STTR PHASE I: Polarization-Independent Liquid-Crystal Fabry-Perot Tunable Filter for Wavelength-Division- Multiplexing Network Applications

本STTR一期项目主要研究用于波分复用（WDM）通信系统的偏振不敏感液晶法布里-珀罗（LC-FP）光滤波器。众所周知，LC-FP是一种高性能滤波器，因为它具有大的调谐范围，高精细度和低电压操作。然而，由于调制是基于光学各向异性的，因此在FP谐振腔中只能调制异常波。这导致极化敏感滤波器大大减少了其在WDM网络中的“现场应用”。虽然极化分集已经被提出并证明可以克服这个问题，但它需要在输入/输出端口进行极化分裂/组合，并导致有效地构成两个FP腔。这增加了包装和生产的困难，使大批量的商业设备制造不切实际。本项目将使用偏振光学来操纵FP腔中的任意偏振光。通过将液晶相位调制器定位在FP谐振器内交叉的四分之一波片之间，滤波器变得与极化无关。该装置结构简单，可批量生产。该STTR方案的成功完成可以解决LC-FP滤波器偏振敏感的缺点，扩大其在WDM网络中的应用。该滤波器的主要应用是有线电视广播、光纤在环WDM网络、长途电信和全光网络。该滤波器也可以应用于光谱分析和基于光纤的环境传感器应用。＊＊＊

*** 9631274 Liu This STTR Phase I project focuses on developing the polarization insensitive liquid-crystal Fabry-Perot (LC-FP) optical filter for wavelength-division-multiplexing (WDM) communication systems. It is well known that LC-FP is a high-performance filter due to its large tuning range, high finesse, and low voltage operations. However, because the modulation is based on the optical anisotropy, only the extra-ordinary wave can be modulated in the FP resonator. This results in a polarization sensitive filter that greatly reduces its "field application" in the WDM networks. Although polarization-diversity has been proposed and demonstrated to overcome this problem, it required polarization splitting/combining at the input/output ports and resulted in what effectively constitutes two FP cavities. This increases packaging and production difficulties, making high-volume commercial device manufacturing impractical. This project will use polarization optics to manipulate the arbitrarily polarized light in the FP cavity. By positioning the liquid crystal phase modulator in between crossed quarter-waveplates within the FP resonator, the filter becomes polarization independent. The device structure is simple and mass producible. Successful completion of this STTR program can resolve the polarization-sensitive drawback of the LC-FP filter and widen its application in the WDM networks. The primary applications for this filter are in cable TV broadcasting, fiber-in-the-loop WDM networks, long distance telecommunication, and all-optical networks. This filter can also be applied to spectroscopic analysis and fiber-based environmental sensor applications. ***