面向大容量长距离波分复用系统的相位敏感光放大器研究

As communication services and applications continue to grow in number and in bandwidth, optical communication systems are driven towards dense wavelength division multiplexing (WDM) systems with single-channel rate of 400Gbit/s, 1Tbit/s and above. Long-haul transmission of high-capacity WDM systems is mainly limited by optical signal-to-noise ratio degradation and impairments due to fiber nonlinearity. Optical amplification is one of the key technologies in fiber-optic backbone networks. However, the noise in current optical amplifiers will degrade the optical signal to noise ratio of the transmitted signals, which will hinder the upgrading of optical communication systems. Thus, low-noise optical amplifiers are required to support the long-haul transmission of high-capacity optical networks. Phase-sensitive amplifiers (PSAs) have the potential for noiseless amplification, but their application in WDM systems is limited by nonlinear crosstalk. The research in this project will focus on the suppression of nonlinear crosstalk in fiber-based PSA in order to realize the ultra-low noise optical amplification in dense WDM systems. We will first investigate the mechanism of nonlinear crosstalk in PSA and the effect of PSA gain on the generation of WDM crosstalk, which is important for the suppression of WDM crosstalk in multi-wavelength amplification. Hybrid PSA-EDFA scheme is also investigated through simulation and experiments. We will investigate its capabilities of ultra-low noise amplification and crosstalk suppression. Furthermore, we will use the hybrid PSA-EDFA scheme in dense WDM systems to show its suitability and system improvement for high-capacity optical communication networks. Based on the theoretical and experiment studies in this project, we are supposed to achieve multi-wavelength optical amplification with ultra-low noise and low crosstalk penalty, which will play a vital role in next-generation fiber-optic networks.

光通信网络业务数目和带宽的不断增长，促使光通信系统向着单波速率400Gbit/s、1Tbit/s及以上的密集波分复用模式发展。光信噪比损伤和非线性信号损伤成为限制长距离传输的主要因素。光放大技术是光纤传输系统的关键技术，但传统光放大器会引入噪声，造成光信噪比损伤，因此大容量光通信系统急需低噪声的光放大器来支持长距离传输。相位敏感放大器（PSA）可以实现无噪声光放大，但非线性串扰限制了传统PSA在波分复用系统中的应用。本项目针对该问题，开展面向波分复用系统的超低噪声光放大技术研究，采用混合PSA-EDFA方案，解决PSA在多波长信号放大方面存在的问题，为实现大容量长距离波分复用系统奠定基础。项目采用理论分析、数值仿真及实验验证，深入研究：①PSA增益对非线性串扰的影响机理及规律；②混合PSA-EDFA方案的噪声特性及对非线性串扰的抑制；③混合PSA-EDFA方案在大容量波分复用系统中的性能。

随着光通信网络业务数目和带宽的不断增长，促使光通信系统向着单波速率400Gbit/s、1Tbit/s及以上的密集波分复用模式发展。光信噪比损伤和非线性信号损伤成为限制长距离传输的主要因素。光放大技术是光纤传输系统的关键技术，但传统光放大器会引入噪声，造成光信噪比损伤，因此大容量光通信系统急需低噪声的光放大器来支持长距离传输。相位敏感放大器（PSA）可以实现无噪声光放大，但非线性串扰限制了传统PSA在波分复用系统中的应用。针对该问题，本项目开展面向大容量长距离光纤通信系统的超低噪声光放大技术研究，采用理论分析、数值仿真及实验验证，深入研究：相位敏感光纤参量放大器（PS-FOPA）四波混频串扰特性；混合PSA-EDFA方案的噪声特性及其对四波混频非线性串扰的抑制；高频谱效率信号的超低噪声放大技术；将光纤参量放大的光学相位共轭特性应用于高频毫米波的超低相位噪声传输。本项目取得了很多有意义的研究成果，有助于推动PSA在大容量长距离光纤通信系统中的实际应用。本在研究过程中，共发表标注项目资助科研学术论文5篇；同时，结合课题研究培养硕士研究生5名。