在多根D型矽核光纖上製作蕭特基近紅外光偵測器

Abstract

在本論文中，我們將自製的矽核光纖側拋研磨成D型，並在此研磨平台上製造蕭特基光偵測器。利用手持式研磨機，我們能快速的生產D型光纖，且能夠在光學顯微鏡下做研磨狀況的即時觀測。先前我們已在蝕刻纖衣的矽核光纖上製作光偵測器有了初步的成果。為了提升元件的響應度及頻寬，我們引入D型光纖來增加光偵測器的表現。首先用模擬軟體TracePro的光追跡法與模擬軟體Rsoft的光傳播法來研究D型矽核光纖中的光學特性，結果顯示D型矽核光纖能增加光線全反射的次數，且光波會較靠近研磨表面，這些特性使元件能夠更有效的利用在光纖中傳輸的光能量。緊接著量測研磨前後光學能量的差異與紅外線攝影機拍攝元件，實驗證實在D型矽核光纖中傳播的光會露出研磨表面，間接驗證了模擬結果。 隨後我們利用D型光纖的光學優勢製作光偵測器，提升了元件的響應度從0.226 mA/W至0.577 mA/W。而因為D型光纖的結構，能夠減少蕭特基金屬接觸的面積，進而減小元件的電容，使元件的頻寬從30 MHz提升至170 MHz。且在此製造方式下，我們能同時在多根光纖上製作光偵測器，並能與商用光纖快速的熔接省除傳統光電元件複雜的耦合步驟，使矽核光纖成為有潛力的矽光子元件。

In this thesis, we polished our homemade silicon-cored fibers (SCFs) into D-shaped and fabricated Schottky photodetectors (PDs) on the polishing platform. By using a handheld polishing machine, we could produce D-shaped SCF fast and able to observe the polishing condition under optical microscope instantly. In the past, we have fabricated a Schottky PD on a cladding-etched SCF and showed good performance. In order to increase the responsivity and bandwidth of the PD, we introduced D-shaped fibers. At first, we used ray tracing method and beam propagation method by simulation software TracePro and Rsoft respectively to study the optical properties in a D-shaped SCF. The simulation results showed that there are more times of internal total reflection occur and the light is closer to the polishing surface in a D-shaped fiber than cladding-etched fiber. These phenomena made a PD utilize the optical power in the fiber more efficiently. Then, we measured the optical power before and after polishing accompanied by the infrared camera upside the polishing surface. The experiments proved that the difference in power was caused by the light leaked out from the D-shaped polishing area. We utilized the optical properties of the D-shaped SCF to fabricate photodetectors. The responsivity increased from 0.226 mA/W to 0.577 mA/W. The 3 dB frequency also increased from 30 MHz to 170 MHz. Under this manufacturing method, we could fabricate multiple Schottky PDs on D-shaped SCFs at the same time and quickly spliced with commercial fibers to eliminate the complicated coupling steps of traditional optoelectronic components. With these advantages of fabrications and optical properties, D-shaped SCF has the potential to realize all-in-fiber sensor and silicon photonics device.