Tunable fiber laser light source

A tunable fiber laser light source comprising:

• an optical fiber loop which serves as an optical path of laser oscillation;
• a gain medium which is connected to said optical fiber loop and has a gain with respect to an oscillating wavelength;
• a light branch incident section which divides a plurality of light from said optical fiber loop and returns light to said optical fiber loop through the same optical path as the divided light;
• a tunable optical filter which receives the plurality of divided light divided by said light branch incident section, selects each same wavelength continuously changed, and supplies light of the selected wavelength said light branch incident section through the same optical path;
• and
• an optical coupler which is connected to said optical fiber loop and takes out a part of light passing through said optical fiber loop, wherein
• said tunable optical filter includes:
• an optical beam deflector which periodically changes a reflecting angle of an optical beam, obtained from said light branch incident section, within a certain range;
• and
• a diffraction grating which receives light deflected by said optical beam deflector and reflects light of selected wavelength changing according to an incident angle in the same direction as the incident angle, wherein
• said optical beam deflector in said tunable optical filter includes:
• a polygon mirror which is disposed on a light axis emitted from said optical fiber and has a plurality of reflecting faces for changing a light reflecting angle by rotation;
• and
• a driver which rotates said polygon mirror for changing light reflecting angle.

A tunable fiber laser light source comprising:

• an optical fiber loop which serves as an optical path of laser oscillation;
• a gain medium which is connected to said optical fiber loop and has a gain with respect to an oscillating wavelength;
• a light branch incident section which divides a plurality of light from said optical fiber loop and returns light to said optical fiber loop through the same optical path as the divided light;
• a tunable optical filter which receives the plurality of divided light divided by said light branch incident section, selects each same wavelength continuously changed, and supplies light of the selected wavelength said light branch incident section through the same optical path;
• and
• an optical coupler which is connected to said optical fiber loop and takes out a part of light passing through said optical fiber loop, wherein
• said tunable optical filter includes:
• an optical beam deflector which periodically changes a reflecting angle of an optical beam, obtained from said light branch incident section, within a certain range;
• and
• a diffraction grating which receives light deflected by said optical beam deflector and reflects light of selected wavelength changing according to an incident angle in the same direction as the incident angle, wherein
• said optical beam deflector in said tunable optical filter includes:
• a mirror which is disposed on a light axis emitted from said optical fiber loop and changes a light reflecting angle by rotation;
• and
• a galvanometer which pivots said mirror at a certain angle range.

A tunable fiber laser light source comprising:

• an optical fiber loop which serves as an optical path of laser oscillation;
• a gain medium which is connected to said optical fiber loop and has a gain with respect to an oscillating wavelength;
• a light branch incident section which divides a plurality of light from said optical fiber loop and returns light to said optical fiber loop through the same optical path as the divided light;
• a tunable optical filter which receives the plurality of divided light divided by said light branch incident section, selects each same wavelength continuously changed, and supplies light of the selected wavelength said light branch incident section through the same optical path;
• and
• an optical coupler which is connected to said optical fiber loop and takes out a part of light passing through said optical fiber loop, wherein
• said tunable optical filter includes:
• an optical beam deflector which periodically changes a reflecting angle of an optical beam, obtained from said light branch incident section, within a certain range;
• and
• a diffraction grating which receives light deflected by said optical beam deflector and reflects light of selected wavelength changing according to an incident angle in the same direction as the incident angle, wherein
• said tunable filter further includes a beam expander which enlarges a beam diameter of a optical beam polarized by said optical beam deflector;
• and
• said beam expander increases an enlargement rate as selected wavelength is shortened.

A tunable fiber laser light source comprising:

• an optical fiber loop which serves as an optical path of laser oscillation;
• a gain medium which is connected to said optical fiber loop and has a gain with respect to an oscillating wavelength;
• a light branch incident section which divides light from said optical fiber loop, and returns light to said optical fiber loop through the same optical path as the divided light;
• a tunable optical filter which receives the divided light divided by said light branch incident section, selects wavelength continuously changed, and supplies light of the selected wavelength to the light branch incident section through the same optical path;
• and
• an optical coupler which is connected to said optical fiber loop, and takes out a part of light passing through said optical fiber loop, wherein
• said tunable optical filter includes:
• an optical beam deflector which reflects optical beam obtained from said light branch incident section, and changes a reflecting angle of the optical beam periodically within a certain range with a central focus on a axis;
• a diffraction grating which receives the light deflected by said optical beam deflector passing through a first optical path, and reflects light of selected wavelength changing according to an incident angle, the reflecting light passing through a second optical path different from said the first optical path in the same direction seen from the axis of said optical beam deflector;
• and
• a mirror which reflects light reflected at said optical beam deflector passing through said second optical path and, then, inputted passing through a third optical path by return to the third optical path.