應用狹縫波導結構控制絕緣上矽波導之極化相依性

Controlling the Polarization Dependence of SOI Waveguides by Using Slot Waveguide Structure

馬躍峰(Yao-Feng Ma)

指導教授 ： 黃鼎偉

國立臺灣大學/電機資訊學院/光電工程學研究所/博士(2011年)

https://doi.org/10.6342/NTU.2011.02304

摘要

在本論文中，一種狹縫波導結構已被成功運用來解決設計基礎絕緣上矽的波導原件中，所衍生極化相依性的問題。藉由精確控制狹縫波導的極化相依性，在此發表一個由狹縫波導構成，極化不相依的雙通道定向耦合器。在垂直狹縫的結構下，原件耦合區域長度可小至23.13 μm 並同時達到消光比大於22 dB以及1-dB頻寬大於100 nm的絕佳效能。而在水平狹縫的結構下，原件耦合區域長度可小至27.33 μm 並同時達到消光比大於27 dB以及1-dB頻寬約200 nm的絕佳效能。對於以上兩者其製程誤差的容忍度也有著墨探討。
更進一步的，先前章節中所發表的極化不相依耦合器，已被應用於實現一個由絕緣上矽狹縫波導所構成、極化不相依的跑道型微環狀共振器；並可藉由狹縫波導幾何結構的最佳化過程，以於寬頻寬範圍內維持一個無極化模態色散的運作。二種相互垂直的極化模態其頻譜響應不僅在操作波長相同，並且於C-band及L-band範圍內的共振波長差，如果是在以垂直狹縫結構來設計元件下可小於0.1 nm，而在以水平狹縫結構來設計元件下可小於0.25 nm。此元件的自由頻譜範圍可以達到大於10 nm ，並同時維持一個小於 30 μm的緊密原件尺寸。就目前所知，這是第一個以狹縫波導結構設計的微環狀共振器，可以達到如此無極化模態色散的絕佳效能。

關鍵字

狹縫波導 ； 絕緣上矽 ； 極化相依性 ； 極化模態色散 ； 定向耦合器 ； 微環狀共振器

並列摘要

In this dissertation, slot waveguide structures are successfully employed to overcome the problem of polarization dependence in designing fundamental silicon-on-insulator waveguide-based components. Through controlling of the polarization dependence of the slot waveguide, a polarization-independent dual channel directional coupler formed by slot waveguides is proposed. For vertical slot, the length of the coupling region of the device is 23.13 μm while delivering the good performance with the extinction ratio of more than 22 dB and 1-dB bandwidth of larger than 100 nm. For horizontal slot, the length of the coupling region of the device is 27.33 μm while delivering the good performance with the extinction ratio of more than 27 dB and 1-dB bandwidth of around 200 nm. The tolerance of the fabrication error on the practical device is also discussed.
Furthermore, the polarization-independent coupler proposed previously is employed to realize a polarization-independent racetrack type micro-ring resonator formed by silicon-on-insulator slot waveguides as well, in which the polarization-mode dispersion-free operation can be perfectly maintained over a wide spectral range by optimizing the slot waveguide geometry. The spectral responses for both polarization modes are nearly identical not only around the designed operating wavelength but also over C- and L-band with a resonance wavelength mismatch between the two orthogonal polarization modes less than 0.1 nm for vertical slot, and less than 0.25 nm for horizontal slot waveguide structures. The free spectral range of more than 10 nm can be achieved as well as a compact device size of less than 30 μm. To the knowledge it is the first micro-ring resonator that achieves such an excellent polarization-mode dispersion-free operation.

並列關鍵字

slot waveguide ； silicon-on-insulator ； polarization dependence ； polarization-mode dispersion ； directional coupler ； micro-ring resonator

參考文獻

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