可調變式光衰減器是光通訊應用中的重要元件之一，在光纖網路的傳送與接收機等均需要安裝可調變式光衰減器，以用來控制光訊號的強度。本論文的主要目的是以微機電技術實現一顆低電壓驅動、沒有動態超越(overshoot) 、且能抗震動的微機電可調變式光衰減器。
由於旋轉式梳狀致動器在轉動方向的剛性遠比三軸方向要低，因此較能承受震動的衝擊，所以本論文選用旋轉式梳狀致動器作為元件的致動器。然而旋轉式梳狀致動器的驅動電壓較高，要降低致動器的驅動電壓，則需使用折曲式彈簧降低彈簧常數。在光衰減架構則設計四種轉動鏡面：懸臂型、鐘擺型、傾斜式與摺疊轉動鏡面。由於致動器轉動角度在兩度以內，因此轉動鏡面必須在兩度內達到>40dB的光衰減。
致動器的參數尺寸設計完成後進行光罩佈局與製程。元件製程部分採用SOI Micromachining製程，以ICP製作高深寬比的元件，並鍍金使鏡面能反射光訊號，最後進行元件量測。
在本論文中已經完成可調變式光衰減器的設計、製造、與量測驗證，證實所設計的光衰減器能在5V低電壓下驅動，並具備400Hz以上的頻寬。步進響應沒有overshoot，Tilted Micromirror設計可達到最大光衰減量55dB，光學動態響應速率<3ms，，介入損失0.95dB，PDL=0.3dB@Atten.=20dB，WDL(1510~90nm)=0.87dB
@Atten.=20dB。

Variable Optical Attenuator (VOA) applied to control the optical signal intensity is an important device for the transceiver/receiver in optical communication system. In this thesis, a low voltage, no overshoot and anti-impact MEMS VOA would be implemented by MEMS technologies.
Rotary comb drive was chosen as the actuator of VOA to prevent impact because its rigidity in rotation direction was much smallr than that in XYZ directions. However, rotary comb drive had high driving voltage. Serpentine spring with low spring constant could help to reduce the driving voltage. Considering the equivalent of mechanical and electrostatic torques, the device parameters were designed to achieve 20 rotation in 5V. Four optical attenuations (cantilever-type, pendulum, tilted, and folded micromirrors) were also devised to have maximum attenuation >40dB in 20 rotation by using TracePro simulation tool.
Mask layout and fabrication followed the device design. SOI micromachining developed the device main structure. Then Au sputter process made the micromirror reflection. Finally, we measured the deices after fabrication completed.
In this thesis, the design, fabrication, and measurement were accomplished. The MEMS VOA implemented could operate in 5V and have 400Hz bandwidth. Its step response showed no overshoot. The Tilted Micromirror design attenuated to maximum 55dB. The optical dynamic response <3ms, insertion loss=0.95dB, PDL=0.3dB, and WDL (1510~1590nm)=0.87dB.

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