以液晶為夾層的光纖耦合器及其相位延遲特性

Abstract

我們分別以正,負介電異向差的液晶取代一般的折射油, 作為研磨式光 纖耦合器的夾層.藉由外加電壓改變液晶的有效折射係數, 以達到控制耦 合比例的要求. 實驗中,我們利用1.3微米的雷射為訊號源,量測在不同的 外加電壓形式及強度下,耦合與未耦合光的變話情形. 我們亦觀察對於不 同的外加電壓頻率下,液晶分子對於外加電壓的延遲現象,並做定性及定量 之分析. We use liquid crystals as an intermediate layer of the optical fiber coupler.Both positive and negative dielectric anisotropy liquid crystals have been used.The effective reflective index of the liquid crystal can be changed to tune thelight coupling ratio. In this experiment, we measure the coupling ratio between the coupled and un-coupled light with a 1.3 micron-meter semiconductor laser light source while applying different values of voltage. Also, the time response of the liquid crystal molecular under various voltage frequency is measured and is analyzedqualitatively and quantitatively.