本論文將絕熱工程(Adiabaticity Engineering)運用於光波導元件設計，透過控制絕熱路徑變化來優化在三種不同波長下的絕熱參數分佈，進而得到新設計波導的結構參數，使模態在元件中絕熱傳輸，大幅縮短轉換區與耦合區的長度，並保持高寬帶與良好的製程容忍度。
基於絕熱工程所設計的絕緣層覆矽超寬帶偏振分束-旋轉器(polarization splitter-rotator, PSR)波導轉換區長度縮短至92μm，僅需要線性設計的約1/3長度即可達到同樣的效果，並且在300nm的帶寬(1.4-1.7μm)中，有> 96%的透射率和高於16dB的消光比，保持高寬帶以及良好的製程容忍度。進一步利用絕熱工程方法重新設計3-dB絕熱分光器，也能夠大幅地增加元件工作寬帶，並且元件耦合區長度只需要40.3μm，即能達到50/50 (-3dB)的分光效果，元件總長度為82.3μm，在300nm的頻寬(1.4-1.7μm)中，其Imbalance(dB)皆能低於0.7dB，並同樣具有良好的製程容忍度。

We present a short and broadband polarization splitter-rotator (PSR) and 3-dB coupler based on silicon-on-insulator (SOI) both designed by adiabaticity engineering. By engineering the adiabaticity distribution using a single control parameter, we obtain shortcuts to adiabaticity in optical waveguides for multi-wavelength systems. Our simulations show that the length of the PSR can be shortened to 141μm. For a wavelength range from 1.4μm to 1.7μm, the PSR exhibits a good performance with larger than 96% transmission and >16dB extinction ratio (ER). The device also has good fabrication tolerance.
Using adiabaticity engineering to further design 3-dB coupler also can shorten the device length to 82.3μm, it has high tolerance to fabrication errors, and the bandwidth is as large as 300nm (from 1.4μm to 1.7μm) with an imbalance of less than 0.7dB.

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