984 research outputs found
A survey on fiber nonlinearity compensation for 400 Gbps and beyond optical communication systems
Optical communication systems represent the backbone of modern communication
networks. Since their deployment, different fiber technologies have been used
to deal with optical fiber impairments such as dispersion-shifted fibers and
dispersion-compensation fibers. In recent years, thanks to the introduction of
coherent detection based systems, fiber impairments can be mitigated using
digital signal processing (DSP) algorithms. Coherent systems are used in the
current 100 Gbps wavelength-division multiplexing (WDM) standard technology.
They allow the increase of spectral efficiency by using multi-level modulation
formats, and are combined with DSP techniques to combat the linear fiber
distortions. In addition to linear impairments, the next generation 400 Gbps/1
Tbps WDM systems are also more affected by the fiber nonlinearity due to the
Kerr effect. At high input power, the fiber nonlinear effects become more
important and their compensation is required to improve the transmission
performance. Several approaches have been proposed to deal with the fiber
nonlinearity. In this paper, after a brief description of the Kerr-induced
nonlinear effects, a survey on the fiber nonlinearity compensation (NLC)
techniques is provided. We focus on the well-known NLC techniques and discuss
their performance, as well as their implementation and complexity. An extension
of the inter-subcarrier nonlinear interference canceler approach is also
proposed. A performance evaluation of the well-known NLC techniques and the
proposed approach is provided in the context of Nyquist and super-Nyquist
superchannel systems.Comment: Accepted in the IEEE Communications Surveys and Tutorial
ASIC Implementation of Time-Domain Digital Backpropagation with Deep-Learned Chromatic Dispersion Filters
We consider time-domain digital backpropagation with chromatic dispersion
filters jointly optimized and quantized using machine-learning techniques.
Compared to the baseline implementations, we show improved BER performance and
>40% power dissipation reductions in 28-nm CMOS.Comment: 3 pages, 3 figures, updated reference list, added one sentence in the
result section for clarit
Optical and digital phase conjugation techniques for fiber nonlinearity compensation
We discuss recent progress on the use of optical and digital phase conjugation techniques for nonlinearity compensation in optical fiber links. We compare the achievable performance gain of phase conjugated twin wave applied in two polarization states and time segments with mid-link optical phase conjugation and digital back propagation. For multicarrier transmission scheme such as orthogonal frequency division multiplexing, two recently proposed schemes, namely phase-conjugated pilots and phase-conjugated subcarrier coding are reviewed
Phase-conjugated pilots for fibre nonlinearity compensation in CO-OFDM transmission
In this paper, we demonstrate a novel fiber nonlinearity compensation technique for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems based on the transmission of phase-conjugated pilots (PCPs). In this scheme, a portion of OFDM subcarriers (up to 50%) is transmitted with its phase conjugates, which is used at the receiver to estimate the nonlinear distortions in the respective subcarriers and other subcarriers, which are not accompanied by PCPs. Simulation and experimental results show that by varying the PCP overhead, a performance improvement up to 4 dB can be achieved. In addition, the proposed technique can be effectively applied in both single polarization and polarization-division multiplexed systems, in both single channel and wavelength-division multiplexing systems, thus, offering highest flexibility in implementations
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