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

* 9631274刘 STTR第一阶段项目的重点是开发用于波分复用（WDM）通信系统的偏振不敏感液晶法布里-珀罗（LC-FP）光学滤波器。众所周知，LC-FP是一种高性能滤波器，因为它具有大调谐范围、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，只有非常波可以在FP谐振腔中调制。这导致偏振敏感滤波器大大减少了其在WDM网络中的“现场应用”。虽然已经提出并证明偏振分集可以克服这个问题，但它需要在输入/输出端口处进行偏振分离/组合，并导致有效地构成两个FP腔。这增加了封装和生产的难度，使得大批量商业设备制造不切实际。本计画将利用偏振光学来操控FP腔中的任意偏振光。通过将液晶相位调制器定位在FP谐振器内的交叉四分之一波片之间，滤波器变得与偏振无关。该器件结构简单，可批量生产。该项目的成功完成，可以解决LC-FP滤波器对偏振敏感的缺点，拓宽其在WDM网络中的应用。 这种滤波器的主要应用是在有线电视广播，光纤在环WDM网络，长途电信，和全光网络。该滤波器还可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. ***