本文討論高折射率差的矽光子之雙模態非對稱Y型波導（解）分模多工器與其模擬，並且定義一個適用於高折射率差的矽光子元件的絕熱參數，沿著傳播方向，透過快速準絕熱動態 (FAQUAD) 來重新分配波導上的絕熱性；利用快速準絕熱動態 (FAQUAD) 將絕熱參數固定成一常數，使得光功率在耦合時會受到限制，讓其不會耦合至其他非需要的模態。根據模擬結果，快速準絕熱動態 (FAQUAD) 計算的波導其長度只需18µm，耦合效率便大過於傳統長度100µm的線性分離波導，而操作頻寬可達到300nm (1400nm～1700nm)，且製程容忍範圍在正負10 nm之間時，其模態串擾仍低於 -20 dB。

A short and broadband high index-contrast silicon asymmetric Y-junction two-mode (de)multiplexer with large fabrication tolerance is proposed and simulated. An adiabaticity parameter is defined, which is suitable for high index-contrast silicon devices. The fast quasiadiabatic dynamics (FAQUAD) protocol is used to homogeneously reassign device adiabaticity along the propagation. The FAQUAD protocol limits the power coupling into the unwanted eigenmode in waveguide under a fixed value of adiabaticity parameter along the propagation. A 18 µm long mode (de)multiplexer with crosstalk lower than -38 dB is obtained. Simulations also show that the operating optical bandwidth is as large as 300 nm (1400 nm ∼ 1700 nm). Finally, the device is also fabrication tolerant from -10 nm to +10 nm.

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