微機電技術之可形變鏡面式可調適光衰減器

Abstract

光衰減器是光纖通訊系統中用來控制光訊號傳輸的重要元件之一。它提供了許多功能，像是雷射功率的調控；分波多工系統中，不同波段的增益控制與平衡；以及光學元件的過載保護。本論文中，我們提出了一個使用靜電力驅動的聚亞醯胺薄膜製成的微機電光衰減器 我們從使用波動光學開始模擬整個系統，並且在光學系統設計軟體（ＺＥＭＡＸＴＭ）中建構我們的模組。接著，我們使用微機電技術製造了一個可形變鏡面來當作此光衰減器的主體。我們藉著熱黏結將此可形變薄膜與一個下電極組裝在一起，形成一個可形變鏡面式光衰減器。當我們施加１８８伏特在此光衰減器時，我們可以量得最大的光衰減為３０.８ｄＢ。由於此鏡面具有幾何對稱的結構，因此跟模擬預期的相當，我們量測到跟極化有關的衰減非常的小。我們也測量了驅動電路的功率損耗，約為１５３毫瓦。因此，由這些測量到的數據，我們認為此可形變鏡面式光衰減器很適合使用在長期的光通訊系統中。

An optical attenuator is one of the important components in optical communication system to control an optical signal transmission. It provides a variety of functions, such as power tuning of laser, dynamic gain controlling and equalizing of different channels in WDM system, and overload protection of optical device. In this thesis, we demonstrate a novel MEMS VOA made of polyimide thin film actuated by electrostatic force. We started with simulating the optical system by wave optics and constructed a model in optical system design software, ZEMAXTM. After, we fabricate a deformable mirror by micro-electro-mechanical system technology to serve as the main structure of the VOA. We assemble the deformable mirror to a bottom electrode by thermal bonging to form a DM-VOA. We measured the maximum optical attenuation is 30.8dB caused by the DM-VOA with 188V applied. The polarization dependent loss is very low due to geometric symmetric structure of the mirror, as simulated. The power consumption of the driving circuit is also measured, which is around 153mW. Therefore, we think the DM-VOA is a good potential for long-haul optical communication system using from these measured properties.