A wavelength conversion device includes a nonlinear optical medium and a controller. The nonlinear optical medium configured to generate light from signal light and excitation light, the excitation light having a wavelength different from a wavelength of the signal light and having a second electric field strength than a first electric field strength of the signal light, the light having a wavelength different from a wavelengths of the signal light and the excitation light. The controller configured to control a first temperature of the nonlinear optical medium based on an intensity of the light.