使用 LCoS 進行二維分光之1×12波長選擇開關的模擬與驗證

Abstract

本論文研究是使用矽基液晶(LCoS)反射式空間光調製器(SLM)，模擬架設一個具有二維光纖陣列的1×12波長選擇開關(WSS)系統，利用電腦全像術(CGH)加上均勻性優化迭代傅立葉變換演算法(IFTA)，達到靈活的相位調製，實現分光偏轉。 本系統模擬使用ZEMAX模擬，在模擬中，可將輸入光同時偏轉至12個二維排列的目標端口，也可個別偏轉至指定目標端口，架設出具有二維光纖陣列的1×12 WSS系統，優化了模擬元件參數，使輸出光更接近於接收光纖，而理論耦合效率可達到96 %，相較於一維架構，提升了約50%，不均勻度下降11.92-14.7 %，而在實驗中串擾，因收光角度偏移誤差導致上升至約-10 dB，雖結果顯示會造成影響，但此為實驗誤差。 在實驗中元件插入損耗約為11.62 ~11.77 dB。在多根偏轉與單根偏轉的實驗中，總系統損耗分別為24.81~32.60 dB與17.35~18.84 dB，與之前團隊所做之結果，皆有所下降。 使用二維光纖陣列的WSS系統，可提高系統靈活性，再增加端口的同時不降低效率，二維架構相比一維架構時相同的端口數，能降低分光角度，並降低偏離中心所造成的損耗與誤差，達到效率的上升。 而人為的實驗誤差在此實驗中占很大的損耗問題，經模擬在最後收光端口，收光角度偏差0.5度時，耦合效率會從96 %下降至73 %，而在所有透鏡x軸位置偏差皆為0.05 mm時，耦合效率僅剩1 %，且皆會導致串擾上升。

The research of this paper uses silicon-based liquid crystal (LCoS) reflective spatial light modulator (SLM) to simulate the establishment of a 1×12 wavelength selective switch (WSS) system with a two-dimensional fiber array. Using computer-generated hologram (CGH) and uses uniformity optimization iterative Fourier transform algorithm (IFTA) to achieve flexible phase modulation and spectral deflection. This system simulation uses ZEMAX simulation. In the simulation, the input light can be deflected to 12 two-dimensionally arranged target ports at the same time, or it can be deflected to designated target ports individually to set up a 1×12 WSS system with a two-dimensional optical fiber array. Compared with the one-dimensional architecture, the theoretical coupling efficiency can reach 96%, which is an increase of about 50%, and the non-uniformity is reduced by 11.92-14.7%. In the experiment, the crosstalk increased to about -10 dB due to the offset error of the light collection angle. Although the results show that it will have an impact, this is an experimental error. In the experiment, the component insertion loss was approximately 11.62 ~11.77 dB . In the experiments of multi-root deflection and single-root deflection, the total system losses were 24.81~32.60 dB and 17.35~18.84 dB, respectively, which were lower than the results of the previous team. The WSS system using a two-dimensional optical fiber array can improve system flexibility and increase ports without reducing efficiency. Compared with the same number of ports in a one-dimensional architecture, the two-dimensional architecture can reduce the light splitting angle and reduce the deviation caused by off-center losses and errors to achieve an increase in efficiency. The artificial experimental error accounts for a large loss problem in this experiment. After simulation, at the final light-collecting port, when the light-collecting angle deviation is 0.5 degrees, the coupling efficiency will drop from 96% to 73%, and at all lens x-axis positions deviation is 0.05 mm, the coupling efficiency is only 1%, and both will lead to increased crosstalk.