The reference frequency illuminant and the super high order accuracy optical frequency measurement system null which utilizes that

摘要

PURPOSE:To obtain a practical reference-frequency light source using a frequency which is equal to 1/2 of the difference between two frequencies having a high frequency probability and stability and a practical superhigh-accuracy optical frequency measuring system which utilizes the light source and is high in frequency probability. CONSTITUTION:This reference-frequency light source is constituted of two different reference-frequency lasers l and 2, a local oscillation laser 4 which is frequency-stabilized by a homodyne type phase locked loop PLL that obtains a difference signal against the frequencies of the lasers 1 and 2 through a sum frequency generator 5 and difference frequency generator 6 by means of photodiodes 7 and 8 and negatively feeds back the difference signal, and a semiconductor laser 3 which is stabilized to the frequency equal to 1/2 of the difference between the frequencies of the lasers 1 and 2 by means of the homodyne type phase locked loop PLL. The output of the laser 3 is used as a reference frequency.