Coherent detection in optical fiber systems.

By Ezra Ip, A. Lau, D. Barros, Joseph M. Kahn. Optics Express, 2008

953 citations recorded by the source corpus.

The drive for higher performance in optical fiber systems has renewed interest in coherent detection. We review detection methods, including noncoherent, differentially coherent, and coherent detection, as well as a hybrid method. We compare modulation methods encoding information in various degrees of freedom (DOF). Polarization-multiplexed quadrature-amplitude modulation maximizes spectral efficiency and power efficiency, by utilizing all four available DOF, the two field quadratures in the two polarizations. Dual-polarization homodyne or heterodyne downconversion are linear processes that can fully recover the received signal field in these four DOF. When downconverted signals are sampled at the Nyquist rate, compensation of transmission impairments can be performed using digital signal processing (DSP). Linear impairments, including chromatic dispersion and polarization-mode dispersion, can be compensated quasi-exactly using finite impulse response filters. Some nonlinear impairments, such as intra-channel four-wave mixing and nonlinear phase noise, can be compensated partially. Carrier phase recovery can be performed using feedforward methods, even when phase-locked loops may fail due to delay constraints. DSP-based compensation enables a receiver to adapt to time-varying impairments, and facilitates use of advanced forward-error-correction codes. We discuss both single- and multi-carrier system implementations. For a given modulation format, using coherent detection, they offer fundamentally the same spectral efficiency and power efficiency, but may differ in practice, because of different impairments and implementation details. With anticipated advances in analog-to-digital converters and integrated circuit technology, DSP-based coherent receivers at bit rates up to 100 Gbit/s should become practical within the next few years.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/aaace1c0302b9c7dd8a25ffe0bbc71a0d349cc54

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In Atomic and Molecular Physics, and Optics

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Citations in the corpus

Performance of Dual-Polarization QPSK for Optical Transport Systems (2009, background): “Coherent detection offers the advantage of access to the amplitude and phase of the optical electric field in the electronic domain at the receiver [1], [2].”
All-Optical Signal Processing (2014, background): “In the more general case for the detection of polarization multiplexed signals, a polarization diversity coherent receiver is used, which employs polarization beam splitters, 90◦ optical hybrids, and BPDs to recover in-phase and quadrature components for both X- and Y-polarizations [30].”
Digital Signal Processing for Short-Reach Optical Communications: A Review of Current Technologies and Future Trends (2018, background): “Interested readers are referred to relevant review papers [4], [5] for a detailed treatment of the subject of DSP for long-haul coherent systems.”
Phase Retrieval via Matrix Completion (2011, background): “Phase retrieval for 1D signals arises in fiber optics [17, 39, 38], terahertz communications [42], and speech recognition [63], as well as in the determination of concentration profiles and the detection of planar disorder in diffraction imaging [12, 70].”
Effect of Mode Coupling on Signal Processing Complexity in Mode-Division Multiplexing (2013, methodology): “Current long-haul systems already use multiplexing in the two polarization modes of a single-mode fiber (SMF), enabled by coherent detection and digital signal processing (DSP) to compensate for chromatic dispersion (CD), polarization-mode dispersion (PMD) and polarization crosstalk [6], [7].”
Fiber Impairment Compensation Using Coherent Detection and Digital Signal Processing (2010, background): “In SC transmission, an additional stage of MZs may be inserted for pulse shaping [4].”
Hardware-Efficient Coherent Digital Receiver Concept With Feedforward Carrier Recovery for $M$ -QAM Constellations (2009, background): “Tremendous studies have already been done on coherent quadrature phase shift keying (QPSK) [1], [2], which can also be regarded as 4-QAM, and first realtime transmission systems have already been demonstrated [3]–[5].”
End-to-End Energy Modeling and Analysis of Long-Haul Coherent Transmission Systems (2014, methodology): “7 as well as those from [4], pre-FEC BER for 1100 km DPQPSK transmission is calculated as less than 10−4 .”
Multiplier-Free Intrachannel Nonlinearity Compensating Algorithm Operating at Symbol Rate (2011, background): “Since linear distortions such as chromatic dispersion (CD) and polarization-mode dispersion (PMD) can be compensated by a linear equalizer in the receiver [1], the nonlinearities are expected to be the major remaining obstacle [2].”
Compensation of Dispersion and Nonlinear Impairments Using Digital Backpropagation (2008, neutral): “An block-based FFT implementation can further reduce the computation requirement further [19].”
Power-Efficient Modulation Formats in Coherent Transmission Systems (2009, background): “When fundamental sensitivity limits for different modulation formats are discussed in textbooks and reviews [10]–[14], an additive white Gaussian noise (AWGN) model is assumed, for which the sensitivity for the chosen modulation format can be calculated.”