FREQUENCY STABILIZATION OF AN EXTERNAL CAVITY LASER DIODE USING ELECTROOPTIC EFFECT

Abstract

An external cavity laser diode, which consists of a LiNbO3 phase modulator, was frequency-stabilized to a resonance frequency of a Fabry-Perot interferometer using electrooptic effect. The optical frequency fluctuation was detected through a Fabry-Perot interferometer and the detected signal was negatively fed back to the phase modulator to reduce the frequency fluctuation. The rear facet of the electrooptic phase modulator was coated with gold and used as an external mirror. At feedback-off state the peak-to-peak frequency fluctuation of the laser diode was 52 MHz in 2 min. At feedback-on state the peak-to-peak frequency fluctuation was reduced to 1.5 MHz. This condition was maintained all the time of our observation, 1 h and 40 min.