Alik Gorshtein

Coherent Compensation for 100G DP-QPSK With One Sample per Symbol Based on Antialiasing Filtering and Blind Equalization MLSE

We propose coherent detection with one sample/symbol. Maximum-likelihood sequence estimation (MLSE) is used to compensate for intersymbol interference introduced by antialiasing filtering. The 100 000-ps/nm chromatic dispersion and 100-ps differential group delay are compensated with 1.5-dB penalty. Blind MLSE equalization is proposed.

Advanced modulation formats and digital signal processing for fiber optic communication

Optical communications is currently undergoing a real technological revolution based on coherent detection. In addition to preserving the phase information of the optical field, in coherent detection the optical channel becomes a linear system, enabling full compensation of optical fiber impairments by the use of digital signal processing techniques. Here, a coherent transmission and reception scheme for ultra-high data rates (100G and above), adopting advanced modulation formats is presented. In turn, symbol rate sampling followed by antialiasing filtering and digital signal processing is applied. This allows reducing the analog to digital conversion rate which forms one of the major bottlenecks at 100G and above data rates.

Ultimate single-carrier recovery for coherent detection

Proposed adaptive decision-feedback CR method is “ultimate” in the sense that it is ML/MMSE optimal (its performance cannot ever be exceeded) while its complexity vs. the number of taps, L, is lowest O(L) order possible.

Symbol Spaced Adaptive MIMO Equalization for Ultrahigh Bit Rate Metro Coherent Optical Links

A novel approach to symbol spaced adaptive multiple-input-multiple-output (MIMO) equalization is proposed. Different functionalities are defined for static versus adaptive equalizers, to minimize noise enhancement. Static equalizers are used for anti-aliasing filtering and bulk CD compensation, and a newly proposed modified-LMS-based adaptive MIMO equalizer is used to compensate for fiber random impairments such as residual CD and PMD. In addition, the proposed technique enables the use of low-cost reduced bandwidth components in both transmit and receive sides, and supports aggressive in-line optical filtering in the existing WDM network. Moreover, the proposed technique perfectly suits coherent metro applications, allowing significant power savings in application specific integrated circuit implementation.

Doubly-Differential Coherent 100G Transmission: Multi-Symbol Decision-Directed Carrier Phase Estimation with Intradyne Frequency Offset Cancellation

The proposed novel carrier phase and frequency recovery system automatically cancels LO frequency offsets, outperforming conventional schemes in mean square phase error, with low complexity linear processing, using a low number of complex-multiply-adds.

Low Cost 112G Direct Detection Metro Transmission System with Reduced Bandwidth (10G) Components and MLSE Compensation

MLSE compensation for reduced bandwidth optoelectronic components, CD, and PMD at multi-wavelength 4x28G transmission with direct detection is proposed. Inclusive comparison analysis with conventional hard decision systems is presented.

Advanced modulation formats and digital signal processing for next generation fiber optics networks

Advanced modulation formats are proposed and analysed for next generation optical networks. The new evolving optical networks data rates of 100G and above require real time analog-to-digital conversion followed by real time digital signal processing. This is in order to allow increased spectral efficiency and full compensation of amplitude and phase distortion imposed by the optical channel in such high bitrates. Various approaches are presented, including discrete multi-tone and optical OFDM.

Coherent Equalization for 111Gbps DP-qpsk with One Sample per Symbol Based on Anti-Aliasing Filtering and MLSE

We propose a coherent detection scheme with one sample per symbol. MLSE is used to compensate for ISI introduced by anti aliasing filtering. 50,000 ps/nm of CD is fully compensated with only 1 dB penalty.