Personne : Lin, Jiachuan
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Université Laval. Centre d'optique, photonique et laser
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Voici les éléments 1 - 10 sur 11
Publication Accès libreLinearly polarized vector modes : enabling MIMO-free mode-division multiplexing(Optical Society of America, 2017-05-10) Mirzaei Nejad, Reza; Lin, Jiachuan; Corsi, Alessandro; LaRochelle, Sophie; Messaddeq, Younès; Wang, Lixian; Rusch, LeslieWe experimentally investigate mode-division multiplexing in an elliptical ring core fiber (ERCF) that supports linearly polarized vector modes (LPV). Characterization show that the ERCF exhibits good polarization maintaining properties over eight LPV modes with effective index difference larger than 1 × 10−4. The ERCF further displays stable mode power and polarization extinction ratio when subjected to external perturbations. Crosstalk between the LPV modes, after propagating through 0.9 km ERCF, is below −14 dB. By using six LPV modes as independent data channels, we achieved the transmission of 32 Gbaud QPSK over 0.9 km ERCF without any multiple-input-multiple-output (MIMO) or polarization-division multiplexing (PDM) signal processing. Publication Accès libreSystem optimization of an all-silicon IQ modulator : achieving 100 Gbaud dual polarization 32QAM(Institute of Electrical and Electronics Engineers, 2020-01-15) Lin, Jiachuan; Zhalehpour, Sasan; Shi, Wei; Zhang, Zhuhong; Guo, Mengqi; Qiao, Yaojun; Rusch, LeslieWe experimentally demonstrate the highest, to the best of our knowledge, reported net rate in a SiP IQ modulator. At 100 Gbaud 32QAM (quadrature amplitude modulation), and assuming 20% FEC (forward error correction) overhead, we achieved a dual polarization net rate of 833 Gb/s. This record was achieved by adapting digital signal processing to the challenging pattern dependent distortion encountered in the nonlinear and bandwidth limited regime. First the Mach Zehnder modulator (MZM) operating point (trading off modulation efficiency and 3 dB bandwidth) and linear compensation (electrical and optical) are jointly optimized. Next, the key application of nonlinear pre- and post-compensation are explored. We show that nonlinear processing at the transmitter, in our case an iterative learning control (ILC) method, is essential as post-processing alone could not achieve reliable communications at 100 Gbaud. Nonlinear post-compensation algorithms pushed the performance under the FEC threshold with the introduction of structured intersymbol interference in post processing and a simple one-step maximum likelihood sequence detector. We provide detailed descriptions of our methodology and results. Publication Accès libreIntegrated flexible-grid WDM transmitter using an optical frequency comb in microring modulators(OSA Publishing, 2018-04-01) Lin, Jiachuan; Xu, Yelong; Dubé-Demers, Raphaël; LaRochelle, Sophie; Shi, Wei; Rusch, LeslieAdvanced optical interconnects require high-speed links, which can be achieved by combining high channel rates with wavelength-division multiplexing (WDM). We report a multi-channel transmitter using cascaded microring modulators (MRMs) in silicon photonics. One MRM works as a flexible-grid optical comb generator, while the others work as channel modulators. With a single-wavelength laser input, we achieve flexible channel spacing (up to 25 GHz) with a tone-to-noise ratio (TNR) above 54 dB, all at low power consumption (less than 4.6 mW). We examine experimentally multichannel transmission modulating data onto adjacent comb lines without significant signal crosstalk. This single-laser, flexible-grid WDM transmitter is a scalable solution: more comb lines can be obtained using uncoupled MRMs in series. This is the first demonstration of monolithic integration of a comb generator and multi-channel modulators for ultracompact, power-efficient WDM photonic interconnects. Publication Accès libreSilicon Photonic IQ Modulators for 400 Gb/s and beyond(Institute of Electrical and Electronics Engineers, 2019-04-11) Lin, Jiachuan; Sepehrian, Hassan; Shi, Wei; Rusch, LeslieSilicon photonics has enormous potential for ultrahigh-capacity coherent optical transceivers. We demonstrate an in-phase and quadrature (IQ) modulator using silicon photonic traveling-wave modulators optimized for higher order quadrature amplitude modulation (QAM). Its optical and RF characteristics are studied thoroughly in simulation and experiment. We propose a system-orientated approach to optimization of the silicon photonic IQ modulator, which minimizes modulator-induced power penalty in a QAM transmission link. We examine the tradeoff between modulation efficiency and bandwidth for the optimal combination of modulator length and bias voltage to maximize the clear distance between adjacent constellation points. This optimum depends on baud rate and modulation format, as well as achievable driving voltage swing. Measured results confirm our prediction using the proposed methodology. Without precompensating bandwidth limitation of the modulator, net data rates up to 232 Gb/s (70 Gbaud 16-QAM) on single polarization are captured, indicating great potential for 400+ Gb/s dual-polarization transmission. Publication Accès libreFrequency comb generation using a CMOS compatible SiP DD-MZM for flexible networks(Institute of Electrical and Electronics Engineers, 2018-07-17) Lin, Jiachuan; Xu, Yelong; Sepehrian, Hassan; Shi, Wei; Rusch, LeslieOn-chip frequency comb generation is a promising solution for seeding a chip-scale optical transmitter for both Nyquist wavelength-division multiplexing (WDM) and orthogonal frequency-division multiplexing. We demonstrate flexible frequency comb generation using a silicon photonic dual-drive Mach-Zehnder modulator fabricated on a CMOS-compatible process. Our on-chip comb has five lines spaced at 20 GHz with a high tone-to-noise ratio of about 40 dB after one stage optical amplification. Our back-to-back transmission achieves bit error rates (BERs) well below 2e-2, the threshold for 20% overhead forward error correction (FEC), for 800 Gb/s using 16-GBd 32QAM on five WDM channels. We also test a seamless 800-Gb/s super-channel using 5×20 GBd 16QAM, with BER below the 7% overhead FEC threshold of 3.8e-3. To the best of our knowledge, this is the first demonstration of high-spectral-efficiency data carried by an all-silicon optical frequency comb. This establishes that a silicon optical frequency comb has sufficient optical signal-to-noise ratio for high-order QAM, as well as excellent stability for super-channels without guard bands, paving the way to an integrated high-spectral-efficiency multi-carrier optical transmitter. Publication Accès libreDemonstration and evaluation of an optimized RFS comb for terabit flexible optical networks(Optical Society of America, 2017-09-20) Lin, Jiachuan; LaRochelle, Sophie; Lyu, Mingyang; Wang, Lixian; Pai, Amruta; Rusch, Leslie; Zhang, XiaoguangWe experimentally demonstrate and evaluate an optimization strategy of a recirculating frequency shifting (RFS) optical comb for terabit flexible optical networks. We achieve an increased optical signal-to-noise ratio (OSNR) with good stability (no system outage) by reducing erbium-doped-fiber amplifier gain in the shifting loop and deploying an in-loop noise suppression filter. We demonstrate that this source can support 20×200 Gb/s dual polarization Nyquist-16QAM transmission. With optimization, the RFS comb has greater and more uniform OSNR per channel. Flexible optical networks with software-defined networking are particularly suited to this enhanced RFS due to 1) programmable frequency spacing, 2) dense, stable spacing enabling very high spectral efficiency, 3) uniform performance across channels, and 4) sufficient OSNR for high-order modulation. The RFS can be used in short links when using low overhead forward error correction (FEC). Distances as great as 1150 km are achieved when using a 20% FEC overhead. Long-distance tests at 4 Tb/s result in a post-FEC net rate of 3.3 Tb/s and 6.3 bit/s/Hz of spectral efficiency. Publication Accès libreThe impact of modal interactions on receiver complexity in OAM fibers(Institute of Electrical and Electronics Engineers,, 2017-09-11) Mirzaei Nejad, Reza; Lin, Jiachuan; LaRochelle, Sophie; Wang, Lixian; Rusch, LeslieWe experimentally study the modal interactions in mode division multiplexing (MDM) links supporting orbital angular momentum (OAM) modes of order zero and one. We use time of flight and channel impulse response measurements to characterize our OAM-MDM link and quantify modal impairments. We examine two OAM fibers with different index profiles and differential mode group delays (DMGD) between supported vector modes. Data transmission experiments probe the impact of modal impairments on digital signal processing complexity and achievable bit error rate for OAM-MDM link. We discuss in particular memory depth requirements for equalizers in separate mode detection schemes, and how memory depth varies with DMGD metrics as well as crosstalk level. Publication Accès libreMitigating pattern dependent nonlinearity in SiP IQ-modulators via iterative learning control predistortion(Optical Society of America, 2018-10-15) Lin, Jiachuan; Zhalehpour, Sasan; Sepehrian, Hassan; Shi, Wei; Rusch, LeslieSilicon based Mach Zehnder modulators, unlike lithium niobate, suffer from nonlinear pattern-dependent behavior beyond simple intersymbol interference. We experimentally demonstrate a novel predistortion method based on the iterative learning control (ILC) technique to address this issue using quasi-real-time adaptation with hardware-in-the-loop. We compare bit error rate performance to that of linear solutions at several M-QAM modulation levels and baud rates. We demonstrate 256QAM at 20 Gbaud which linear compensation alone cannot achieve. For 40 Gbaud 128QAM, we improve power sensitivity by 4.4 dB. We combine optical compensation with ILC to improve power sensitivity by ∼ 5 dB for 60 Gbaud 32QAM. Publication Accès libreSemiconductor optical amplifier based wavelength conversion of Nyquist-16QAM for flex-grid optical networks(Institute of Electrical and Electronics Engineers, 2016-06-01) Lin, Jiachuan; Filion, Benoît; LaRochelle, Sophie; Zhang, Xiaoguang; Rusch, Leslie; Nguyen, An T.We experimentally demonstrate semiconductor opti-cal amplifier (SOA) based wavelength conversion of 3×25 Gbaud Nyquist-16QAM signal for a flex-grid network. The conversion efficiency and power penalty of each of three channels during sin-gle pumped SOA wavelength conversion are studied with respect to three different channel spacings (or frequency grids). The BER performance of all converted channels fall below the FEC thresh-old of 3.8e-3, even with a 50 GHz grid. The results show the trade-off between channel spacing, conversion efficiency and BER power penalty. Closely packed channels, which clearly increase spectral efficiency, are also shown to decrease conversion power penalty, potentially counter balancing increased crosstalk levels. These re-sults can be used to optimize routing and spectrum allocation strategy when SOA wavelength converter(s) are present in the optical link. Publication Accès libreSingle-carrier 72 GBaud 32QAM and 84 GBaud 16QAM transmission using a SiP IQ modulator with joint digital-optical pre-compensation(Optical Society of America, 2019-02-18) Lin, Jiachuan; Sepehrian, Hassan; Shi, Wei; Rusch, LeslieWe establish experimentally the suitability of an all-silicon optical modulator to support future ultra-high-capacity coherent optical transmission links beyond 400 Gb/s. We present single-carrier data transmission from 400 Gb/s to 600 Gb/s using an all-silicon IQ modulator produced with a generic foundry process. The operating point of the silicon photonic transmitter is carefully optimized to find the best efficiency bandwidth trade-off. We present a methodology to split pre-compensation between digital and optical stages. For the 400 Gb/s transmission, we achieved 60 Gbaud dual-polarization (DP)-16QAM, reaching a distance of 1,520 km. Transmission of 500 Gb/s was further tested using 75 Gbaud 16QAM and 60 Gbaud 32QAM, reaching 1,120 km and 480 km, respectively. We finally demonstrated 72 Gbaud DP-32QAM (720 Gb/s) transmitted over 160 km and 84 Gbaud DP-16QAM (672 Gb/s) transmitted over 720 km, meeting the threshold for 20% forward error correction overhead and achieving net rates of 600 Gb/s and 576 Gb/s, respectively. To the best of our knowledge, these are the highest baud-rate coherent transmission results achieved using an all-silicon IQ modulator. We have demonstrated that we can reap the myriad advantages of SiP integration for transmission at extreme bit rates.