利用雙光子聚合技術製作高耦合效率波導陣列光纖耦合器

Fabrication of Efficient Fiber Coupler Based on Waveguide Array Structure by Two Photon Polymerization Technique

趙師章(Shih-Chang Chao)

指導教授 ： 戴朝義

國立中央大學/理學院/光電科學研究所/碩士(2010年)

摘要

本論文主要目的是驗證概念，利用波導陣列結構製作出高耦合效率光纖耦合器。在數值模擬上，利用時域有限差分法模擬光傳播圖形，模擬結果顯示波長操作於633nm且外型為高斯函數分布的平面波入射進波導陣列結構後，在出口端後方可以得到聚焦光點，其中波導核心層和覆蓋層的折射率差為0.01。當波導數目N=5、波導寬度W=0.5μm、波導間距G=0.5μm和波導長度L=2μm的波導陣列，在出口端的光場(光點大小=4.946μm)與光纖的基模(模態大小=5.888μm)在空間上最匹配，耦合效率可達95%。在製程方面，利用雙光子聚合技術製作波導陣列結構。波導陣列能讓光束聚焦的機制可以利用耦合理論來解釋，由於耦合效應使得在波導陣列中傳播的光場呈現收斂的形式，若波導陣列的長度被調整在耦合長度附近，則入射光可以在波導陣列的出口端重新分布成為聚焦光點。

關鍵字

波導陣列 ； 光纖耦合器 ； 光通訊

並列摘要

We introduced a concept of efficient fiber coupler based on waveguide array structure. In numerical simulation, we used the Finite Difference Time Domain method to simulate propagation patterns. The simulation results showed that a Gaussian profile planar wave operated at λ=633nm which was sent into waveguide array structure could be a focal spot, where the refractive index difference Δn was 0.01. When waveguide number N=5, waveguide width W=0.5μm, waveguide gap G=0.5μm and waveguide length L=2μm, the diffraction field was matched the fundamental mode of optical fiber. The coupling efficiency η could achieve 95%. We fabricated the waveguide array by two photon polymerization technique. The focus mechanism can be realized by coupling theory. Because of the coupling effect, the wavefront of propagation wave in the waveguide array is in the form of convergence. If the waveguide length is cut around the coupling length range, the incident wave will be redistributed like a focal spot behind the output plane of waveguide array. In this work, the highest coupling efficiency is 52.64%.

並列關鍵字

array waveguide grating ； optical fiber coupler ； optical communications

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