Dual-frequency continuous wave optical parametric oscillator

This article shows a dual-frequency OPO with multi-grating (28.5-31.5 mu m) periodically poled MgO:LiNbO3 (MgO:PPLN) pumped by a dual-frequency continuous wave at 1.064 mu m. The wavelengths of idler and signal varying versus temperature at different periods of inverted domains were numerical simulated. It proves that as the temperature rises, or as the poling period increases, the idler wavelength shortens and signal wavelength lengthens. The pump is a 30 W dual-frequency fiber laser MOPA with beat note frequency varying from 125 MHz to 175 MHz. The pump threshold of the bow-tie ring cavity OPO was 3 W. An average dual-frequency idler output power of 2.6 W was obtained when the pump power was 17.2 W at 45 degrees C. The idler wavelength was 3.4 mu m when the poling period was 30.5 mu m. The idler wavelength could be tuned from 2.9 mu m to 3.9 mu m by changing the temperature and the poling period, and the beat note frequency was proved to be equal to that of the pump.