Analysis on the laser linewidth tolerance for uplink in coherent OFDMA-PON system

Abstract

Low-cost optical access networks have the capability to fulfill the requirements of industrial passive optical networks (PONs) that demand high capacity and flexible scheduling. Techniques such as multiplexing and coherent detection enhance system sensitivity, although an increase in users also results in elevated costs. Injection locking technology aims to effectively address this challenge. We have conducted measurements on the locking range, verified the linewidth control of the main laser over the slave laser in an injection-locked state, and investigated the linewidth tolerance of a multi-user OFDMA-PON system. Simulation results indicated that the linewidth tolerance of 100G bit/s 16QAM OFDMA system with 64/2048 subcarriers is approximately 5.9MHz/45KHz for multiple ONU scheme, with forward error correction (FEC) limit = 10e-3 and receiver optical power (ROP) = -24dBm which reconcile with offline experimental parameters.