Wavelength conversion device with microlens and optical package incorporating the same

• US 8,111,452 B2
• Filed: 02/22/2010
• Issued: 02/07/2012
• Est. Priority Date: 02/22/2010
• Status: Expired due to Fees

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Butler, Douglas Llewellyn, Hu, Martin Hai, Liu, Anping
• Primary Examiner(s): Sanghavi, Hemang
• Application Number:
  US12/709,719
• Publication Number:
  US 20110205619A1
• Time in Patent Office: 715 Days
• Field of Search: None
• US Class Current: 359/332
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02F 1/3558 Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: G02F 1/377 in an optical waveguide structure
• CPC Class Codes: H01S 3/108 using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering mode locking using a non-linear element H01S3/1112
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 5/02375 Positioning of the laser chips
• CPC Class Codes: H01S 5/125 Distributed Bragg reflector [DBR] lasers
• CPC Class Codes: H01S 5/14 External cavity lasers H01S5/18 takes precedence; mode locking H01S5/065

Abstract

An optical package is provided comprising a laser diode and a wavelength conversion device. The laser diode and the wavelength conversion device define an external laser cavity and the wavelength conversion device is tilted relative to the output face of the laser diode to define a tilt angle φ that is less than approximately 85°. The input face of the wavelength conversion device comprises a pair of tapered facets and a microlens. The pair of tapered facets and the microlens are defined on the input face such that they share respective portions of the facial waveguide region on the input face, with the tapered facets occupying peripheral portions of the facial waveguide region on the input face and the microlens occupying an interior portion of the facial waveguide region on the input face. Each of the pair of tapered facets define a facet angle α within the facial waveguide region that is less than the facet angle α and is greater than approximately 45°. Additional embodiments are disclosed and claimed.

Claims

1. An optical package comprising a laser diode and a wavelength conversion device, wherein:

the laser diode and the wavelength conversion device define an external laser cavity extending along an optical path between a wavelength selective component of the laser diode and an output reflector of the optical package;

the wavelength conversion device comprises an input face, an output face, and a waveguide extending from the input face to the output face within the external laser cavity;

the waveguide of the wavelength conversion device defines an input facial waveguide region on the input face of the wavelength conversion device;

the laser diode is positioned such that an output face of the laser diode is proximity-coupled to the waveguide of the wavelength conversion device;

the wavelength conversion device is tilted relative to the output face of the laser diode to define a tilt angle φ

that is less than approximately 85°

;

the input face of the wavelength conversion device comprises a pair of tapered facets and a microlens;

the pair of tapered facets and the microlens are defined on the input face such that they share respective portions of the facial waveguide region on the input face, with the tapered facets occupying peripheral portions of the facial waveguide region on the input face and the microlens occupying an interior portion of the facial waveguide region on the input face;

each of the pair of tapered facets define a facet angle α

within the facial waveguide region that is less than the facet angle α

relative to the waveguide of the wavelength conversion device and is greater than approximately 45°

.

2. An optical package as claimed in claim 1 wherein the microlens is bounded by the tapered facets on the input face of the wavelength conversion device.

3. An optical package as claimed in claim 1 wherein the tapered facets extend from the microlens to respective edge portions of the wavelength conversion device.

4. An optical package as claimed in claim 1 wherein the tapered facets occupy a surface area on the input face of the wavelength conversion device that is at least two orders of magnitude larger than the surface area occupied by the microlens on the input face of the wavelength conversion device.

5. An optical package as claimed in claim 1 wherein the microlens is a relatively spherical or aspherical curved surface and the tapered facets are relatively planar surfaces.

6. An optical package as claimed in claim 1 wherein the microlens defines a concave or convex profile on the input face.

7. An optical package as claimed in claim 1 wherein the microlens comprises a cylindrical lens.

8. An optical package as claimed in claim 1 wherein:

the laser diode is configured to generate an output beam defining an ellipsoidal beam cross section; and

the microlens is configured to reduce the degree to which the ellipsoidal cross section of the output beam varies from a circular reference.

9. An optical package as claimed in claim 1 wherein:

the laser diode is configured to generate an output beam defining an ellipsoidal beam cross section; and

the microlens comprises an anamorphic lens element configured to reduce the degree to which the ellipsoidal cross section of the output beam varies from a circular reference.

10. An optical package as claimed in claim 1 wherein:

the facial waveguide region on the input face of the wavelength conversion device covers between approximately 10 μ

m² and approximately 100 μ

m²; and

the interior portion of the facial waveguide region occupied by the microlens covers between approximately 3 μ

m² and approximately 50 μ

m².

11. An optical package as claimed in claim 1 wherein the microlens comprises a cylindrical lens or anamorphic lens comprising a surface component arc characterized by a radius of curvature that is less than approximately 10 μ

m.

12. An optical package as claimed in claim 1 wherein the microlens comprises an aspheric lens component comprising at least one surface component arc characterized by a radius of curvature that is less than approximately 10 μ

m.

13. An optical package as claimed in claim 1 wherein the pair of tapered facets are configured to form a symmetrical or asymmetrical wedge on the input face of the wavelength conversion device.

14. An optical package as claimed in claim 1 wherein:

the input face of the wavelength conversion device comprises an additional pair of tapered facets; and

the two pairs of tapered facets collectively form a symmetrical or asymmetrical double wedge on the input face of the wavelength conversion device.

15. An optical package as claimed in claim 1 wherein each of the pair of tapered facets comprises a unitary facet or a compound facet.

16. An optical package as claimed in claim 1 wherein the laser diode is proximity-coupled to the waveguide portion of the wavelength conversion device without the use of intervening optical components.

17. An optical package as claimed in claim 1 wherein the laser diode is proximity-coupled to the waveguide portion of the wavelength conversion device by a proximity spacing of less than approximately 20 μ

m.

18. An optical package comprising a laser diode and a wavelength conversion device, wherein:

the laser diode and the wavelength conversion device define an external laser cavity extending along an optical path between a wavelength selective component of the laser diode and an output reflector of the optical package;

the wavelength conversion device comprises an input face, an output face, and a waveguide extending from the input face to the output face within the external laser cavity;

the waveguide of the wavelength conversion device defines an input facial waveguide region on the input face of the wavelength conversion device;

the laser diode is positioned such that an output face of the laser diode is proximity-coupled to the waveguide of the wavelength conversion device by a proximity spacing of less than approximately 20 μ

m and without the use of intervening optical components;

the wavelength conversion device is tilted relative to the output face of the laser diode to define a tilt angle φ

that is between approximately 70° and

80°

;

the input face of the wavelength conversion device comprises a pair of tapered facets and a microlens;

the pair of tapered facets and the microlens are defined on the input face such that they share respective portions of the facial waveguide region on the input face, with the tapered facets occupying peripheral portions of the facial waveguide region on the input face and the microlens occupying an interior portion of the facial waveguide region on the input face; and

each of the pair of tapered facets define a facet angle α

within the facial waveguide region that is less than the facet angle α

relative to the waveguide of the wavelength conversion device and is greater than approximately 45°

.