光功率分光器目前被廣泛地應用在光電積體電路上，譬如光訊號的傳輸、光交換器、波長濾波器和光監測功能…等，此論文以0.25µm厚的SOI為設計平台，以馬赫詹德干涉(Mach-Zehnder Interferometer)為理論提出兩種新穎的多模干涉(Multimode Interference; MMI)耦合器與混合電漿波導(Hybrid Plasmonic Waveguide; HPW)耦合器，以及表面電漿生物感測器，除了理論的架構建立外，數值模擬方面主要是藉由商用Photon Design軟體中，以FDTD (Finite Difference Time Domain)為主的OmniSim和以FDM (Finite Difference Method)為架構的FIMMWAVE來完成。
本論文將S-bend MMI應用於輸出比例可調節之光功率分光器，S-bend MMI主要功能是建構在自我成像原理及彎曲波導導致模態重新分佈的理論上，我們以多模干涉為理論基礎，設計出2x2非等比例寬頻譜之光功率耦合器。在符合單模條件下，我們以0.45µm寬度與0.25µm深度的矽線(Silicon-wire)波導作為多模干涉器的輸入與輸出端，經過計算並求得最佳化條件後，S-bend MMI參數為多模波導寬度為3µm，長度為13.2µm、10.8µm及彎曲半徑為38µm、31µm時，可得到在1520-1600nm的波長頻寬的光功率分光比分別為0.97±0.015與0.76±0.01，並利用此分光比之光功率分光器取代傳統方向耦合器(Directional Coupler; DC)於延遲馬赫詹德干涉(Delay Mach-Zehnder Interferometer; DMZI)波長濾波器中波長較敏感的特性。接著會探討由兩段相同以及兩段不同彎曲半徑所組成之S-bend MMI在相位的變化，並藉由理論計算與實驗數據證明此探討結果。
另一探討寬頻光功率分光器的主題為混合電漿波導為主之馬赫詹德方向耦合器(Mach-Zehnder Directional Coupler; MZDC)。在此論文中，我們提出表面電漿干涉的概念來取代非耦合區，並考慮輸入與輸出彎曲波導的耦合量對於分光比的影響，除了可大幅縮小元件尺寸，其波長不敏感的特性更可涵蓋S至C波段，50/50、70/30、80/20、95/5四種分光比之寬頻譜能量分光器將於論文中展示。
本論文也利用矽線波導表面電漿之馬赫詹德干涉來產生生物感測器效應，與一般矽線波導表面電漿感測器不同的是，我們將金屬完全覆蓋並環繞在感測區，此感測機制是當光傳遞到金屬時，會在矽波導與金屬交接面產生一表面電漿波以及金屬與介質待測物交接面產生另一表面電漿波，當此兩表面電漿波傳至金屬層尾端時，最後會在矽波導層結合，等同於一馬赫詹德干涉儀，因感測區三面都有覆蓋金屬，干涉疊加使得靈敏度模擬結果可達 2891 nm/Refractive Index Unit (RIU)，並利用兩表面電漿波之折射率代入公式計算，解釋此結構靈敏度增加的原因。

The optical power splitters are widely utilized in photonic integrated circuits for optical signal transmission, optical switch, wavelength filter, and power monitoring. In this thesis, the novel couplers from MMI (multimode interference) and HPW (hybrid plasmonic waveguide) as well as the surface plasma biosensor, all constructed by the Mach-Zehnder interferometer (MZI), have been proposed, designed, and simulated on a 0.25-µm thick silicon-on-insulator platform. The numerical calculation was carried with the help of the OmniSim based on FDTD (Finite Difference Time Domain) and the FIMMWAVE based on FDM (Finite Difference Method) commercial software.
In this thesis, the S-bend MMI is utilized to adjust the output optical power. The S-bend MMI main function is combining the self-imaging and bend waveguide for mode redistribution to demonstrate a 2x2 broadband optical power splitter with any ratio. A 0.45-μm width and 0.25-μm depth are taken to be operated in the single-mode region of silicon wire for transmission. The multimode conditions of S-bend MMI are 3-μm width, 13.2-μm length, and 38-μm bend radius for the splitting ratio of 0.97±0.015 from 1520 to 1600 nm wavelength. And another 0.76±0.01 ratio comes from 3-μm width, 10.8-μm length, and 31-μm bend radius. Moreover, the S-bend MMI will be used to replace the wavelength sensitive directional coupler (DC) in delayed Mach-Zehnder interferometer (DMZI) wavelength filter for better extinction ratio. Finally a S-bend MMI composed of two bend radii will be theoretically studied for the phase and splitting ratio simultaneously.
Another broadband optical power splitter is the Mach-Zehnder directional coupler (MZDC) based hybrid plasmonic waveguide. Here, the surface plasma interference (SPI) is utilized to replace MZDC decoupled region. Moreover, the input and output bend effect on the splitting ratio will be further illustrated. In addition to the significant size reduction, the SPI splitter can be insensitive to the wavelength range between C and L-bands.
In this thesis, a MZI based silicon wire is utilized as the biological sensors through surface plasmon polaritons. The structure we propose different from the previous publication is the metal surrounding around the waveguide in the sensing area. The optical mode in the sensing region will be converted to the surface plasmon polariton between the silicon and metal. At the end of the surface plasma region, all the modes will interfere with each other to form MZI. The calculation shows that the sensitivity can achieve 2891 nm/Refractive Index Unit (RIU), the sensitivity increase is mainly from two interfered refractive indices of two surface plasma polaritons.

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