The Experts below are selected from a list of 4764 Experts worldwide ranked by ideXlab platform
Alan E. Willner - One of the best experts on this subject based on the ideXlab platform.
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true time delays using conversion dispersion with flat magnitude response for wideband analog rf signals
Optics Express, 2012Co-Authors: Omer F Yilmaz, Lior Yaron, Salman Khaleghi, Reza M Chitgarha, Moshe Tur, Alan E. WillnerAbstract:We demonstrate optical true time delays using wavelength conversion coupled with chromatic dispersion. The transfer function of the delay system is investigated, and it is shown that 3-dB bandwidth of the system can be increased over 40 GHz by using offset Pumps. A flat magnitude response ( 30 dB peak-to-sidelobe-ratio. The effect of Pump Depletion during wavelength conversion is also investigated.
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640 Gb/s All-Optical Regenerator Based on a Periodically Poled Lithium Niobate Waveguide
Journal of Lightwave Technology, 2012Co-Authors: Antonella Bogoni, Scott R. Nuccio, Xiaoxia Wu, Alan E. WillnerAbstract:640 Gb/s all-optical ON-OFF keying signal regeneration based on nonlinearities in a periodically poled lithium niobate (PPLN) waveguide is demonstrated and characterized. The data are transferred from the distorted original optical time division multiplexing (OTDM) signal onto a high quality and locally generated 640 GHz clock by Pump Depletion simultaneously operating a wavelength conversion. The thresholding behavior and the saturation effect of Pump Depletion in the PPLN waveguide for low and high Pump power values, respectively, allow for a noise compression on the wavelength-converted replica of the original signal. The use of a stable clock with a shorter pulsewidth also allows for a sort of sampling of the original OTDM frame in the bit time center, resulting in a pulse reshaping that eliminates all noise contributions on the pulse tails. This operation produces a reduction of the original time jitter of the signal. The sampling operation also results in a compression of the new OTDM frame pulses compensating for the residual chromatic dispersion effects. After having characterized the transfer function of the proposed regeneration scheme, we evaluate its effectiveness as a function of optical signal-to-noise ratio (OSNR), pulse broadening, and time jitter of the input signal. Regeneration performance is measured in terms of bit error rate (BER) and power penalty @ BER = 10-9. Error-free operation can be recovered and maintained over an input signal OSNR range of 8 dB. This results in a BER improvement up to several orders of magnitude, obtained when the input OSNR is reduced by 20 dB with respect to the baseline. The time jitter of input signals with original jitter values from 100 to 300 fs has been reduced of nearly one order of magnitude to values lower than 40 fs. We also demonstrate that a pulse broadening up to 20% of the original pulsewidth can be compensated. Finally, wavelength tunability of the regenerator input and output signal can be, in principle, guaranteed over the whole C-band and beyond.
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160 gb s time domain channel extraction insertion and all optical logic operations exploiting a single ppln waveguide
Journal of Lightwave Technology, 2009Co-Authors: Antonella Bogoni, I Fazal, Alan E. WillnerAbstract:160 Gb/s all-optical signal processing is demonstrated exploiting Pump Depletion in addition to sum and difference frequency generation (SFG/DFG) in a single periodically poled lithium-niobate (PPLN) waveguide. 160 Gb/s time-domain extraction and insertion operations of channels are obtained in an optical time division multiplexing (OTDM) system. Moreover, 160 Gb/s digital operations including half-adder, half-subtracter and AND/OR/XOR functions are carried out. The use of Pump Depletion effect allows to process ultrafast signals due to its high efficiency and ultrafast dynamics. 160 Gb/s bit error rate (BER) measurements confirm the effectiveness of all presented functionalities.
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photonic processing of 320 gbits s based on sum difference frequency generation and Pump Depletion in a single ppln waveguide
Optics Letters, 2009Co-Authors: Antonella Bogoni, I Fazal, Alan E. WillnerAbstract:The possibilities and limitations of using nonlinearities in periodically poled lithium-niobate waveguides for ultrafast all-optical processing are experimentally investigated. A combination of the sum-/difference-frequency generation and Pump Depletion effect are exploited to obtain optical demultiplexing, add/drop multiplexing, and wavelength conversion of up to 320 Gbits/s.
Luc Thevenaz - One of the best experts on this subject based on the ideXlab platform.
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increasing robustness of bipolar pulse coding in brillouin distributed fiber sensors
Optics Express, 2016Co-Authors: Zhisheng Yang, Marcelo A Soto, Luc ThevenazAbstract:The robustness of bipolar pulse coding against Pump Depletion issues in Brillouin distributed fiber sensors is theoretically and experimentally investigated. The presented analysis points out that the effectiveness of bipolar coding in Brillouin sensing can be highly affected by the power unbalance between -1's and + 1's elements resulting from Depletion and amplification of coded Pump pulses. In order to increase robustness against those detrimental effects and to alleviate the probe power limitation imposed by Pump Depletion, a technique using a three-tone probe is proposed. Experimental results demonstrate that this method allows increasing the probe power by more than 12.5 dB when compared to the existing single-probe tone implementation. This huge power increment, together with the 13.5 dB signal-to-noise enhancement provided by 512-bit bipolar Golay codes, has led to low-uncertainty measurements (< 0.9 MHz) of the local Brillouin peak gain frequency over a real remoteness of 100 km, using a 200 km-long fiber-loop and 2 m spatial resolution. The method is evaluated with a record figure-of-merit of 380'000.
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analytical model and experimental verification of the critical power for modulation instability in optical fibers
Optics Express, 2015Co-Authors: Mehdi Alem, Marcelo A Soto, Luc ThevenazAbstract:Modulation instability is thoroughly investigated and a simple analytical model for its power critically modifying the wave properties in terms of system parameters is derived and experimentally validated. The differences on the modulation instability gain spectrum in lossless and lossy optical fibers are analyzed based on theoretical models and numerical simulations. In particular the impact of background noise on the behavior of modulation instability is studied analytically and verified by measurements and simulations. The proposed analytical model is experimentally validated by monitoring the wave propagation along an optical fiber using a Brillouin optical time-domain analyzer. This way, the evolution of the optical signal traveling through optical fibers, especially, the Pump Depletion and the recurrence phenomenon are investigated.
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mitigation of modulation instability in brillouin distributed fiber sensors by using orthogonal polarization pulses
International Conference on Optical Fibre Sensors (OFS24), 2015Co-Authors: Javier Urricelqui, Luc Thevenaz, Mehdi Alem, Mikel Sagues, Alayn Loayssa, Marcelo A SotoAbstract:A technique based on the use of orthogonally-polarized pulses is proposed to mitigate the detrimental impact of modulation instability on Brillouin distributed fiber sensors. While the theoretical underpinnings of the method are described by introducing a detailed model for the vector modulation instability, the technique is experimentally validated in a 25-km sensing link. Numerical and experimental results demonstrate that the use of orthogonally-polarized pulses not only mitigates the impact of modulation instability, but also the four-wave mixing occurring in systems using Pumps with parallel polarization; thus, providing an important sensing range enhancement with a reduced Pump Depletion.
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modelling the Depletion length induced by modulation instability in distributed optical fibre sensors
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 2014Co-Authors: Mehdi Alem, Marcelo A Soto, Luc ThevenazAbstract:An analytical model for the Depletion length of modulation instability in single-mode optical fibres is proposed. The model gives the possibility to determine the maximum sensing distance that distributed optical fibre sensors can reach before being limited by the Pump Depletion induced by modulation instability. The important role of the noise level in the evolution of both modulation instability and the respective power Depletion is clarified. The model gives a closed form expression helpful for a predictive design and is validated comparing the analytical results obtained by the model with measurements in a 25 km long Brillouin fibre sensor.
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modeling and evaluating the performance of brillouin distributed optical fiber sensors
Optics Express, 2013Co-Authors: Marcelo A Soto, Luc ThevenazAbstract:A thorough analysis of the key factors impacting on the performance of Brillouin distributed optical fiber sensors is presented. An analytical expression is derived to estimate the error on the determination of the Brillouin peak gain frequency, based for the first time on real experimental conditions. This expression is experimentally validated, and describes how this frequency uncertainty depends on measurement parameters, such as Brillouin gain linewidth, frequency scanning step and signal-to-noise ratio. Based on the model leading to this expression and considering the limitations imposed by nonlinear effects and Pump Depletion, a figure-of-merit is proposed to fairly compare the performance of Brillouin distributed sensing systems. This figure-of-merit offers to the research community and to potential users the possibility to evaluate with an objective metric the real performance gain resulting from any proposed configuration.
Antonella Bogoni - One of the best experts on this subject based on the ideXlab platform.
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ppln based ook and dqpsk optical grooming by amplitude and phase signal multiplexing through Pump Depletion
Optics Letters, 2013Co-Authors: Sergio Pinna, Antonio Malacarne, Emma Lazzeri, Antonella BogoniAbstract:We propose and characterize a simple, integrable, and wavelength-preserving scheme able to groom a 40 Gbps (D)QPSK signal with a 20 Gbps OOK one into a 20 Gbaud (60 Gbps) 8-APSK signal. The proposed all-optical scheme is based on the second-order nonlinear signal-Depletion effect in a single periodically poled lithium niobate (PPLN) waveguide. Performance of the device, characterized by means of BER measurements, attests error-free operation and a power penalty below 4.1 dB.
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640 Gb/s All-Optical Regenerator Based on a Periodically Poled Lithium Niobate Waveguide
Journal of Lightwave Technology, 2012Co-Authors: Antonella Bogoni, Scott R. Nuccio, Xiaoxia Wu, Alan E. WillnerAbstract:640 Gb/s all-optical ON-OFF keying signal regeneration based on nonlinearities in a periodically poled lithium niobate (PPLN) waveguide is demonstrated and characterized. The data are transferred from the distorted original optical time division multiplexing (OTDM) signal onto a high quality and locally generated 640 GHz clock by Pump Depletion simultaneously operating a wavelength conversion. The thresholding behavior and the saturation effect of Pump Depletion in the PPLN waveguide for low and high Pump power values, respectively, allow for a noise compression on the wavelength-converted replica of the original signal. The use of a stable clock with a shorter pulsewidth also allows for a sort of sampling of the original OTDM frame in the bit time center, resulting in a pulse reshaping that eliminates all noise contributions on the pulse tails. This operation produces a reduction of the original time jitter of the signal. The sampling operation also results in a compression of the new OTDM frame pulses compensating for the residual chromatic dispersion effects. After having characterized the transfer function of the proposed regeneration scheme, we evaluate its effectiveness as a function of optical signal-to-noise ratio (OSNR), pulse broadening, and time jitter of the input signal. Regeneration performance is measured in terms of bit error rate (BER) and power penalty @ BER = 10-9. Error-free operation can be recovered and maintained over an input signal OSNR range of 8 dB. This results in a BER improvement up to several orders of magnitude, obtained when the input OSNR is reduced by 20 dB with respect to the baseline. The time jitter of input signals with original jitter values from 100 to 300 fs has been reduced of nearly one order of magnitude to values lower than 40 fs. We also demonstrate that a pulse broadening up to 20% of the original pulsewidth can be compensated. Finally, wavelength tunability of the regenerator input and output signal can be, in principle, guaranteed over the whole C-band and beyond.
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160 gb s time domain channel extraction insertion and all optical logic operations exploiting a single ppln waveguide
Journal of Lightwave Technology, 2009Co-Authors: Antonella Bogoni, I Fazal, Alan E. WillnerAbstract:160 Gb/s all-optical signal processing is demonstrated exploiting Pump Depletion in addition to sum and difference frequency generation (SFG/DFG) in a single periodically poled lithium-niobate (PPLN) waveguide. 160 Gb/s time-domain extraction and insertion operations of channels are obtained in an optical time division multiplexing (OTDM) system. Moreover, 160 Gb/s digital operations including half-adder, half-subtracter and AND/OR/XOR functions are carried out. The use of Pump Depletion effect allows to process ultrafast signals due to its high efficiency and ultrafast dynamics. 160 Gb/s bit error rate (BER) measurements confirm the effectiveness of all presented functionalities.
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photonic processing of 320 gbits s based on sum difference frequency generation and Pump Depletion in a single ppln waveguide
Optics Letters, 2009Co-Authors: Antonella Bogoni, I Fazal, Alan E. WillnerAbstract:The possibilities and limitations of using nonlinearities in periodically poled lithium-niobate waveguides for ultrafast all-optical processing are experimentally investigated. A combination of the sum-/difference-frequency generation and Pump Depletion effect are exploited to obtain optical demultiplexing, add/drop multiplexing, and wavelength conversion of up to 320 Gbits/s.
Marcelo A Soto - One of the best experts on this subject based on the ideXlab platform.
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increasing robustness of bipolar pulse coding in brillouin distributed fiber sensors
Optics Express, 2016Co-Authors: Zhisheng Yang, Marcelo A Soto, Luc ThevenazAbstract:The robustness of bipolar pulse coding against Pump Depletion issues in Brillouin distributed fiber sensors is theoretically and experimentally investigated. The presented analysis points out that the effectiveness of bipolar coding in Brillouin sensing can be highly affected by the power unbalance between -1's and + 1's elements resulting from Depletion and amplification of coded Pump pulses. In order to increase robustness against those detrimental effects and to alleviate the probe power limitation imposed by Pump Depletion, a technique using a three-tone probe is proposed. Experimental results demonstrate that this method allows increasing the probe power by more than 12.5 dB when compared to the existing single-probe tone implementation. This huge power increment, together with the 13.5 dB signal-to-noise enhancement provided by 512-bit bipolar Golay codes, has led to low-uncertainty measurements (< 0.9 MHz) of the local Brillouin peak gain frequency over a real remoteness of 100 km, using a 200 km-long fiber-loop and 2 m spatial resolution. The method is evaluated with a record figure-of-merit of 380'000.
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analytical model and experimental verification of the critical power for modulation instability in optical fibers
Optics Express, 2015Co-Authors: Mehdi Alem, Marcelo A Soto, Luc ThevenazAbstract:Modulation instability is thoroughly investigated and a simple analytical model for its power critically modifying the wave properties in terms of system parameters is derived and experimentally validated. The differences on the modulation instability gain spectrum in lossless and lossy optical fibers are analyzed based on theoretical models and numerical simulations. In particular the impact of background noise on the behavior of modulation instability is studied analytically and verified by measurements and simulations. The proposed analytical model is experimentally validated by monitoring the wave propagation along an optical fiber using a Brillouin optical time-domain analyzer. This way, the evolution of the optical signal traveling through optical fibers, especially, the Pump Depletion and the recurrence phenomenon are investigated.
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mitigation of modulation instability in brillouin distributed fiber sensors by using orthogonal polarization pulses
International Conference on Optical Fibre Sensors (OFS24), 2015Co-Authors: Javier Urricelqui, Luc Thevenaz, Mehdi Alem, Mikel Sagues, Alayn Loayssa, Marcelo A SotoAbstract:A technique based on the use of orthogonally-polarized pulses is proposed to mitigate the detrimental impact of modulation instability on Brillouin distributed fiber sensors. While the theoretical underpinnings of the method are described by introducing a detailed model for the vector modulation instability, the technique is experimentally validated in a 25-km sensing link. Numerical and experimental results demonstrate that the use of orthogonally-polarized pulses not only mitigates the impact of modulation instability, but also the four-wave mixing occurring in systems using Pumps with parallel polarization; thus, providing an important sensing range enhancement with a reduced Pump Depletion.
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modelling the Depletion length induced by modulation instability in distributed optical fibre sensors
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 2014Co-Authors: Mehdi Alem, Marcelo A Soto, Luc ThevenazAbstract:An analytical model for the Depletion length of modulation instability in single-mode optical fibres is proposed. The model gives the possibility to determine the maximum sensing distance that distributed optical fibre sensors can reach before being limited by the Pump Depletion induced by modulation instability. The important role of the noise level in the evolution of both modulation instability and the respective power Depletion is clarified. The model gives a closed form expression helpful for a predictive design and is validated comparing the analytical results obtained by the model with measurements in a 25 km long Brillouin fibre sensor.
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Extending the real remoteness of long-range brillouin optical time-domain fiber analyzers
Journal of Lightwave Technology, 2014Co-Authors: Marcelo A Soto, Sang Hoon Chin, Xabier Angulo-vinuesa, Juan Diego Ania-casta??on, Etienne Rochat, Sonia Martin-lopez, Pedro Corredera, Miguel Gonzalez-herraez, Luc Th??venazAbstract:The real remoteness of a distributed optical fiber sen- sor based on Brillouin optical time-domain analysis is considerably extended in this paper using seeded second-order Raman ampli- fication and optical pulse coding. The presented analysis and the experimental results demonstrate that a proper optimization of both methods combined with a well-equalized two-sideband probe wave provide a suitable solution to enhance the signal-to-noise ra- tio of the measurements when an ultra-long sensing fiber is used. In particular, the implemented system is based on an extended optical fiber length, in which half of the fiber is used for sensing purposes, and the other half is used to carry the optical signals to the most distant sensing point, providing also a long fiber for dis- tributed Raman amplification. Power levels of all signals launched into the fiber are properly optimized in order to avoid nonlinear effects, Pump Depletion, and especially any power imbalance be- tween the two sidebands of the probe wave.This last issue turns out to be extremely important in ultra-long Brillouin sensing to pro- vide strong robustness of the system against Pump Depletion. This way, by employing a 240 km-long optical fiber-loop, sensing from the interrogation unit up to a 120 km remote position (i.e., corre- sponding to the real sensing distance away from the sensor unit) is experimentally demonstrated with a spatial resolution of 5 m. Furthermore, this implementation requires no powered element in the whole 240 km fiber loop, providing considerable advantages in situations where the sensing cable crosses large unmanned areas.
Benjamin J Eggleton - One of the best experts on this subject based on the ideXlab platform.
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tunable microwave photonic phase shifter using on chip stimulated brillouin scattering
Conference on Lasers and Electro-Optics, 2015Co-Authors: Mattia Pagani, David Marpaung, Duk-yong Choi, Steve Madden, Barry Lutherdavies, Benjamin J EggletonAbstract:We present the first microwave photonic phase shifter using on-chip stimulated Brillouin scattering. We show that shorter integrated platforms can potentially achieve lower insertion loss than fiber implementations, due to their higher Pump Depletion threshold.
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tunable wideband microwave photonic phase shifter using on chip stimulated brillouin scattering
Optics Express, 2014Co-Authors: Mattia Pagani, David Marpaung, Duk-yong Choi, Steve Madden, Barry Lutherdavies, Benjamin J EggletonAbstract:We present the first microwave photonic phase shifter using stimulated Brillouin scattering (SBS) on-chip. The unique ability of SBS to generate both narrowband gain and loss resonances allows us to achieve low ±1.5 dB amplitude fluctuations, which is a record for integrated devices, along with 240° continuously tunable phase shift. Contrary to previous SBS-based approaches, the phase shift tuning mechanism relies on tuning the power, not the frequency, of two SBS Pumps, making it more suited to on-chip implementations. We finally demonstrate that SBS Pump Depletion leads to amplitude response fluctuations, as well as increasing the insertion loss of the phase shifter. Advantageously, shorter integrated platforms possess higher Pump Depletion thresholds compared to long fibers, thus offering greater potential for reducing the insertion loss.
