8PSK Signals with 50% RZ Clock for Optical Access System Applications Using Phase Equalization Technique in MSPE

A multi-symbol phase modulation format, the 8 phase shift keying (8PSK) with 50% return-to-zero (RZ) clock, is proposed and demonstrated in this scheme for 30-Gb/s optical access downlink transmission applications using phase equalization technique in MSPE. RZ-8PSK optical signals are generated by cascading three phase modulators and a dual-arm Mach-Zehnder modulator. Superimposed 50% RZ clock is extracted and recovered for achieving access restoration. The result show the reception performance of 50% RZ-8PSK signals with phase equalization after transmission over SMF-28 is good.