一种新型的DPSK解调系统及性能研究  

Novel DPSK Demodulation System and Its Performance

作　　者：齐跃峰[1,2] 王玉琳 朱奕铖 杨子雄 李天 金琢然 Qi Yuefeng;Wang Yulin;Zhu Yicheng;Yang Zixiong;Li Tian;Jin Zhuoran(School of Information Science and Engineering,Yanshan University,Qinhuangdao 066004,Hebei,China;Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province,Qinhuangdao 066004,Hebei,China)

机构地区：[1]燕山大学信息科学与工程学院,河北秦皇岛066004 [2]河北省特种光纤和光纤传感器重点实验室,河北秦皇岛066004

出　　处：《光学学报》2023年第5期61-69,共9页Acta Optica Sinica

基　　金：国家自然科学基金重点项目(61735011);河北省科技研发重点项目(19251703D);中央引导地方科技发展专项(19941708G)。

摘　　要：针对基于传统马赫-曾德尔干涉仪的差分相移键控(DPSK)解调系统对光源相干性的要求高、臂长差和码速失配容忍度低、容易受到振动和温度的影响等问题,提出了一种基于新型马赫-曾德尔干涉结构的DPSK解调系统,采用光信号两次经过马赫-曾德尔干涉结构、参考臂和干涉臂之间相对延时1 bit干涉的方式实现了DPSK信号的解调。通过仿真和实验相结合的方法验证了新型解调系统的原理正确性及其性能。在系统Q值大于7的情况下,新型解调系统臂长差和调制码速率之间的失配因子容忍区间达到了0.25~1.73,其中Q值下降小于3 dB的区间达到了0.79~1.09。最后通过DPSK调制与解调实验以及温度稳定性验证实验证明了:在采用宽带光源(臂长差大于光源相干长度)的条件下,新型解调系统能够实现DPSK信号解调,降低了对光源相干性的要求,并且在0~70℃的环境中系统Q值在10以上,证明了系统具有较好的温度稳定性。Objective In the field of fiber-optic communication,further optical transmission and better communication quality presuppose the modulation of the optical signal,that is,to load the information to be transmitted into the optical signal by modulation for long-distance transmission.Therefore,a variety of modulation methods have been developed,such as differential phase-shift keying(DPSK)and on-off keying(OOK).With lower requirements on the optical signal-to-noise ratio,DPSK modulation shows superb performance in fiber-optic communication systems and has also become a research hotspot for fiber-optic communication technologies in recent years.DPSK signals are generally demodulated by a Mach-Zehnder interferometer.However,demodulation systems based on the traditional Mach-Zehnder interferometer are strict with the light source,modulation code rate,and arm length difference.Such a system requires a narrow-linewidth light source and is easily affected by temperature.To solve the above problems,this paper proposes a DPSK demodulation system based on a novel Mach-Zehnder interference structure.Compared with the traditional demodulation system,the novel demodulation system has higher robustness to arm length difference mismatch,better temperature stability,and lower requirements on the coherence properties of the light source,enabling wide-linewidth light sources to be applicable to DPSK demodulation systems as well.Methods This paper adopts the research method of combining simulation with experiment.Specifically,the transmission process of an optical signal in the system is derived mathematically,and the demodulation principle of the novel Mach-Zehnder interference structure is thereby described in detail.Then,a demodulation system based on the novel Mach-Zehnder interference structure is built in simulation software to verify whether the simulation results are consistent with the theoretical derivation results and prove the correctness of the system principle.Furthermore,the Q value of the system is calculated,and the n

关 键 词：光通信 新型马赫-曾德尔干涉结构 差分相移键控调制与解调 臂长差失配 温度 光源线宽 

分 类 号：TN253[电子电信—物理电子学]