雷射二極體與光子晶體光纖在光耦合上之探討

Abstract

在本論文中，我們提出一種可以改善光子晶體光纖光耦合效率的架構。在此架構中，我們使用單模的光子晶體光纖，連接上錐狀的光纖透鏡，有效率地收集雷射二極體所發出的光，目前得到最好的效率為46%，這比沒有光纖透鏡時的效率約好上4倍。我們也探討了此種光耦合架構對於多種波長的特性，以及量測雷射光由光子晶體光纖射出的光傳播性質。 在模擬上，我們利用高斯光束，ABCD矩陣法與光束傳播法來分析光源的光腰，光纖透鏡的形狀，對光耦合行為的影響。同時也驗證了本文中計算出來的光子晶體光纖的場在模擬光耦合上的正確性。光子晶體光纖射出的光在自由空間的傳播特性上與高斯光束有類似的行為，但量測的數據與理論預測的數值仍有差異。

In this thesis, we propose a coupling scheme for improving the coupling efficiency of photonic crystal fibers. In this scheme, the optical fiber used is a single-mode photonic crystal fiber, which is connected with a tapered fiber lens for efficiently collecting the light from a laser diode. The best coupling efficiency so far is 46 %, 4 times more in comparison with butt coupling. We also discuss the dependence of this coupling scheme on wavelengths, and measure the beam property when laser light emitting from the photonic crystal fiber.

In the simulations, we use the Gaussian beam property, ABCD matrix law and beam-propagation method to analyze the beam waist of the light source, the shapes of the fiber lenses, and their influences on coupling behavior. And we also verified the validity of the calculated field of the photonic crystal employed in such simulation of optical coupling. The beams from the lensed photonic crystal fibers have similar behaviors as Gaussian beams, but the data gotten from the measurement and the theory are still discrepant.