic holonomic quantum computation with nitrogen-vacancy center electron spins, which are characterized by fast quantum gates and long qubit coherence times. By varying the detuning, amplitudes, and phase difference of lasers applied to a nitrogen-vacancy center, one can directly realize an arbitrary single-qubit holonomic gate on the spin. Meanwhile, with the help of cavity-assisted interactions, a nontrivial two-qubit holonomic quantum gate can also be induced. The distinct merit of this scheme is that all the quantum gates are obtained via an all-optical geometric manipulation of the solid-state spins. Therefore, our scheme opens the possibility for robust quantum computation using solid-state spins in an all-optical way.

  4. Invited Article: All-optical multichannel logic based on coherent perfect absorption in a plasmonic metamaterial

    Directory of Open Access Journals (Sweden)

    Maria Papaioannou

    2016-12-01

    Full Text Available The exponential growth of telecommunications bandwidth will require next generation optical networks, where multiple spatial information channels will be transmitted in parallel. To realise the full potential of parallel optical data channels, fast and scalable multichannel solutions for processing of optical data are of paramount importance. Established solutions based on the nonlinear wave interaction in photorefractive materials are slow. Here we experimentally demonstrate all-optical logical operations between pairs of simulated spatially multiplexed information channels using the coherent interaction of light with light on a plasmonic metamaterial. The approach is suitable for fiber implementation and—in principle—operates with diffraction-limited spatial resolution, 100 THz bandwidth, and arbitrarily low intensities, thus promising ultrafast, low-power solutions for all-optical parallel data processing.

  5. Invited Article: All-optical multichannel logic based on coherent perfect absorption in a plasmonic metamaterial

    Science.gov (United States)

    Papaioannou, Maria; Plum, Eric; Valente, João; Rogers, Edward T. F.; Zheludev, Nikolay I.

    2016-12-01

    The exponential growth of telecommunications bandwidth will require next generation optical networks, where multiple spatial information channels will be transmitted in parallel. To realise the full potential of parallel optical data channels, fast and scalable multichannel solutions for processing of optical data are of paramount importance. Established solutions based on the nonlinear wave interaction in photorefractive materials are slow. Here we experimentally demonstrate all-optical logical operations between pairs of simulated spatially multiplexed information channels using the coherent interaction of light with light on a plasmonic metamaterial. The approach is suitable for fiber implementation and—in principle—operates with diffraction-limited spatial resolution, 100 THz bandwidth, and arbitrarily low intensities, thus promising ultrafast, low-power solutions for all-optical parallel data processing.

  6. Cascadable all-optical inverter based on a nonlinear vertical-cavity semiconductor optical amplifier

    Science.gov (United States)

    Zhang, Haijiang; Wen, Pengyue; Esener, Sadik

    2007-07-01

    We report, for the first time to our knowledge, the operation of a cascadable, low-optical-switching-power(˜10 μW) small-area (˜100 μm2) high-speed (80 ps fall time) all-optical inverter. This inverter employs cross-gain modulation, polarization gain anisotropy, and highly nonlinear gain characteristics of an electrically pumped vertical-cavity semiconductor optical amplifier (VCSOA). The measured transfer characteristics of such an optical inverter resemble those of standard electronic metal-oxide semiconductor field-effect transistor-based inverters exhibiting high noise margin and high extinction ratio (˜9.3 dB), making VCSOAs an ideal building block for all-optical logic and memory.

  7. All-Optical Noninvasive Control of Unstable Steady States in a Semiconductor Laser

    Science.gov (United States)

    Schikora, S.; Hövel, P.; Wünsche, H.-J.; Schöll, E.; Henneberger, F.

    2006-11-01

    All-optical noninvasive control of a multisection semiconductor laser by means of time-delayed feedback from an external Fabry-Perot cavity is realized experimentally. A theoretical analysis, in both a generic model as well as a device-specific simulation, points out the role of the optical phase. Using phase-dependent feedback we demonstrate stabilization of the continuous-wave laser output and noninvasive suppression of intensity pulsations.

  8. Transmission enhancement by deployment of interferometric wavelength converters within all-optical cross connects

    DEFF Research Database (Denmark)

    Poulsen, Henrik Nørskov; Mikkelsen, Benny; Stubkjær, Kristian

    1997-01-01

    Wavelength-division multiplexing (WDM) networks are expected to utilize all-optical cross connects (OXCN) for signal routing. Because a signal path is likely to contain a number of OXCNs, their cascadability is essential. Furthermore, because wavelength converters in the OXCNs improve traffic per...... performance and ease network management, their cascadability, in particular, is important. Using interferometric wavelength converters (IWCs) we have previously demonstrated experimentally a cascade of 10 converters at 10 Gbit/s with...

  9. Resolution-Enhanced All-Optical Analog-to-Digital Converter Employing Cascade Optical Quantization Operation

    OpenAIRE

    Kang, Zhe; Zhang, Xianting; Yuan, Jinhui; Sang, Xinzhu; Wu, Qiang

    2014-01-01

    In this paper, a cascade optical quantization scheme is proposed to realize all-optical analog-to-digital converter with efficiently enhanced quantization resolution and achievable high analog bandwidth of larger than 20 GHz. Employing the cascade structure of an unbalanced Mach-zehnder modulator and a specially designed optical directional coupler, we predict the enhancement of number-of-bits can be up to 1.59-bit. Simulation results show that a 25 GHz RF signal is efficiently digitalized wi...

  10. All-optical signal processing in novel highly nonlinear fibres and waveguides

    OpenAIRE

    Ettabib, Mohamed A.

    2014-01-01

    All-optical signal processing has recently become an attractive research field, a result of nonlinear optical systems making major advances in terms of cost, compactness, energy consumption, integrability and reliability. This technology has impacted several areas ranging from telecommunications and biomolecular sensing to military and quantum communications, and spanning a vast range of frequencies from the near to mid-infrared. This PhD research project was aimed at investigating the featur...

  11. Realization of all-optical switch and diode via Raman gain process using a Kerr field

    Science.gov (United States)

    Abbas, Muqaddar; Qamar, Sajid; Qamar, Shahid

    2016-08-01

    The idea of optical photonic crystal, which is generated using two counter-propagating fields, is revisited to study gain-assisted all-optical switch and diode using Kerr field. Two counter-propagating fields with relative detuning Δ ν generate standing-wave field pattern which interacts with a four-level atomic system. The standing-wave field pattern acts like a static photonic crystal for Δ ν =0 , however, it behaves as a moving photonic crystal for Δ ν \

  12. All-Optical Switching Improvement Using Photonic-Crystal Fano Structures

    DEFF Research Database (Denmark)

    Yu, Yi; Xue, Weiqi; Hu, Hao

    2016-01-01

    by incorporating a partially transmitting element in the waveguide. Compared to traditional Lorentzian structures, the Fano structure shows improved switching contrast and speed without adding any extra phase modulation, corresponding to a much lower chirp parameter. Using a simple and ultracompact InP photonic......-crystal Fano structure with broken mirror symmetry, we experimentally demonstrate 20-Gb/s all-optical switching with low-energy consumption....

  13. Femtojoule-scale all-optical latching and modulation via cavity nonlinear optics.

    Science.gov (United States)

    Kwon, Yeong-Dae; Armen, Michael A; Mabuchi, Hideo

    2013-11-15

    We experimentally characterize Hopf bifurcation phenomena at femtojoule energy scales in a multiatom cavity quantum electrodynamical (cavity QED) system and demonstrate how such behaviors can be exploited in the design of all-optical memory and modulation devices. The data are analyzed by using a semiclassical model that explicitly treats heterogeneous coupling of atoms to the cavity mode. Our results highlight the interest of cavity QED systems for ultralow power photonic signal processing as well as for fundamental studies of mesoscopic nonlinear dynamics.

  14. Ultracompact all-optical full-adder and half-adder based on nonlinear plasmonic nanocavities

    OpenAIRE

    Xie Jingya; Niu Xinxiang; Hu Xiaoyong; Wang Feifan; Chai Zhen; Yang Hong; Gong Qihuang

    2017-01-01

    Ultracompact chip-integrated all-optical half- and full-adders are realized based on signal-light induced plasmonic-nanocavity-modes shift in a planar plasmonic microstructure covered with a nonlinear nanocomposite layer, which can be directly integrated into plasmonic circuits. Tremendous nonlinear enhancement is obtained for the nanocomposite cover layer, attributed to resonant excitation, slow light effect, as well as field enhancement effect provided by the plasmonic nanocavity. The featu...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... are the limitations of Pelvic Ultrasound Imaging? What is Pelvic Ultrasound Imaging? Ultrasound is safe and painless, ... top of page What are some common uses of the procedure? In women, a pelvic ultrasound is ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  17. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to produce pictures of a man’s prostate ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones ... to Ultrasound - Pelvis Videos related to ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... 3-D ultrasound or sonohysterography for patients with infertility. In this setting, three-dimensional ultrasound provides information ... Ultrasound page for more information. In men and women, a pelvic ultrasound exam can help identify: kidney ...

  20. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Ultrasound - Prostate Ultrasound of the prostate uses sound waves to produce pictures of a man’s prostate gland ... of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or sonography , ...

  1. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Prostate Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces ... of page What are some common uses of the procedure? A transrectal ultrasound of the prostate gland ...

  2. Chip-integrated ultrawide-band all-optical logic comparator in plasmonic circuits.

    Science.gov (United States)

    Lu, Cuicui; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2014-01-27

    Optical computing opens up the possibility for the realization of ultrahigh-speed and ultrawide-band information processing. Integrated all-optical logic comparator is one of the indispensable core components of optical computing systems. Unfortunately, up to now, no any nanoscale all-optical logic comparator suitable for on-chip integration applications has been realized experimentally. Here, we report a subtle and effective technical solution to circumvent the obstacles of inherent Ohmic losses of metal and limited propagation length of SPPs. A nanoscale all-optical logic comparator suitable for on-chip integration applications is realized in plasmonic circuits directly. The incident single-bit (or dual-bit) logic signals can be compared and the comparison results are endowed with different logic encodings. An ultrabroad operating wavelength range from 700 to 1000 nm, and an ultrahigh output logic-state contrast-ratio of more than 25 dB are realized experimentally. No high power requirement is needed. Though nanoscale SPP light source and the logic comparator device are integrated into the same plasmonic chip, an ultrasmall feature size is maintained. This work not only paves a way for the realization of complex logic device such as adders and multiplier, but also opens up the possibility for realizing quantum solid chips based on plasmonic circuits.

  3. All-optical tunable buffering with coupled ultra-high Q whispering gallery mode microcavities.

    Science.gov (United States)

    Yoshiki, Wataru; Honda, Yoshihiro; Tetsumoto, Tomohiro; Furusawa, Kentaro; Sekine, Norihiko; Tanabe, Takasumi

    2017-09-06

    All-optical tunable buffering was recently achieved on a chip by using dynamically tuned coupled mode induced transparency, which is an optical analogue of electromagnetically induced transparency. However, the small Q s of about 105 used in those systems were limiting the maximum buffering time to a few hundred ps. Although employing an ultra-high Q whispering gallery mode (WGM) microcavity can significantly improve the maximum buffering time, the dynamic tuning of the WGM has remained challenging because thermo-optic and pressure tunings, which are widely used for WGM microcavities, have a very slow response. Here we demonstrate all-optical tunable buffering utilizing coupled ultra-high Q WGM cavities and the Kerr effect. The Kerr effect can change the refractive index instantaneously, and this allowed us to tune the WGM cavity very quickly. In addition, from among the various WGM cavities we employed a silica toroid microcavity for our experiments because it has an ultra-high Q factor (>2 × 107) and a small mode volume, and can be fabricated on a chip. Use of the Kerr effect and the silica toroid microcavity enabled us to observe an on-chip all-optical tunable buffering operation and achieve a maximum buffering time of 20 ns.

  4. Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

    Science.gov (United States)

    Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

    2014-08-01

    Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

  5. All-Optical Wavelength Conversion by Picosecond Burst Absorption in Colloidal PbS Quantum Dots.

    Science.gov (United States)

    Geiregat, Pieter; Houtepen, Arjan J; Van Thourhout, Dries; Hens, Zeger

    2016-01-26

    All-optical approaches to change the wavelength of a data signal are considered more energy- and cost-effective than current wavelength conversion schemes that rely on back and forth switching between the electrical and optical domains. However, the lack of cost-effective materials with sufficiently adequate optoelectronic properties hampers the development of this so-called all-optical wavelength conversion. Here, we show that the interplay between intraband and band gap absorption in colloidal quantum dots leads to a very strong and ultrafast modulation of the light absorption after photoexcitation in which slow components linked to exciton recombination are eliminated. This approach enables all-optical wavelength conversion at rates matching state-of-the-art convertors in speed, yet with cost-effective solution-processable materials. Moreover, the stronger light-matter interaction allows for implementation in small-footprint devices with low switching energies. Being a generic property, the demonstrated effect opens a pathway toward low-power integrated photonics based on colloidal quantum dots as the enabling material.

  6. Chip-integrated ultrawide-band all-optical logic comparator in plasmonic circuits

    Science.gov (United States)

    Lu, Cuicui; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2014-01-01

    Optical computing opens up the possibility for the realization of ultrahigh-speed and ultrawide-band information processing. Integrated all-optical logic comparator is one of the indispensable core components of optical computing systems. Unfortunately, up to now, no any nanoscale all-optical logic comparator suitable for on-chip integration applications has been realized experimentally. Here, we report a subtle and effective technical solution to circumvent the obstacles of inherent Ohmic losses of metal and limited propagation length of SPPs. A nanoscale all-optical logic comparator suitable for on-chip integration applications is realized in plasmonic circuits directly. The incident single-bit (or dual-bit) logic signals can be compared and the comparison results are endowed with different logic encodings. An ultrabroad operating wavelength range from 700 to 1000 nm, and an ultrahigh output logic-state contrast-ratio of more than 25 dB are realized experimentally. No high power requirement is needed. Though nanoscale SPP light source and the logic comparator device are integrated into the same plasmonic chip, an ultrasmall feature size is maintained. This work not only paves a way for the realization of complex logic device such as adders and multiplier, but also opens up the possibility for realizing quantum solid chips based on plasmonic circuits. PMID:24463956

  7. Broadband Electromagnetic Technology

    Science.gov (United States)

    2011-06-23

    The objectives of this project are to continue the enhancements to the combined Broadband Electromagnetic and Full Encirclement Unit (BEM-FEU) technologies and to evaluate the systems capability in the laboratory and the field. The BEM instrument ...

  8. Broadband Radiometric LED Measurements.

    Science.gov (United States)

    Eppeldauer, G P; Cooksey, C C; Yoon, H W; Hanssen, L M; Podobedov, V B; Vest, R E; Arp, U; Miller, C C

    2016-01-01

    At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed.

  9. Broadband Radiometric LED Measurements

    Science.gov (United States)

    Eppeldauer, G. P.; Cooksey, C. C.; Yoon, H. W.; Hanssen, L. M.; Podobedov, V. B.; Vest, R. E.; Arp, U.; Miller, C. C.

    2017-01-01

    At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed. PMID:28649167

  10. All-optical XOR and OR by Mach-Zehnder Interferometer engineered photonic crystal fibers

    Science.gov (United States)

    Sales, J. C.; Filho, A. F. G. F.; Ferreira, A. C.; Sousa, J. R. R.; Sobrinho, C. S.; Menezes, J. W. M.; Guimarães, G. F.; Sombra, A. S. B.

    2017-09-01

    In this paper, we present a numerical investigation of all-optical logic gates based on a Mach-Zehnder Interferometer (MZI) configuration of micro structured fibers, also known as photonic crystal fibers (PCF) under optical OOK (on-off keying). We determine several relevant quantities to characterize the system performance, such as transmission and extinction ratio as a function of the nonlinearity profile (β) added to one of the Mach-Zehnder Interferometer (MZI) arms. High-order effects such as third-order dispersion, intrapulse Raman scattering and self-steepening were included in the generalized nonlinear Schrödinger equation describing the pulse propagation. For this study, we used an optical pulse with a shape of hyperbolic secant of 100 fs (femtosecond). A pumped laser with three power values was simulated. With critical power Pc = 103.5 kW (P = Pc), below the critical power P = 90 kW (P Pc). We added a nonlinearity profile in one of the Mach-Zehnder Interferometer (MZI) arms. Nonlinearity profiles were expressed in terms of the parameter β. We studied three different profiles: constant, increasing and decreasing. Our results show that the proposed device can be used to obtain all-optical OR and XOR logic gates as well as logic functions A and A . B bar . The OR logic gate was the one which achieved the greatest FOMELG (Figure of Merit of Logic Gates) when using increasing profile with critical power (P0 = 103.5 kW) for β = 1.05 and FOMELG = 15.68 dB. The XOR logic gate presented the greatest FOMELG = 7.75 dB when using the decreasing profile with power below the critical (P0 = 90 kW) for β = 1.44. These results provide support for applications in all-optical networks.

  11. Sensitivity improvement of optical fiber acoustic probe for all-optical photoacoustic imaging system

    Science.gov (United States)

    Seki, Atsushi; Iwai, Katsumasa; Katagiri, Takashi; Matsuura, Yuji

    2017-07-01

    An acoustic probe based on a Fabry-Perot interferometer composed of a polymer film attached to the end of an optical fiber was designed and fabricated for an endoscopic, all-optical photoacoustic imaging system. The finesse of the interferometer was improved by forming a half-mirror at the end of the fiber and a partial reflection mirror on the outer surface of the polymer film. A photoacoustic imaging system was constructed by combining the fiber-optic acoustic probe with a bundle of hollow optical fibers used for the excitation of the photoacoustic wave, and an image of blood capillaries in a fish ovarian membrane was successfully obtained.

  12. Simple nonlinear interferometer-based all-optical thresholder and its applications for optical CDMA.

    Science.gov (United States)

    Kravtsov, Konstantin; Prucnal, Paul R; Bubnov, Mikhail M

    2007-10-01

    We present an experimental demonstration of an ultrafast all-optical thresholder based on a nonlinear Sagnac interferometer. The proposed design is intended for operation at very small nonlinear phase shifts. Therefore, it requires an in-loop nonlinearity lower than for the classical nonlinear loop mirror scheme. Only 15 meters of conventional (non-holey) silica-based fiber is used as a nonlinear element. The proposed thresholder is polarization insensitive and is good for multi-wavelength operation, meeting all the requirements for autocorrelation detection in various optical CDMA communication systems. The observed cubic transfer function is superior to the quadratic transfer function of second harmonic generation-based thresholders.

  13. Self-deflection and all-optical beam steering in CdZnTe.

    Science.gov (United States)

    Shwartz, Sharon; Segev, Mordechai; El-Hanany, Uri

    2004-04-01

    We report on the experimental observation of very large self-deflection of optical beams, along with all-optical steering, and electro-optic beam deflection. We observe as many as 27 resolvable spots of deflection at 1-W/cm2 intensity. These deflections arise from enhanced photorefractive effects in CdZnTe:V, giving rise to optically induced index changes in excess of 0.08, which is to our knowledge the strongest nonlinearity ever reported for any bulk semiconductor.

  14. All-optical XOR and NAND logic gates based on plasmonic nanoparticles

    Science.gov (United States)

    Nozhat, Najmeh; Alikomak, Hamid; Khodadadi, Maryam

    2017-06-01

    In this paper, all-optical XOR and NAND logic gates based on gold disk-shaped nanoparticles have been proposed. The proposed structure consists of a non-periodic array of disk-shaped nanoparticles that are placed on SiO2 substrate. The gates function is based on the constructive and destructive interferences between the input signals. For the NAND gate the phase difference between the input signals has been used to create a destructive interference. The most advantages of these structures are subwavelength dimensions and high contrast ratio of about 26 dB and 24 dB for the XOR and NAND logic gates, respectively.

  15. Efficient all-optical switch using a Λ atom in a cavity QED system

    DEFF Research Database (Denmark)

    Nielsen, Anne E. B.; Kerckhoff, Joseph

    2011-01-01

    We propose an all-optical switch constructed from a two-mode optical resonator containing a strongly coupled, three-state system. The coupling allows a weak, continuous wave laser drive to incoherently control the transmission of a much stronger, continuous wave signal laser into (and through......) the resonator. We demonstrate that in this simple setup the presence of a control drive with 1/10th the power of the signal drive can induce near complete reflection of the signal, while its absence allows for near complete transmission. The switch can also be operated as a set-reset relay with two control...

  16. All-optical mitigation of amplitude and phase-shift drift noise in semiconductor optical amplifiers

    Science.gov (United States)

    Rocha, Peterson; Gallep, Cristiano M.; Conforti, Evandro

    2015-10-01

    An all-optical scheme aimed at minimizing distortions induced by semiconductor optical amplifiers (SOAs) over modulated optical carriers is presented. The scheme employs an additional SOA properly biased to act as a saturated absorber, and thus counteract the distortions induced by the first amplifying device. The scheme here is demonstrated in silico, for 40 and 100 Gb/s (10 and 25 Gbaud, 16 QAM), with reasonable total gain (>20 dB) for symbol error rate below the forward error correction limit.

  17. Design of integrated all optical digital to analog converter (DAC) using 2D photonic crystals

    Science.gov (United States)

    Moniem, Tamer A.; El-Din, Eman S.

    2017-11-01

    A novel design of all optical 3 bit digital to analog (DAC) converter will be presented in this paper based on 2 Dimension photonic crystals (PhC). The proposed structure is based on the photonic crystal ring resonators (PCRR) with combining the nonlinear Kerr effect on the PCRR. The total size of the proposed optical 3 bit DAC is equal to 44 μm × 37 μm of 2D square lattice photonic crystals of silicon rods with refractive index equal to 3.4. The finite different time domain (FDTD) and Plane Wave Expansion (PWE) methods are used to back the overall operation of the proposed optical DAC.

  18. Resolution-enhanced all-optical analog-to-digital converter employing cascade optical quantization operation.

    Science.gov (United States)

    Kang, Zhe; Zhang, Xianting; Yuan, Jinhui; Sang, Xinzhu; Wu, Qiang; Farrell, Gerald; Yu, Chongxiu

    2014-09-08

    In this paper, a cascade optical quantization scheme is proposed to realize all-optical analog-to-digital converter with efficiently enhanced quantization resolution and achievable high analog bandwidth of larger than 20 GHz. Employing the cascade structure of an unbalanced Mach-zehnder modulator and a specially designed optical directional coupler, we predict the enhancement of number-of-bits can be up to 1.59-bit. Simulation results show that a 25 GHz RF signal is efficiently digitalized with the signal-to-noise ratio of 33.58 dB and effective-number-of-bits of 5.28-bit.

  19. All-optical Data Vortex node using an MZI-SOA switch array

    DEFF Research Database (Denmark)

    Jung, H.D.; Tafur Monroy, Idelfonso; Koonen, A.M.J.

    2007-01-01

    We propose and demonstrate a new structure of a Data Vortex switch node for all-optical routing of wavelength-division-multiplexing (WDM) 10-Gb/s optical packets. The proposed node consists of two Mach-Zehnder interferometers with integrated semiconductor optical amplifier: an optical AND gate...... and a high-speed optical switch. In the experiment, WDM 10-Gb/s data packets are successfully routed with 1-dB power penalty at a bit-error rate of 10(-9)....

  20. All-Optical Control of the Ultrafast Dynamics of a Hybrid Plasmonic System

    Science.gov (United States)

    Utikal, Tobias; Stockman, Mark I.; Heberle, Albert P.; Lippitz, Markus; Giessen, Harald

    2010-03-01

    We demonstrate complete all-optical and phase-stable control of the linear optical polarization and the nonlinear coherent response (third-harmonic generation) of a hybrid nanoplasmonic-photonic system. A few tens of femtoseconds after the excitation, we turn the response on and off at any given point in time and probe its temporal evolution throughout the control process with a three-pulse nonlinear optical technique. After being switched off, the polarization and the nonlinear radiation remain off permanently. All experiments agree well with numerical simulations based on a damped harmonic oscillator model.

  1. Simultaneous all-optical AND and NOR gates for NRZ differential phase-shift-keying signals

    DEFF Research Database (Denmark)

    Xu, Jing; Zhang, X.; Dong, J.

    2008-01-01

    A scheme for realizing all-optical logic AND and NOR gates simultaneously for nonreturn-to-zero differential phase-shift-keying signals is proposed and demonstrated based on a delayed interferometer and two semiconductor optical amplifiers. Experimental demonstration at 20 Gb/s verifies the logic...... integrity of this scheme. The final results are derived in the ON–OFF keying format with clear open eyes and extinction ratios over 10 dB. The proposed scheme can be expanded to realize arbitrary logic gate....

  2. All-optical 10 Gb/s AND logic gate in a silicon microring resonator

    DEFF Research Database (Denmark)

    Xiong, Meng; Lei, Lei; Ding, Yunhong

    2013-01-01

    An all-optical AND logic gate in a single silicon microring resonator is experimentally demonstrated at 10 Gb/s with 50% RZ-OOK signals. By setting the wavelengths of two intensity-modulated input pumps on the resonances of the microring resonator, field-enhanced four-wave mixing with a total input...... power of only 8.5 dBm takes place in the ring, resulting in the generation of an idler whose intensity follows the logic operation between the pumps. Clear and open eye diagrams with a bit-error- ratio below 10−9 are achieved....

  3. All-optical time-resolved measurement of laser energy modulation in a relativistic electron beam

    Directory of Open Access Journals (Sweden)

    D. Xiang

    2011-11-01

    Full Text Available We propose and demonstrate an all-optical method to measure laser energy modulation in a relativistic electron beam. In this scheme the time-dependent energy modulation generated from the electron-laser interaction in an undulator is converted into time-dependent density modulation with a chicane, which is measured to infer the laser energy modulation. The method, in principle, is capable of simultaneously providing information on femtosecond time scale and 10^{-5} energy scale not accessible with conventional methods. We anticipate that this method may have wide applications in many laser-based advanced beam manipulation techniques.

  4. Improving Multi Access Interference Suppression in Optical CDMA by using all-Optical Signal Processing

    Directory of Open Access Journals (Sweden)

    T. B. Osadola

    2013-06-01

    Full Text Available This paper presents the study of a novel all-optical method for processing optical CDMA signals towards improving suppression of multi access interference. The main focus is on incoherent OCDMA systems using multiwavelength 2D-WH/TS codes generated using FBG based encoders and decoders. The MAI suppression capabilities based on its ability to eliminate selective wavelength pulse processing have been shown. A novel transmitter architecture that achieves up to 3dB power saving was also presented. As a result of hardware savings, processing cost will be significantly reduced and power budget improvement resulted in improved performance.

  5. Theoretical modeling of index contrast towards all-optical switching in fiber Bragg grating

    Science.gov (United States)

    Koli, Shradha C.; Pandey, Chandan A.; Hornyak, Gabor L.; Mohammed, Waleed S.

    2015-07-01

    This paper deals with mathematical modeling and study of nonlinear switching in optical fiber Bragg gratings (FBG) by a transfer matrix method. Critical parameters contributing to high performance nonlinear fiber Bragg grating were studied. The transmission spectrum centered at 1550 nm was analyzed with varying number of layers and refractiveindices. The study showed that by proper modification in grating length of the FBG, we were able to optimize transmission spectrum for required application. The nonlinear behavior of FBGs can be further applied in optical switching applications (all-optical logic gates).

  6. A type of all-optical logic gate based on graphene surface plasmon polaritons

    Science.gov (United States)

    Wu, Xiaoting; Tian, Jinping; Yang, Rongcao

    2017-11-01

    In this paper, a novel type of all-optical logic device based on graphene surface plasmon polaritons (GSP) is proposed. By utilizing linear interference between the GSP waves propagating in the different channels, this new structure can realize six different basic logic gates including OR, XOR, NOT, AND, NOR, and NAND. The state of ;ON/OFF; of each input channel can be well controlled by tuning the optical conductivity of graphene sheets, which can be further controlled by changing the external gate voltage. This type of logic gate is compact in geometrical sizes and is a potential block in the integration of nanophotonic devices.

  7. Ultrasensitive plano-concave optical microresonators for ultrasound sensing

    Science.gov (United States)

    Guggenheim, James A.; Li, Jing; Allen, Thomas J.; Colchester, Richard J.; Noimark, Sacha; Ogunlade, Olumide; Parkin, Ivan P.; Papakonstantinou, Ioannis; Desjardins, Adrien E.; Zhang, Edward Z.; Beard, Paul C.

    2017-11-01

    Highly sensitive broadband ultrasound detectors are needed to expand the capabilities of biomedical ultrasound, photoacoustic imaging and industrial ultrasonic non-destructive testing techniques. Here, a generic optical ultrasound sensing concept based on a novel plano-concave polymer microresonator is described. This achieves strong optical confinement (Q-factors > 105) resulting in very high sensitivity with excellent broadband acoustic frequency response and wide directivity. The concept is highly scalable in terms of bandwidth and sensitivity. To illustrate this, a family of microresonator sensors with broadband acoustic responses up to 40 MHz and noise-equivalent pressures as low as 1.6 mPa per √Hz have been fabricated and comprehensively characterized in terms of their acoustic performance. In addition, their practical application to high-resolution photoacoustic and ultrasound imaging is demonstrated. The favourable acoustic performance and design flexibility of the technology offers new opportunities to advance biomedical and industrial ultrasound-based techniques.

  8. Direct UV-written broadband directional broadband planar waveguide couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    We report the fabrication of broadband directional couplers by direct UV-writing. The fabrication process is shown to be beneficial, robust and flexible. The components are compact and show superior performance in terms of loss and broadband operation....

  9. Experimental validation of optical layer performance monitoring using an all-optical network testbed

    Science.gov (United States)

    Vukovic, Alex; Savoie, Michel J.; Hua, Heng

    2004-11-01

    Communication transmission systems continue to evolve towards higher data rates, increased wavelength densities, longer transmission distances and more intelligence. Further development of dense wavelength division multiplexing (DWDM) and all-optical networks (AONs) will demand ever-tighter monitoring to assure a specified quality of service (QoS). Traditional monitoring methods have been proven to be insufficient. Higher degree of self-control, intelligence and optimization for functions within next generation networks require new monitoring schemes to be developed and deployed. Both perspective and challenges of performance monitoring, its techniques, requirements and drivers are discussed. It is pointed out that optical layer monitoring is a key enabler for self-control of next generation optical networks. Aside from its real-time feedback and the safeguarding of neighbouring channels, optical performance monitoring ensures the ability to build and control complex network topologies while maintaining an efficiently high QoS. Within an all-optical network testbed environment, key performance monitoring parameters are identified, assessed through real-time proof-of-concept, and proposed for network applications for the safeguarding of neighbouring channels in WDM systems.

  10. Ultracompact all-optical logic gates based on nonlinear plasmonic nanocavities

    Science.gov (United States)

    Yang, Xiaoyu; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2017-01-01

    In this study, nanoscale integrated all-optical XNOR, XOR, and NAND logic gates were realized based on all-optical tunable on-chip plasmon-induced transparency in plasmonic circuits. A large nonlinear enhancement was achieved with an organic composite cover layer based on the resonant excitation-enhancing nonlinearity effect, slow light effect, and field confinement effect provided by the plasmonic nanocavity mode, which ensured a low excitation power of 200 μW that is three orders of magnitude lower than the values in previous reports. A feature size below 600 nm was achieved, which is a one order of magnitude lower compared to previous reports. The contrast ratio between the output logic states "1" and "0" reached 29 dB, which is among the highest values reported to date. Our results not only provide an on-chip platform for the study of nonlinear and quantum optics but also open up the possibility for the realization of nanophotonic processing chips based on nonlinear plasmonics.

  11. Design and analysis of an all-optical Demultiplexer based on photonic crystals

    Science.gov (United States)

    Goodarzi, K.; Mir, A.

    2015-01-01

    An all-optical 1of 2 De-multiplexer (D-mux) based on silicon rods in the air, created by two dimensional square lattice photonic crystals (PCs), is proposed and demonstrated. The device operation is because of line and point defects and phase difference between input beams that created by point defects. The device has a selection line, S, an input data port, A, and three output data ports, Q0, Q1 and Q2. Photonic band gap (PBG) calculation is done by plane wave expansion (PWE) method and electrical field distribution (EFD) in the device by finite difference time domain (FDTD) method. Power levels lower than "0.25P0" is considered as "0" logic value and higher than "0.4P0" as "1" logic value. When S = 0, the data of port A, is directed to Q0 and when S = 1, is directed to Q1. Moreover, one of the output ports, Q1 or Q2, can be used as an AND logic gate. The device is applicable for all-optical processors and integrated circuit.

  12. Design of an All-Optical Network Based on LCoS Technologies

    Science.gov (United States)

    Cheng, Yuh-Jiuh; Shiau, Yhi

    2016-06-01

    In this paper, an all-optical network composed of the ROADMs (reconfigurable optical add-drop multiplexer), L2/L3 optical packet switches, and the fiber optical cross-connection for fiber scheduling and measurement based on LCoS (liquid crystal on silicon) technologies is proposed. The L2/L3 optical packet switches are designed with optical output buffers. Only the header of optical packets is converted to electronic signals to control the wavelength of input ports and the packet payloads can be transparently destined to their output ports. An optical output buffer is designed to queue the packets when more than one incoming packet should reach to the same destination output port. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The wavelength of input ports is designed for routing incoming packets using LCoS technologies. Finally, the proposed OFS (optical flow switch) with input buffers can quickly transfer the big data to the output ports and the main purpose of the OFS is to reduce the number of wavelength reflections. The all-optical content delivery network is comprised of the OFSs for a large amount of audio and video data transmissions in the future.

  13. On-chip passive three-port circuit of all-optical ordered-route transmission

    Science.gov (United States)

    Liu, Li; Dong, Jianji; Gao, Dingshan; Zheng, Aoling; Zhang, Xinliang

    2015-05-01

    On-chip photonic circuits of different specific functions are highly desirable and becoming significant demands in all-optical communication network. Especially, the function to control the transmission directions of the optical signals in integrated circuits is a fundamental research. Previous schemes, such as on-chip optical circulators, are mostly realized by Faraday effect which suffers from material incompatibilities between semiconductors and magneto-optical materials. Achieving highly functional circuits in which light circulates in a particular direction with satisfied performances are still difficult in pure silicon photonics platform. Here, we propose and experimentally demonstrate a three-port passive device supporting optical ordered-route transmission based on silicon thermo-optic effect for the first time. By injecting strong power from only one port, the light could transmit through the three ports in a strict order (1→2, 2→3, 3→1) while be blocked in the opposite order (1→3, 3→2, 2→1). The blocking extinction ratios and operation bandwidths have been investigated in this paper. Moreover, with compact size, economic fabrication process and great extensibility, this proposed photonic integrated circuit is competitive to be applied in on-chip all-optical information processing systems, such as path priority selector.

  14. Ultrafast all-optical modulation with hyperbolic metamaterial integrated in Si photonic circuitry.

    Science.gov (United States)

    Neira, Andres D; Wurtz, Gregory A; Ginzburg, Pavel; Zayats, Anatoly V

    2014-05-05

    The integration of optical metamaterials within silicon integrated photonic circuitry bears significantly potential in the design of low-power, nanoscale footprint, all-optical functionalities. We propose a novel concept and provide detailed analysis of an on-chip ultrafast all-optical modulator based on an hyperbolic metamaterial integrated in a silicon waveguide. The anisotropic metamaterial based on gold nanorods is placed on top of the silicon waveguide to form a modulator with a 300x440x600 nm(3) footprint. For the operating wavelength of 1.5 μm, the optimized geometry of the device has insertion loss of about 5 dB and a modulation depth of 35% with a sub-ps switching rate. The switching energy estimated from nonlinear transient dynamic numerical simulations is 3.7 pJ/bit when the transmission is controlled optically at a wavelength of 532 nm, resonant with the transverse plasmonic mode of the metamaterial. The switching mechanism is based on the control of the hybridization of eigenmodes in the metamaterial slab and the Si waveguide.

  15. All-Optical Reversible Logic Gates with Optically Controlled Bacteriorhodopsin Protein-Coated Microresonators

    Directory of Open Access Journals (Sweden)

    Sukhdev Roy

    2012-01-01

    Full Text Available We present designs of all-optical reversible gates, namely, Feynman, Toffoli, Peres, and Feynman double gates, with optically controlled microresonators. To demonstrate the applicability, a bacteriorhodopsin protein-coated silica microcavity in contact between two tapered single-mode fibers has been used as an all-optical switch. Low-power control signals (<200 μW at 532 nm and at 405 nm control the conformational states of the protein to switch a near infrared signal laser beam at 1310 or 1550 nm. This configuration has been used as a template to design four-port tunable resonant coupler logic gates. The proposed designs are general and can be implemented in both fiber-optic and integrated-optic formats and with any other coated photosensitive material. Advantages of directed logic, high Q-factor, tunability, compactness, low-power control signals, high fan-out, and flexibility of cascading switches in 2D/3D architectures to form circuits make the designs promising for practical applications.

  16. All optical NAND gate based on nonlinear photonic crystal ring resonator

    Directory of Open Access Journals (Sweden)

    Somaye Serajmohammadi

    2016-06-01

    Full Text Available In this paper we proposed a new design for all optical NAND gate. By combining nonlinear Kerr effect with photonic crystal ring resonators, we designed an all optical NAND gate. A typical NAND gate is a logic device with one bias and two logic input and one output ports. It has four different combinations for its logic input ports. The output port of the NAND gate is OFF, when both logic ports are ON, otherwise the output port will be ON. The switching power threshold obtained for this structure equals to 1.5 kW/μm2. For designing the proposed optical logic gate we employed one resonant ring whose resonant wavelength is at 1554 nm. The functionality of the proposed NAND gate depends on the operation of this resonant ring. When the power intensity of optical waves is less than the switching threshold the ring will couple optical waves into drop waveguide otherwise the optical waves will propagate on the bus waveguide.

  17. M-Burst: A Framework of SRLG Failure Localization in All-Optical Networks

    KAUST Repository

    Ali, Mohammed L.

    2012-07-27

    Fast and unambiguous failure localization for shared risk link groups (SRLGs) with multiple links is essential for building a fully survivable and functional transparent all-optical mesh network. Monitoring trails (m-trails) have been proposed as an effective approach to achieve this goal. However, each m-trail traverses through each link by constantly taking a wavelength channel, causing a significant amount of resource consumption. In this paper, a novel framework of all-optical monitoring for SRLG failure localization is proposed. We investigate the feasibility of periodically launching optical bursts along each m-trail instead of assigning it a dedicated supervisory lightpath to probe the set of fiber segments along the m-trail, aiming to achieve a graceful compromise between resource consumption and failure localization latency. This paper defines the proposed framework and highlights the relevant issues regarding its feasibility. We provide theoretical justifications of the scheme. As a proof of concept, we formulate the optimal burst scheduling problem via an integer linear program (ILP) and implement the method in networks of all possible SRLGs with up to d=3 links. A heuristic method is also proposed and implemented for multiple-link SRLG failure localization, keeping all the assumptions the same as in the ILP method. Numerical results for small networks show that the scheme is able to localize single-link and multiple-link SRLG failures unambiguously with a very small amount of failure localization latency.

  18. Ultracompact all-optical logic gates based on nonlinear plasmonic nanocavities

    Directory of Open Access Journals (Sweden)

    Yang Xiaoyu

    2016-09-01

    Full Text Available In this study, nanoscale integrated all-optical XNOR, XOR, and NAND logic gates were realized based on all-optical tunable on-chip plasmon-induced transparency in plasmonic circuits. A large nonlinear enhancement was achieved with an organic composite cover layer based on the resonant excitation-enhancing nonlinearity effect, slow light effect, and field confinement effect provided by the plasmonic nanocavity mode, which ensured a low excitation power of 200 μW that is three orders of magnitude lower than the values in previous reports. A feature size below 600 nm was achieved, which is a one order of magnitude lower compared to previous reports. The contrast ratio between the output logic states “1” and “0” reached 29 dB, which is among the highest values reported to date. Our results not only provide an on-chip platform for the study of nonlinear and quantum optics but also open up the possibility for the realization of nanophotonic processing chips based on nonlinear plasmonics.

  19. All-optical formation of coherent dark states of silicon-vacancy spins in diamond.

    Science.gov (United States)

    Pingault, Benjamin; Becker, Jonas N; Schulte, Carsten H H; Arend, Carsten; Hepp, Christian; Godde, Tillmann; Tartakovskii, Alexander I; Markham, Matthew; Becher, Christoph; Atatüre, Mete

    2014-12-31

    Spin impurities in diamond can be versatile tools for a wide range of solid-state-based quantum technologies, but finding spin impurities that offer sufficient quality in both photonic and spin properties remains a challenge for this pursuit. The silicon-vacancy center has recently attracted much interest because of its spin-accessible optical transitions and the quality of its optical spectrum. Complementing these properties, spin coherence is essential for the suitability of this center as a spin-photon quantum interface. Here, we report all-optical generation of coherent superpositions of spin states in the ground state of a negatively charged silicon-vacancy center using coherent population trapping. Our measurements reveal a characteristic spin coherence time, T2*, exceeding 45 nanoseconds at 4 K. We further investigate the role of phonon-mediated coupling between orbital states as a source of irreversible decoherence. Our results indicate the feasibility of all-optical coherent control of silicon-vacancy spins using ultrafast laser pulses.

  20. Dual broadband metamaterial absorber.

    Science.gov (United States)

    Kim, Young Ju; Yoo, Young Joon; Kim, Ki Won; Rhee, Joo Yull; Kim, Yong Hwan; Lee, YoungPak

    2015-02-23

    We propose polarization-independent and dual-broadband metamaterial absorbers at microwave frequencies. This is a periodic meta-atom array consisting of metal-dielectric-multilayer truncated cones. We demonstrate not only one broadband absorption from the fundamental magnetic resonances but additional broadband absorption in high-frequency range using the third-harmonic resonance, by both simulation and experiment. In simulation, the absorption was over 90% in 3.93-6.05 GHz, and 11.64-14.55 GHz. The corresponding experimental absorption bands over 90% were 3.88-6.08 GHz, 9.95-10.46 GHz and 11.86-13.84 GHz, respectively. The origin of absorption bands was elucidated. Furthermore, it is independent of polarization angle owing to the multilayered circular structures. The design is scalable to smaller size for the infrared and the visible ranges.

  1. All-optical signal processing of OTDM and OFDM signals based on time-domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Clausen, Anders; Guan, Pengyu; Mulvad, Hans Christian Hansen

    2014-01-01

    All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented.......All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented....

  2. All-optical characterization of large-signal modulation bandwidth of a monolithically integrated DFB-EA

    DEFF Research Database (Denmark)

    Blaaberg, Søren; Mulvad, Hans Christian Hansen; Oxenløwe, Leif Katsuo

    2009-01-01

    We use an all-optical method to characterize the modulation bandwidth of a DFB-EA designed for 100 Gb/s Ethernet. In a large-signal wavelength conversion set-up, we show the device has an all-optical bandwidth of 83 GHz....

  3. Multi-band radio over fiber system with all-optical halfwave rectification, transmission and frequency down-conversion

    DEFF Research Database (Denmark)

    Prince, Kamau; Tafur Monroy, Idelfonso

    2011-01-01

    We introduce a novel application of all-optical half-wave rectification in the transportation and delivery of multi-frequency radio-over fiber signals. System evaluation was performed of transmission over various optical fiber types and all-optical envelope detection was implemented to achieve...

  4. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... kidney stones bladder tumors other disorders of the urinary bladder In children, pelvic ultrasound can help evaluate: pelvic ... Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  5. An ultra-small, low-power, all-optical flip-flop memory on a silicon chip

    DEFF Research Database (Denmark)

    Liu, Liu; Kumar, R.; Huybrechts, K.

    2010-01-01

    Ultra-small, low-power, all-optical switching and memory elements, such as all-optical flip-flops, as well as photonic integrated circuits of many such elements, are in great demand for all-optical signal buffering, switching and processing. Silicon-on-insulator is considered to be a promising...... platform to accommodate such photonic circuits in large-scale configurations. Through heterogeneous integration of InP membranes onto silicon-on-insulator, a single microdisk laser with a diameter of 7.5 mu m, coupled to a silicon-on-insulator wire waveguide, is demonstrated here as an all-optical flip-flop...... the only electrically pumped, all-optical flip-flop on silicon built upon complementary metal-oxide semiconductor technology....

  6. Imaging and detection of early stage dental caries with an all-optical photoacoustic microscope

    Science.gov (United States)

    Hughes, D. A.; Sampathkumar, A.; Longbottom, C.; Kirk, K. J.

    2015-01-01

    Tooth decay, at its earliest stages, manifests itself as small, white, subsurface lesions in the enamel. Current methods for detection in the dental clinic are visual and tactile investigations, and bite-wing X-ray radiographs. These techniques suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease due to the small size (techniques allow. PA images were cross referenced with histology photographs to validate our experimental results. Our PA system provides a noncontact method for early detection of white-spot lesions with a high detection bandwidth that offers advantages over previously demonstrated ultrasound methods. The technique provides the sensing depth of an ultrasound system, but with the spatial resolution of an optical system.

  7. Experimental and theoretical investigation of semiconductor optical amplifier (SOA) based all-optical switches

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup

    2004-01-01

    optical networks. The factors governing the modulation bandwidth of SOAs are determined, and schemes for reducing detrimental patterning effects are discussed. Three types of SOA-based switches are investigated numerically: so-called standardmode and differential-mode switches, and the filtering assisted......This thesis analyzes semiconductor optical amplifier (SOA) based all-optical switches experimentally and through numerical simulations. These devices are candidates for optical signal processing functionalities such as wavelength conversion, regeneration, and logic processing in future transparent...... switch. Differential -mode switches are shown to eliminate one contribution to the patterning effects, referred to as the linear patterning. This enables operation at bitrates far beyond the limit set by the carrier lifetime, but ultimately a saturation-induced patterning effect, nonlinear patterning...

  8. Modeling of semiconductor devices for high-speed all-optical signal processing

    DEFF Research Database (Denmark)

    Bischoff, Svend; Højfeldt, Sune; Mørk, Jesper

    2001-01-01

    The all-optical signal processing performance of devices based on active semiconductor waveguides is investigated. A large signal model is used to analyse the physical mechanisms limiting the high-speed performance of both semiconductor optical amplifiers (SOAs) and electro-absorption modulators...... (EAMs). Wavelength conversion and signal regeneration in EAMs is discussed at 10 and 40 Gbit/s. The finite carrier sweep-out time is shown to limit the EAM performance. Four-wave mixing (FWM) in SOAs is almost instantaneous. However, with increasing bit rates and advanced processing functionalities some...... limitations arise. These limitations are elucidated by studying bi-directional simultaneous clear and drop (de-multiplexing) for a 4x40 Gbit/s signal. The simultaneous clearing and de-multiplexing (drop) of an optical time division multiplexing signal channel for an 8x40 Gbit/s signal is investigated...

  9. Electroabsorption modulators used for all-optical signal processing and labelling

    DEFF Research Database (Denmark)

    Xu, Lin

    2004-01-01

    This thesis concerns the applications of semiconductor components, primarily electroabsorption modulators (EAMs), in optical signal processing and labelling for future all optical communication networks. An introduction to electroabsorption modulators is given and several mechanisms that form...... and various signal-processing functions based on Polarization Shift Keying (PolSK) modulation format are demonstrated. Polarization modulation is implemented by a normal Mach Zednder Modulator operating in a special but simple way. Detection and erasure of polarization information are realised by a device...... with the signal wavelength, indicating that an optimum wavelength can be found as a trade-off between the on-off ratio and the signal-to-noise ratio. The chirp property and the small signal bandwidth for electrical-to-optical modulation of the EAM are investigated. It is found that the measured chirp α...

  10. Silicon Nanowires for All-Optical Signal Processing in Optical Communication

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Ji, Hua

    2012-01-01

    such as four-wave mixing (FWM) which is an imperative process for optical signal processing. Since the current mature silicon fabrication technology enables a precise dimension control on nanowires, dispersion engineering can be performed by tailoring nanowire dimensions to realize an efficient nonlinear...... process. In the last four years, we investigated and demonstrated different ultra-fast all-optical nonlinear signal processing applications in silicon nanowires for optical time domain multiplexing (OTDM) systems, including wavelength conversion, signal regeneration, ultra-fast waveform sampling......, demultiplexing, and multicasting, which shows great potentials in the future optical communication systems. Although the strong light confinement in nanowires allows efficient nonlinear optical signal processing, it also leads to coupling difficulty between on-chip sub-micron nanowires and micro-size fibers due...

  11. A nonlinear plasmonic resonator for three-state all-optical switching

    KAUST Repository

    Amin, Muhammad

    2014-01-01

    A nonlinear plasmonic resonator design is proposed for three-state all-optical switching at frequencies including near infrared and lower red parts of the spectrum. The tri-stable response required for three-state operation is obtained by enhancing nonlinearities of a Kerr medium through multiple (higher order) plasmons excited on resonator\\'s metallic surfaces. Indeed, simulations demonstrate that exploitation of multiple plasmons equips the proposed resonator with a multi-band tri-stable response, which cannot be obtained using existing nonlinear plasmonic devices that make use of single mode Lorentzian resonances. Multi-band three-state optical switching that can be realized using the proposed resonator has potential applications in optical communications and computing. © 2014 Optical Society of America.

  12. All-optical broadcast and multicast technologies based on PPLN waveguide

    DEFF Research Database (Denmark)

    Ye, Lingyun; Wang, Ju; Hu, Hao

    2013-01-01

    All-optical 1×4 broadcast and 1×3 multicast experiments of a 40-Gb/s return-to-zero on-off keying (RZ-OOK) signal based on a periodically poled lithium niobate (PPLN) waveguide are demonstrated in this letter. Clear opened eye diagrams and error-free performance are achieved for the broadcast...... signals at 1541.3, 1543.7, 1548.5, and 1550.9 nm. Multicast technology uses cascaded second-harmonic generation and difference-frequency generation in a Ti:PPLN waveguide. An error-free operation with a negligible power penalty is achieved for the three wavelength-division multiplexing multicast signals...

  13. All-optical modulation in dye-doped nematic liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper; Bjarklev, Anders Overgaard

    2004-01-01

    Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs......) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate an all-optical modulator, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid...... crystal. We demonstrate a modulation frequency of 2kHz for a moderate pump power of 2-3mW and describe two pump pulse regimes in which there is an order of magnitude difference between the decay times....

  14. Comparison of delay-interferometer and time-lens-based all-optical OFDM demultiplexers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Mulvad, Hans Christian Hansen; Galili, Michael

    2015-01-01

    In this paper we present the first detailed numerical comparison of two promising all-optical schemes to demultiplex orthogonal frequency-division multiplexing (OFDM) signals. The investigated schemes are the optical discrete Fourier transformation (O-DFT) and the optical spectral magnification (SM...... filters, is investigated. In the latter scheme the OFDM spectrum is magnified, allowing for simple optical bandpass filtering of the individual subcarriers with reduced ICI. Ideally only a single unit consisting of two time lenses is needed, reducing the complexity and potentially the energy consumption...... compared to the type of O-DFT scheme relying on many active gates. The bit-error-rate is estimated down to ∼10−6 by Monte Carlo bit-error counting for a 32-subcarrier OFDM input signal, showing that a performance close to the ideal O-DFT is achievable for both the reduced-complexity O-DFT and the SM scheme....

  15. Banded all-optical OFDM super-channels with low-bandwidth receivers.

    Science.gov (United States)

    Song, Binhuang; Zhu, Chen; Corcoran, Bill; Zhuang, Leimeng; Lowery, Arthur James

    2016-08-08

    We propose a banded all-optical orthogonal frequency division multiplexing (AO-OFDM) transmission system based on synthesising a number of truncated sinc-shaped subcarriers for each sub-band. This approach enables sub-band by sub-band reception and therefore each receiver's electrical bandwidth can be significantly reduced compared with a conventional AO-OFDM system. As a proof-of-concept experiment, we synthesise 6 × 10-Gbaud subcarriers in both conventional and banded AO-OFDM systems. With a limited receiver electrical bandwidth, the experimental banded AO-OFDM system shows 2-dB optical signal to noise ratio (OSNR) benefit over conventional AO-OFDM at the 7%-overhead forward error correction (FEC) threshold. After transmission over 800-km of single-mode fiber, ≈3-dB improvement in Q-factor can be achieved at the optimal launch power at a cost of increasing the spectral width by 14%.

  16. All-optical generation of DFT-S-OFDM superchannels using periodic sinc pulses.

    Science.gov (United States)

    Lowery, Arthur James; Zhu, Chen; Viterbo, Emanuele; Corcoran, Bill

    2014-11-03

    Discrete-Fourier-transform spread (DFT-S) optical Orthogonal Frequency Division Multiplexed (OFDM) signals offer improved nonlinearity performance in long haul optical communications systems, and can be used to form superchannels. In this paper we propose how DFT-S-OFDM superchannels can be generated and demultiplexed using all-optical techniques, and demonstrate the feasibility using numerical simulations. We also discuss how each wavelength channel is similar to recently proposed Orthogonally Time-Division Multiplexed (OrthTDM) systems using periodic-sinc pulses from, for example, a Nyquist laser. The key difference between OrthTDM and DFT-S-OFDM is the synchronization of the symbol boundaries of every modulation tributary; because of this we show that OrthTDM cannot be formed into superchannels that can be demultiplexed without penalties, but DFT-S-OFDM can be.

  17. Comparison of Delay-Interferometer and Time- Lens-Based All-Optical OFDM Demultiplexers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Mulvad, Hans Christian Hansen; Galili, Michael

    2015-01-01

    In this letter, we present the first detailed numerical comparison of two promising all-optical schemes to demultiplex orthogonal frequency-division multiplexing (OFDM) signals. The investigated schemes are the optical discrete Fourier transformation (O-DFT) and the optical spectral magnification...... bandpass filters, is investigated. In the latter scheme, the OFDM spectrum is magnified, allowing for simple optical bandpass filtering of the individual subcarriers with reduced ICI. Ideally, only a single unit consisting of two time lenses is needed, reducing the complexity and potentially the energy...... consumption compared with the type of O-DFT scheme relying on many active gates. The bit-error-rate is estimated down to ~10-6 by Monte Carlo bit-error counting for a 32-subcarrier OFDM input signal, showing that a performance close to the ideal O-DFT is achievable for both the reduced-complexity O...

  18. Artificial eye for scotopic vision with bioinspired all-optical photosensitivity enhancer.

    Science.gov (United States)

    Liu, Hewei; Huang, Yinggang; Jiang, Hongrui

    2016-04-12

    The ability to acquire images under low-light conditions is critical for many applications. However, to date, strategies toward improving low-light imaging primarily focus on developing electronic image sensors. Inspired by natural scotopic visual systems, we adopt an all-optical method to significantly improve the overall photosensitivity of imaging systems. Such optical approach is independent of, and can effectively circumvent the physical and material limitations of, the electronics imagers used. We demonstrate an artificial eye inspired by superposition compound eyes and the retinal structure of elephantnose fish. The bioinspired photosensitivity enhancer (BPE) that we have developed enhances the image intensity without consuming power, which is achieved by three-dimensional, omnidirectionally aligned microphotocollectors with parabolic reflective sidewalls. Our work opens up a previously unidentified direction toward achieving high photosensitivity in imaging systems.

  19. Investigations and Simulations of All optical Switches in linear state Based on Photonic Crystal Directional Coupler

    Directory of Open Access Journals (Sweden)

    S. Maktoobi

    2014-10-01

    Full Text Available Switching is a principle process in digital computers and signal processing systems. The growth of optical signal processing systems, draws particular attention to design of ultra-fast optical switches. In this paper, All Optical Switches in linear state Based On photonic crystal Directional coupler is analyzed and simulated. Among different methods, the finite difference time domain method (FDTD is a preferable method and is used. We have studied the application of photonic crystal lattices, the physics of optical switching and photonic crystal Directional coupler. In this paper, Electric field intensity and the power output that are two factors to improve the switching performance and the device efficiency are investigated and simulated. All simulations are performed by COMSOL software.

  20. Reconfigurable dual-channel all-optical logic gate in a silicon waveguide using polarization encoding.

    Science.gov (United States)

    Gao, Shiming; Wang, Xiaoyan; Xie, Yanqiao; Hu, Peiran; Yan, Qiang

    2015-04-01

    A reconfigurable dual-channel all-optical logic gate is proposed and experimentally demonstrated using four-wave mixing in a silicon waveguide for polarization encoding signals. Six logic functions, XNOR, AND, NOR, XOR, AB¯, and A¯B are implemented at two different wavelength channels by adjusting the polarization states of two 10 Gb/s non-return-to-zero polarization-shift keying (NRZ-PolSK) signals modulated by 10-bit on-off keying (OOK) sequences. The eye diagrams of the logic signals are clearly observed, and the logic functions are well demonstrated as the two incident NRZ-PolSK signals are both modulated by the OOK sequences, which originate from 2(31)-1 pseudo-random binary sequences.

  1. All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators

    CERN Document Server

    O'Shea, D; Poellinger, M; Vogler, A; Rauschenbeutel, A

    2011-01-01

    We review our recent work on tunable, ultrahigh quality factor whispering-gallery-mode bottle microresonators and highlight their applications in nonlinear optics and in quantum optics experiments. Our resonators combine ultra-high quality factors of up to Q = 3.6 \\times 10^8, a small mode volume, and near-lossless fiber coupling, with a simple and customizable mode structure enabling full tunability. We study, theoretically and experimentally, nonlinear all-optical switching via the Kerr effect when the resonator is operated in an add-drop configuration. This allows us to optically route a single-wavelength cw optical signal between two fiber ports with high efficiency. Finally, we report on progress towards strong coupling of single rubidium atoms to an ultra-high Q mode of an actively stabilized bottle microresonator.

  2. Graphene oxide doped PDLC films for all optically controlled light valve structures

    Science.gov (United States)

    Marinova, Vera; Tong, Zhon Fang; Petrov, Stefan; Karashanova, Daniela; Lin, Yi Hsin; Lin, Shiuan Huei; Hsu, Ken Yuh

    2016-09-01

    We study the effect of graphene oxide (GrO) on the switching voltage of polymer dispersed liquid crystal (PDLC). The threshold voltage decreases with addition of GrO nanoparticles. Scanning electron microscopy (SEM) supported that the size of LC droplets in GrO-doped PDLC increase in comparison with non-doped one. PDLC:GrO layer was combined with Bi12SiO20 (BSO) inorganic substrate into a hybrid structure and based on the surface activated photorefractive phenomena typical for BSO, it allows the opaque-transparent states to be all optically controlled, operating faster and requiring less intensity due to the GrO addition in PDLC.

  3. Manipulating exchange bias using all-optical helicity-dependent switching

    Science.gov (United States)

    Vallobra, P.; Fache, T.; Xu, Y.; Zhang, L.; Malinowski, G.; Hehn, M.; Rojas-Sánchez, J.-C.; Fullerton, E. E.; Mangin, S.

    2017-10-01

    Deterministic all-optical control of magnetization without an applied magnetic field has been reported for various materials such as ferrimagnetic and ferromagnetic thin films, as well as granular recording media. Here we demonstrate optical control of the magnetic configuration of an antiferromagnetic layer through the exchange bias interaction using the helicity of a femtosecond pulsed laser on IrMn /[Co/Pt ] xN antiferromagnetic/ferromagnetic heterostructures. We show that the magnitude and the sign of the exchange bias field can be deterministically controlled without any applied magnetic field, only by changing the helicity of the light, the laser fluence, or the number of light pulses. We also present the combined effects of laser pulses with an applied magnetic field. This study lays the foundation for the development of new applications based on spintronic devices where the exchange bias phenomenon is routinely used to pin the magnetization orientation of a magnetic layer in one direction.

  4. Plasmon-enhanced optical nonlinearity for femtosecond all-optical switching

    Science.gov (United States)

    Wang, Kuidong; Chen, Long; Zhang, Haijuan; Hsiao, Hui-Hsin; Tsai, Din Ping; Chen, Jie

    2017-10-01

    Ultrafast all-optical switching in metals can be an efficient way for high-speed active photonic devices. However, with the improvement in modulation speed, typically by reducing the optical switching pulse width from picoseconds to femtoseconds, the nonlinear optical response of the metal will decrease significantly, which hinders the realization of the sufficient modulation depth at femtosecond optical control. Here, by combining two optical nonlinear enhancement effects of surface plasmon polaritons, including their extreme sensitivity to refractive index change and their capability to induce strong localized optical fields, we have achieved an ˜50-times enhancement in the modulation depth simultaneously with a switching time of ˜75-fs. Such enhancement was found to be independent of the control intensity, which sets a basis for the future application of femtosecond switching at a minimum power.

  5. All-optical phase modulation in a cavity-polariton Mach–Zehnder interferometer

    Science.gov (United States)

    Sturm, C.; Tanese, D.; Nguyen, H.S.; Flayac, H.; Galopin, E.; Lemaître, A.; Sagnes, I.; Solnyshkov, D.; Amo, A.; Malpuech, G.; Bloch, J.

    2014-01-01

    Quantum fluids based on light is a highly developing research field, since they provide a nonlinear platform for developing optical functionalities and quantum simulators. An important issue in this context is the ability to coherently control the properties of the fluid. Here we propose an all-optical approach for controlling the phase of a flow of cavity-polaritons, making use of their strong interactions with localized excitons. Here we illustrate the potential of this method by implementing a compact exciton–polariton interferometer, which output intensity and polarization can be optically controlled. This interferometer is cascadable with already reported polariton devices and is promising for future polaritonic quantum optic experiments. Complex phase patterns could be also engineered using this optical method, providing a key tool to build photonic artificial gauge fields. PMID:24513781

  6. All-optical intensity modulation based on graphene-coated microfibre waveguides

    Science.gov (United States)

    Wang, Ruiduo; Li, Diao; Jiang, Man; Wu, Hao; Xu, Xiang; Ren, Zhaoyu

    2018-03-01

    We investigate graphene-covered microfibre (GCM) waveguides, and analyse the microfibres' evanescent field distributions in different diameters and lengths by numerically simulation. According to the simulation results, we designed a graphene-based all-optical modulator using 980 nm and Amplified Spontaneous Emission (ASE) lasers, employing the microfibre's evanescent field induced light-graphene interaction. We studied the modulation effect that is influenced by the microfibre's diameter, number of graphene layers, and effective graphene length. Compared to a single graphene layer of shorter length, the double graphene layer with longer length presents stronger absorption and higher modulation depth. Using a 2- μm diameter microfibre covered by ∼0.3 cm double graphene sheets, we achieved a modulation depth of 8.45 dB. This modulator features ease of fabrication, low cost, and a controllable modulation depth.

  7. All-Optical Switching of Magnetic Tunnel Junctions with Single Subpicosecond Laser Pulses

    Science.gov (United States)

    Chen, Jun-Yang; He, Li; Wang, Jian-Ping; Li, Mo

    2017-02-01

    The magnetic tunnel junction (MTJ) is one of the most important building blocks of spintronic logic and memory components for beyond-CMOS computation and communication. Although switching of MTJs without magnetic field has been achieved by charge and spin current injection, the operation speed is limited fundamentally by the spin-precession time to many picoseconds. We report the demonstration of ultrafast all-optical switching of an MTJ using single subpicosecond infrared laser pulses. This optically switchable MTJ uses ferrimagnetic Gd(Fe,Co) as the free layer and its switching is read out by measuring its tunneling magnetoresistance with a Δ R /R ratio of 0.6%. A switching repetition rate at MHz has been demonstrated, but the fundamental upper limit should be higher than tens of GHz rate. This result represents an important step toward integrated optospintronic devices that combines spintronics and photonics technologies to enable ultrafast conversion between fundamental information carriers of electron spins and photons.

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam may be part of a pelvic ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... What are the limitations of Prostate Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces pictures of the inside of the body using ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... What are the limitations of Pelvic Ultrasound Imaging? What is Pelvic Ultrasound Imaging? Ultrasound is safe and painless, and produces pictures of the inside of the body using ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... a pelvic ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... and processes the sounds and creates graphs or color pictures that represent the flow of blood through ...

  14. Obstetrical Ultrasound

    Science.gov (United States)

    ... are similar to sonar used by boats and submarines. The ultrasound image is immediately visible on a ... has been described by patients as a whooshing noise. Doppler ultrasound, a special application of ultrasound, measures ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... What are the limitations of Pelvic Ultrasound Imaging? What is Pelvic Ultrasound Imaging? Ultrasound is safe and ... as the liver or kidneys. top of page What are some common uses of the procedure? In ...

  16. Prostate Ultrasound

    Medline Plus

    Full Text Available ... What are the limitations of Prostate Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is ... in front of the rectum. top of page What are some common uses of the procedure? A ...

  17. Intravascular ultrasound

    Science.gov (United States)

    IVUS; Ultrasound - coronary artery; Endovascular ultrasound; Intravascular echocardiography ... A tiny ultrasound wand is attached to the top of a thin tube. This tube is called a catheter. The catheter ...

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and organs ... of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or sonography , ...

  19. Prostate Ultrasound

    Medline Plus

    Full Text Available ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ... other imaging methods. Ultrasound imaging uses no ionizing radiation. Ultrasound scanning may be able to give a ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such ...

  1. Transvaginal ultrasound

    Science.gov (United States)

    ... ultrasound; Menstrual bleeding - transvaginal ultrasound; Infertility - transvaginal ultrasound; Ovarian - transvaginal ... benign and malignant epithelial and germ cell neoplasms, sex-cord stromal tumors. In: Lentz GM, Lobo RA, Gershenson DM, ...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently ... pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam ...

  3. Ultrafast all-optical arithmetic logic based on hydrogenated amorphous silicon microring resonators

    Science.gov (United States)

    Gostimirovic, Dusan; Ye, Winnie N.

    2016-03-01

    For decades, the semiconductor industry has been steadily shrinking transistor sizes to fit more performance into a single silicon-based integrated chip. This technology has become the driving force for advances in education, transportation, and health, among others. However, transistor sizes are quickly approaching their physical limits (channel lengths are now only a few silicon atoms in length), and Moore's law will likely soon be brought to a stand-still despite many unique attempts to keep it going (FinFETs, high-k dielectrics, etc.). This technology must then be pushed further by exploring (almost) entirely new methodologies. Given the explosive growth of optical-based long-haul telecommunications, we look to apply the use of high-speed optics as a substitute to the digital model; where slow, lossy, and noisy metal interconnections act as a major bottleneck to performance. We combine the (nonlinear) optical Kerr effect with a single add-drop microring resonator to perform the fundamental AND-XOR logical operations of a half adder, by all-optical means. This process is also applied to subtraction, higher-order addition, and the realization of an all-optical arithmetic logic unit (ALU). The rings use hydrogenated amorphous silicon as a material with superior nonlinear properties to crystalline silicon, while still maintaining CMOS-compatibility and the many benefits that come with it (low cost, ease of fabrication, etc.). Our method allows for multi-gigabit-per-second data rates while maintaining simplicity and spatial minimalism in design for high-capacity manufacturing potential.

  4. All-optical switching using a new photonic crystal directional coupler

    Directory of Open Access Journals (Sweden)

    B. Vakili

    2015-07-01

    Full Text Available In this paper all-optical switching in a new photonic crystal directional coupler is performed.  The structure of the switch consists of a directional coupler and a separate path for a control signal called “control waveguide”. In contrast to the former reported structures in which the directional couplers are made by removing a row of rods entirely, the directional coupler in our optical switch is constructed by two reduced-radius line-defect waveguides separated by the control waveguide. Furthermore, in our case the background material has the nonlinear Kerr property. Therefore, in the structure of this work, no frequency overlap occurs between the control waveguide mode and the directional coupler modes. It is shown that such a condition provides a very good isolation between the control and the probe signals at the output ports. In the control waveguide, nonlinear Kerr effect causes the required refractive index change by the presence of a high power control (pump signal. Even and odd modes of the coupler are investigated by applying the distribution of the refractive index change in the nonlinear region of a super-cell so that a switching length of about 94 µm is obtained at the wavelength of 1.55 µm. Finally, all-optical switching of the 1.55 µm probe signal using a control signal at the wavelength of 1.3 µm, is simulated through the finite-difference time-domain method, where both signals are desirable in optical communication systems. A very high extinction ratio of 67 dB is achieved and the temporal characteristics of the switch are demonstrated.

  5. All-optical histology using two photon laser scanning microscopy and ablation with ultrashort pulses

    Science.gov (United States)

    Tsai, Philbert S.

    This dissertation discusses the use of ultrashort laser pulses to image and manipulate tissue for the purpose of three-dimensional histological reconstruction of extended brain structures. Two photon laser scanning microscopy (TPLSM) and ultrashort pulsed laser ablation are used to provide in situ three-dimensional imaging through thick preparations of fixed tissue. Surface regions of fixed tissue are first imaged using TPLSM. The imaged regions are then removed by ablation with amplified, ultrashort laser pulses, thereby exposing a previously underlying tissue region for imaging. This process of imaging and ablation proceeds iteratively until the desired tissue volume has been processed. First, the principles, design, and construction of a two photon laser scanning microscope are discussed, followed by a discussion of the physical mechanisms of tissue ablation with ultrashort laser pulses. The compatibility of tissue ablation using ultrashort pulses with subsequent histological analysis, particularly with fluorescent microscopy, is evaluated. Tissue ablation with ultrashort laser pulses is found to produce ablated tissue surfaces that are smooth to within a micrometer. Intrinsic fluorescence as well as immunoreactivity are found to be resilient to the ablation process. The all-optical histological technique is demonstrated on brain tissue from rats and mice, including tissue from embryonic mouse as early at E15. The ablation process is shown to preserve both macroscopic and microscopic structures within tissue. To facilitate the all-optical histological analysis of neuronal vasculature and its relative distribution to surrounding neuronal tissue, a fluorescent gel perfusion technique is developed that provides a temperature-stabilized fluorescent label of the neuronal vasculature. The use of immunohistochemistry to label specific cell populations throughout an 800 micrometer-thick tissue section is demonstrated. Additionally, the immersion of fixed tissue in high

  6. 160-Gb/s all-optical phase-transparent wavelength conversion through cascaded SFG-DFG in a broadband linear-chirped PPLN waveguide.

    Science.gov (United States)

    Lu, Guo-Wei; Shinada, Satoshi; Furukawa, Hideaki; Wada, Naoya; Miyazaki, Tetsuya; Ito, Hiromasa

    2010-03-15

    We experimentally demonstrated ultra-fast phase-transparent wavelength conversion using cascaded sum- and difference-frequency generation (cSFG-DFG) in linear-chirped periodically poled lithium niobate (PPLN). Error-free wavelength conversion of a 160-Gb/s return-to-zero differential phase-shift keying (RZ-DPSK) signal was successfully achieved. Thanks to the enhanced conversion bandwidth in the PPLN with linear-chirped periods, no optical equalizer was required to compensate the spectrum distortion after conversion, unlike a previous demonstration of 160-Gb/s RZ on-off keying (OOK) using fixed-period PPLN.

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: ...

  8. Calcaneal ultrasound analysis of Nigerian adults with type 2 diabetes

    African Journals Online (AJOL)

    Research Design and Methods: A total of 50 patients (25M/25F) with type 2 diabetes and 50 healthy controls (20M/30F) were recruited at the Jos University ... Results: Both male and females subjects with type 2 diabetes had superior ultrasound parameters including broadband ultrasound attenuation (BUA), speed of sound ...

  9. Ultra-Fast All-Optical Self-Aware Protection Switching Based on a Bistable Laser Diode

    DEFF Research Database (Denmark)

    An, Yi; Vukovic, Dragana; Lorences Riesgo, Abel

    2014-01-01

    We propose a novel concept of all-optical protection switching with link failure automatic awareness based on AOWFF. The scheme is experimentally demonstrated using a single MG-Y laser diode with a record switching time ~200 ps....

  10. All-optical AND gate at 10 Gbit/s based on cascaded single-port-couple SOAs.

    Science.gov (United States)

    Zhang, Xinliang; Wang, Ying; Sun, Junqiang; Liu, Deming; Huang, Dexiu

    2004-02-09

    An all-optical logical AND gate at 10 Gbit/s based on cross-gain modulation (XGM) in two cascaded semiconductor optical amplifiers (SOAs) is demonstrated. Single-port-coupled SOAs are employed and specially designed to improve the output extinction ratio as well as the output performance of the logic operation. The output signal power and extinction ratio from the first-stage wavelength converter are critical to achieving all-optical logical AND operation.

  11. All-optical cryptography of M-QAM formats by using two-dimensional spectrally sliced keys.

    Science.gov (United States)

    Abbade, Marcelo L F; Cvijetic, Milorad; Messani, Carlos A; Alves, Cleiton J; Tenenbaum, Stefan

    2015-05-10

    There has been an increased interest in enhancing the security of optical communications systems and networks. All-optical cryptography methods have been considered as an alternative to electronic data encryption. In this paper we propose and verify the use of a novel all-optical scheme based on cryptographic keys applied on the spectral signal for encryption of the M-QAM modulated data with bit rates of up to 200 gigabits per second.

  12. Synchronization Algorithm for SDN-controlled All-Optical TDM Switching in a Random Length Ring Network

    DEFF Research Database (Denmark)

    Kamchevska, Valerija; Cristofori, Valentina; Da Ros, Francesco

    2016-01-01

    We propose and demonstrate an algorithm that allows for automatic synchronization of SDN-controlled all-optical TDM switching nodes connected in a ring network. We experimentally show successful WDM-SDM transmission of data bursts between all ring nodes.......We propose and demonstrate an algorithm that allows for automatic synchronization of SDN-controlled all-optical TDM switching nodes connected in a ring network. We experimentally show successful WDM-SDM transmission of data bursts between all ring nodes....

  13. All-optical label and payload separator for a time-serial RZ-IM/IM scheme

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Tafur Monroy, Idelfonso; Koonen, A.M.J.

    2006-01-01

    We demonstrate an all-optical label and payload separator based on nonlinear optical signal processing with a semiconductor optical amplifier. The separator handles return-to-zero intensity modulated packets with high bandwidth efficiency utilization.......We demonstrate an all-optical label and payload separator based on nonlinear optical signal processing with a semiconductor optical amplifier. The separator handles return-to-zero intensity modulated packets with high bandwidth efficiency utilization....

  14. First-principles and model simulation of all-optical spin reversal

    Science.gov (United States)

    Zhang, G. P.; Babyak, Z.; Xue, Y.; Bai, Y. H.; George, Thomas F.

    2017-10-01

    All-optical spin switching is a potential trailblazer for information storage and communication at an unprecedented fast rate free of magnetic fields. However, the current wisdom is largely based on semiempirical models of effective magnetic fields and heat pulses, so it is difficult to provide high-speed design protocols for actual devices. Here, we carry out a massively parallel first-principles and model calculation for 13 spin systems and magnetic layers, free of any effective field, to establish a simpler and alternative paradigm of laser-induced ultrafast spin reversal and to point out a path to a full-integrated photospintronic device. It is the interplay of the optical selection rule and sublattice spin orderings that underlines seemingly irreconcilable helicity-dependent and -independent switchings. Using realistic experimental parameters, we predict that strong ferrimagnets, in particular, Laves phase C15 rare-earth alloys, meet the telecommunication energy requirement of 10 fJ, thus allowing a cost-effective subpicosecond laser to switch spin in the gigahertz region.

  15. Ultrafast all-optical order-to-chaos transition in silicon photonic crystal chips

    KAUST Repository

    Bruck, Roman

    2016-06-08

    The interaction of light with nanostructured materials provides exciting new opportunities for investigating classical wave analogies of quantum phenomena. A topic of particular interest forms the interplay between wave physics and chaos in systems where a small perturbation can drive the behavior from the classical to chaotic regime. Here, we report an all-optical laser-driven transition from order to chaos in integrated chips on a silicon photonics platform. A square photonic crystal microcavity at telecom wavelengths is tuned from an ordered into a chaotic regime through a perturbation induced by ultrafast laser pulses in the ultraviolet range. The chaotic dynamics of weak probe pulses in the near infrared is characterized for different pump-probe delay times and at various positions in the cavity, with high spatial accuracy. Our experimental analysis, confirmed by numerical modelling based on random matrices, demonstrates that nonlinear optics can be used to control reversibly the chaotic behavior of light in optical resonators. (Figure presented.) . © 2016 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  16. All-Optical Signal Processing for 640 Gbit/s Applications

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen

    2008-01-01

    This thesis concerns all-optical signal processing technologies for ultra-high serial data rates up to 640 Gbit/s. Firstly, time-division add-drop multiplexing at 640 Gbit/s is demonstrated for the first time using two different fibre-based switching techniques. Secondly, a novel principle......-based technique. Et væsentligt forskningsområde indenfor optisk kommunikation er forøgelsen af de nuværende data hastigheder, hvilket især er nødvendiggjort pga. den hastigt stigende Internet trafik. Denne afhandling omhandler teknikker til optisk signalbehandling af data signaler med bit hastigheder op til 640...... Gbit/s, herunder tidslig add-drop multiplexing (TADM), demultiplexing, samt klokkegendannelse. Optisk signal behandling udføres direkte på det optiske data signal (infrarødt laserlys), uden at det konverteres til et elektrisk signal. Fordelen ved den optiske tilgang er at den tillader signalbehandling...

  17. Ultracompact all-optical full-adder and half-adder based on nonlinear plasmonic nanocavities

    Science.gov (United States)

    Xie, Jingya; Niu, Xinxiang; Hu, Xiaoyong; Wang, Feifan; Chai, Zhen; Yang, Hong; Gong, Qihuang

    2017-06-01

    Ultracompact chip-integrated all-optical half- and full-adders are realized based on signal-light induced plasmonic-nanocavity-modes shift in a planar plasmonic microstructure covered with a nonlinear nanocomposite layer, which can be directly integrated into plasmonic circuits. Tremendous nonlinear enhancement is obtained for the nanocomposite cover layer, attributed to resonant excitation, slow light effect, as well as field enhancement effect provided by the plasmonic nanocavity. The feature size of the device is three orders of magnitude compared with previous reports. The operating threshold power is determined to be 300 μW (corresponding to a threshold intensity of 7.8 MW/cm2), which is reduced by two orders of magnitude compared with previous reports. The intensity contrast ratio between two output logic states, "1" and "0," is larger than 27 dB, which is among the highest values reported to date. Our work is the first to experimentally realize on-chip half- and full-adders based on nonlinear plasmonic nanocavities having an ultrasmall feature size, ultralow threshold power, and high intensity contrast ratio simultaneously. This work not only provides a platform for the study of nonlinear optics, but also paves a way to realize ultrahigh-speed signal computing chips.

  18. Diffraction-unlimited all-optical imaging and writing with a photochromic GFP.

    Science.gov (United States)

    Grotjohann, Tim; Testa, Ilaria; Leutenegger, Marcel; Bock, Hannes; Urban, Nicolai T; Lavoie-Cardinal, Flavie; Willig, Katrin I; Eggeling, Christian; Jakobs, Stefan; Hell, Stefan W

    2011-09-11

    Lens-based optical microscopy failed to discern fluorescent features closer than 200 nm for decades, but the recent breaking of the diffraction resolution barrier by sequentially switching the fluorescence capability of adjacent features on and off is making nanoscale imaging routine. Reported fluorescence nanoscopy variants switch these features either with intense beams at defined positions or randomly, molecule by molecule. Here we demonstrate an optical nanoscopy that records raw data images from living cells and tissues with low levels of light. This advance has been facilitated by the generation of reversibly switchable enhanced green fluorescent protein (rsEGFP), a fluorescent protein that can be reversibly photoswitched more than a thousand times. Distributions of functional rsEGFP-fusion proteins in living bacteria and mammalian cells are imaged at <40-nanometre resolution. Dendritic spines in living brain slices are super-resolved with about a million times lower light intensities than before. The reversible switching also enables all-optical writing of features with subdiffraction size and spacings, which can be used for data storage.

  19. Femtosecond laser fabricated all-optical fiber sensors with ultrahigh refractive index sensitivity: modeling and experiment

    Science.gov (United States)

    Jiang, Lan; Zhao, Longjiang; Wang, Sumei; Yang, Jinpeng; Xiao, Hai

    2011-08-01

    All-optical fiber sensors based on ultracompact fiber inline Mach-Zehnder interferometer (MZI) are fabricated by side-ablating a U-shape microcavity in a single-mode optical fiber with the fiber core partially removed using femtosecond (fs) laser pulses, in which the two light paths are accordingly formed in the remaining D-type fiber core and the U-shape microcavity. Beam propagation method (BPM) analysis is utilized to illustrate the dependences of good transmission spectra on parameters including the ablation depth, ablation length and the refractive index of U-shape micocavity, which gives some guidelines to optimize parameters for fs laser micromachining and predicts RI (refractive index) sensitivities within given RI ranges. The modeling results of ultrahigh RI sensitivities for gases and solutions are -3243.75 ± 0.65nm/RIU (refractive index unit) and -10789.29 ± 18.91nm/RIU, respectively. In RI testing experiments, the sensor exhibits ultrahigh RI sensitivities of -3754.79 ± 44.24nm/RIU with refractive indices ranging from 1.0001143 to 1.0002187 by testing different mixture ratios of N2 and He gases, and -12162.01 ± 173.92nm/RIU with refractive indices ranging from 1.3330 to 1.33801 by testing different concentrations of sucrose solutions, which is essentially in agreement with the modeling results.

  20. All-Optical Chirality-Sensitive Sorting via Reversible Lateral Forces in Interference Fields.

    Science.gov (United States)

    Zhang, Tianhang; Mahdy, Mahdy Rahman Chowdhury; Liu, Yongmin; Teng, Jing Hua; Lim, Chwee Teck; Wang, Zheng; Qiu, Cheng-Wei

    2017-04-25

    Separating substances by their chirality faces great challenges as well as opportunities in chemistry and biology. In this study, we propose an all-optical solution for passive sorting of chiral objects using chirality-dependent lateral optical forces induced by judiciously interfered fields. First, we investigate the optical forces when the chiral objects are situated in the interference field formed by two plane waves with arbitrary polarization states. When the plane waves are either linearly or circularly polarized, nonzero lateral forces are found at the particle's trapping positions, making such sideways motions observable. Although the lateral forces have different magnitudes on particles with different chirality, their directions are the same for opposite handedness particles, rendering it difficult to separate the chiral particles. We further solve the sorting problem by investigating more complicated polarization states. Finally, we achieve the chiral-selective separation by illuminating only one beam toward the chiral substance situated at an interface between two media, taking advantage of the native interference between the incident and reflective beams at the interface. Our study provides a robust and insightful approach to sort chiral substances and biomolecules with plausible optical setups.

  1. All-Optical dc Nanotesla Magnetometry Using Silicon Vacancy Fine Structure in Isotopically Purified Silicon Carbide

    Directory of Open Access Journals (Sweden)

    D. Simin

    2016-07-01

    Full Text Available We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-^{28}SiC and reveal not yet considered terms in the spin Hamiltonian, originated from the trigonal pyramidal symmetry of this spin-3/2 color center. These terms give rise to additional spin transitions, which would be otherwise forbidden, and lead to a level anticrossing in an external magnetic field. We observe a sharp variation of the photoluminescence intensity in the vicinity of this level anticrossing, which can be used for a purely all-optical sensing of the magnetic field. We achieve dc magnetic field sensitivity better than 100  nT/sqrt[Hz] within a volume of 3×10^{-7}mm^{3} at room temperature and demonstrate that this contactless method is robust at high temperatures up to at least 500 K. As our approach does not require application of radio-frequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3  mm^{3}, the projection noise limit is below 100  fT/sqrt[Hz].

  2. Current Developments on Optical Feedback Interferometry as an All-Optical Sensor for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Julien Perchoux

    2016-05-01

    Full Text Available Optical feedback interferometry (OFI sensors are experiencing a consistent increase in their applications to biosensing due to their contactless nature, low cost and compactness, features that fit very well with current biophotonics research and market trends. The present paper is a review of the work in progress at UPC-CD6 and LAAS-CNRS related to the application of OFI to different aspects of biosensing, both in vivo and ex vivo. This work is intended to present the variety of opportunities and potential applications related to OFI that are available in the field. The activities presented are divided into two main sensing strategies: The measurement of optical path changes and the monitoring of flows, which correspond to sensing strategies linked to the reconstruction of changes of amplitude from the interferometric signal, and to classical Doppler frequency measurements, respectively. For optical path change measurements, measurements of transient pulses, usual in biosensing, together with the measurement of large displacements applied to designing palliative care instrumentation for Parkinson disease are discussed. Regarding the Doppler-based approach, progress in flow-related signal processing and applications in real-time monitoring of non-steady flows, human blood flow monitoring and OFI pressure myograph sensing will be presented. In all cases, experimental setups are discussed and results presented, showing the versatility of the technique. The described applications show the wide capabilities in biosensing of the OFI sensor, showing it as an enabler of low-cost, all-optical, high accuracy biomedical applications.

  3. All-optical atom trap trace analysis for rare krypton isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Woelk, Pablo; Kohler, Markus; Sieveke, Carsten; Hebel, Simon; Sahling, Peter [Carl Friedrich von Weizsaecker Centre for Science and Peace Research, University of Hamburg (Germany); Becker, Christoph; Sengstock, Klaus [Institut fuer Laser-Physik, University of Hamburg (Germany)

    2016-07-01

    The isotope Krypton-85 is an excellent indicator for the detection of nuclear reprocessing activities. However, for the analysis of atmospheric air samples, sensitive measuring methods down to the single atom level are required because of the small concentrations. Furthermore, for a practical and effective detection of clandestine reprocessing, small sample sizes and a high sample throughput rate are desirable. Established methods using Atom Trap Trace Analysis (ATTA) allow high sensitivity but have a limited throughput of about 200 samples per year, since the vacuum chambers have to be flushed for several hours after each measurement to avoid cross contamination due to the RF-driven excitation of metastable states. Here we present an enhanced ATTA apparatus, which in contrast to the established methods, produces metastable Kr all-optically. This avoids cross contamination, therefore allowing a much higher throughput rate. The apparatus is based on a self-made VUV-lamp and a 2D-3D magneto-optical trap setup. In the 2D trap metastable krypton is produced and a beam of atoms is formed by Doppler-cooling simultaneously.

  4. All-optical optoacoustic microscopy based on probe beam deflection technique

    Directory of Open Access Journals (Sweden)

    Saher M. Maswadi

    2016-09-01

    Full Text Available Optoacoustic (OA microscopy using an all-optical system based on the probe beam deflection technique (PBDT for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i efficient coupling of laser excitation energy to the samples being imaged through the probing laser beam, (ii undistorted coupling of acoustic waves to the detector without the need for separation of the optical and acoustic paths, (iii high sensitivity and (iv ultrawide bandwidth. Because of the unimpeded optical path in PBDT, diffraction-limited lateral resolution can be readily achieved. The sensitivity of the current PBDT sensor of 22 μV/Pa and its noise equivalent pressure (NEP of 11.4 Pa are comparable with these parameters of the optical micro-ring resonator and commercial piezoelectric ultrasonic transducers. Benefits of the present prototype OA microscope were demonstrated by successfully resolving micron-size details in histological sections of cardiac muscle.

  5. Design of all-optical multi-level regenerators based on Mach-Zehnder interferometer

    Science.gov (United States)

    Kong, Xiangjian; Wu, Baojian; Zhou, Xingyu; Wan, Qingyao; Jiang, Shanglong; Wen, Feng; Qiu, Kun

    2016-12-01

    We propose a design method for all-optical multi-level regenerators by mimicking the normalized power transfer function (PTF) in the first-order approximation to the ideal step-like PTF, in which a key step is to appropriately select the amplitude and phase conditions of Mach-Zehnder-interferometer (MZI)-based regenerators. As an example, we describe the design process of the self-phase-modulation (SPM)-based MZI regenerator constructed by a section of nonlinear fiber and an optical phase shifter (OPS). It is shown that the parameter of reference power level (RPL) can be regarded as the upper limit of input power, which is useful for the measure of the multi-level regeneration performance. The number of regenerative power levels increases with the RPL parameter. For 4-level pulse amplitude modulated (4PAM) optical signals degraded by the Gaussian noises with the standard deviation of 0.02, the SPM-based MZI regenerator has an average noise reduction ratio (NRR) of 6.5 dB, better than that of 1st-order regenerator by about 5 dB.

  6. Current Developments on Optical Feedback Interferometry as an All-Optical Sensor for Biomedical Applications

    Science.gov (United States)

    Perchoux, Julien; Quotb, Adam; Atashkhooei, Reza; Azcona, Francisco J.; Ramírez-Miquet, Evelio E.; Bernal, Olivier; Jha, Ajit; Luna-Arriaga, Antonio; Yanez, Carlos; Caum, Jesus; Bosch, Thierry; Royo, Santiago

    2016-01-01

    Optical feedback interferometry (OFI) sensors are experiencing a consistent increase in their applications to biosensing due to their contactless nature, low cost and compactness, features that fit very well with current biophotonics research and market trends. The present paper is a review of the work in progress at UPC-CD6 and LAAS-CNRS related to the application of OFI to different aspects of biosensing, both in vivo and ex vivo. This work is intended to present the variety of opportunities and potential applications related to OFI that are available in the field. The activities presented are divided into two main sensing strategies: The measurement of optical path changes and the monitoring of flows, which correspond to sensing strategies linked to the reconstruction of changes of amplitude from the interferometric signal, and to classical Doppler frequency measurements, respectively. For optical path change measurements, measurements of transient pulses, usual in biosensing, together with the measurement of large displacements applied to designing palliative care instrumentation for Parkinson disease are discussed. Regarding the Doppler-based approach, progress in flow-related signal processing and applications in real-time monitoring of non-steady flows, human blood flow monitoring and OFI pressure myograph sensing will be presented. In all cases, experimental setups are discussed and results presented, showing the versatility of the technique. The described applications show the wide capabilities in biosensing of the OFI sensor, showing it as an enabler of low-cost, all-optical, high accuracy biomedical applications. PMID:27187406

  7. Ultracompact all-optical full-adder and half-adder based on nonlinear plasmonic nanocavities

    Directory of Open Access Journals (Sweden)

    Xie Jingya

    2017-06-01

    Full Text Available Ultracompact chip-integrated all-optical half- and full-adders are realized based on signal-light induced plasmonic-nanocavity-modes shift in a planar plasmonic microstructure covered with a nonlinear nanocomposite layer, which can be directly integrated into plasmonic circuits. Tremendous nonlinear enhancement is obtained for the nanocomposite cover layer, attributed to resonant excitation, slow light effect, as well as field enhancement effect provided by the plasmonic nanocavity. The feature size of the device is <15 μm, which is reduced by three orders of magnitude compared with previous reports. The operating threshold power is determined to be 300 μW (corresponding to a threshold intensity of 7.8 MW/cm2, which is reduced by two orders of magnitude compared with previous reports. The intensity contrast ratio between two output logic states, “1” and “0,” is larger than 27 dB, which is among the highest values reported to date. Our work is the first to experimentally realize on-chip half- and full-adders based on nonlinear plasmonic nanocavities having an ultrasmall feature size, ultralow threshold power, and high intensity contrast ratio simultaneously. This work not only provides a platform for the study of nonlinear optics, but also paves a way to realize ultrahigh-speed signal computing chips.

  8. Network connectivity enhancement by exploiting all optical multicast in semiconductor ring laser

    Science.gov (United States)

    Siraj, M.; Memon, M. I.; Shoaib, M.; Alshebeili, S.

    2015-03-01

    The use of smart phone and tablet applications will provide the troops for executing, controlling and analyzing sophisticated operations with the commanders providing crucial documents directly to troops wherever and whenever needed. Wireless mesh networks (WMNs) is a cutting edge networking technology which is capable of supporting Joint Tactical radio System (JTRS).WMNs are capable of providing the much needed bandwidth for applications like hand held radios and communication for airborne and ground vehicles. Routing management tasks can be efficiently handled through WMNs through a central command control center. As the spectrum space is congested, cognitive radios are a much welcome technology that will provide much needed bandwidth. They can self-configure themselves, can adapt themselves to the user requirement, provide dynamic spectrum access for minimizing interference and also deliver optimal power output. Sometimes in the indoor environment, there are poor signal issues and reduced coverage. In this paper, a solution utilizing (CR WMNs) over optical network is presented by creating nanocells (PCs) inside the indoor environment. The phenomenon of four-wave mixing (FWM) is exploited to generate all-optical multicast using semiconductor ring laser (SRL). As a result same signal is transmitted at different wavelengths. Every PC is assigned a unique wavelength. By using CR technology in conjunction with PC will not only solve network coverage issue but will provide a good bandwidth to the secondary users.

  9. Ultra fast all-optical fiber pressure sensor for blast event evaluation

    Science.gov (United States)

    Wu, Nan; Wang, Wenhui; Tian, Ye; Niezrecki, Christopher; Wang, Xingwei

    2011-05-01

    Traumatic brain injury (TBI) is a great potential threat to soldiers who are exposed to explosions or athletes who receive cranial impacts. Protecting people from TBI has recently attracted a significant amount of attention due to recent military operations in the Middle East. Recording pressure transient data in a blast event is very critical to the understanding of the effects of blast events on TBI. However, due to the fast change of the pressure during blast events, very few sensors have the capability to effectively track the dynamic pressure transients. This paper reports an ultra fast, miniature and all-optical fiber pressure sensor which could be mounted at different locations of a helmet to measure the fast changing pressure simultaneously. The sensor is based on Fabry-Perot (FP) principle. The end face of the fiber is wet etched. A well controlled thickness silicon dioxide diaphragm is thermal bonded on the end face to form an FP cavity. A shock tube test was conducted at Natick Soldier Research Development and Engineering Center, where the sensors were mounted in a shock tube side by side with a reference sensor to measure the rapidly changing pressure. The results of the test demonstrated that the sensor developed had an improved rise time (shorter than 0.4 μs) when compared to a commercially available reference sensor.

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  11. Prostate Ultrasound

    Medline Plus

    Full Text Available ... are the limitations of Prostate Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces ... top of page What are some common uses of the procedure? A transrectal ultrasound of the prostate ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... both sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Pelvic Ultrasound Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal ...

  13. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal

    Science.gov (United States)

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-01-01

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature ‘prototype’ PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits. PMID:27491391

  14. All-optical transistor- and diode-action and logic gates based on anisotropic nonlinear responsive liquid crystal.

    Science.gov (United States)

    Wang, Cheng-Yu; Chen, Chun-Wei; Jau, Hung-Chang; Li, Cheng-Chang; Cheng, Chiao-Yu; Wang, Chun-Ta; Leng, Shi-Ee; Khoo, Iam-Choon; Lin, Tsung-Hsien

    2016-08-05

    In this paper, we show that anisotropic photosensitive nematic liquid crystals (PNLC) made by incorporating anisotropic absorbing dyes are promising candidates for constructing all-optical elements by virtue of the extraordinarily large optical nonlinearity of the nematic host. In particular, we have demonstrated several room-temperature 'prototype' PNLC-based all-optical devices such as optical diode, optical transistor and all primary logic gate operations (OR, AND, NOT) based on such optical transistor. Owing to the anisotropic absorption property and the optical activity of the twist alignment nematic cell, spatially non-reciprocal transmission response can be obtained within a sizeable optical isolation region of ~210 mW. Exploiting the same mechanisms, a tri-terminal configuration as an all-optical analogue of a bipolar junction transistor is fabricated. Its ability to be switched by an optical field enables us to realize an all-optical transistor and demonstrate cascadability, signal fan-out, logic restoration, and various logical gate operations such as OR, AND and NOT. Due to the possibility of synthesizing anisotropic dyes and wide ranging choice of liquid crystals nonlinear optical mechanisms, these all-optical operations can be optimized to have much lower thresholds and faster response speeds. The demonstrated capabilities of these devices have shown great potential in all-optical control system and photonic integrated circuits.

  15. Broadband Radio Service (BRS) and Educational Broadband Service (EBS) Transmitters

    Data.gov (United States)

    Department of Homeland Security — The Broadband Radio Service (BRS), formerly known as the Multipoint Distribution Service (MDS)/Multichannel Multipoint Distribution Service (MMDS), is a commercial...

  16. Photoacoustic active ultrasound element for catheter tracking

    Science.gov (United States)

    Guo, Xiaoyu; Tavakoli, Behnoosh; Kang, Hyun-Jae; Kang, Jin U.; Etienne-Cummings, Ralph; Boctor, Emad M.

    2014-03-01

    In recent years, various methods have been developed to improve ultrasound based interventional tool tracking. However, none of them has yet provided a solution that effectively solves the tool visualization and mid-plane localization accuracy problem and fully meets the clinical requirements. Our previous work has demonstrated a new active ultrasound pattern injection system (AUSPIS), which integrates active ultrasound transducers with the interventional tool, actively monitors the beacon signals and transmits ultrasound pulses back to the US probe with the correct timing. Ex vivo and in vivo experiments have proved that AUSPIS greatly improved tool visualization, and provided tool-tip localization accuracy of less than 300 μm. In the previous work, the active elements were made of piezoelectric materials. However, in some applications the high driving voltage of the piezoelectric element raises safety concerns. In addition, the metallic electrical wires connecting the piezoelectric element may also cause artifacts in CT and MR imaging. This work explicitly focuses on an all-optical active ultrasound element approach to overcome these problems. In this approach, the active ultrasound element is composed of two optical fibers - one for transmission and one for reception. The transmission fiber delivers a laser beam from a pulsed laser diode and excites a photoacoustic target to generate ultrasound pulses. The reception fiber is a Fabry-Pérot hydrophone. We have made a prototype catheter and performed phantom experiments. Catheter tip localization, mid-plan detection and arbitrary pattern injection functions have been demonstrated using the all-optical AUSPIS.

  17. Broadband terahertz fiber directional coupler

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Jepsen, Peter Uhd

    2010-01-01

    We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber by micro......We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0:6 THz centered at 1:4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber...

  18. Broadband sound pressure enhancement in passive metafluids

    Science.gov (United States)

    Popa, Bogdan-Ioan

    2017-09-01

    Acoustic sensors operating in lossy environments, such as water, require significant sensitivity to overcome the sound attenuation in the environment and thus see farther. We show here that a surprisingly large class of passive fluids has the ability to enhance the sound pressure propagating inside them without employing active actuation. Specifically, the general requirements for this remarkable property are fluid impedance higher than the impedance of the environment and negligible insertion loss as sound propagates from the environment into the high impedance fluid. We demonstrate the pressure enhancing effect by designing a broadband isotropic metafluid that increases the pressure of sound waves impinging from water. We validate the design in numerical simulations showing that significant sound pressure level increases are achievable in realistic metafluid structures in large bandwidths covering several octaves. Our approach opens up unexplored avenues towards improving acoustic transducer sensitivity, which is critical in applications, such as medical ultrasound imaging, sonar, and acoustic communications.

  19. Toward broadband mechanical spectroscopy

    DEFF Research Database (Denmark)

    Hecksher, Tina; Torchinsky, Darius; Klieber, Christoph

    2017-01-01

    Diverse material classes exhibit qualitatively similar behavior when made viscous upon cooling toward the glass transition, suggesting a common theoretical basis. We used seven different measurement methods to determine the mechanical relaxation kinetics of a prototype molecular glass former over...... a temporal range of 13 decades and over a temperature range spanning liquid to glassy states. The data conform to time–temperature superposition for the main (alpha) process and to a scaling relation of schematic mode-coupling theory. The broadband mechanical measurements demonstrated have fundamental...

  20. BPL (Broadband Power Line)

    OpenAIRE

    Peralta, Arturo

    2010-01-01

    El mundo actual requiere cada vez más el estar conectados con la sociedad de la Información y el Conocimiento, esto demanda que en los hogares, lugares de turismo, trabajos, universidades, etcétera, se cuente con una conexión a Internet de Alta Velocidad, que además sea segura y confiable. En este documento se presenta las características más importantes de la tecnología BPL (Broadband Power Line) o PLC (Power Line Comunication), la cual permite brindar el servicio de Internet ...

  1. Broadband frequency conversion

    DEFF Research Database (Denmark)

    Sanders, Nicolai; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter

    We present a simple, passive and static setup for broadband frequency conversion. By using simple optical components like lenses, mirrors and gratings, we obtain the spectral angular dispersion to match the second harmonic generation phasematching angles in a nonlinear BiBO crystal. We are able...... to frequency double a single-frequency diode laser, tunable in the 1020-1090 nm range, with almost equal efficiency for all wavelengths. In the experimental setup, the width of the phasematch was increased with a factor of 50. The method can easily be extended to other wavelength ranges and nonlinear crystals...

  2. High contrast all-optical diode based on direction-dependent optical bistability within asymmetric ring cavity

    Science.gov (United States)

    Xia, Xiu-Wen; Zhang, Xin-Qin; Xu, Jing-Ping; Yang, Ya-Ping

    2016-08-01

    We propose a simple all-optical diode which is comprised of an asymmetric ring cavity containing a two-level atomic ensemble. Attributed to spatial symmetry breaking of the ring cavity, direction-dependent optical bistability is obtained in a classical bistable system. Therefore, a giant optical non-reciprocity is generated, which guarantees an all-optical diode with a high contrast up to 22 dB. Furthermore, its application as an all-optical logic AND gate is also discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11274242, 11474221, and 11574229), the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. U1330203), and the National Key Basic Research Special Foundation of China (Grant Nos. 2011CB922203 and 2013CB632701).

  3. 160 Gb/s all-optical AND gate using bulk SOA turbo-switched Mach-Zehnder interferometer

    Science.gov (United States)

    Rendón-Salgado, I.; Gutiérrez-Castrejón, R.

    2017-09-01

    A novel architecture to implement an all-optical AND gate that relies on the use of a bulk semiconductor optical amplifier-based active Mach-Zehnder interferometer and the turbo-switch effect is presented. Its performance is analyzed in terms of relevant physical parameters and its power consumption calculated. Error-free operation at 160 Gb/s is numerically demonstrated, thus becoming the fastest AND gate of its kind. Accurate simulations using a well-tested design suite predict a 2.7 dB improvement in terms of quality factor when compared to a conventional scheme. The performance advantages of the proposed architecture remain when combined with a turbo-switched XOR gate: the resulting all-optical half-adder also operates error-free at 160 Gb/s. Our research work boosts the potential of interferometric turbo-switched photonic structures as ultra-fast all-optical processing elements.

  4. Spatiotemporal monitoring of high-intensity focused ultrasound therapy with passive acoustic mapping

    National Research Council Canada - National Science Library

    Jensen, Carl R; Ritchie, Robert W; Gyöngy, Miklós; Collin, James R T; Leslie, Tom; Coussios, Constantin-C

    2012-01-01

    To demonstrate feasibility of monitoring high-intensity focused ultrasound (HIFU) treatment with passive acoustic mapping of broadband and harmonic emissions reconstructed from filtered-channel radiofrequency data in ex vivo bovine tissue...

  5. IST-LASAGNE: Towards all-optical label swapping employing optical logic gates and optical flip-flops

    DEFF Research Database (Denmark)

    Ramos, F.; Kehayas, E.; Martinez, J.M.

    2005-01-01

    The Information Society Technologies - all-optical LAbel SwApping employing optical logic Gates in NEtwork nodes (IST-LASAGNE) project aims at designing and implementing the first, modular, scalable, and truly all-optical photonic router capable of operating at 40 Gb/s. The results of the first p...... project year are presented in this paper, with emphasis on the implementation of network node functionalities employing optical logic gates and optical flip-flops, as well as the definition of the network architecture and migration scenarios. © 2005 IEEE....

  6. All-Optical 2R Regeneration of a 160-Gbit/s RZOOK Serial Data Signal Using a FOPA

    DEFF Research Database (Denmark)

    Wang, Ju; Ji, Hua; Hu, Hao

    2012-01-01

    All-optical 2R regeneration of a 160-Gbit/s RZ-OOK signal is demonstrated in a fiber optical parametric amplifier using a highly nonlinear fiber with the data as pump. Bit error rate bathtub curves validate the regeneration performance.......All-optical 2R regeneration of a 160-Gbit/s RZ-OOK signal is demonstrated in a fiber optical parametric amplifier using a highly nonlinear fiber with the data as pump. Bit error rate bathtub curves validate the regeneration performance....

  7. All-Optical Wavelength Conversion of a High-Speed RZ-OOK Signal in a Silicon Nanowire

    DEFF Research Database (Denmark)

    Hu, Hao; Ji, Hua; Galili, Michael

    2011-01-01

    All-optical wavelength conversion of a 320 Gb/s line-rate RZ-OOK signal is demonstrated based on four-wave mixing in a 3.6 mm long silicon nanowire. Bit error rate measurements validate the performance within FEC limits.......All-optical wavelength conversion of a 320 Gb/s line-rate RZ-OOK signal is demonstrated based on four-wave mixing in a 3.6 mm long silicon nanowire. Bit error rate measurements validate the performance within FEC limits....

  8. Real-time all-optical OFDM transmission system based on time-domain optical fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Kong, Deming; Røge, Kasper Meldgaard

    2014-01-01

    We propose a novel simple all-optical OFDM transmission system based on time-domain OFT using time-lenses. A real-time 160 Gbit/s DPSK OFDM transmission with 16 decorrelated data subcarriers is successfully demonstrated over 100 km.......We propose a novel simple all-optical OFDM transmission system based on time-domain OFT using time-lenses. A real-time 160 Gbit/s DPSK OFDM transmission with 16 decorrelated data subcarriers is successfully demonstrated over 100 km....

  9. Burst switching without guard interval in all-optical software-define star intra-data center network

    Science.gov (United States)

    Ji, Philip N.; Wang, Ting

    2014-02-01

    Optical switching has been introduced in intra-data center networks (DCNs) to increase capacity and to reduce power consumption. Recently we proposed a star MIMO OFDM-based all-optical DCN with burst switching and software-defined networking. Here, we introduce the control procedure for the star DCN in detail for the first time. The timing, signaling, and operation are described for each step to achieve efficient bandwidth resource utilization. Furthermore, the guidelines for the burst assembling period selection that allows burst switching without guard interval are discussed. The star all-optical DCN offers flexible and efficient control for next-generation data center application.

  10. Prostate Ultrasound

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  11. Ultrasound -- Pelvis

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  12. Ultrasound -- Pelvis

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  8. Prostate Ultrasound

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  13. Ultrasound -- Pelvis

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  14. Prostate Ultrasound

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  15. Ultrasound -- Pelvis

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  16. Prostate Ultrasound

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  18. Ultrasound -- Pelvis

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  19. Prostate Ultrasound

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  20. Ultrasound -- Pelvis

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  1. Prostate Ultrasound

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  4. Ultrasound -- Pelvis

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  5. Prostate Ultrasound

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  6. Endoscopic ultrasound

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007646.htm Endoscopic ultrasound To use the sharing features on this page, please enable JavaScript. Endoscopic ultrasound is a type of imaging test. It is ...

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  13. Ultrasound -- Pelvis

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  15. Prostate Ultrasound

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  16. Ultrasound -- Pelvis

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  20. Prostate Ultrasound

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    Full Text Available ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ... bowel (rectum) removed during prior surgery are not good candidates for ultrasound of the prostate gland because ...

  1. 75 FR 29516 - Broadband Researchers' Data Workshop

    Science.gov (United States)

    2010-05-26

    ... Administration Broadband Researchers' Data Workshop AGENCY: National Telecommunications and Information... demonstrated in the agency's October 30, 2009, Broadband Data Transparency Public Workshop.\\2\\ \\2\\ See http...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... transducer sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Pelvic Ultrasound Imaging? Ultrasound waves are ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and organs in the lower abdomen and pelvis. There are three types of pelvic ultrasound: abdominal, ...

  4. Carotid Ultrasound

    Science.gov (United States)

    ... this page from the NHLBI on Twitter. Carotid Ultrasound Also known as carotid duplex. Carotid ultrasound is a painless imaging test that uses high- ... of your carotid arteries. This test uses an ultrasound machine, which includes a computer, a screen, and ...

  5. Prostate Ultrasound

    Medline Plus

    Full Text Available ... other imaging methods. Ultrasound imaging uses no ionizing radiation. Ultrasound scanning may be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as ...

  6. All-Optical flip-flop operation using a SOA and DFB laser diode optical feedback combination

    DEFF Research Database (Denmark)

    D'Oosterlinck, W.; Öhman, Filip; Buron, Jakob Due

    2007-01-01

    We report on the switching of an all-optical flip-flop consisting of a semiconductor optical amplifier (SOA) and a distributed feedback laser diode (DFB), bidirectionally coupled to each other. Both simulation and experimental results are presented. Switching times as low as 50ps, minimal required...

  7. All-optical flip-flop operation based on asymmetric active-multimode interferometer bi-stable laser diodes

    DEFF Research Database (Denmark)

    Jiang, H.; Chaen, Y.; Hagio, T.

    2011-01-01

    We demonstrate fast and low energy all optical flip-flop devices based on asymmetric active-multimode interferometer using high-mesa waveguide structure. The implemented devices showed high speed alloptical flip-flop operation with 25ps long pulses. The rising and falling times of the output signal...

  8. All-Optical Flip-Flop Based on an SOA/DFB-Laser Diode Optical Feedback Scheme

    DEFF Research Database (Denmark)

    D'Oosterlinck, W.; Buron, Jakob Due; Öhman, Filip

    2007-01-01

    We report on the dynamic all-optical flip-flop (AOFF) operation of an optical feedback scheme consisting of a semiconductor optical amplifier (SOA) and a distributed feedback laser diode (DFB-LD), bidirectionally coupled to each other. The operation of the AOFF relies on the interplay between...

  9. All-optical 2R regeneration at 40 Gbit/s in an SOA-based Mach-Zehnder interferometer

    DEFF Research Database (Denmark)

    Wolfson, David; Hansen, Peter Bukhave; Fjelde, Tina

    1999-01-01

    All-optical 2 R regeneration, with wavelength conversion, at 40 Gbit/s is demonstarted in an all-active Mach-Zehnder interferometer showing the capability of improving the signal-to-noise ratio by more than 20 db....

  10. Performance analysis of an all-optical OFDM system in presence of non-linear phase noise.

    Science.gov (United States)

    Hmood, Jassim K; Harun, Sulaiman W; Emami, Siamak D; Khodaei, Amin; Noordin, Kamarul A; Ahmad, Harith; Shalaby, Hossam M H

    2015-02-23

    The potential for higher spectral efficiency has increased the interest in all-optical orthogonal frequency division multiplexing (OFDM) systems. However, the sensitivity of all-optical OFDM to fiber non-linearity, which causes nonlinear phase noise, is still a major concern. In this paper, an analytical model for estimating the phase noise due to self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM) in an all-optical OFDM system is presented. The phase noise versus power, distance, and number of subcarriers is evaluated by implementing the mathematical model using Matlab. In order to verify the results, an all-optical OFDM system, that uses coupler-based inverse fast Fourier transform/fast Fourier transform without any nonlinear compensation, is demonstrated by numerical simulation. The system employs 29 subcarriers; each subcarrier is modulated by a 4-QAM or 16-QAM format with a symbol rate of 25 Gsymbol/s. The results indicate that the phase variance due to FWM is dominant over those induced by either SPM or XPM. It is also shown that the minimum phase noise occurs at -3 dBm and -1 dBm for 4-QAM and 16-QAM, respectively. Finally, the error vector magnitude (EVM) versus subcarrier power and symbol rate is quantified using both simulation and the analytical model. It turns out that both EVM results are in good agreement with each other.

  11. Experimental demonstration of cascaded transmission and all-optical label swapping of orthogonal IM/FSK labelled signal

    DEFF Research Database (Denmark)

    Chi, Nan; Zhang, Jianfeng; Holm-Nielsen, Pablo Villanueva

    2003-01-01

    A network node is demonstrated with two-hop transmission and all-optical label swapping. It is based on a Mach-Zehnder semiconductor optical amplifier interferometer and electroabsorption modulator of a two-level optically labelled signal using an orthogonal IM/FSK modulation format with an overall...

  12. New all-optical RIN suppressing, image rejection receiver with efficient use of LO- and signal-power

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Ebskamp, F.

    1993-01-01

    An all-optical method of achieving a heterodyne signal is presented whereby the local oscillator (LO) relative intensity noise (RIN) and the image channel have been suppressed while efficient use of both LO and signal power is made. This is achieved with only one photodetector, compared to four f...

  13. Time Lens based Optical Fourier Transformation for All-Optical Signal Processing of Spectrally-Efficient Data

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Lillieholm, Mads

    2017-01-01

    four-wave mixing (FWM), separated by a dispersive medium, which enables time-to-frequency and frequency-to-time conversions simultaneously, thus performing an exchange between the temporal and spectral profiles of the input signal. Using the proposed complete OFT, several advanced all-optical signal...

  14. All-Optical Network Subsystems Using Integrated SOA-Based Optical Gates and Flip-Flops for Label-Swapped Netorks

    DEFF Research Database (Denmark)

    Seoane, Jorge; Holm-Nielsen, Pablo Villanueva; Kehayas, E.

    2006-01-01

    In this letter, we demonstrate that all-optical network subsystems, offering intelligence in the optical layer, can be constructed by functional integration of integrated all-optical logic gates and flip-flops. In this context, we show 10-Gb/s all-optical 2-bit label address recognition by interc......In this letter, we demonstrate that all-optical network subsystems, offering intelligence in the optical layer, can be constructed by functional integration of integrated all-optical logic gates and flip-flops. In this context, we show 10-Gb/s all-optical 2-bit label address recognition...... by interconnecting two optical gates that perform xor operation on incoming optical labels. We also demonstrate 40-Gb/s all-optical wavelength-switching through an optically controlled wavelength converter, consisting of an integrated flip-flop prototype device driven by an integrated optical gate. The system...

  15. Broadband Advanced Spectral System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NovaSol proposes to develop an advanced hyperspectral imaging system for earth science missions named BRASS (Broadband Advanced Spectral System). BRASS combines...

  16. Does broadband internet affect fertility?

    OpenAIRE

    Billari, Francesco C.; Giuntella, Osea; Stella, Luca

    2017-01-01

    The spread of high-speed Internet epitomizes the digital revolution, affecting several aspects of our life. Using German panel data, we test whether the availability of broadband Internet influences fertility choices in a low-fertility setting, which is well-known for the difficulty to combine work and family life. We exploit a strategy devised by Falck et al. (2014) to obtain causal estimates of the impact of broadband on fertility. We find positive effects of highspeed Internet availability...

  17. High-density all-optical magnetic recording using a high-NA lens illuminated by circularly polarized pulse lights

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yaoju [College of Physics and Electronic Information, Wenzhou University, Wenzhou 325035 (China)], E-mail: zhangyaoju@sohu.com; Bai Jianping [School of Physics and Electronic Engineering, Nanyang Normal College, Nanyang 472000 (China)

    2008-10-06

    We propose a method for high-density all-optical magnetic recording. Our analyses, based on the vector diffraction theory, show that owing to the inverse Faraday effect, circularly polarized laser pulses focused by a high numerical aperture (NA) lens can induce a small magnetization domain. For an example, the FWHM of the effective magnetization domain is 0.4646{lambda} when NA=0.85. The magnetization direction is basically perpendicular to the surface of the optic-magneto film within the effective magnetization domain and the switching direction of magnetization can be controlled by the helicity of the incident circularly polarized light. These characteristics are useful to next-generation high-density all-optical magnetic storage.

  18. All-Optical Ultra-High-Speed OFDM to Nyquist-WDM Conversion Based on Complete Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

    2016-01-01

    We propose a novel all-optical ultra-high-speed orthogonal frequency-division multiplexing (OFDM) to Nyquist wavelength-division multiplexing (Nyquist-WDM) conversion scheme, achieved by exchanging the temporal and spectral profiles using a complete optical Fourier transformation (OFT). This scheme...... enables high-speed OFDM to Nyquist-WDM conversion without complex optical/electrical/optical conversion. The all-optical OFDM transmitter is based on the generation of OFDM symbols with a low duty cycle by rectangular temporal gating, which in combination with optical time-division multiplexing yields...... a higher symbol-rate OFDM signal. In the receiver, the converted Nyquist-WDM super-channel is WDM demultiplexed into individual Nyquist-WDM channels using a rectangular optical bandpass filter, followed by optical sampling at the intersymbol-interference free point. In the experimental demonstration...

  19. Performance analysis of relay-assisted all-optical FSO networks over strong atmospheric turbulence channels with pointing errors

    KAUST Repository

    Yang, Liang

    2014-12-01

    In this study, we consider a relay-assisted free-space optical communication scheme over strong atmospheric turbulence channels with misalignment-induced pointing errors. The links from the source to the destination are assumed to be all-optical links. Assuming a variable gain relay with amplify-and-forward protocol, the electrical signal at the source is forwarded to the destination with the help of this relay through all-optical links. More specifically, we first present a cumulative density function (CDF) analysis for the end-to-end signal-to-noise ratio. Based on this CDF, the outage probability, bit-error rate, and average capacity of our proposed system are derived. Results show that the system diversity order is related to the minimum value of the channel parameters.

  20. Critical switching fluence of L10-FePt nanoparticles with practical size to ultrafast all-optical polarization switching

    Science.gov (United States)

    Huang, Tao; Wang, Haiwei; Cheng, Weiming; Zou, Yuhao; Xie, Changsheng

    2017-06-01

    The magnetic storage industry will be pushed into a new era by emerging magnetic materials and ingenious read/write techniques. Recently, L10-FePt nanoparticles with exceptionally high uniaxial anisotropy, combined with the technique of all-optical magnetic switching, have increasingly drawn the attention of researchers. Focusing on L10-FePt nanoparticles, we report the superparamagnetic size limits and three elaborate stages of magnetic orientation switching, which demonstrate that in terms of the opto-magnetic responses of L10-FePt nanoparticles with the size of 6 nm, the fluence of an ultrashort laser pulse should not be larger than the level of 40 mJ/cm2 in order to achieve the helicity-dependent all-optical switching.

  1. All-Optical Preparation of Coherent Dark States of a Single Rare Earth Ion Spin in a Crystal.

    Science.gov (United States)

    Xia, Kangwei; Kolesov, Roman; Wang, Ya; Siyushev, Petr; Reuter, Rolf; Kornher, Thomas; Kukharchyk, Nadezhda; Wieck, Andreas D; Villa, Bruno; Yang, Sen; Wrachtrup, Jörg

    2015-08-28

    All-optical addressing and coherent control of single solid-state based quantum bits is a key tool for fast and precise control of ground-state spin qubits. So far, all-optical addressing of qubits was demonstrated only in a very few systems, such as color centers and quantum dots. Here, we perform high-resolution spectroscopic of native and implanted single rare earth ions in solid, namely, a cerium ion in yttrium aluminum garnet (YAG) crystal. We find narrow and spectrally stable optical transitions between the spin sublevels of the ground and excited optical states. Utilizing these transitions we demonstrate the generation of a coherent dark state in electron spin sublevels of a single Ce^{3+} ion in YAG by coherent population trapping.

  2. EW WEIGHT DEPENDENT ROUTING AND WAVELENGTH ASSIGNMENT STRATEGY FOR ALL OPTICAL NETWORKS IN ABSENCE OF WAVELENGTH CONVERTERS

    Directory of Open Access Journals (Sweden)

    Shilpa S. Patil

    2015-09-01

    Full Text Available In wavelength division multiplexed all optical networks; lightpath establishes a connection between sending and receiving nodes bypassing the electronic processing at intermediate nodes. One of the prime objectives of Routing and Wavelength Assignment (RWA problem is to maximize the number of connections efficiently by choosing the best routes. Although there are several algorithms available, improving the blocking performance in optical networks and finding optimal solutions for RWA problem has still remained a challenging issue. Wavelength conversion can be helpful in restricting the problem of wavelength continuity constraint but it increases complexity in the network. In this paper, we propose new weight dependent routing and wavelength assignment strategy for all optical networks without use of wavelength converters. Proposed weight function reduces blocking probability significantly, improving the network performance at various load conditions. Further, due to absence of wavelength converters, the cost and complexity of network reduces. Results show that the proposed strategy performs better than earlier reported methods.

  3. All-optical half adder using an SOA and a PPLN waveguide for signal processing in optical networks.

    Science.gov (United States)

    Kumar, Saurabh; Willner, Alan E; Gurkan, Deniz; Parameswaran, Krishnan R; Fejer, Martin M

    2006-10-30

    We demonstrate an all-optical half adder for bit-wise addition of two serial data streams that simultaneously generates Sum and Carry outputs. The module performs the required XOR and AND operations using only two nonlinear optical elements. Difference Frequency Generation in a periodically poled lithium niobate waveguide serves as the AND gate and cross-gain modulation in a semiconductor optical amplifier is employed to generate the XOR output. Error free operation for RZ data is reported.

  4. Broadband accelerator control network

    Energy Technology Data Exchange (ETDEWEB)

    Skelly, J.; Clifford, T.; Frankel, R.

    1983-01-01

    A broadband data communications network has been implemented at BNL for control of the Alternating Gradient Synchrotron (AG) proton accelerator, using commercial CATV hardware, dual coaxial cables as the communications medium, and spanning 2.0 km. A 4 MHz bandwidth Digital Control channel using CSMA-CA protocol is provided for digital data transmission, with 8 access nodes available over the length of the RELWAY. Each node consists of an rf modem and a microprocessor-based store-and-forward message handler which interfaces the RELWAY to a branch line implemented in GPIB. A gateway to the RELWAY control channel for the (preexisting) AGS Computerized Accelerator Operating system has been constructed using an LSI-11/23 microprocessor as a device in a GPIB branch line. A multilayer communications protocol has been defined for the Digital Control Channel, based on the ISO Open Systems Interconnect layered model, and a RELWAY Device Language defined as the required universal language for device control on this channel.

  5. Broadband transmission EPR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wilfred R Hagen

    Full Text Available EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9-10 GHz range. Most (biomolecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin - nuclear spin interactions and electron spin - electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8-2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed.

  6. ATST visible broadband imager

    Science.gov (United States)

    McBride, William R.; Wöger, Friedrich; Hegwer, Steve L.; Ferayorni, Andrew; Gregory, B. Scott

    2012-09-01

    The Advanced Technology Solar Telescope (ATST) is a 4 meter class telescope for observation of the solar atmosphere currently in the construction phase. The Visible Broadband Imager (VBI) is a diffraction limited imaging instrument planned to be the first-light instrument in the ATST instrumentation suite. The VBI is composed of two branches, the "VBI blue" and the "VBI red", and uses state-of-the-art narrow bandwidth interference filters and two custom designed high speed filter wheels to take bursts of images that will be re-constructed using a Graphics Processing Unit (GPU) optimized near-real-time speckle image reconstruction engine. At first light, the VBI instrument will produce diffraction-limited movies of solar activity at eight discrete wavelengths with a field of view of 2 arc minutes square. In this contribution, the VBI design team will discuss the capabilities of the VBI and describe the design of the instrument, highlighting the unique challenges faced in the development of this unique instrument.

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  8. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce pictures ... limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and painless, and produces ...

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... inserted into a man's rectum to view the prostate. Transvaginal ultrasound. The transducer is inserted into a ... Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview Images related to General Ultrasound Videos ...

  10. Broadband Rotational Spectroscopy

    Science.gov (United States)

    Pate, Brooks

    2014-06-01

    The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

  11. Broadband Transmission EPR Spectroscopy

    Science.gov (United States)

    Hagen, Wilfred R.

    2013-01-01

    EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9–10 GHz range. Most (bio)molecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin – nuclear spin interactions and electron spin – electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8–2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed. PMID:23555819

  12. Driving demand for broadband networks and services

    CERN Document Server

    Katz, Raul L

    2014-01-01

    This book examines the reasons why various groups around the world choose not to adopt broadband services and evaluates strategies to stimulate the demand that will lead to increased broadband use. It introduces readers to the benefits of higher adoption rates while examining the progress that developed and emerging countries have made in stimulating broadband demand. By relying on concepts such as a supply and demand gap, broadband price elasticity, and demand promotion, this book explains differences between the fixed and mobile broadband demand gap, introducing the notions of substitution and complementarity between both platforms. Building on these concepts, ‘Driving Demand for Broadband Networks and Services’ offers a set of best practices and recommendations aimed at promoting broadband demand.  The broadband demand gap is defined as individuals and households that could buy a broadband subscription because they live in areas served by telecommunications carriers but do not do so because of either ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... body. Doppler ultrasound, a special application of ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of blood cells causes a change in pitch of the reflected sound waves (called the Doppler effect). A computer collects ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ultrasound procedures requiring insertion of the transducer, such as transvaginal or transrectal exams, the device is covered with a sheath and lubricated before insertion. ...

  15. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ultrasound procedures such as transrectal exams that require insertion of an imaging probe, also called a transducer, the device is covered and lubricated with a gel. top of ...

  16. Prostate Ultrasound

    Medline Plus

    Full Text Available ... transducer sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Prostate Ultrasound Imaging? Men who have ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... are some common uses of the procedure? In women, a pelvic ultrasound is most often performed to evaluate the: uterus cervix ovaries fallopian tubes bladder Pelvic ultrasound exams are also used to monitor the health and development of an embryo or fetus during ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ultrasound procedures requiring insertion of the transducer, such as transvaginal or transrectal exams, the device is covered with a sheath and lubricated before ...

  20. Prostate Ultrasound

    Medline Plus

    Full Text Available ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ultrasound procedures such as transrectal exams that require insertion of an imaging probe, also called a transducer, the device is covered and lubricated with a gel. top ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... then uses those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show ...

  2. Ultrasound - Scrotum

    Science.gov (United States)

    ... then uses those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show ...

  3. Prostate Ultrasound

    Medline Plus

    Full Text Available ... then uses those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show ...

  4. Prostate Ultrasound

    Medline Plus

    Full Text Available ... as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Prostate Ultrasound Imaging? Men who have had the tail end of their bowel ( ...

  5. Prostate Ultrasound

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of ...

  6. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging ...

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... if a finding is stable or changed over time. top of page What are the benefits vs. risks? Benefits Ultrasound is widely ...

  8. Sports Ultrasound

    Science.gov (United States)

    Finnoff, Jonathan T.; Ray, Jeremiah; Corrado, Gianmichael; Kerkhof, Deanna; Hill, John

    2016-01-01

    Background: Traditionally, ultrasound has been used to evaluate musculoskeletal injuries in athletes; however, ultrasound applications extend well beyond musculoskeletal conditions, many of which are pertinent to athletes. Evidence Acquisition: Articles were identified in PubMed using the search terms ultrasound, echocardiogram, preparticipation physical examination, glycogen, focused assessment with sonography of trauma, optic nerve, and vocal cord dysfunction. No date restrictions were placed on the literature search. Study Design: Clinical review. Level of Evidence: Level 4. Results: Several potential applications of nonmusculoskeletal ultrasound in sports medicine are presented, including extended Focused Assessment with Sonography for Trauma (eFAST), limited echocardiographic screening during preparticipation physical examinations, assessment of muscle glycogen stores, optic nerve sheath diameter measurements in athletes with increased intracranial pressure, and assessment of vocal cord dysfunction in athletes. Conclusion: Ultrasound can potentially be used to assist athletes with monitoring their muscle glycogen stores and the diagnosis of multiple nonmusculoskeletal conditions within sports medicine. PMID:27519599

  9. Adaptive Beamforming for Medical Ultrasound Imaging

    DEFF Research Database (Denmark)

    Holfort, Iben Kraglund

    This dissertation investigates the application of adaptive beamforming for medical ultrasound imaging. The investigations have been concentrated primarily on the Minimum Variance (MV) beamformer. A broadband implementation of theMV beamformer is described, and simulated data have been used...... of the influence of sound speed errors on the adaptive beamformers; MV and the Amplitude and Phase EStimation (APES) beamformer. Furthermore, the investigations of previously suggested adaptive spectral Doppler techniques are continued by additional in-vivo measurements. These investigations shows...

  10. An improved approximate network blocking probability model for all-optical WDM Networks with heterogeneous link capacities

    Science.gov (United States)

    Khan, Akhtar Nawaz

    2017-11-01

    Currently, analytical models are used to compute approximate blocking probabilities in opaque and all-optical WDM networks with the homogeneous link capacities. Existing analytical models can also be extended to opaque WDM networking with heterogeneous link capacities due to the wavelength conversion at each switch node. However, existing analytical models cannot be utilized for all-optical WDM networking with heterogeneous structure of link capacities due to the wavelength continuity constraint and unequal numbers of wavelength channels on different links. In this work, a mathematical model is extended for computing approximate network blocking probabilities in heterogeneous all-optical WDM networks in which the path blocking is dominated by the link along the path with fewer number of wavelength channels. A wavelength assignment scheme is also proposed for dynamic traffic, termed as last-fit-first wavelength assignment, in which a wavelength channel with maximum index is assigned first to a lightpath request. Due to heterogeneous structure of link capacities and the wavelength continuity constraint, the wavelength channels with maximum indexes are utilized for minimum hop routes. Similarly, the wavelength channels with minimum indexes are utilized for multi-hop routes between source and destination pairs. The proposed scheme has lower blocking probability values compared to the existing heuristic for wavelength assignments. Finally, numerical results are computed in different network scenarios which are approximately equal to values obtained from simulations. Since January 2016, he is serving as Head of Department and an Assistant Professor in the Department of Electrical Engineering at UET, Peshawar-Jalozai Campus, Pakistan. From May 2013 to June 2015, he served Department of Telecommunication Engineering as an Assistant Professor at UET, Peshawar-Mardan Campus, Pakistan. He also worked as an International Internship scholar in the Fukuda Laboratory, National

  11. Integrated all-optical wavelength multicasting for 40 Gbit/s PDM-QPSK signals using a single silicon waveguide

    Science.gov (United States)

    Feng, Xianglian; Wu, Zhihang; Wang, Xiaoyan; Gao, Shiming

    2017-09-01

    All-optical wavelength multicasting is presented and experimentally demonstrated for 40 Gbit/s polarization-division-multiplexed (PDM) nonreturn-to-zero quadrature phase-shift keying (QPSK) signals using four-wave mixing (FWM) with angled-polarization pumps in a silicon waveguide. Five multicast channels are obtained on the generated idlers. The eye diagrams, constellation diagrams, and bit error rates (BERs) of the QPSK sequences on the two polarization states are measured for each wavelength channel. The power penalties of all these multicast QPSK sequences on x or y polarization state are less than 2.0 dB at the BER of 3 × 10-3.

  12. Design and modeling of an all-optical frequency modulated MEMS strain sensor using nanoscale Bragg gratings

    DEFF Research Database (Denmark)

    Reck, Kasper; Almind, Ninia Sejersen; Mar, Mikkel Dysseholm

    2009-01-01

    We present modeling and design of an all-optical MEMS Bragg grating (half-pitch of 125 nm) strain sensor for single-fiber distributed sensing. Low optical loss and the use of frequency modulation rather than amplitude modulation, makes this sensor better suited for distributed systems than...... comparable designs, e.g. Fabry-Perot and Mach-Zender. Also, multiplexing of several sensors with different period gratings, allow sensors to be connected to a single fiber, thereby minimizing cabling and simplifying readout. We show through analytical analysis and finite element modeling (FEM) that large...

  13. Parametric Phase-sensitive and Phase-insensitive All-optical Signal Processing on Multiple Nonlinear Platforms - Invited talk

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Da Ros, Francesco; Vukovic, Dragana

    -optical signal processing. In this presentation, we will review our recent results on the demonstration of all-optical para- metric signal processing using dierent nonlinear platforms, including highly nonlinear optical bers (HNLFs), silicon nanowires, and periodically-poled lithium niobate (PPLN) waveguides....... In particu- lar, we will show how phase-sensitive processes can be engineered to demonstrate phase-quadrature separation, which we have recently demonstrated in HNLFs [1] and PPLN waveguides [2]. Silicon nanowires are particularly attractive for signal processing thanks to their compact size, CMOS...

  14. Ultrafast all-optical switching in a silicon-nanocrystal-based silicon slot waveguide at telecom wavelengths.

    Science.gov (United States)

    Martínez, Alejandro; Blasco, Javier; Sanchis, Pablo; Galán, José V; García-Rupérez, Jaime; Jordana, Emmanuel; Gautier, Pauline; Lebour, Youcef; Hernández, Sergi; Guider, Romain; Daldosso, Nicola; Garrido, Blas; Fedeli, Jean Marc; Pavesi, Lorenzo; Martí, Javier; Spano, Rita

    2010-04-14

    We demonstrate experimentally all-optical switching on a silicon chip at telecom wavelengths. The switching device comprises a compact ring resonator formed by horizontal silicon slot waveguides filled with highly nonlinear silicon nanocrystals in silica. When pumping at power levels about 100 mW using 10 ps pulses, more than 50% modulation depth is observed at the switch output. The switch performs about 1 order of magnitude faster than previous approaches on silicon and is fully fabricated using complementary metal oxide semiconductor technologies.

  15. Ultra-low power all-optical switch using a single quantum dot embedded in a photonic wire

    DEFF Research Database (Denmark)

    Nguyen, H.A.; Grange, T.; Malik, N.S.

    [1,2]. We exploit here its broad operation bandwidth (>100 nm around 950 nm) to efficiently address two different transitions of the QD with two cw laser beams (fig. 1b). The laser coupled to the upper transition leads to a Rabi splitting of the intermediate state (Autler-Townes effect), affecting...... the resonant reflectivity of the laser coupled to the lower transition (see fig. 1c). By performing reflectivity experiment, we show that a coupling laser of 10 nW (50 photons per emitter lifetime) can modify the transmission of the probe laser, realizing an ultra-low power all-optical switch....

  16. Controlled absorption and all-optical diode action due to collisions of self-induced transparency solitons

    CERN Document Server

    Novitsky, Denis

    2012-01-01

    We study inelastic collisions of counter-propagating self-induced transparency solitons in a homogeneously broadened two-level medium. The energy of the pulse can be almost totally absorbed in the medium due to asymmetric collision with a properly chosen control pulse. The medium state thus prepared demonstrates the property of an all-optical diode which transmits pulses from one direction and blocks from another. The saturation process of a controlled absorption effect, local-field correction influence, and the parameter ranges for the diode action are studied as well.

  17. All-optical switchable holographic Fresnel lens based on azo-dye-doped polymer-dispersed liquid crystals.

    Science.gov (United States)

    Jashnsaz, Hossein; Nataj, Nahid Hosain; Mohajerani, Ezeddin; Khabbazi, Amir

    2011-08-01

    Fabrication of an all-optical switchable holographic liquid crystal (LC) Fresnel lens based on azo-dye-doped polymer-dispersed LCs is reported using a Michelson interferometer. It is found that, upon circularly polarized photoirradiation, the diffraction efficiency of the fabricated Fresnel lens was increased significantly in a reversible manner. We believe this is due to the anisotropy induced by reorientation of the LC molecules coupled with azo-dye molecule orientation due to trans-cis-trans photoisomerization, which modulates the refractive index of the LC-rich regions. We also studied the effect of azo dye on the polarization dependency of the fabricated lens.

  18. All-optical, ultra-wideband microwave I/Q mixer and image-reject frequency down-converter.

    Science.gov (United States)

    Gao, Yongsheng; Wen, Aijun; Chen, Wei; Li, Xiaoyan

    2017-03-15

    An all-optical and ultra-wideband microwave in-phase/quadrature (I/Q) mixer, based on a dual-parallel Mach-Zehnder modulator and a wavelength division multiplexer, is proposed. Due to the simultaneous frequency down-conversion and 360-deg tunable phase shifting in the optical domain, the proposed I/Q mixer has the advantages of high conversion gain and excellent quadrature phase balance (analog or digital intermediate-frequency quadrature coupler, an image-reject frequency down-converter is then implemented, with an image rejection exceeding 50 dB over the working band.

  19. 160-Gb/s Silicon All-Optical Packet Switch for Buffer-less Optical Burst Switching

    DEFF Research Database (Denmark)

    Hu, Hao; Ji, Hua; Pu, Minhao

    2015-01-01

    We experimentally demonstrate a 160-Gb/s Ethernet packet switch using an 8.6-mm-long silicon nanowire for optical burst switching, based on cross phase modulation in silicon. One of the four packets at the bit rate of 160 Gb/s is switched by an optical control signal using a silicon based 1 × 1 all......-optical packet switch. Error free performance (BER switched packet. The use of optical burst switching protocols could eliminate the need for optical buffering in silicon packet switch based optical burst switching, which might be desirable for high-speed interconnects within a short...

  20. All-optical three-input logic minterms generation using semiconductor optical amplifier-based Sagnac interferometer

    DEFF Research Database (Denmark)

    Lei, L.; Da Ros, Francesco; Xu, Jing

    2013-01-01

    experimentally demonstrated in a Sagnac interferometer. Correct and clear temporal waveforms are successfully observed. Bit error ratios and optical signal-to-noise ratios are measured to demonstrate the effectiveness of the method. As the basic units of combinational logic operations, logic minterms......All-optical three-input logic minterms are generated at 42 Gbit/s with a Sagnac interferometer by using cross-phase modulation in a semiconductor optical amplifier. To the best of the author's knowledge, this is the first time that high-speed logic operations with more than two inputs have been...... are promising candidates to construct reconfigurable and programmable logic functions....

  1. High-Capacity Wireless Signal Generation and Demodulation in 75- to 110-GHz Band Employing All-Optical OFDM

    DEFF Research Database (Denmark)

    Zibar, Darko; Sambaraju, Rakesh; Caballero Jambrina, Antonio

    2011-01-01

    We present a radio-frequency (RF) and bit-rate scalable technique for multigigabit wireless signal generation based on all-optical orthogonal frequency-division multiplexing (OFDM) and photonic up-conversion. Coherent detection supported by digital signal processing is used for signal demodulation...... and data recovery. In order to demonstrate the RF frequency scalability and bit-rate transparency, the system is tested at 60 GHz and in the 75- to 110-GHz band at the baud rates of 5 and 10 Gbaud. In terms of the bit rate, the proposed system is experimentally tested up to 40 Gb/s for wireless signal...

  2. Cranial Ultrasound/Head Ultrasound

    Science.gov (United States)

    ... then uses those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show ...

  3. Observations involving broadband impedance modelling

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    Results for single- and multi-bunch instabilities can be significantly affected by the precise model that is used for the broadband impedance. This paper discusses three aspects of broadband impedance modelling. The first is an observation of the effect that a seemingly minor change in an impedance model has on the single-bunch mode coupling threshold. The second is a successful attempt to construct a model for the high-frequency tails of an r.f. cavity. The last is a discussion of requirements for the mathematical form of an impedance which follow from the general properties of impedances. (author)

  4. Ultrasound physics.

    Science.gov (United States)

    Shriki, Jesse

    2014-01-01

    Bedside ultrasound has become an important modality for obtaining critical information in the acute care of patients. It is important to understand the physics of ultrasound in order to perform and interpret images at the bedside. The physics of both continuous wave and pulsed wave sound underlies diagnostic ultrasound. The instrumentation, including transducers and image processing, is important in the acquisition of appropriate sonographic images. Understanding how these concepts interplay with each other enables practitioners to obtain the best possible images. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Ultrafast all-optical flip-flop based on passive micro Sagnac waveguide ring with photonic crystal fiber.

    Science.gov (United States)

    Xu, Ming; Yang, Wan; Hong, Tao; Kang, TangZhen; Ji, JianHua; Wang, Ke

    2017-06-01

    Ultrafast all-optical flip-flop based on a passive micro Sagnac waveguide ring is studied through theoretical analysis and numerical simulation in this paper. The types of D, R-S, J-K, and T flip-flop are designed by controlling the cross-phase modulation effect of lights in this special microring. The high nonlinearity of the hollow-core photonic crystal fiber is implanted on a chip to shorten the length of the ring and reduce input power. By sensible management, the pulse width ratio of the input and the control signal, problems of pulse narrowing, and residual pedestal at the out port are solved. The parameters affecting the performance of flip-flops are optimized. The results show that the all-optical flip-flops have stable performance, low power consumption, high transmission rate (up to 100  Gb/s), and response time in picosecond order. The small size microwaveguide structure is suitable for photonic integration.

  6. Monitoring burst (M-burst) — A novel framework of failure localization in all-optical mesh networks

    KAUST Repository

    Ali, Mohammed L.

    2011-10-10

    Achieving instantaneous and precise failure localization in all-optical wavelength division multiplexing (WDM) networks has been an attractive feature of network fault management systems, and is particularly important when failure-dependent protection is employed. The paper introduces a novel framework of real-time failure localization in all-optical WDM mesh networks, called monitoring-burst (m-burst), which aims to initiate a graceful compromise between consumed monitoring resources and monitoring delay. Different from any previously reported solution, the proposed m-burst framework has a single monitoring node (MN) which launches optical bursts along a set of pre-defined close-loop routes, called monitoring cycles (m-cycles), to probe the links along the m-cycles. Bursts along different m-cycles are kept non-overlapping through any link of the network. By identifying the lost bursts due to single link failure events only, the MN can unambiguously localize the failed link in at least 3-connected networks. We will justify the feasibility and applicability of the proposed m-burst framework in the scenario of interest. To avoid possible collision among optical bursts launched by the MN, we define the problem of collision-free scheduling and formulate it into an integer linear program (ILP) in order to minimize the monitoring delay. Numerical results demonstrate the effectiveness of the proposed framework and the proposed solution.

  7. Harnessing mode-selective nonlinear optics for on-chip multi-channel all-optical signal processing

    Directory of Open Access Journals (Sweden)

    Ming Ma

    2016-11-01

    Full Text Available All-optical signal processing based on nonlinear optical effects allows for the realization of important functions in telecommunications including wavelength conversion, optical multiplexing/demultiplexing, Fourier transformation, and regeneration, amongst others, on ultrafast time scales to support high data rate transmission. In integrated photonic subsystems, the majority of all-optical signal processing systems demonstrated to date typically process only a single channel at a time or perform a single processing function, which imposes a serious limitation on the functionality of integrated solutions. Here, we demonstrate how nonlinear optical effects can be harnessed in a mode-selective manner to perform simultaneous multi-channel (two and multi-functional optical signal processing (i.e., regenerative wavelength conversion in an integrated silicon photonic device. This approach, which can be scaled to a higher number of channels, opens up a new degree of freedom for performing a broad range of multi-channel nonlinear optical signal processing functions using a single integrated photonic device.

  8. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum.

    Science.gov (United States)

    Guo, Peijun; Schaller, Richard D; Ocola, Leonidas E; Diroll, Benjamin T; Ketterson, John B; Chang, Robert P H

    2016-09-29

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals.

  9. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum

    Science.gov (United States)

    Guo, Peijun; Schaller, Richard D.; Ocola, Leonidas E.; Diroll, Benjamin T.; Ketterson, John B.; Chang, Robert P. H.

    2016-09-01

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals.

  10. Harnessing mode-selective nonlinear optics for on-chip multi-channel all-optical signal processing

    Science.gov (United States)

    Ma, Ming; Chen, Lawrence R.

    2016-11-01

    All-optical signal processing based on nonlinear optical effects allows for the realization of important functions in telecommunications including wavelength conversion, optical multiplexing/demultiplexing, Fourier transformation, and regeneration, amongst others, on ultrafast time scales to support high data rate transmission. In integrated photonic subsystems, the majority of all-optical signal processing systems demonstrated to date typically process only a single channel at a time or perform a single processing function, which imposes a serious limitation on the functionality of integrated solutions. Here, we demonstrate how nonlinear optical effects can be harnessed in a mode-selective manner to perform simultaneous multi-channel (two) and multi-functional optical signal processing (i.e., regenerative wavelength conversion) in an integrated silicon photonic device. This approach, which can be scaled to a higher number of channels, opens up a new degree of freedom for performing a broad range of multi-channel nonlinear optical signal processing functions using a single integrated photonic device.

  11. 75 FR 27984 - Broadband Technology Opportunities Program

    Science.gov (United States)

    2010-05-19

    ... interoperability framework for use across the United States. The FCC's National Broadband Plan recognized that... Research, Projects, at http://www.pscr.gov/projects/broadband/700mhz/700mhz.php . Pursuant to the eligible...

  12. Compact All-optical Parity calculator based on a single all-active Mach-Zehnder Interferometer with an all-SOA amplified feedback

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup; Petersen, Martin Nordal; Nord, Martin

    2003-01-01

    An all-optical signal processing circuit capable of parity calculations is demonstrated using a single integrated all-active SOA-based MZI, exploiting the integrated SOAs for feedback amplification.......An all-optical signal processing circuit capable of parity calculations is demonstrated using a single integrated all-active SOA-based MZI, exploiting the integrated SOAs for feedback amplification....

  13. All-optical signal regeneration at 40 Gbit/s using a Mach-Zehnder Interferometer based on semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Bischoff, Svend; Mørk, Jesper

    2000-01-01

    Summary form only given. All-optical signal regeneration and processing are interesting for high bit-rate transmission systems. The Mach-Zehnder interferometer (MZI) is a promising device for functionalities like all-optical add/drop and signal regeneration. Wavelength conversion up-to 20 Gbit...

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  18. Broadband Synthetic Ground Motion Records

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The dataset contains broadband synthetic ground motion records for three events: 1) 1994 M6.7 Northridge, CA, 2) 1989 M7.0 Loma Prieta, CA, and 3) 1999 M7.5 Izmit,...

  19. Broadband gradient impedance matching using an acoustic metamaterial for ultrasonic transducers.

    Science.gov (United States)

    Li, Zheng; Yang, Dan-Qing; Liu, Shi-Lei; Yu, Si-Yuan; Lu, Ming-Hui; Zhu, Jie; Zhang, Shan-Tao; Zhu, Ming-Wei; Guo, Xia-Sheng; Wu, Hao-Dong; Wang, Xin-Long; Chen, Yan-Feng

    2017-02-17

    High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding -6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems.

  20. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... data into 3-D images. A Doppler ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ...