OPTICAL FREQUENCY MEASUREMENT SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an optical frequency measurement system for achieving high speed and high resolution measurement of an optical frequency.SOLUTION: A laser beam is modulated by an optical frequency comb generator 43 and the frequency of the laser beam is taken as a central frequency. A first optical frequency comb having a sideband wave at intervals of modulation frequency f+Δf and a second optical frequency comb having a sideband wave at intervals of modulation frequency of fare alternately generated at intervals of prescribed timeτ. Thus, a difference frequency or a sum frequency, is measured by a frequency counter 49, between a first frequency signal from a detector 48A for detecting the change of an optical strength due to an interference of an optical frequency comb to which a time delay of a prescribed timτis applied by a delay fiber 45 and a frequency shift of +fis applied and a laser beam to be measured, a second frequency signal from a second detector 48B for detecting the change of an optical strength due to an interference of the optical frequency comb and the laser beam to be measured and a third frequency signal from a third detector 48C for detecting the change of an optical strength due to an interference of the optical frequency comb to which a frequency shift of -fis applied and the laser beam to be measured.