Optical cross-coupling mitigation system for multi-wavelength beam combining systems

• US 9,256,073 B2
• Filed: 03/15/2013
• Issued: 02/09/2016
• Est. Priority Date: 03/05/2010
• Status: Active Grant

• Current Assignee: Panasonic Corporation Of North America (Panasonic Holdings Corporation)
• Original Assignee: TeraDiode, Inc. (Panasonic Holdings Corporation)
• Inventors: Chann, Bien, Huang, Robin, Tayebati, Parviz
• Primary Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US13/841,821
• Publication Number:
  US 20130208361A1
• Time in Patent Office: 1,061 Days
• Field of Search: 359/618, 359/299, 359/624, 359/245, 359/241, 359/244, 359/288, 359/305, 359/285, 359/308, 359311-312, 359290-292, 359/872, 359/263, 359223-224, 359/318, 359/649, 359/846, 359/129, 359/496, 359/631, 359/629, 359/634, 359/636, 359638-640, 359/831, 359833-834, 359/630, 359/341.3, 359/341.33, 359/337.21, 353/31, 353/34, 353/81, 451/28, 451/41, 372/25, 372/92, 372/98, 372/102
• US Class Current: 1/1
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence
• CPC Class Codes: H01S 5/4062 with an external cavity or using internal filters, e.g. Talbot filters
• CPC Class Codes: H01S 5/4068 with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

A system and method for increasing efficiency and power output of a multi-wavelength beam combining system through providing a common output coupler to reflect feedback that stabilizes or individually seeds each emitter, and wherein the individual feedback is preserved by mitigating cross-coupling, wherein a multi-wavelength beam comprised of radiation having a plurality of wavelengths, high brightness and power.

Claims

1. A multi-wavelength beam combining laser system comprising:

a dispersive element, positioned along a beam combining dimension, to receive a plurality of converging beams emitted by a plurality of diode elements, and transmit the beams;

a cross-coupling mitigation system positioned to receive and transmit the beams; and

a partially-reflecting output coupler positioned within the Rayleigh range of the beams transmitted by the cross-coupling mitigation system and arranged to receive the beams from the cross-coupling mitigation system, to reflect a portion of the beams toward the cross-coupling mitigation system, and to transmit the beams as a multi-wavelength beam,

wherein the cross-coupling mitigation system is configured to receive the reflected beams and direct the reflected beams onto the dispersive element at an angle that reduces cross coupling into the plurality of diode elements.

2. The multi-wavelength beam combining laser system of claim 1, wherein the cross-coupling mitigation system comprises first and second optical elements, and wherein the focal length of the first optical element is substantially greater than the focal length of the second optical element.

3. The multi-wavelength beam combining laser system of claim 1, further including an optical combining element positioned between the plurality of diode elements and the dispersive element, wherein the optical combining element is configured to cause the beams emitted by the diode elements to converge along a beam combining dimension.

4. The multi-wavelength beam combining laser system of claim 1, wherein each diode element is comprised of a gain medium positioned between a reflective back surface and a partially-reflecting front surface.

5. The multi-wavelength beam combining laser system of claim 4, wherein a resonator is formed between the output coupler and the back reflective surfaces of each diode element.

6. The multi-wavelength beam combining laser system of claim 1, wherein the cross-coupling mitigation system is an afocal telescope.

7. The multi-wavelength beam combining laser system of claim 2, wherein the first optical element of the cross-coupling mitigation system is positioned within the Rayleigh range of the multi-wavelength beam transmitted by the dispersive element.

8. The multi-wavelength beam combining laser system of claim 2, wherein the output coupler is positioned within the Rayleigh range of the beams transmitted by the second optical element of the optical system.

9. A multi-wavelength beam combining method comprising the steps of:

causing a plurality of beams to converge along a beam combining dimension at a plane;

positioning a dispersive element along the beam combining dimension to receive the converging beams and transmit the beams;

positioning a cross-coupling mitigation system comprised of first and second optical elements, to receive and transmit the beams from the dispersive element, wherein the focal length of the first optical element is substantially larger than the focal length of the second optical element;

positioning a partially reflective output coupler within the Rayleigh range of the beams transmitted by the cross-coupling mitigation system;

reflecting a portion of the beams back into the cross-coupling mitigation system with a partially reflective output coupler; and

transmitting the non-reflected portion of the beams as a multi-wavelength beam.

10. The multi-wavelength beam combining method of claim 9, wherein the plurality of beams are generated by a plurality of diode elements, and further including the step of positioning an optical combining element between the plurality of diode elements and the dispersive element, wherein the optical combining element is configured to cause the beams to converge along a beam combining dimension.

11. The multi-wavelength beam combining method of claim 10, wherein each diode element is comprised of a gain medium positioned between a reflective back surface and a partially-reflecting front surface.

12. The multi-wavelength beam combining method of claim 11, further including the step of forming a resonator between the output coupler and the back reflective surfaces of each diode element.

13. The multi-wavelength beam combining laser method of claim 9, wherein the first optical element of the cross-coupling mitigation system is positioned within the Rayleigh range of the multi-wavelength beam transmitted by the dispersive element.

14. The multi-wavelength beam combining laser method of claim 9, wherein the output coupler is positioned within the Rayleigh range of the multi-wavelength beam transmitted by the second optical element of the cross-coupling mitigation system.

15. The multi-wavelength beam combining method of claim 9, further including wavelength stabilizing and resonating a plurality of emitters by feedback from the output coupler that passes through the cross-coupling mitigation system, through the dispersive element and into the plurality of emitters.

16. A multi-wavelength beam combining laser system comprising:

a dispersive element, positioned along a beam combining dimension, to receive a plurality of converging beams emitted by a plurality of diode elements, and transmit the beams;

a cross-coupling mitigation system positioned to receive and transmit the beams, and wherein the cross-coupling mitigation system causes each of the transmitted beams to increase their divergence; and

a partially-reflecting output coupler positioned within the Rayleigh range of the beams transmitted by the cross-coupling mitigation system and arranged to receive the beams from the cross-coupling mitigation system, to reflect a portion of the beams toward the cross-coupling mitigation system, and to transmit the beams as a multi-wavelength beam,

wherein the cross-coupling mitigation system is configured to receive the reflected beams and direct the reflected beams onto the dispersive element at an angle that reduces cross coupling into the plurality of diode elements.

17. The multi-wavelength beam combining laser system of claim 16, wherein feedback from the output coupler causes each of the diode elements to resonate at a unique wavelength.

18. The multi-wavelength beam combining laser system of claim 16, wherein the cross-coupling mitigation system is comprised of a plurality of optical elements.