| 摘要: | 本論文提出懸臂式聲波應力感測結構整合至具三維波導光路之矽光學平台，其設計之架構，除了結合懸臂式應力感測結構之外，更整合了面射型雷射與光偵測器於此平台上，解決在目前的懸臂式聲波應力感測結構的研究中，光傳輸的部分多用光纖對光纖的問題。
此架構是製作在SOI(silicon-on-insulator)基板之上，在光子元件層使用非等向性濕蝕刻製作出三維波導光路，更在矽基波導光路中間以半導體製程截斷形成懸臂式波導，最後搭配不同的深蝕刻製程，製作出結合三維波導光路以及聲波應力感測結構之矽基平台。
本研究之量測結果分為兩個部分，第一，針對製程優化後架構之光學量測，基板厚度為300 µm的架構，光學傳播損耗為-12.168 dB，1 dB下位移容忍度範圍，輸入端的X軸範圍是-4 µm至+5 µm、Z軸為-4 µm至+4 µm，輸出端的X軸是-14 µm至+19 µm、Z軸為-14 µm至+20 µm；第二，是針對懸臂式聲波應力感測結構進行振動位移量之量測，輸入標準音源(1 kHz、10 µs/點)，聲音大小有94 dB、100 dB、105 dB以及108 dB，其對應之振動位移結果為，±2 nm、±4 nm、±5.5 nm和±10 nm。本研究成功提供了一個矽基平台以整合光波導以及懸臂式聲波應力感測結構。;In research area of cantilever sensing element, most of approaches are based on the methodology of fiber-to-fiber coupling, which is unsuitable for the integration of laser source and photodetector (PD) into the platform of cantilever structure. In this thesis, a three-dimensional optical path on silicon optical bench (SiOB) with cantilever waveguide sensing element is proposed for the first time to overcome the bottleneck of laser and PD integration. In the proposed approach, the three-dimensional optical path consists of input 45-degree micro reflector, cantilever waveguide, and output 45-degree micro reflector. A vertical-cavity-surface-emitted-laser (VCSEL) and a PD could be easily integrated into the SiOB by three-dimensional optical path.
The proposed SiOB is realized on a silicon-on-insulator (SOI) wafer. The three-dimensional optical waveguide is fabricated on the photonic layer of SOI wafer by wet etching process, and the cantilever waveguide is defined by three kind of different deep etching processes.
The measurement result divides into optics part and vibration part. In the optics part, under the substrate thickness of 300 μm, the optical transmission efficiency is -12.168 dB, and the alignment tolerance of x-axis and z-axis at input port ranges from -4 μm to +5 μm and -4 μm to +4 μm, respectively. At output port, the alignment tolerance of x-axis ranges from -14 μm to +19 μm, and it ranges from -14 μm to +20 μm for z-axis. In the vibration part, considering that the exterior sound source levels at 1 kHz frequency are 94, 100, 105 and 108 dB, the displacement amplitude of cantilever waveguide sensing element are ±2 nm, ±4 nm, ±5.5 nm and ±10 nm, respectively.
Based on the unique optical bench design, it provides a platform to integrate optical waveguide and cantilever waveguide sensing element, and further possible to integrate laser source and PD. |
