Abstract
在本篇論文，我們用光纖費比- 皮洛特共振腔來實驗、分析在相對於光纖雙折性軸的幾個方向施加側向應力對極化保持光纖的影響。經由這種方法，我們可以分離兩個極化模態而不需用到極化器。在我們的實驗中，由在光纖兩端面上鍍鋁薄膜來製作光纖費比- 皮洛特共振腔。這些共振腔的靈敏度可高至12且可以輕易地達成。共振腔內的兩個模態可以清楚地分開，並且能容易地經由數位示波器來觀察。對於受應力下的高雙折性光纖費比- 皮洛特共振腔，我們提出它的理論模型和數值計算。當一個側向應力以偏於光纖主軸的角度施於這種共振腔時，它的兩個共振腔模態會改變高度大小。因此，可藉由此特性清楚地找出主軸的所在。由於極化保持光纖的非等向特性，施一個應力在慢軸或快軸附近所造成的影響是不同的。依據理論分析和實驗結果，我們提出了一個新的找軸方法。它不僅能找出並且可以分辨光纖的主軸位置。在此論文中，我們同時用一個已知的對軸方法來比較我們的實驗結果。就我們所知，這是第一個用此方法來找出極化保持光纖主軸的實驗。決定光纖主軸位置的精確度可以到達 +-1度。我們的研究對於發展高品質的光纖極化器和其它光纖元件是極具幫助的。我們可解析地研究且實際地製作出一種共振腔架構。它是用一個 2*2的光纖偶合器在其四端放上鏡面而形成的。我們採用一種矩陣計算方法使得推導過程容易些。這是對於這種新奇光纖共振器的實驗工作。實驗結果和理論預測相吻合。一些應用和進一步的研究方向也會在本論文中討論。In this thesis, the effects of lateral stress applied onpolarization-maintaining fibers (PMFs) from variousdirections with respect to fiber birefringent axes wasexperimentally analyzed by constructing fiber Fabry-Perotcavities (FFPC). By this way, two polarization modes areseparated without using analyzers. Fiber Fabry-Perot cavit- iesare formed by depositing Al on fiber ends and finesse as highas 12 were achieved without diff- iculty in our experiments.When a lateral stress is exerted on a FFPC with a mis-alignedangle to either one of the fiber principal axes, theamplitudes of two cavity modes will vary. Therefore, we canclearly locate the principal axes. Due to theanisotropic properties of PMFs, the effects are quitedifferent when a force is applied near the slow or fastaxes of fibers. Based on theoretical analyses andexperimental results, we proposed a new method capable offinding and distinguishing the principal axes of fibers. Inthis thesis, results were also verified by using a well-knownmethod based on the elasto-optic alignment. To ourknowledgement, it was the first such an experiment toidentify the principal axes of PMFs. An accuracy of +-1degree in locating principal axes was achieved by us. Ourcurrent research is fruitful in developing high-performance fiber polarizers and other fiber components.A resonant structure based on a 2*2 fiber directionalcoupler with four end mirrors was also analyticallystudied and physically constructed by us. To facilitatethe derivations of this structure, a method based on thematrix algebra was used. Our experiments agreed withtheoretical derivations. Applications and further suggestedresearch orientations were also discussed in this thesis.