Light source device and external cavity laser module

A light source device comprising:

• a plurality of external cavity laser modules configured to emit a plurality of laser beams of different peak wavelengths, each of the plurality of external cavity laser modules configured to emit a respective one of the plurality of laser beams;
• and
• a beam combiner configured to coaxially combine the plurality of laser beams to generate a wavelength-combined beam, wherein:
• each of the plurality of external cavity laser modules comprises:
• a collimation laser light source having a Littrow configuration, and
• a diffraction grating configured to selectively reflect and transmit light of a predetermined wavelength,
• the plurality of external cavity laser modules are arranged so that the plurality of laser beams are incident at different angles on a same region of the beam combiner, and
• each of the plurality of external cavity laser modules comprises:
• a support member supporting the collimation laser light source and the diffraction grating, and
• a base rotatably supporting the support member to correct an axial direction of a laser beam emitted from a respective one of the plurality of external cavity laser modules.