Spectrally-Sliced Coherent Receiver Utilizing a Gain-Switched Optical Frequency Comb

The spectrally-sliced coherent receiver is an attractive solution for future optical access network applications where cost is a sensitive factor, as it enables reduced bandwidth of the analog front-end components and analog-to-digital convertors when compared to a conventional intradyne coherent receiver. In a proof-of-concept experiment, we demonstrate a single-polarization 50 Gb/s QPSK C-band transmission experiment over 40 km of standard (G.652) fiber using receiver bandwidths as low as 6.25 GHz and also utilize an array of local oscillator lines derived from an injection locked gain-switched optical frequency comb, which can be realized as a compact photonic integrated circuit. This paper also analyses the influence of optical frequency comb properties on the quality of the reconstructed signal. The critical parameters considered in this study include comb power and flatness, mutual comb line coherence, and the comb line suppression ratio after demultiplexing the comb lines. We have shown that with practically achievable comb parameter values, the receiver can operate with less than a 1 dB sensitivity penalty compared to a conventional intradyne receiver. The scheme has the potential to provide a low-cost coherent receiver solution for next-generation access networks.