12Tbps-16QAM Uncompensated Long-Haul Transmission Employing a New Self-Oscillating Optical Frequency Comb Generator Both at Transmitter and Receiver

A new optoelectronic oscillator (OEO) is implemented for a novel self-sustained flat-topped selfoscillating optical frequency comb generator (SOOFCG), which can be deployed in terahertz optical transmission. The OFCG is designed from a cascaded configuration of an electro-absorption modulator and a polarization controller. In this work, the radio frequency source of a traditional-OFC scheme is replaced by the OEO. The frequency spacing of the generated spectrum is defined by the OEO∼20GHz that contains 15-healthy frequency tones. The carriers are modulated using the 16-quadrature amplitude modulation technique and transmitted across an SSMF implemented in a loop to complete a fiber span of 80km-240km. Overall, 1.12Tbps transmission can be achieved with the help of the given setup. At the receiver side, a homodyne coherent receiver is designed using the proposed OFCG to receive the signal. The conventional local oscillator lasers are replaced by the SO-OFCG generated from the received central optical carrier. Through offline DSP, the received optical signals are remunerated from various signal distortions and nonlinear impairments by utilizing digital backpropagation, constant modulus algorithm, and blind phase search algorithm at the receiving end. The system is analyzed regarding the bit error rate, symbol error rate, Q-factor, and error vector magnitude.