Two-node demonstration of optical labeling using half-bit delayed dark RZ payload and DPSK label

Half-bit delayed dark return-to-zero (HBDDRZ) payload with differential-phase-shift-keying (DPSK) orthogonal labeling is demonstrated. High extinction-ratio of both modulations improves receiver margin. The HBDDRZ causes negligible effect on the RZ-like demodulated DPSK label