光纖通訊系統的發展上，耦合器是一不可或缺的基礎元件，其功能是控制功率。傳統的光方向耦合器對波長、極化方向、元件長度敏感，且在寬頻和元件長度兩者之間無法兼顧，要想獲得短的元件達到較大的頻寬，幾乎無法達成。然而，絕熱式(adiabatic)光方向完全耦合器具有對光極化，光波長以及元件長度不敏感特性，所以針對於此本研究探討如何在低串擾值時同時可得到較短的耦合器和適當頻寬特性，利用田口穩健設計法配合BeamPROP模擬優化我們所提出的四種不同的耦合器函數，並找出適當的耦合器結構參數的加工裕度範圍，進而在此範圍內修改適當的結構參數來達到優化絕熱式光方向耦合器，以提供實際製作上的參數值。 在研究的結果顯示，使用BeamPROP輔助設計方式配合田口穩健設計法可有效的減少設計優化光方向完全耦合器的實驗數，在本研究中若考慮全因子法，在未考慮到交互作用因子的情況下就共需81組實驗，實驗數太多且沒有效率，所以決定採用田口穩健設計法實驗組合較少的特性以少量的實驗數據來取代全因子法繁複的實驗過程，以快速求得絕熱式光方向完全耦合器結構參數的加工裕度範圍。在此我們分別優化提出的Chen、Blackman、Hamming與Modification-hamming四種不同的耦合器函數，在實驗的優化數據結果中，我們得到四個耦合器函數在串擾值設定為-40dB時所對應的耦合器長度與頻寬的總平均，長度不超過7000 且頻寬均達到200nm，達到我們所訂定的低串擾值、短耦合器長度與滿足一定大小的寬頻目標。 In the optical communication system, coupler is one of indispensable components. The purpose of couplers is about to control power. To meet this demand for optical directional couplers, the adiabatic optical directional full coupler (AODFC) which is one of adiabatic directional coupler (ADC) is a nice choice. This coupler has some advantages over the conventional one such as more bandwidth, polarization insensitivity to fabrication. The optimal design for ADOFC function conditions determined by Taguchi’s method with beam propagation method (BPM) to try and find the best sets of coupling waveguide structure tolerance parameters range of adiabatic optical directional full coupler for reducing the low crosstalk、short coupler length and board bandwidth. In accordance with Taguchi’s method and BPM simulation process, the working time of simulation and optimization experimentally can be greatly reduced. Taguchi’s method his contributions have also made the practitioner work simpler by advocating the use of fewer experimental designs. In this paper, the result of optimization coupling waveguide structure design of AODFC by Chen、Blackman、Hamming and Modification-hamming function are investigated. When the crosstalk has been set -40dB, the Total average of coupler length is below 7000 , bandwidth is over 200nm.
