Lee Joungmoon, Park Jinwoo, Ha Inho, Han Sang-Kook
Opt Express. 2024 May 6;32(10):16983-16998. doi: 10.1364/OE.521013.
In this paper, we propose a dual-polarization Mach-Zehnder modulator-based photonic nonlinear analog self-interference cancellation (SIC) technique for in-band full duplex (IBFD) systems. By using the proposed technique, an arbitrary 4th order nonlinear transfer function can be generated, meaning the performance limitation caused by the nonlinearity of the analog SIC circuit can be overcome by imitating the nonlinear transfer function of the analog SIC circuit before cancellation. This paper also presents a performance analysis through simulations and the results of a proof-of-concept demonstration. In the experiment, the proposed nonlinear SIC technique could achieve 29 dB cancellation over 500 MHz bandwidth centered at 1.25 GHz frequency along various degree of distortion caused by nonlinearity. In addition, the performance enhancements achieved by the proposed technique are evaluated in terms of error vector magnitudes (EVMs) and constellations of the signal-of-interest (SOI) in the simulation which is based on the experimental SIC results. More than 3 dB of SOI power gain could be obtained in evaluated EVM performances.
在本文中，我们提出了一种基于双偏振马赫曾德尔调制器的光子非线性模拟自干扰消除（SIC）技术，用于带内全双工（IBFD）系统。通过使用所提出的技术，可以生成任意四阶非线性传递函数，这意味着在消除之前通过模仿模拟SIC电路的非线性传递函数，可以克服模拟SIC电路非线性所导致的性能限制。本文还通过仿真进行了性能分析，并给出了概念验证演示的结果。在实验中，所提出的非线性SIC技术能够在以1.25 GHz频率为中心的500 MHz带宽上，针对由非线性引起的各种失真程度实现29 dB的干扰消除。此外，基于实验SIC结果的仿真中，根据感兴趣信号（SOI）的误差矢量幅度（EVM）和星座图，评估了所提出技术实现的性能提升。在所评估的EVM性能中，可以获得超过3 dB的SOI功率增益。
