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

A wavelength monitor, comprising:

• a laser source temperature detector for detecting a temperature of a laser source, wherein the temperature of the laser source monotonously increases or monotonously decreases with respect to a wavelength of a laser light output from the laser source;
• a wavelength calculation section for detecting a transmittance of the laser light through an optical filter, wherein the transmittance of the laser light periodically varies with respect to the wavelength of the laser light;
• an optical output calculation section for detecting an intensity of the laser light output from the laser source, wherein the intensity of the laser light monotonously increases or monotonously decreases with respect to a light intensity of the laser light;
• and
• a wavelength drift detector for detecting a wavelength drift of the laser light from a target wavelength based on the temperature detected by the temperature detector, the transmittance detected by the wavelength calculation section, and the intensity detected by the optical output calculation section.

A wavelength drift detection method, comprising:

• a laser source temperature detection step of detecting a temperature of a laser source, wherein the temperature of the laser source monotonously increases or monotonously decreases with respect to a wavelength of a laser light output from the laser source;
• a wavelength calculation step of detecting a transmittance of the laser light through an optical filter, wherein the transmittance of the laser light periodically varies with respect to the wavelength of the laser light;
• an optical output calculation step of detecting an intensity of the laser light output from the laser source, wherein the intensity of the laser light monotonously increases or monotonously decreases with respect to a light intensity of the laser light;
• and
• a step of detecting a wavelength drift of the laser light from a target wavelength based on the detected temperature of the laser source, the detected transmittance of the laser light through the optical filter, and the detected intensity of the laser light.