使用布拉格光纖光柵當作光學回授元件以窄化Fabry-Perot雷射線寬

Abstract

本專題研究計畫主要目的為研製一台窄線寬雷射，並且利用此窄線寬雷射未來能提供雷射光譜以及頻率量測實驗室量測更精細的乙炔(Acetylene)分子之飽和吸收光譜，本研究使用光纖布拉格光柵(Fiber Bragg Grating, FBG)具有篩選特定波長進行光學回授的機制，將光纖布拉格光柵作為Fabry-Perot Laser Diode的光學回授元件，來形成光纖布拉格光柵外腔式二極體雷射(Fiber-Bragg-Grating External Cavity Diode Laser, FBG-ECDL)，並架設具有高解析度且不須額外光源之自我延遲外差法(Delayed Self-homodyne method, DSH)儀器架構以量測其FBG-ECDL線寬，而本專題研究計畫所研究之實驗成果，已成功將雷射線寬窄化至40 kHz，證明出光纖布拉格光纖光柵明顯的具有窄化Fabry-Perot雷射線寬的效果，利用此簡單的架構即可研製成一台具有窄線寬之光纖雷射，而研究成果將提供往後使用此光纖布拉格光柵外腔式二極體雷射之人員作參考。

The development of a narrow linewidth laser is the main purpose of this project. And we will investigate the high resolution saturated absorption spectroscopy of Acetylene in the future by using this narrow linewidth laser in the Laser Spectroscopy and Frequency Metrology Lab. This study uses Fiber Bragg Grating with a mechanism that reflects optical feedback at specific wavelengths. We use Fiber Bragg grating as the optical feedback element for the Fabry-Perot Laser Diode to develop a Fiber-Bragg-Grating External Cavity Diode Laser. And we set up an experimental apparatus with delayed self-homodyne method in the laboratory to measure the linewidth of the FBG-ECDL. The linewidth of this FBG-ECDL was measured as 40 kHz. This result demonstrates that we can narrow the Fabry-Perot laser linewidth by using Fiber Bragg Grating. We can manufacture narrow linewidth laser with a simple experimental scheme. The results of this research will be provided for researchers who will use this Fiber-Bragg-Grating External Cavity Diode Laser.