Optical frequency standard and optical frequency standard calibrating apparatus

摘要

PURPOSE:To achieve a smaller size of the apparatus by a method wherein an output of a photodetector undergoes a modulation frequency of a light source to perform a control so that the center frequency of the light source becomes zero with the inversion of the polarity of the output before and after a scanning when the frequency undergoes the scanning. CONSTITUTION:An output light of a reference light frequency generator 201 whose frequency is modulated at a frequency f0 is combined with an output light of a semiconductor laser 204 whose frequency is modulated in frequency at a frequency f1 by means of a fiber type directional connector 203 and checked 207 to be detected 208 through a collimator lens 205 and a Fabry-Perot etalon 206. With a feedback circuit 209, the temperature of the etalon 206 is controlled so that it becomes zero with the inversion of the polarity of the a phase detector 208. At the same, an output of a light intensity detector 207 is detected 210 in phase at the frequency f1 and the current of the laser is controlled with a feedback circuit 211 and a semiconductor laser drive circuit 214 so that an output of a phase detector 210 is zero. An output light of the laser 204 is branched 212 in two and one part thereof is combined 203 with the output light of the generator 201.