Generation of 21.3 Gbaud 8PSK signal using an SOA-based all-optical phase modulator

We demonstrate a novel SOA-based all-optical π/4 phase modulator producing 21.3 Gbaud 8PSK from 21.3 Gbit/s OOK and 21.3 Gbaud QPSK inputs. Coherent detection-based bit error rate measurements indicate a 2.4 dB excess penalty.