Optical transmission module, wavelength monitor, and wavelength drift detection method

Abstract

To detect a wavelength drift of laser light with no error, an optical transmission module () includes: a laser diode (); a laser temperature calculation section () for detecting the temperature of the laser diode () that monotonously increases with respect to a wavelength of the laser light; a wavelength calculation section () for detecting a transmittance of the laser light incident on an etalon filter () whose transmittance periodically varies with respect to the wavelength of the incident light, and a laser wavelength corresponding to the transmittance; and a wavelength error obtaining section () for detecting a wavelength error (wavelength drift), from a target wavelength, of the laser light output from the laser diode (), based on the temperature detected by the laser temperature calculation section () and the laser wavelength detected by the wavelength calculation section ().