Wavelength tunable light source

A wavelength tunable light source, comprising:

• a broadband seed light source generating a broadband light beam;
• a light input path receiving the broadband light beam from the broadband seed light source;
• a Volume Bragg Grating (VBG) having an entrance surface and an exit surface, positioned relative to the light input path such that the broadband light beam impinges on the entrance surface at an incidence angle with respect to a normal to said entrance surface, the VBG outputting a diffracted light beam exiting the exit surface at a diffraction angle with respect to a normal to said exit surface, the diffraction angle being equal and opposite to the incidence angle, the diffracted light beam having a spectral profile comprising a selected waveband of the broadband light beam accompanied by out-of-band features spatially dispersed by the VBG;
• a light output path;
• and
• a wavelength tuning mechanism, comprising:
• a VBG rotation stage operable to rotate the VBG to change the incidence angle by a VBG rotation angle, thereby tuning the selected waveband of the diffracted light beam;
• a displacement device configured to displace at least one of the light input path and the light output path relative to the VBG so as to change a relative alignment therebetween by twice the VBG rotation angle;
• and
• a controller jointly controlling the VBG rotation stage and the displacement device;
• wherein the light output path comprises an opening sized to allow at least a portion of the selected waveband through while substantially blocking the out-of-band features.