Optical cross-coupling mitigation systems for wavelength beam combining laser systems

Patent metadata

Field	Value
Publication number	US-10444482-B2
Application number	US-201815992593-A
Country	US
Kind code	B2
Filing date	May 30, 2018
Priority date	Mar 5, 2010
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

In various embodiments, wavelength beam combining laser systems incorporate optical cross-coupling mitigation systems and/or engineered partially reflective output couplers in order to reduce or substantially eliminate unwanted back-reflection of stray light.

First claim

What is claimed is:

1. A wavelength beam combining laser system comprising:
a plurality of beam emitters each emitting a beam;
a dispersive element for receiving and dispersing the beams;
a cross-coupling mitigation system for receiving and transmitting the dispersed beams while reducing cross-coupling thereof, the cross-coupling mitigation system comprising a first optical element and a second optical element, the first optical element being disposed optically upstream of the second optical element; and
a partially reflecting output coupler positioned to receive the beams transmitted by the cross-coupling mitigation system, transmit a first portion thereof as a multi-wavelength output beam, and reflect a second portion thereof back toward the cross-coupling mitigation system,
wherein (i) the first optical element is disposed within a Rayleigh range of the dispersed beams from the dispersive element, and/or (ii) the partially reflecting output coupler is disposed within a Rayleigh range of the beams transmitted by the second optical element.

2. The system of claim 1 , wherein the first optical element is disposed within a Rayleigh range of the dispersed beams from the dispersive element.

3. The system of claim 2 , wherein the partially reflecting output coupler is disposed within a Rayleigh range of the beams transmitted by the second optical element.

4. The system of claim 1 , wherein the partially reflecting output coupler is disposed within a Rayleigh range of the beams transmitted by the second optical element.

5. The system of claim 1 , wherein the cross-coupling mitigation system comprises an afocal telescope.

6. The system of claim 1 , wherein a focal length of the first optical element is at least two times greater than a focal length of the second optical element.

7. The system of claim 1 , wherein a focal length of the first optical element is at least seven times greater than a focal length of the second optical element.

8. The system of claim 1 , wherein each of the first and second optical elements comprises a lens.

9. The system of claim 1 , wherein an optical distance between the first and second optical elements is approximately equal to a sum of a focal length of the first optical element and a focal length of the second optical element.

10. The system of claim 1 , further comprising focusing optics for receiving the beams emitted by the beam emitters and focusing the beams toward the dispersive element.

11. The system of claim 10 , wherein an optical distance between the plurality of beam emitters and the focusing optics is approximately equal to a focal length of the focusing optics.

12. The system of claim 10 , wherein an optical distance between the plurality of beam emitters and the focusing optics is greater than a focal length of the focusing optics.

13. A wavelength beam combining laser system comprising:
a plurality of beam emitters each emitting a beam;
a dispersive element for receiving and dispersing the beams;
a cross-coupling mitigation system for receiving and transmitting the dispersed beams; and
a partially reflecting output coupler positioned to receive the beams transmitted by the cross-coupling mitigation system, transmit a first portion thereof as a multi-wavelength output beam, and reflect a second portion thereof back toward the cross-coupling mitigation system,
wherein (i) the cross-coupling mitigation system is configured to receive the reflected beams and transmit the reflected beams at an angle that reduces cross-coupling into the plurality of beam emitters, and (ii) the partially reflecting output coupler is disposed within a Rayleigh range of the beams transmitted by the cross-coupling mitigation system.

14. The system of claim 13 , wherein the cross-coupling mitigation system comprises an afocal telescope.

15. The system of claim 13 , wherein the cross-coupling mitigation system comprises a first optical element having a first focal length and a second optical element having a second focal length, the first optical element being disposed optically upstream of the second optical element.

16. The system of claim 15 , wherein the first focal length is at least two times greater than the second focal length.

17. The system of claim 15 , wherein the first focal length is at least seven times greater than the second focal length.

18. The system of claim 15 , wherein each of the first and second optical elements comprises a lens.

19. The system of claim 15 , wherein an optical distance between the first and second optical elements is approximately equal to a sum of the first and second focal lengths.

20. The system of claim 13 , further comprising focusing optics for receiving the beams emitted by the beam emitters and focusing the beams toward the dispersive element.

21. The system of claim 20 , wherein an optical distance between the plurality of beam emitters and the focusing optics is approximately equal to a focal length of the focusing optics.

22. The system of claim 20 , wherein an optical distance between the plurality of beam emitters and the focusing optics is greater than a focal length of the focusing optics.

23. A method of beam combining, the method comprising:
causing a plurality of beams to converge toward each other along a beam-combining dimension;
receiving the beams and dispersing the beams with a dispersive element;
receiving the beams from the dispersive element and transmitting the beams with a cross-coupling mitigation system, the cross-coupling mitigation system reducing cross-coupling of the beams; and
with a partially reflecting output coupler, receiving the beams transmitted by the cross-coupling mitigation system, transmitting a first portion thereof as a multi-wavelength output beam, and reflecting a second portion thereof back through the cross-coupling mitigation system toward the dispersive element,
wherein the partially reflecting output coupler is disposed within a Rayleigh range of the beams transmitted by the cross-coupling mitigation system.

24. The method of claim 23 , wherein (i) the plurality of beams are emitted by a plurality of beam emitters, and (ii) the beams reflected back through the cross-coupling mitigation system by the partially reflecting output coupler are transmitted as stabilizing feedback to the plurality of beam emitters.

25. The method of claim 23 , wherein (i) the plurality of beams are emitted by one or more beam emitters, and (ii) the beams are caused to converge toward each other by focusing optics.

26. The method of claim 25 , wherein an optical distance between the one or more beam emitters and the focusing optics is approximately equal to a focal length of the focusing optics.

27. The method of claim 25 , wherein an optical distance between the one or more beam emitters and the focusing optics is greater than a focal length of the focusing optics.

Assignees

• Chann Bien
• Teradiode Inc

Inventors

• Chann Bien

Classifications

• G02B27/4244

  in wavelength selecting devices (spectrometry G01J) · CPC title

• G02B19/0014

  at least one surface having optical power · CPC title

• G02B6/29317

  Light guides of the optical fibre type · CPC title

• G02B19/0028

  refractive and reflective surfaces, e.g. non-imaging catadioptric systems · CPC title

• G02B27/0905

  Dividing and/or superposing multiple light beams · CPC title