以負介電異向差液晶為夾層之光纖器及其對外加電壓的響應

Abstract

我們以負介電向差(Δε<0)的液晶取代一般的折射油，做為研磨式光 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1.3μm的雷射，量測在不同的外加 電壓強度下，耦合與未耦合光的變化情形。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頻率的響應。 We use liquid crystal with negative dielectric anisotropy (Δ ε<0) as anintermediate layer of the optical fiber coupler, instead of the refractiveindex liquid. By varying the applied voltage, we can change the effectiverefractive index of the liquid crystal to tune the light coupling ratio. In this experiment, we measure the coupling ratio between the coupled anduncoupled light by applying the different value of the voltage with a 1.3μmsemiconductor laser light. Also, the time response of the liquid crystal molecular under various frequency is observed.