1Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 2University of Chinese Academy of Sciences, Beijing 100049
Abstract：A frequency stabilizing system for a pulsed injection seeded 1550 nm optical parametric oscillator (OPO) at 20 Hz repetition rate is demonstrated. The optical heterodyne method is used to measure the frequency difference between the seed laser and the OPO output. Using the frequency difference as the error signal, a proportional-integral controller in combination with a scanner is applied to stably match the OPO cavity length to the seed laser frequency. The root-mean-square (rms) error of the frequency discrimination method is $ < $0.07 MHz according to a 'frequency shifting-chopping-beat' evaluation. The frequency fluctuation of the frequency-stabilized OPO is 0.29 MHz (rms), and the Allan deviation is less than 20 kHz for averaging time of more than 3 s.
2018, Vol. 35 
