Wavelength Collision-Free and Low-Loss Full-Duplex Transmission over Switchable Full-Coupling or Half-Split Coherent WDM-PON System with Shared Protection

We propose low-loss and high-tolerance shared protection for full-duplex coherent wavelength division multiplexing-passive optical network systems, achieving < 2 dB penalty with small back reflection in wavelength collision-free secondary link transmissions with primary link failure.