Method and system for providing directional light sources with broad spectrum

• US 9,362,720 B1
• Filed: 07/07/2015
• Issued: 06/07/2016
• Est. Priority Date: 05/17/2010
• Status: Active Grant

• Current Assignee: Kyocera SLD Laser Incorporated (Kyocera Corporation)
• Original Assignee: Soraa Laser Diode, Inc. (Kyocera Corporation)
• Inventors: Raring, James W., Schmidt, Mathew C., Chang, Yu-Chia
• Primary Examiner(s): Nguyen, Dung
• Application Number:
  US14/793,339
• Time in Patent Office: 336 Days
• US Class Current: 1/1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/0045 the devices being superluminescent diodes
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 5/0427 for applying modulation to the laser
• CPC Class Codes: H01S 5/06251 Amplitude modulation
• CPC Class Codes: H01S 5/0651 Mode control
• CPC Class Codes: H01S 5/0652 Coherence lowering or collapse, e.g. multimode emission by additional input or modulation
• CPC Class Codes: H01S 5/2031 characterized by special waveguide layers, e.g. asymmetric waveguide layers or defined bandgap discontinuities
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/34 comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers H01S5/36 takes precedence
• CPC Class Codes: H01S 5/3407 characterised by special barrier layers
• CPC Class Codes: H01S 5/3414 by vacancy induced interdiffusion
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: H01S 5/4043 with vertically stacked active layers
• CPC Class Codes: H01S 5/405 Two-dimensional arrays
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

A system and method for providing laser diodes with broad spectrum is described. GaN-based laser diodes with broad or multi-peaked spectral output operating are obtained in various configurations by having a single laser diode device generating multiple-peak spectral outputs, operate in superluminescene mode, or by use of an RF source and/or a feedback signal. In some other embodiments, multi-peak outputs are achieved by having multiple laser devices output different lasers at different wavelengths.

Claims

1. An optical device comprising:

a gallium and nitrogen containing surface having a first crystalline surface region orientation, the first crystalline surface region orientation being nonpolar or semi-polar;

an active region comprising at least one quantum well and at least one barrier layer;

a first cavity member overlaying the active region, the cavity having a length of at least 100 um, a width of at least 0.5 um, and being configured to emit laser light with a spectral width of at least 0.5 nm; and

an RF source electrically coupled to the active region for providing RF modulation, the RF modulation being configured to induce spectral broadening and increase the spectral width to at least 1.5 nm.

2. The device of claim 1 further comprising a second cavity member.

3. The device of claim 1 wherein the spectral width of laser after RF modulation is at least 3 nm.

4. The device of claim 1 wherein the first crystalline surface region orientation comprises a semipolar plane such as {20-21}, {30-31}, {20-2-1}, {30-3-1}, or {11-22}.

5. The device of claim 1 further comprising a first electrode and second electrode coupled the first cavity member, the first electrode and the second electrode being insulated from each other, the first electrode being electrically coupled to a driver signal, the second electrode being electrically coupled to the RF source.

6. The device of claim 1 wherein the laser light is blue or green light.

7. An optical device comprising:

a gallium and nitrogen containing surface having a first crystalline surface region orientation;

an active region comprising at least one quantum well and at least one barrier layer;

a first cavity member overlaying the active region, the cavity having a length of at least 100 um, a width of at least 0.5 um, and being configured to emit laser light with a spectral width of at least 0.5 nm; and

an RF source electrically coupled to the active region for providing RF modulation, the RF modulation being configured to induce spectral broadening and increase the spectral width to at least 1.5 nm.

8. The device of claim 7 further comprising a second cavity member, the first crystalline surface region being either non-polar or semi-polar.

9. The device of claim 7 wherein the spectral width of laser after RF modulation is at least 3 nm.

10. The device of claim 7 wherein the first crystalline surface region orientation comprises a semipolar plane such as {20-21}, {30-31}, {20-2-1}, {30-3-1}, or {11-22}.

11. The device of claim 7 further comprising a first electrode and second electrode coupled the first cavity member, the first electrode and the second electrode being insulated from each other, the first electrode being electrically coupled to a driver signal, the second electrode being electrically coupled to the RF source.

12. The device of claim 7 wherein the laser light is blue or green light.

13. The device of claim 7 wherein the first crystalline surface region orientation is either non-polar or semi-polar.

14. The device of claim 7 wherein the active region comprises at least the quantum well or double hetereostructure emitting layer and a barrier layer.

15. The device of claim 7 wherein the first cavity member is characterized by a length along a c-plane, the first cavity member being configured to emit laser characterized by a spectral width of at least 1 nm.

16. The device of claim 7 wherein the first cavity member functions as a waveguide for a laser diode.

17. The device of claim 7 further comprising an optical feedback signal source coupled to the active region for inducing mode hopping.

18. The device of claim 16 wherein the laser diode is configured to emit a multiple peak wavelength obtained by utilizing light generated in the laser diode or by an adjacent light emitting device to provide optical feedback and induce mode hopping.

19. A method for operating an optical device comprising:

providing a laser device comprising a gallium and nitrogen containing surface including a first crystalline surface region orientation, an active region comprising at least one quantum well and at least one barrier layer; and

a first cavity member overlaying the active region, the cavity having a length of at least 100 um, a width of at least 0.5 um, and being configured to emit laser light with a spectral width of at least 0.5 nm; and

inducing spectral broadening using an RF source electrically coupled to the active region for providing RF modulation, the RF modulation being configured to induce the spectral broadening and increase the spectral width to at least 1.5 nm.

20. The method of claim 19 wherein the laser device is configured to emit a multiple peak wavelength obtained by utilizing light generated in a laser diode or by an adjacent light emitting device to provide optical feedback and induce mode hopping.