The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Shah M. Alam - One of the best experts on this subject based on the ideXlab platform.
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Design of a Polarization-Maintaining Equiangular Spiral Photonic Crystal Fiber for Residual Dispersion Compensation Over $E{+}S{+}C{+}L{+}U$ Wavelength Bands
IEEE Photonics Technology Letters, 2012Co-Authors: Md. Asiful Islam, Shah M. AlamAbstract:An equiangular spiral photonic crystal fiber has been designed and numerically optimized to obtain its Residual Chromatic Dispersion compensation property in the wavelength range of 1350-1675 nm. The results show that the fiber exhibits an average Dispersion of -227 ps/nm-km with a flattened Dispersion profile. It is also demonstrated that the fiber shows a high birefringence of 0.0221 at the wavelength 1550 nm. An elliptical air hole is introduced as a defect in the core region and this gives an additional flexibility to tailor the Dispersion property. The proposed fiber can be used as an excellent candidate in wavelength-division-multiplexing optical fiber transmission system for Residual Chromatic Dispersion compensation and also for maintaining single polarization.
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A liquid crystal infiltrated single polarization spiral photonic crystal fiber with large negative flat Dispersion
2012 7th International Conference on Electrical and Computer Engineering, 2012Co-Authors: Md. Asiful Islam, Shah M. AlamAbstract:A Dispersion compensating fiber having average Dispersion profile of -259 ps/nm-km with Dispersion variation of about 4.58 ps/nm-km has been obtained over the wavelength range 1.35 μm to 1.675 μm using an equiangular spiral photonic crystal fiber (ES-PCF). The proposed fiber also exhibits single polarization behavior with one of its fundamental modes (x or y polarized) completely suppressed. To obtain these properties, liquid crystal (LC) is infiltrated in the defected core of ES-PCF. These unique features of the proposed fiber can be used in wavelength-division-multiplexing (WDM) optical fiber transmission system for Residual Chromatic Dispersion compensation and also for maintaining single polarization.
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Design Optimization of Equiangular Spiral Photonic Crystal Fiber for Large Negative Flat Dispersion and High Birefringence
Journal of Lightwave Technology, 2012Co-Authors: Md. Asiful Islam, Shah M. AlamAbstract:The design of a Residual Dispersion compensating fiber in an equiangular spiral photonic crystal fiber (ES-PCF) structure is presented in the wavelength range 1350-1650 nm. A step-by-step design optimization is demonstrated and a maximum optimized value of average Dispersion - 393 ps/nm km with a flattened Dispersion profile with a very high birefringence is reported. It has been found that for the ES-PCF, a very high birefringence of 0.0278 at the wavelength 1550 nm can be obtained by employing an elliptical air hole as defect in the core region. An efficient full-vectorial finite-element method with vector edge element is employed in this study. The proposed ES-PCF can be an excellent candidate to be used in a wavelength-division-multiplexing optical fiber transmission system for Residual Chromatic Dispersion compensation as well as maintaining single polarization.
Chao Lu - One of the best experts on this subject based on the ideXlab platform.
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Chromatic Dispersion Monitoring Based on Variance of Received Optical Power
IEEE Photonics Technology Letters, 2011Co-Authors: Linghao Cheng, Zhaohui Li, Chao LuAbstract:For lightwave transmission systems employing advanced modulation formats such as phase-shift keying (PSK) and quadrature-amplitude modulation (QAM), Chromatic Dispersion monitoring based on average variance of optical power has been demonstrated. Theoretical analyses are verified by simulations, and experiment results show that the variance of optical power at the receiver is a simple and effective statistical parameter to monitor the Residual Chromatic Dispersion of a transmission link.
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Signed Chromatic Dispersion monitoring of 100Gbit/s CS-RZ DQPSK signal by evaluating the asymmetry ratio of delay tap sampling.
Optics express, 2010Co-Authors: Zhaohui Li, Alan Pak Tao Lau, Yanfu Yang, Zhao Jian, Changyuan Yu, Linghao Cheng, Hwa-yaw Tam, Chao Lu, P K A WaiAbstract:In this paper, we theoretically and experimentally demonstrated the Residual Chromatic Dispersion (CD) monitoring of 100-Gbit/s carrier suppress return-to-zero differential quadrature phase shift keying (CS-RZ DQPSK) signals by evaluating the asymmetry ratio of delay tap asynchronous sampling. This scheme can easily differentiate the positive and negative Residual CD of the fiber link. The resolution of this scheme is better than 8 ps/nm and the measurable range is around +/- 24 ps/nm for 100 Gbit/s CS-RZ DQPSK signals. We can also simultaneously realize both signed CD monitoring and demodulation of CS-RZ DQPSK signal based on only one demodulator.
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100Gbit/s RZ-DQPSK signal monitoring using delay tap sampling and asymmetry ratio evaluation
2009 14th OptoElectronics and Communications Conference, 2009Co-Authors: Zhaohui Li, Yanfu Yang, Linghao Cheng, Jian Zhao, Chao LuAbstract:We demonstrate a novel in-line Chromatic Dispersion monitoring scheme for 100 Gbit/s RZ-DQPSK signal based on delay tap sampling and asymmetry ratio evaluation. This scheme can differentiate positive and negative Residual Chromatic Dispersion.
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Suppression of PMD and chirp effects in Chromatic Dispersion monitoring
Proceedings of SPIE, 2005Co-Authors: Wen-de Zhong, Linghao Cheng, Yixin Wang, Chao LuAbstract:In today's high-bit-rate WDM systems, it is essential to monitor the Residual Chromatic Dispersion (CD) to ensure that it does not exceed the designed tolerance. Among the schemes for CD monitoring reported so far, inband subcarrier tone method is relatively simple and effective for CD monitoring. However, this technique may be influenced by both polarization mode Dispersion (PMD) and the chirp fluctuation of the external modulator. In this paper, we investigate the effect of PMD and chirp on CD monitoring and show that the presence of PMD and chirp induces significant CD monitoring errors. To tackle this problem, we propose a CD monitoring technique to suppress the influence caused by PMD and chirp fluctuation. In the proposed CD monitoring scheme, two RF tones are added at the transmitter. The light is coupled into an apriori known Dispersion offset and then split into two branches in the monitoring module. A fiber Bragg grating filter which can remove one sideband is inserted before the photodetector of one branch. The PMD effect is eliminated by optically sideband filtering and RF power ratio detection, and the monitoring error induced by the small chirp fluctuation can be suppressed using two RF tones and a Dispersion offset. The operational principle is analyzed and the experimental investigation is presented. Experimental results show that this technique can accurately monitor the accumulated CD without being affected by the PMD and small chirp fluctuation.
Md. Asiful Islam - One of the best experts on this subject based on the ideXlab platform.
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Design of a Polarization-Maintaining Equiangular Spiral Photonic Crystal Fiber for Residual Dispersion Compensation Over $E{+}S{+}C{+}L{+}U$ Wavelength Bands
IEEE Photonics Technology Letters, 2012Co-Authors: Md. Asiful Islam, Shah M. AlamAbstract:An equiangular spiral photonic crystal fiber has been designed and numerically optimized to obtain its Residual Chromatic Dispersion compensation property in the wavelength range of 1350-1675 nm. The results show that the fiber exhibits an average Dispersion of -227 ps/nm-km with a flattened Dispersion profile. It is also demonstrated that the fiber shows a high birefringence of 0.0221 at the wavelength 1550 nm. An elliptical air hole is introduced as a defect in the core region and this gives an additional flexibility to tailor the Dispersion property. The proposed fiber can be used as an excellent candidate in wavelength-division-multiplexing optical fiber transmission system for Residual Chromatic Dispersion compensation and also for maintaining single polarization.
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A liquid crystal infiltrated single polarization spiral photonic crystal fiber with large negative flat Dispersion
2012 7th International Conference on Electrical and Computer Engineering, 2012Co-Authors: Md. Asiful Islam, Shah M. AlamAbstract:A Dispersion compensating fiber having average Dispersion profile of -259 ps/nm-km with Dispersion variation of about 4.58 ps/nm-km has been obtained over the wavelength range 1.35 μm to 1.675 μm using an equiangular spiral photonic crystal fiber (ES-PCF). The proposed fiber also exhibits single polarization behavior with one of its fundamental modes (x or y polarized) completely suppressed. To obtain these properties, liquid crystal (LC) is infiltrated in the defected core of ES-PCF. These unique features of the proposed fiber can be used in wavelength-division-multiplexing (WDM) optical fiber transmission system for Residual Chromatic Dispersion compensation and also for maintaining single polarization.
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Design Optimization of Equiangular Spiral Photonic Crystal Fiber for Large Negative Flat Dispersion and High Birefringence
Journal of Lightwave Technology, 2012Co-Authors: Md. Asiful Islam, Shah M. AlamAbstract:The design of a Residual Dispersion compensating fiber in an equiangular spiral photonic crystal fiber (ES-PCF) structure is presented in the wavelength range 1350-1650 nm. A step-by-step design optimization is demonstrated and a maximum optimized value of average Dispersion - 393 ps/nm km with a flattened Dispersion profile with a very high birefringence is reported. It has been found that for the ES-PCF, a very high birefringence of 0.0278 at the wavelength 1550 nm can be obtained by employing an elliptical air hole as defect in the core region. An efficient full-vectorial finite-element method with vector edge element is employed in this study. The proposed ES-PCF can be an excellent candidate to be used in a wavelength-division-multiplexing optical fiber transmission system for Residual Chromatic Dispersion compensation as well as maintaining single polarization.
David V. Plant - One of the best experts on this subject based on the ideXlab platform.
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168-Gb/s Single Carrier PAM4 Transmission for Intra-Data Center Optical Interconnects
IEEE Photonics Technology Letters, 2017Co-Authors: Eslam El-fiky, Mohamed Morsy-osman, Mathieu Chagnon, Mohammed Sowailem, Alireza Samani, David V. PlantAbstract:We experimentally demonstrate 168-Gb/s single polarization four-level pulse amplitude modulation (PAM4) transmission over 10 km of single mode fiber (SMF) in the O-band below the 400-GbE task force operating bit error rate (BER) of 2 × 10-4. To the best of our knowledge, this rate is the highest bit rate reported for single polarization direct detection PAM4 transmission over 10 km of SMF in the O-band. We evaluate the BER performance of the PAM4 signal versus bit rate, number of equalizer taps, received power, and reach. Results reveal that up to 176-Gb/s bit rate can be transmitted over 10 km at a BER of 4 × 10-4 and 8 dBm of received signal power. Finally, we show that the Residual Chromatic Dispersion at up to 88 Gbaud is negligible by fixing the received power over varying reach, demonstrating that the BER is solely governed by the received signal power.
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Experimental Parametric Study of a Silicon Photonic Modulator Enabled 112-Gb/s PAM Transmission System With a DAC and ADC
Journal of Lightwave Technology, 2015Co-Authors: Mathieu Chagnon, Mohamed Morsy-osman, Michel Poulin, Carl Paquet, Stéphane Lessard, David V. PlantAbstract:A packaged silicon photonic traveling wave Mach-Zehnder modulator operating at 1310 nm is presented and studied. The modulator is a series push-pull device and requires a bias applied to the common n-doped region. Effects of varying the bias voltage on the modulator's Vπ bandwidth, and on chip-insertion loss are studied, and its impact on transmission performance are experimentally investigated for PAM-4 and PAM-8 formats at a throughput of 112 Gb/s, over varying distances of 0, 2, 10, and 20 km. Residual Chromatic Dispersion is shown to have no impact on performance up to 20 km. The PAM RF driving waveform is generated by an 8-bit digital-to-analog converter, while direct detection is done with a PIN+TIA followed by an 8-bit analog-to-digital converter. This IM/DD system utilizes digital signal processing with transmitter spectral compensation and receiver Residual equalization. The performance impact for a varying number of transmitter precompensation taps and receiver equalization taps is studied, which has a direct impact on the transceiver's power consumption. Using PAM-4, a BER below the FEC limit is obtained for either combinations of (transmitter, receiver) tap lengths: (19,19), (7,27), or (35,7), allowing flexibility in power consumption distribution.
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Low overhead and nonlinear-tolerant adaptive zero-guard-interval CO-OFDM.
Optics Express, 2014Co-Authors: Wei Wang, Qunbi Zhuge, Mohamed Morsy-osman, Mathieu Chagnon, Xian Xu, David V. PlantAbstract:We propose an adaptive channel estimation (CE) method for zero-guard-interval (ZGI) coherent optical (CO)-OFDM systems, and demonstrate its performance in a single channel 28 Gbaud polarization-division multiplexed ZGI CO-OFDM experiment with only 1% OFDM processing overhead. We systematically investigate its robustness against various transmission impairments including Residual Chromatic Dispersion, polarization-mode Dispersion, state of polarization rotation, sampling frequency offset and fiber nonlinearity. Both experimental and numerical results show that the adaptive CE-aided ZGI CO-OFDM is highly robust against these transmission impairments in fiber optical transmission systems.
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Experimental Study of a novel adaptive decision-directed channel equalizer in 28 GBaud RGI-DP-CO-OFDM transport systems
Optics Express, 2012Co-Authors: Mohammad E. Mousa-pasandi, Qunbi Zhuge, Mathieu Chagnon, Xian Xu, Mohamed Osman, David V. PlantAbstract:We report and experimentally investigate the performance of an adaptive decision-directed channel equalizer (ADDCE) in reduced-guard-interval dual-polarization coherent-optical orthogonal-frequency-division-multiplexing (RGI-DP-CO-OFDM) transport systems. ADDCE retrieves an estimation of the phase noise value after an initial decision making stage by extracting and averaging the phase drift of all OFDM sub-channels. Moreover, it updates the channel transfer matrix on a symbol-by-symbol basis. We experimentally compare the performance of the ADDCE and the conventional equalizer (CE) combined with maximum-likelihood (ML) phase noise compensation and inter-subcarrier-frequency-averaging (ISFA) algorithms. The study is conducted at 28 GBaud for RGI-DP-CO-OFDM systems with quadrature-phase-shift-keying (QPSK) and 16 quadrature amplitude modulation (16-QAM) formats. Using ADDCE, zero-overhead laser phase noise compensation is accomplished and the overhead due to training symbol (TSs) insertion is significantly reduced. In addition, ADDCE offers a superior performance over the CE in the presence of synchronization timing errors and Residual Chromatic Dispersion (CD). We also achieve a longer transmission distance than when using the CE. At a forward-error-correction (FEC) threshold of 3.8 × 10−3, using a cumulative overhead of less than 2.6%, transmission distances of 5500 km and 400 km were achieved for the cases of QPSK and 16-QAM RGI-DP-CO-OFDM, respectively.
Zhaohui Li - One of the best experts on this subject based on the ideXlab platform.
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Chromatic Dispersion Monitoring Based on Variance of Received Optical Power
IEEE Photonics Technology Letters, 2011Co-Authors: Linghao Cheng, Zhaohui Li, Chao LuAbstract:For lightwave transmission systems employing advanced modulation formats such as phase-shift keying (PSK) and quadrature-amplitude modulation (QAM), Chromatic Dispersion monitoring based on average variance of optical power has been demonstrated. Theoretical analyses are verified by simulations, and experiment results show that the variance of optical power at the receiver is a simple and effective statistical parameter to monitor the Residual Chromatic Dispersion of a transmission link.
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Signed Chromatic Dispersion monitoring of 100Gbit/s CS-RZ DQPSK signal by evaluating the asymmetry ratio of delay tap sampling.
Optics express, 2010Co-Authors: Zhaohui Li, Alan Pak Tao Lau, Yanfu Yang, Zhao Jian, Changyuan Yu, Linghao Cheng, Hwa-yaw Tam, Chao Lu, P K A WaiAbstract:In this paper, we theoretically and experimentally demonstrated the Residual Chromatic Dispersion (CD) monitoring of 100-Gbit/s carrier suppress return-to-zero differential quadrature phase shift keying (CS-RZ DQPSK) signals by evaluating the asymmetry ratio of delay tap asynchronous sampling. This scheme can easily differentiate the positive and negative Residual CD of the fiber link. The resolution of this scheme is better than 8 ps/nm and the measurable range is around +/- 24 ps/nm for 100 Gbit/s CS-RZ DQPSK signals. We can also simultaneously realize both signed CD monitoring and demodulation of CS-RZ DQPSK signal based on only one demodulator.
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100Gbit/s RZ-DQPSK signal monitoring using delay tap sampling and asymmetry ratio evaluation
2009 14th OptoElectronics and Communications Conference, 2009Co-Authors: Zhaohui Li, Yanfu Yang, Linghao Cheng, Jian Zhao, Chao LuAbstract:We demonstrate a novel in-line Chromatic Dispersion monitoring scheme for 100 Gbit/s RZ-DQPSK signal based on delay tap sampling and asymmetry ratio evaluation. This scheme can differentiate positive and negative Residual Chromatic Dispersion.