Achievable information rates estimates in optically amplified transmission systems using nonlinearity compensation and probabilistic shaping

Achievable information rates (AIRs) of wideband optical communication systems using a ∼40  nm (∼5  THz)∼40  nm (∼5  THz) erbium-doped fiber amplifier and ∼100  nm (∼12.5  THz)∼100  nm (∼12.5  THz) distributed Raman amplification are estimated based on a first-order perturbation analysis. The AIRs of each individual channel have been evaluated for DP-64QAM, DP-256QAM, and DP-1024QAM modulation formats. The impact of full-field nonlinear compensation (FF-NLC) and probabilistically shaped constellations using a Maxwell–Boltzmann distribution were studied and compared to electronic dispersion compensation. It has been found that a probabilistically shaped DP-1024QAM constellation, combined with FF-NLC, yields achievable information rates of ∼75  Tbit/s∼75  Tbit/s for the EDFA scheme and ∼223  Tbit/s∼223  Tbit/s for the Raman amplification scheme over a 2000 km standard single-mode fiber transmission

Achievable information rates of square MQAM modulation formats after carrier phase estimation

The performance of a pragmatic carrier phase estimation algorithm is evaluated over a range of SNRs. The optimal SNR regions for MQAM are compared to an AWGN channel observing gains of up to 40% in throughput

Fast wavelength switching 6 GBd dual polarization 16QAM digital coherent burst mode receiver

A commercially available digital supermode distributed Bragg reflector tunable laser is employed as a fast wavelength switching local oscillator (LO) in a dual polarization (DP) 16-quadrature amplitude modulation (16QAM) coherent burst mode receiver. A digital coherence enhancement technique is used to compensate both the Lorentzian and non-Lorentzian distributed phase noise of the tunable LO laser. It is shown that differential decoding is not sufficient to overcome the substantial bit errors caused by the LO laser phase noise. However, the coherence enhancement technique enables the reception of low symbol rate DP-16QAM bursts, with an average optical signal to noise ratio penalty of 3.5 dB observed relative to theory at the forward error correction threshold (1.5 × 10-2). © 1989-2012 IEEE

Transceiver-limited high spectral efficiency Nyquist-WDM systems

We experimentally examine the maximum achievable transmission performance of a 7 channel Nyquist-WDM system with 10GBd per carrier. Back-to-back, a maximum of 11.9 bit/sym and 13.8 bit/sym can be transmitted for DP-64QAM and DP-256QAM respectively, while after 2 spans of transmission, a maximum of 12.4 bit/sym and 11.6 bit/sym can be achieved