Tunable dual-wavelength laser based on Nd:YVO4/Nd:GdVO4 combined crystal

A tunable dual-wavelength laser (DWL) based on Nd:YVO4/Nd:GdVO4 combined crystal is presented. The frequency separation tuning characteristics of the DWL are investigated experimentally. In the experiments. the DWL with tunable frequency separation is obtained with fixed pumping power and controlled heat sink temperature (T-c) of the combined crystal. The frequency separations are measured at 351.11-316.15 GHz by varying T-c, from 5.0 degrees C to 40.0 degrees C, with a slope of 0.95 GHz/degrees C. When T-c, is kept at 32.3 degrees C, a 435-mW power-balanced DWL signal is achieved with frequency separation at 324.29 GHz. By analyzing the experimental results from the perspective of thermal-induced emission cross section (ECS) spectra evolution of the combined crystal, it is found the frequency separation tuning of the DWL is caused by the different ECS spectral wavelength shifting rates of the Nd:YVO4 and Nd:GdVO4 crystals with T-c varying. The analysis results are in good agreement with the experimental results. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement