國立臺灣大學電機資訊學院光電工程學研究所碩士論文

Abstract

本論文探討4種1×3多模干涉光功率分離器，並從中選出兩種以高分子材料來製作。其中一種是1×3長方形的多模干涉器，而另一種是梯形結合長方形的多模干涉器。波導圖案係以紫外光雷射照射法來製作，即以波長248nm雷射照射，穿過石英光罩到達鍍有苯並環丁烯的矽晶片。波導寬度設定為7µm，多模干涉區寬度為60µm，兩個多模干涉器之折射率差皆設定為0.0027。結果顯示長度為1500µm 時的長方形分離器效果最好，其不等分率為1.02 dB，傳輸率為90.85 %。在相同長度下，另一個多模干涉器的不等分率為2.85 dB，傳輸率為92.66 %，後者傳輸率較前者高。本研究目的就是希望得到較高的傳輸率及均勻的輸出能量分布。雖然很多研究都以1×2N（N為偶數）為主，但本實驗結果顯示1×N（N 為奇數）仍會有好的表現。本研究不僅實驗上有較高的傳輸率結果，在模擬上也得到一樣的證明。

Four 1×3 multimode interference (MMI) optical power splitters were designed but only two out of the four 1×3 multimode interference (MMI) optical power splitters were fabricated. One of the fabricated devices is the 1×3 buried-type rectangular MMI section and the other one is a 1×3 linearly tapered input MMI section optical power splitters. The ultraviolet laser light illumination process was used to develop waveguide patterns on benzocyclobutene (BCB).coated silicon substrate. The laser source of 248nm is illuminated through the quartz mask to the BCB polymer wafer. The device is designed to have an input waveguide of 7μm wide and the central part or the MMI section is 60μm wide and of course three single mode waveguide outputs each as wide as the input waveguide. A refractive index change of 0.0027 was used for the design of both devices. The best 1The best 1×3 with a rectangular MMI section at an MMI length of 1500µm will exhibit an imbalance of 1.02dB and total transmission output of 90.85%. The best 1×3 linearly tapered input MMI section will give an imbalance of 2.85dB and a total transmission output of 92.66%. By tapering the input portion of the MMI section of the optical power splitter the transmission can be improved. This can be proved by comparing the results obtained from the two 1×3 MMI optical power splitters. The aim of this research is to obtain a better transmission for the 1×3 MMI power splitters and also to obtain a fair power distribution. Since 1×N (with N being odd) cannot easily perform the later reason many researchers are focused on the fabrication of 1×2N (where N is an even number). This research was able to achieve an experimental result that agrees very well with the simulation results that is, to obtain a higher output transmission.