基于光路复用技术的光纤延迟线及其相位稳定性研究

Fiber-optic delay line (FDL) has been widely used in military and optical communication area. Most of its applications demand long delay-time and high phase stability of transmitted signals. In this proposal, based on optical-path multiplexing technique, we will develop reflection based FDL (double multiplexing), reflection + polarization multiplexing FDL (double multiplexing), multi reflection + polarization multiplexing FDL (4 times multiplexing) and fiber ring based FDL (N time multiplexing). In fiber ring based FDL, signal transmitted along fiber loop with their frequencies shifted in every loop by a single side band modulator. The number of circular loop can be controlled by adjusting the frequency shift signal, hence the FDL system are tuned with discrete time delay. The optical-path-multiplexing schemes reduce volume of FDL dramatically, thus the influence on fiber by environment is also reduced. Therefore, phase stability of transmitted signal is enhanced correspondingly. In this proposal, phase stability, of all proposed FDL systems are investigated, by comparing its temperature feature with that of normal FDL system. Based on optical-path multiplexing technique, variable FDL system with small size, high phase stability will be realized to improve its application.

光纤延迟线（FDL）广泛应用于军事和光纤通信领域，其中越来越多的应用要求更高的延时以及传输信号相位的高稳定性。高的延时意味着更长的光纤、更大的体积，将会对FDL的应用带来很大的限制。本项目基于光路复用传输的技术，将实现反射式双程FDL；偏振复用式双程FDL；多次反射+偏振复用式四程FDL；基于光纤环中移频传输的FDL。在基于光纤环的FDL系统中，通过控制频移频率，来控制信号在光纤环中循环的次数，从而实现了FDL的调谐。光路复用结构极大的减小了光纤体积，并由于光纤体积的减小，降低了环境对光纤的影 响，一定程度上改善了传输信号的相位稳定性。本项目通过对比了基于光路复用的FDL和普通FDL的温度特性（主要是相位稳定性），观察研究光路复用技术对FDL系统温度特性的影响，以应用于FDL的稳相传输方案中。本项目的研究有助于实现小型化、可调谐、以及稳定延时的光纤延时线。

光纤延迟线广泛应用于军事和光纤通信领域，在很多系统中要求信号更高的延时并且同时具有高的相位稳定性。高延时系统通常具有更大的体积，对光纤延迟线的应用带来很大的限制，并且同时影响了信号的稳定性。本项目基于多光程传输的原理，研究反射式双程光纤延迟线；反射+偏振复用式双程光纤延迟线；多次反射+偏振复用式四程光纤延迟线等高效的延时线系统。多程结构极大的减小了光纤体积，并由于光纤体积的减小，降低了环境对光纤的影响，一定程度上提高了传输信号的相位稳定性。在项目中还将基于光路复用的研究成果应用于小型化光纤延时线、一机多天线系统的光纤稳相传输、基于微波光子的光电振荡器系统中，有效提高系统性能。