Investigation and applications of variable optical attenuators

• Main Author: 賴宜君
• Other Authors: 廖顯奎
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/33718980086660537501

碩士 === 國立臺灣科技大學 === 電子工程系 === 92 === In this thesis, we investigate the fabrication of the variable optical attenuators (VOAs). The major technique that we used is the Micro-Electro-Mechanical-System (MEMS), which may find many potential applications because of the characteristics of light weight, small size, low power consumption, and novel structure. The VOA devices are built in a silicon-based structure with only step of mask process is necessary. We design three types of VOAs, the concepts of them are by moving back and forth of the mirror, by rotating the angle between mirror with optical fiber, and misalignment the two section of fiber cores. We use the Inductively Coupled Plasma-Reactive Ion Etching (ICP-RIE) to fabricate micro mirrors, micro actuators and U-grooves on the silicon substrate. Then the micro actuator is droved by electrostatic method. The driving voltage, insertion loss and the dynamic range of home-made VOAs are 12.5-60 volt, 8dB and 12 dB, respectively. Beside investigation of VOA with MEMS technology, another three kinds of methods are proposed to fabricate VOAs. They are based on the concept of fiber bending loss and precisely fiber cores alignment. For the firs kind VOA, its dynamic range is as high as 35dB. And it insertion loss is less than 1.0 dB thank to the all fiber based construction. However, it has the drawback power fluctuation due to fiber bending. Nevertheless, neither polarization mode dispersion (PMD) nor polarization dependent loss (PDL) is observed. For the design of machine-based VOA, which includes a mirror, a shutter and a pair of collimated fibers. The optical power may attenuate partly or entirely by moving the shutter and result to power attenuation. Its dynamic range is 58dB with merits of good reliability and high resolution.