Enhanced Self-Coherent Optical Decision-Feedback-Aided Detection of Multi-Symbol M-DPSK/PolSK in particular 8-DPSK/BPolSK at 40 Gbps

Direct-detection sensitivity for M-DPSK/BPolSK with large M is improved generating self-coherent gain without an actual local oscillator light source by means of a novel optical decision-feedback-aided tapped-delay-line-interferometer, along with a 90deg optical hybrid, and analog-post processing.