Intrachannel nonlinearity is considered a major distortion in high-capacity transmission systems particular for the case without inline optical chromatic dispersion compensation. In this paper, low-complexity intrachannel nonlinear compensator operating at symbol rate proposed based on perturbation predistortion dual-polarization quadrature phase-shift keying (DP-QPSK) systems. Compared with widely studied backpropagation algorithm, algorithm achieves comparable performance significantly...

In the evolution of optical networks, spectral efficiency (SE) enhancement has been most cost-efficient and thus main driver for capacity increase decades. As a result, development transport systems focused on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C$ </tex-math></inline-formula> - notation="LaTeX">$L$ -bands, where silica fiber exhibits lowest attenuation, erbium-doped amplifiers provide an...

To address the open and diverse situation of future optical networks, it is necessary to find a methodology accurately estimate value target quantity in an performance monitor (OPM) depending on high-level monitoring objectives declared by network operator. Using machine learning techniques partially enables trainable OPM; however, still requires feature selection before process. Here, we show OPM that uses convolutional neural (CNN) with digital coherent receiver deal abundance training...

One stage per span is commonly considered as the lower boundary for implementation complexity of nonlinear equalizer based on digital backpropagation. The proposed method overcomes this and improves efficiency by about four times.

Previous investigations have revealed that the impairments of cross-phase modulation (XPM) in dense wavelength-division multiplexing (DWDM) systems include two aspects: XPM-induced phase noise and polarization scattering. Such XPM phenomena are strongly dependent on transmission system configurations nonintuitive. In this paper, a simple fiber model is proposed to facilitate determination effects. By employing model, scattering calculated based time-consuming computation by split step...

An improved feed-forward carrier phase estimation scheme with further complexity reduction is presented and numerically verified for quadrature amplitude modulation (QAM) formats. Based on the blind search (BPS) algorithm, a general two-stage configuration first derived by removing several restrictions assumed in prior art. Two guidelines determining design parameters are then proposed to minimize computational while mitigating pattern effect maintaining tolerance laser linewidth. Taking...

We propose a "living network" as key enabler for open reconfigurable optical add/drop multiplexer (ROADM) networks that, unlike today's use of static planning tools, adapts to varying network conditions, and allows operation close actual performance. experimentally demonstrate the living in various conditions that autonomously keeps record its path-level The more services are added, accurate performance newly be established service is estimated through learning process, which shows...

We have developed a fiber-longitudinal monitor that visualizes distance-wise optical power throughout the entire multi-span link by using signal waveform obtained coherent receiver placed at receiver-end. This is an in-situ estimates profile along link-longitudinal axis from its incoming employing digital post-processing of data. demonstrate through experiments our method can simultaneously visualize and localize multiple attenuation anomalies over fiber transmission links. data...

We demonstrate a modified constant modulus algorithm (CMA) for polarization de-multiplexing and equalization. By designing the initial tap values CMA, degeneration of two tributaries can be avoided.

We present a digital frequency offset compensator for optical coherent QPSK receivers. The compensation accuracy reaches ± 30 MHz while the range covers 5 GHz. This would realize receivers with common off-the-shelf tunable lasers.

A novel nonlinear compensation scheme is proposed and demonstrated with 112 Gb/s DP-QPSK format using digital coherent receiver. The Q-improvement by the exceeded 2 dB after 20 span (1200 km) transmission.

A novel back-propagation algorithm is proposed based on perturbation analysis to compensate the intra-channel nonlinearity. It reduces 85% stages in an experiment of dual polarization QPSK transmission over 1500 km dispersion uncompensated link.

Conventional Gardner clock recovery method fails on Nyquist signal with sinc pulse shape. A novel algorithm is proposed and verified by experiment. It has lower timing jitter, its tolerance to various distortions investigated.

We experimentally demonstrate that a convolutional neural network (CNN) can acquire an accurate OSNR estimation functionality from asynchronously sampled data right after intradyne coherent detection, while the feature selection before CNN be omitted.

Three modulation formats are compared by numerical simulation of highly dense (75-GHz-spaced for 40 Gb/s channel), long-haul (600-1800 km) wavelength division multiplexed systems with three fiber types. Nonreturn-to-zero (NRZ) format, being the most spectrally compact and simplest in transmitter receiver configuration three, seems to be capable enough at shorter transmission distances than 1000 km regardless type. Carrier-suppressed return-to-zero (RZ) tolerant self-phase effect, showed...

We report on our study the nonlinear photodetection (NL-PD) scheme, which we have proposed and demonstrated as an extremely simple configuration for optoelectronic millimeter-wave (MM-wave) mixing. The topics described in this paper are follows: (1) advantageous optical MM-wave link architectures employing NL-PD techniques; (2) operation principle of NL-PD; (3) detailed characterization mixer properties a waveguide p-i-n photodiode; (4) experimental demonstration performance analog digital...

An enhanced digital coherent receiver including a novel blind equalization approach and maximum-likelihood sequence detection (MLSD) is proposed for dual-polarization quadrature duobinary (DP-QDB) systems. In virtue of the compact spectrum DP-QDB signals approaching Nyquist limit, implemented at symbol rate, which relaxes demand on sampling speed analog-to-digital converters (ADCs). The symbol-rate verified by 43 Gb/s experiments in presence chromatic dispersion polarization-mode dispersion....

We have proposed a dynamically configurable and fast optical impairment model for the abstraction of physical layer, enabling new capabilities such as indirect estimation operating parameters in multivendor networks based on pre-FEC BER information machine learning. is commonly reported by deployed coherent transponders; therefore, this scheme does not increase hardware cost. The estimated can subsequently be used to predict signal quality at receiver not-already-established connections more...

An optical digital-to-analog converter (DAC) is a promising solution for the efficient generation of multilevel modulation signals without high-speed electrical DAC and large swing linear driver. We report design characterization an all-Si segmented Mach-Zehnder modulator transmitter. The comprises forward-biased positive intrinsic negative (PIN) phase shifter integrated with passive resistance capacitance (RC) equalizer (PIN-RC) to optimize tradeoff between efficiency analog bandwidth....

A new class of digital signal processing (DSP)-based fiber-longitudinal optical power profile monitor has recently been proposed and demonstrated toward network tomography that captures the whole physical status an network, including in-span wavelength-specific profiles over a multi-span transmission light path. In this invited paper, we review disentangles waveforms received by standard coherent receiver to distance-wise link discuss its implementation aspect, advantages limitations...

A novel independent component analysis based algorithm is proposed for polarization demultiplexing. It solves the converge-to-same-source problem of constant modulus while possesses similar tracking capability.

We propose a decision-aided intra-channel nonlinear equalizer based on perturbation method, which offers one-stage compensation and symbol rate operation. It tolerates errors in data shows fine performance 128Gbit/s DP-QPSK transmission experiment.