在這篇論文中，主要是利用串接不同耦合區長度的對稱型指向耦合器來達到分波多工器的功能。元件使用二維的有限差分時域法來進行模擬、分析。以一極短脈衝波為輸入光源，並利用傅立葉轉換，可以輕易的得到此結構的全頻譜響應。我們可藉由頻譜分析來設計此分波多工器元件。這篇論文證實了此分波多工器可以將1.5μm-1.6μm的波長範圍內分出四個輸出通道。並且文中也會探討如何增進此元件能量強度對比的方法。

A wavelength division multiplexer (WDM) formed by cascaded symmetric directional couplers was studied in this thesis. The device was simulated and analyzed using 2D finite-difference time-domain method. A full-frequency spectrum of the device was easily obtained using an ultra-short optical pulse input followed by fast Fourier transform on the time variation of EM wave. Based on the spectrum analysis, a WDM performance of four channels in the wavelength range from 1.5μm to 1.6μm was simulated and verified. Furthermore, it was demonstrated that channel contrasts was improved by adding more identical couplers at the same cascaded order.

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