Burst-Mode Digital Signal Processing for Coherent Optical Time-Division Multiple Access

TL;DR

This paper introduces a coherent burst-mode digital signal processing method for 200G optical time-division multiple access, enabling fast parameter estimation and reliable channel equalization for Beyond 50G optical communication systems.

Contribution

It proposes a novel Co-BM-DSP with designed preambles for efficient burst processing in 200G coherent optical TDMA, including theoretical proof of channel estimation uniqueness.

Findings

Fast estimation of polarization, frequency, and timing offsets.

Reliable channel equalization based on designed preambles.

Paves the way for Beyond 50G coherent optical access applications.

Abstract

As the 50G optical access gradually matures, it is time to discuss Beyond 50G optical access. According to the evolution rules of optical access standards, Beyond 50G optical access data rate may achieve 200Gb/s. Direct detection faces great challenges for Beyond 50G optical access, which makes coherent detection a potential solution. Similar to 50G optical timing-division-multiple access (TDMA), burst-mode digital signal processing (BM-DSP) is also required for Beyond 50G coherent optical TDMA (CO-TDMA). This paper proposes coherent BM-DSP (Co-BM-DSP) based on approximately 10ns designed preambles to process the burst signal for 200G CO-TDMA, which can fast estimate the state of polarization, frequency offset, sampling phase offset, synchronization position, and equalizer coefficients. Meanwhile, for obtaining the equalizer coefficients based on the designed preamble, the channel estimation based on the minimum-mean-square-error criterion is theoretically proven to have a unique solution for ensuring reliability. In conclusion, the proposed Co-BM-DSP based on the designed preambles paves the way for the applications of Beyond 50G CO-TDMA.