Spectral beam combiner supporting embedded auto-alignment scheme
An apparatus includes an auto-alignment laser configured to generate an auto-alignment laser beam. The apparatus also includes a spectral beam combiner having a diffraction grating. The diffraction grating is configured to diffract multiple input laser beams to produce a combined beam having a higher power or energy compared to the individual input laser beams. The diffraction grating is also configured to diffract the auto-alignment laser beam so that a portion of the auto-alignment laser beam co-propagates in a common direction with the combined beam. Wavelengths of the input laser beams and the auto-alignment laser beam may be selected such that portions of the input laser beams and the portion of the auto-alignment laser beam diffract from the diffraction grating in the common direction. The portion of the auto-alignment laser beam that co-propagates with the combined beam may include a higher-order diffraction of the auto-alignment laser beam from the diffraction grating.
1. An apparatus comprising:
an auto-alignment laser configured to generate an auto-alignment laser beam; and
a spectral beam combiner comprising a diffraction grating that is configured to:
diffract multiple input laser beams to produce a combined beam having a higher power or energy compared to the individual input laser beams; and
diffract the auto-alignment laser beam so that a portion of the auto-alignment laser beam co-propagates in a common direction with the combined beam.
2. The apparatus of claim 1 , wherein wavelengths of the input laser beams and the auto-alignment laser beam are selected such that portions of the input laser beams and the portion of the auto-alignment laser beam diffract from the diffraction grating in the common direction.
3. The apparatus of claim 2 , wherein the common direction is dependent on (i) angles of arrival of the input laser beams and the auto-alignment laser beam at the diffraction grating and (ii) the wavelengths of the input laser beams and the auto-alignment laser beam.
4. The apparatus of claim 1 , wherein the portion of the auto-alignment laser beam that co-propagates with the combined beam comprises a higher-order diffraction of the auto-alignment laser beam from the diffraction grating.
5. The apparatus of claim 4 , wherein:
the higher-order diffraction of the auto-alignment laser beam comprises a second-order diffraction of the auto-alignment laser beam;
the input laser beams have wavelengths within a specified range of a nominal value; and
the auto-alignment laser beam has a wavelength that is approximately half of the nominal value.
6. The apparatus of claim 1 , wherein the auto-alignment laser beam follows a same optical path through a laser system as the input laser beams and the combined beam.
7. The apparatus of claim 1 , wherein the auto-alignment laser and multiple input lasers that are configured to generate the input laser beams collectively form an embedded laser array.
8. A laser system comprising:
an auto-alignment laser configured to generate an auto-alignment laser beam;
a spectral beam combiner comprising a diffraction grating that is configured to:
diffract multiple input laser beams to produce a high-energy laser (HEL) beam having a higher power or energy compared to the individual input laser beams; and
diffract the auto-alignment laser beam so that a portion of the auto-alignment laser beam co-propagates in a common direction with the HEEL beam;
a sensor configured to sense at least part of the portion of the auto-alignment laser beam that co-propagates with the HEL beam; and
a controller configured to control at least part of the laser system based on measurements from the sensor.
9. The laser system of claim 8 , wherein wavelengths of the input laser beams and the auto-alignment laser beam are selected such that portions of the input laser beams and the portion of the auto-alignment laser beam diffract from the diffraction grating in the common direction.
10. The laser system of claim 9 , wherein the common direction is dependent on (i) angles of arrival of the input laser beams and the auto-alignment laser beam at the diffraction grating and (ii) the wavelengths of the input laser beams and the auto-alignment laser beam.
11. The laser system of claim 8 , wherein the portion of the auto-alignment laser beam that co-propagates with the HEL beam comprises a higher-order diffraction of the auto-alignment laser beam from the diffraction grating.
12. The laser system of claim 11 , wherein:
the higher-order diffraction of the auto-alignment laser beam comprises a second-order diffraction of the auto-alignment laser beam;
the input laser beams have wavelengths within a specified range of a nominal value; and
the auto-alignment laser beam has a wavelength that is approximately half of the nominal value.
13. The laser system of claim 8 , wherein the auto-alignment laser beam follows a same optical path through the laser system as the input laser beams and the HEL beam.
14. The laser system of claim 8 , further comprising:
multiple input lasers configured to generate the multiple input laser beams.
15. The laser system of claim 14 , wherein the input lasers and the auto-alignment laser collectively form an embedded laser array.
16. The laser system of claim 8 , wherein the sensor comprises at least one position sensitive detector configured to sense a location of the at least part of the portion of the auto-alignment laser beam and a location of part of the HEL beam.
17. The laser system of claim 16 , wherein:
the laser system further comprises optics configured to direct the HEL beam, the optics including a fast steering mirror; and
the controller is configured to adjust the fast steering mirror based on the sensed locations.
18. A method comprising:
generating an auto-alignment laser beam;
diffracting multiple input laser beams using a diffraction grating to produce a combined beam having a higher power or energy compared to the individual input laser beams; and
diffracting the auto-alignment laser beam using the diffraction grating so that a portion of the auto-alignment laser beam co-propagates in a common direction with the combined beam.
19. The method of claim 18 , wherein wavelengths of the input laser beams and the auto-alignment laser beam are selected such that portions of the input laser beams and the portion of the auto-alignment laser beam diffract from the diffraction grating in the common direction.
20. The method of claim 18 , wherein the portion of the auto-alignment laser beam that co-propagates with the combined beam comprises a higher-order diffraction of the auto-alignment laser beam from the diffraction grating.