以可調波長外差干涉儀作絕對距離的量測

Abstract

本文題出一種使用可調波長之半導體雷射為光源,及外差干涉儀的技術來 作絕對距離量測的方法.實驗系統中,我們使用電光晶體來對光的水平與垂 直偏極態作移頻,以得到所需的外差調變信號.從干涉信號相位差變化量與 波長變化量的關係換算得到絕對距離.此外 ,我們引入另一參考干涉儀於 量測系統中,將測試干涉儀信號與參考干涉儀信號比較,可以減少量測誤 差.此技術具有: 1.半導體雷射波長可調,可量測絕對距離; 2.使用雙干涉 儀,可以減少量測誤差; 3.使用電光晶體調制的外差干涉儀其光路是近似 共光軸的,受外界影響較小; 4.電光調制的頻率較小(2kHz),方便電子信號 處理等優點;可適用於工業檢測,塊規及機械工具的校正等等. We present a tunable wavelength heterodyne interferometer that uses tunable semiconductor laser diode for absolute distance measurement . In our experiment ,we use EO crystal to shift the horizontal and vertical polarization states frequency to get the heterdyne optical signal . The absolute distance can be computed by the relation between the wavelengths difference and the phase difference . Anthor Michelson interferometer is introduced into this system as a reference to reduce error.This technique has the favor of 1. absolute distance measurement,2. error redution by using reference Michelson interferometer, 3. the stable heterodyne signal generated by EO modulated and 4. easy electronic signal processing with lower EO frequency modulation . The system can be used as gauge adjustment, industrial testing,machine tooling testing and so on.