Evaluation of low-complexity digital coherent receivers for short-reach transmission systems

Digital coherent reception is an attractive candidate for increasing the channel capacity without expanding the bandwidth needed. The receiver DSP circuit must be able to compensate for the IQ-phase/power mismatch with low computation power requirements. In this paper, we propose a novel DSP circuit suitable for short-reach transmission systems including intra-datacenter networks. The proposed DSP circuit offers polarization-mode demultiplexing, compensation for IQ-phase/power mismatch, and estimation of carrier phase and frequency offset. The proposed DSP circuit consists of three-stage one-tap FIR filters; therefore, complicated calculations are not required. Its good demodulation performance is confirmed by simulations.