Electronic equalization for enabling communications at OC-192 rates using OC-48 components

Abstract

We propose using electronic equalization technology to allow components typically used in 2.5Gb/s systems to be used at 10Gb/s. We simulate the performance of links exploiting this concept and study the effect of receiver bandwidth on equalized systems in general. Links utilizing transmitters designed for 2.5Gb/s rates are experimentally demonstrated. Experiments also show that photo-receivers with 2.5 GHz bandwidths add minimal penalty when post-detection electronic equalization is employed.

Impact of DCF properties on system design

“…Equalizers rather address the symptoms of dispersive pulse broadening on the signal quality by minimizing inter-symbol interference (ISI), which is simultaneously generated by residual dispersion [81][82][83][84] and other signal distortions, such as PMD [83][84][85] limited-bandwidth transmit or receive hardware [86,87], narrow-band in-line optical filtering [88] or fiber nonlinearity. Equalization can be performed in the optical domain and in the electrical domain, and can either substitute or complement impairment-specific compensators (TDC, PMDC), as shown in the advanced optical receiver setup of Fig.…”

“…On the other hand, logic processing and bitwise feedback at high data rates is not easily implemented in the optical domain. Studied for over 10 years for lightwave systems [81][82][83][84][85][86], electronic equalization at 10 Gb/s has recently experienced a boost by progress in high-speed integrated circuits, and has proven a powerful tool to increase dispersion tolerance [91][92][93][94][95]. Equalization techniques range from multi-tap feed-forward and decision feedback structures to sophisticated schemes employing multiple thresholds in conjunction with FEC.…”