Burst Mode Receiver for 112 Gb/s DP-QPSK with parallel DSP.

A burst mode 112 Gb/s DP-QPSK digital coherent optical receiver with parallel DSP suitable for implementation in a CMOS ASIC with a 218.75 MHz clock speed is presented. The receiver performance is validated in a five channel 50 GHz grid WDM burst switching experiment using a commercially available wavelength tunable laser as the local oscillator. A new equalizer initialization scheme that overcomes the degenerate convergence problem and ensures rapid convergence is introduced. We show that the performance of the tunable local oscillator is commensurate with burst mode coherent reception when differential decoding in employed and that required parallel DSP implementation does not seriously impair the polarization and frequency tracking performance of a digital coherent receiver under burst mode operation. We report a burst acquisition time of less than 200 ns.