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Weisheng Hu - One of the best experts on this subject based on the ideXlab platform.

  • power budget improvement of symmetric 40 gb s dml based twdm pon system
    Optics Express, 2014
    Co-Authors: Meihua Bi, Hao He, Shilin Xiao, Lilin Yi, Jun Li, Xuelin Yang, Weisheng Hu
    Abstract:

    We propose a symmetric 40-Gb/s time and wavelength division multiplexed passive optical network (TWDM-PON) system with directly modulated laser (DML) as both downstream and upstream transmitters. A single bi-pass Delay Interferometer (DI), deployed in the optical line terminal (OLT), is used to mitigate multiple channels’ signal distortions induced by laser chirp and fiber chromatic dispersion. With the help of the DI, we successfully demonstrate error-free transmission with the aggregate capacity of 40 Gb/s over different transmission distance. And in back-to-back case, by using a 0.2-nm free spectrum range (FSR) DI, ~11 dB optical power budget improvement is achieved at a bit error ratio of 1e-3. Owing to this high power budget, the maximum reach can be extended to 50 km for 1024 splits, 75 km for 256 splits, and 100 km for 64 splits. Meanwhile, the impacts of FSR of DI and laser wavelength shift on system performance are investigated in terms of receiver sensitivity. It is shown that, our system can achieve more than 43-dB power budget and support ± 2.5-GHz wavelength shift when the FSR is less than 0.2 nm.

Shilin Xiao - One of the best experts on this subject based on the ideXlab platform.

  • experimental demonstration of symmetric 100 gb s dml based twdm pon system
    IEEE Photonics Technology Letters, 2015
    Co-Authors: Zhao Zhou, Shilin Xiao, Yunhao Zhang
    Abstract:

    In this letter, first, the symmetric 100-Gb/s time and wavelength-division-multiplexed passive optical network system is experimentally demonstrated, based on the directly modulated lasers (DMLs) modulated by 25-Gb/s none-return-to-zero signals. A bypass Delay Interferometer (DI) is deployed in the optical line terminal to mitigate the signal distortion caused by the DML chirp and fiber chromatic dispersion. The experimental results show that with the DI, error free transmission is achieved over 25-km single mode fiber with a power budget of 42 dB, which could support 1:1024 splitting ratio. Moreover, the transmission performance of differential fiber length and burst-mode operation is also investigated.

  • power budget improvement of symmetric 40 gb s dml based twdm pon system
    Optics Express, 2014
    Co-Authors: Meihua Bi, Hao He, Shilin Xiao, Lilin Yi, Jun Li, Xuelin Yang, Weisheng Hu
    Abstract:

    We propose a symmetric 40-Gb/s time and wavelength division multiplexed passive optical network (TWDM-PON) system with directly modulated laser (DML) as both downstream and upstream transmitters. A single bi-pass Delay Interferometer (DI), deployed in the optical line terminal (OLT), is used to mitigate multiple channels’ signal distortions induced by laser chirp and fiber chromatic dispersion. With the help of the DI, we successfully demonstrate error-free transmission with the aggregate capacity of 40 Gb/s over different transmission distance. And in back-to-back case, by using a 0.2-nm free spectrum range (FSR) DI, ~11 dB optical power budget improvement is achieved at a bit error ratio of 1e-3. Owing to this high power budget, the maximum reach can be extended to 50 km for 1024 splits, 75 km for 256 splits, and 100 km for 64 splits. Meanwhile, the impacts of FSR of DI and laser wavelength shift on system performance are investigated in terms of receiver sensitivity. It is shown that, our system can achieve more than 43-dB power budget and support ± 2.5-GHz wavelength shift when the FSR is less than 0.2 nm.

Liankuan Chen - One of the best experts on this subject based on the ideXlab platform.

  • rayleigh noise reduction in 10 gb s carrier distributed wdm pons using in band optical filtering
    Journal of Lightwave Technology, 2011
    Co-Authors: Jing Xu, Ming Li, Liankuan Chen
    Abstract:

    To circumvent the challenging issue of Rayleigh noise reduction in wavelength-division-multiplexed passive optical network (WDM-PON), we provide an insight into the source of Rayleigh noise, and confirm that the suppression of carrier Rayleigh backscattering (RB) should be the primary target in the design of Rayleigh noise-resilient upstream receiver module for a transmission reach up to 60 km. Then we propose and demonstrate a novel scheme to effectively suppress the carrier RB in carrier-distributed WDM-PONs. By simply replacing the upstream modulation format of conventional on-off keying (OOK) with differential phase-shift keying (DPSK), the system tolerance to carrier RB is substantially enhanced by 19 dB, as the carrier RB can be considerably rejected by the notch filter-like destructive port of the Delay-Interferometer (DI) at the optical line terminal (OLT), which is used simultaneously to demodulate the upstream DPSK signal. The dependence of carrier RB suppression on DI's extinction ratio (ER) and optical carrier's line width is also theoretically analyzed. Experimental demonstration of 10-Gb/s upstream signal is achieved with less than 2.5-dB power penalty induced by Rayleigh noise after the transmission in 60-km single mode fiber, without using any amplifier in outside plant. The relation between system margin and the gain of optical network unit (ONU) is also studied.

  • a simple ami rz transmitter based on single arm intensity modulator and optical Delay Interferometer
    Optics Communications, 2005
    Co-Authors: Liankuan Chen, Chunkit Chan
    Abstract:

    In the paper, we propose and demonstrate a simple alternate-mark inversion return-to-zero (AMI-RZ) transmitter upgraded from existing plain RZ-OOK transmitter by employing an additional Mach–Zehnder Delay Interferometer (MZDI), eliminating the use of high-speed RF circuit and dual-drive Mach–Zehnder modulator. A Delay-and-subtract operation is performed by the MZDI on the RZ-OOK signal to achieve alternating phases in successive mark pulses. The nonlinearity tolerance of the generated AMI-RZ signal was characterized by experiment at 10 Gb s 1 and simulation at 40 Gb s 1 . The ghost-pulse, due to intra-channel four-wave-mixing (IFWM), with generated AMI-RZ and RZOOK formats was also investigated respectively at 40 Gb s 1 . The results showed that the generated AMI-RZ exhibited higher nonlinear tolerance over RZ-OOK, especially the tolerance against IFWM in the 40-Gb s 1 optical transmission system. This AMI-RZ transmitter scheme is simple, potentially low cost and can be integrated easily with the existing RZ-OOK transmitters for upgrading to AMI-RZ transmitters. 2005 Elsevier B.V. All rights reserved. PACS: 42.79.S

Xuelin Yang - One of the best experts on this subject based on the ideXlab platform.

  • key distribution based on phase fluctuation between polarization modes in optical channel
    IEEE Photonics Technology Letters, 2018
    Co-Authors: Adnan A E Hajomer, Xuelin Yang, Amber Sultan
    Abstract:

    This letter proposes and experimentally demonstrates an approach for generating and sharing a secret key based on the random phase fluctuation between orthogonal polarization modes (OPMs). A Delay Interferometer (DI) is placed to extract the phase differences inside the optical channel, where reconfigurable lengths of polarization-maintaining fiber are applied as the main source of fluctuation. It is proven that the output signals from the DI can generate random and highly correlated waveforms that can be extracted as the key and shared between the two communication parties. Due to the environment-related randomness and channel-dependent uniqueness of phase fluctuation in OPMs, the security enhancement of the proposed scheme is evaluated with the capability against various tapping attacks. As a proof of concept, the key generation rate of 220 bits/s with bit-error rate of 5% is successfully demonstrated over 25-km standard single-mode fiber. Moreover, the proposed scheme has the advantage of low cost, compatible with current optical fiber networks, and suitable for long-distance transmission, since optical amplifiers can be applied.

  • power budget improvement of symmetric 40 gb s dml based twdm pon system
    Optics Express, 2014
    Co-Authors: Meihua Bi, Hao He, Shilin Xiao, Lilin Yi, Jun Li, Xuelin Yang, Weisheng Hu
    Abstract:

    We propose a symmetric 40-Gb/s time and wavelength division multiplexed passive optical network (TWDM-PON) system with directly modulated laser (DML) as both downstream and upstream transmitters. A single bi-pass Delay Interferometer (DI), deployed in the optical line terminal (OLT), is used to mitigate multiple channels’ signal distortions induced by laser chirp and fiber chromatic dispersion. With the help of the DI, we successfully demonstrate error-free transmission with the aggregate capacity of 40 Gb/s over different transmission distance. And in back-to-back case, by using a 0.2-nm free spectrum range (FSR) DI, ~11 dB optical power budget improvement is achieved at a bit error ratio of 1e-3. Owing to this high power budget, the maximum reach can be extended to 50 km for 1024 splits, 75 km for 256 splits, and 100 km for 64 splits. Meanwhile, the impacts of FSR of DI and laser wavelength shift on system performance are investigated in terms of receiver sensitivity. It is shown that, our system can achieve more than 43-dB power budget and support ± 2.5-GHz wavelength shift when the FSR is less than 0.2 nm.

Xinliang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • integrated all optical programmable logic array based on semiconductor optical amplifiers
    Optics Letters, 2018
    Co-Authors: Wenchan Dong, Zhuyang Huang, Jie Hou, Rui Santos, Xinliang Zhang
    Abstract:

    The all-optical programmable logic array (PLA) is one of the most important optical complex logic devices that can implement combinational logic functions. In this Letter, we propose and experimentally demonstrate an integrated all-optical PLA at the operation speed of 40 Gb/s. The PLA mainly consists of a Delay Interferometer (DI) and semiconductor optical amplifiers (SOAs) of different lengths. The DI is used to pre-code the input signals and improve the reconfigurability of the scheme. The longer SOAs are nonlinear media for generating canonical logic units (CLUs) using four-wave mixing. The shorter SOAs are used to select the appropriate CLUs by changing the working states; then reconfigurable logic functions can be output directly. The results show that all the CLUs are realized successfully, and the optical signal-to-noise ratios are above 22 dB. The exclusive NOR gate and exclusive OR gate are experimentally demonstrated based on output CLUs.

  • reconfigurable four input photonic logic minterms and maxterms generation using soas
    IEEE Photonics Technology Letters, 2012
    Co-Authors: Yin Zhang, Jianji Dong, Lei Lei, Xinliang Zhang
    Abstract:

    A generation approach of photonic logic minterms and maxterms, which is fully reconfigured minterms and maxterms for four-input 40-Gb/s differential phase-shift keying (DPSK) signals, has been demonstrated based on Delay Interferometers and semiconductor optical amplifiers. The maxterms are directly derived by inverting the corresponding minterms, according to their complementary characteristics. Reconfigurations of the scheme, enabled by tuning either the phase shift of Delay Interferometer or input wavelength, are shown among 16 minterms, as well as corresponding maxterms. A full set of minterms and maxterms are captured with clear open eye diagrams and extinction ratios of over 10 and 8 dB, respectively, which indicate the potential of further realizing arbitrary complex logic operations.

  • simultaneous all optical digital comparator and dual directional half subtractor for two input 40 gbit s dpsk signals employing soas
    Optics Communications, 2012
    Co-Authors: Yin Zhang, Jianji Dong, Xinliang Zhang
    Abstract:

    Abstract A module of simultaneous implementation of all-optical digital comparator and dual-directional half-subtractor is proposed. Proof-of-concept experiment is performed at 40 Gbit/s employing the four-wave mixing and cross gain modulation in three parallel semiconductor optical amplifiers. All output results with over 10 dB extinction ratios, clear and wide open eye diagrams, are obtained without using assistant/holding light beam. All-optical half-adder can also be obtained by adjusting the phase shifter of Delay Interferometer in the proposed module because of its inherent reconfigurability and flexibility. The module would be a promising digital logic elementary circuit in all-optical networks and computing systems.

  • photonic generation of a microwave signal by incorporating a Delay Interferometer and a saturable absorber
    Optics Letters, 2008
    Co-Authors: Guojie Chen, Xinliang Zhang, Dexiu Huang, Hui Cao
    Abstract:

    A novel approach to generate microwave signals is presented by employing a dual-wavelength erbium-doped fiber ring laser. By using a Delay Interferometer as a comb filter cascaded with a tunable bandpass filter and a saturable absorber formed by an unpumped polarization-maintaining erbium-doped fiber, a stable wavelength-tunable dual-wavelength single longitudinal-mode laser is achieved. A microwave signal at 20.07 GHz with a linewidth of <25 kHz is demonstrated by beating the two wavelengths at a photodetector.

  • all optical clock recovery from nrz dpsk signal
    IEEE Photonics Technology Letters, 2006
    Co-Authors: Yu Yu, Xinliang Zhang, Dexiu Huang
    Abstract:

    All-optical clock recovery (CR) from 20-Gb/s nonreturn-to-zero differential phase-shift-keying (NRZ-DPSK) signal is demonstrated, with an all-fiber Delay Interferometer (DI) and a mode-locked semiconductor optical amplifier (SOA) fiber laser. The tunable DI serves as an all-optical DPSK demodulator and the phase-modulated NRZ-DPSK signal is converted into the intensity-modulated pseudoreturn-to-zero (PRZ) signal, with the enhancement of the clock component. Followed SOA fiber-laser is used to achieve CR from the PRZ signal. Fixed bit pattern and 231-1 pseudorandom binary sequence NRZ-DPSK signals are used to test the performance of the proposed system. It is shown that the recovered clock signal with the extinction ratio over 10 dB and the root-mean-square timing jitter of 800 fs can be achieved