CONTROL DEVICE, LIGHT SOURCE DEVICE, TRANSMISSION MODULE, OPTICAL TRANSCEIVER, AND CONTROL METHOD

In order to enable oscillation of transmission light at any oscillation frequency even in an environment in which an environmental temperature varies significantly from an assumed temperature, a control device for a light source including a wavelength variable filter includes a temperature reception means for receiving substrate temperature information being information indicating a substrate temperature being a temperature of a substrate on which the light source is provided, and housing temperature information being information indicating a housing temperature being a temperature of a housing containing the substrate; and a control means for controlling, based on the substrate temperature information and the housing temperature information, the substrate temperature and a refractive index of the wavelength variable filter in such a way that a frequency of transmission light being output by the light source becomes a desired frequency.