System and method for wavelength beam combination on a single laser emitter

• US 9,124,065 B2
• Filed: 06/25/2013
• Issued: 09/01/2015
• 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): Jones, James
• Application Number:
  US13/927,093
• Publication Number:
  US 20130287058A1
• Time in Patent Office: 798 Days
• Field of Search: 359/556
• 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: H01S 2301/03 Suppression of nonlinear conversion, e.g. specific design to suppress for example stimulated brillouin scattering [SBS], mainly in optical fibres in combination with multimode pumping
• CPC Class Codes: H01S 3/094003 the pumped medium being a fibre
• CPC Class Codes: H01S 3/094096 Multi-wavelength pumping
• CPC Class Codes: H01S 3/0941 of a laser diode
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• 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 5/4012 Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H01S 5/405 Two-dimensional arrays
• CPC Class Codes: H01S 5/4062 with an external cavity or using internal filters, e.g. Talbot filters
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

A system and method for reducing the M² value of a single asymmetric laser emitter while maintaining the power output of the emitter. In some embodiments the brightness of the output of such a system is equivalent to a portioned section of the single laser emitter. A WBC step is performed along a portioned or non-portioned single laser emitter to reduce the M² value.

Claims

1. A diode pump comprising:

a single diode emitter emitting a single multi-mode beam, the multi-mode beam comprising a plurality of discrete wavelengths and having a beam size;

a portioning element configured to portion the multi-mode beam into a plurality of partitions, each partition comprising only one of the wavelengths of the multi-mode beam and having a partition size smaller than the beam size, the beam size substantially equaling a sum of the partition sizes;

a combining element configured to receive and converge each partition onto a dispersive element, wherein the dispersive element transmits the converged partitions; and

a partially-reflective output coupler arranged to receive the converged partitions from the dispersive element, to reflect a portion of the converged partitions toward the dispersive element, and to transmit an output beam having (i) the plurality of wavelengths and (ii) a size substantially equal to one of the partition sizes.

2. The diode pump of claim 1, further comprising an optical rotator configured to rotate the partitions prior the partitions being converged onto the dispersive element.

3. The diode pump of claim 1, wherein the output beam has an M² value less than 3.

4. The diode pump of claim 1, wherein the single diode emitter has a width greater than 100 microns.

5. The diode pump of claim 1, wherein the number of partitions is equal to the M² value along a length of the multi-mode beam.

6. A diode pump comprising:

a single diode emitter emitting a single multi-mode beam, the multi-mode beam comprising a plurality of discrete wavelengths and having a beam width;

a combining element configured to receive and converge only the single multi-mode beam along a first dimension onto a dispersive element, wherein the dispersive element transmits a reduced beam having a width less than the beam width; and

a partially-reflective output coupler arranged to receive the reduced beam from the dispersive element, to reflect a portion of the reduced beam toward the dispersive element, and to transmit an output beam having (i) the plurality of wavelengths and (ii) an M² value less than 3.

7. A method for reducing the emission M² value of a single diode emitter that emits a single multi-mode beam having (i) a plurality of discrete wavelengths, (ii) a first M² value along a first dimension of the multi-mode beam, and (iii) a second M² value along a second dimension of the multi-mode beam, the first M² value being greater than the second M² value, the method comprising:

along the first dimension of the multi-mode beam;

causing only the multi-mode beam to converge onto a dispersive element and be dispersed, thereby forming a dispersed beam, and

transmitting the dispersed beam onto a partially reflective output coupler, thereby (i) causing a first portion of the dispersed beam to reflect back towards the dispersive element and into the single diode emitter, and (ii) transmitting a second portion of the dispersed beam through the partially reflective output coupler, the second portion of the dispersed beam having (a) the plurality of wavelengths and (b) an M² value less than the first M² value.

8. A method for reducing the emission M² value of a single diode emitter that emits a single multi-mode beam having (i) a plurality of discrete wavelengths, (ii) a first M² value along a first dimension of the multi-mode beam, and (iii) a second M² value along a second dimension of the multi-mode beam, the first M² value being greater than the second M² value, the method comprising:

along the first dimension of the multi-mode beam;

portioning the multi-mode beam into a plurality of partitions, each partition comprising only one of the wavelengths of the multi-mode beam and having a partition size smaller than the beam size, the beam size substantially equaling a sum of the partition sizes;

causing the partitions to converge onto a dispersive element and be dispersed, thereby forming a plurality of dispersed beams, and

transmitting the plurality of dispersed beams onto a partially reflective output coupler, thereby (i) causing a first portion of the plurality of dispersed beams to reflect back towards the dispersive element and into the single diode emitter, and (ii) transmitting a second portion of the plurality of dispersed beams through the partially reflective output coupler, the second portion of the plurality of dispersed beams constituting an output beam having (a) the plurality of wavelengths and (b) an M² value less than the first M² value.

9. The method of claim 8, wherein the multi-mode beam is portioned into a plurality of equal partitions.

10. The method of claim 9, wherein the number of equal partitions is approximately equal to the first M² value.