Wavelength combiner photonic integrated circuit with grating coupling of lasers

Patent metadata

Field	Value
Publication number	US-2019196208-A1
Application number	US-201816216918-A
Country	US
Kind code	A1
Filing date	Dec 11, 2018
Priority date	Dec 11, 2017
Publication date	Jun 27, 2019
Grant date	—

Abstract

Systems, devices, and methods of manufacturing optical engines and laser projectors that are well-suited for use in wearable heads-up displays (WHUDs) are described. Generally, the optical engines of the present disclosure integrate a plurality of laser diodes (e.g., 3 laser diodes, 4 laser diodes) within a single, hermetically or partially hermetically sealed, encapsulated package. Photonic integrated circuits having grating couplers thereon may be used to wavelength multiplex beams of light emitted by the plurality of laser diodes into a coaxially superimposed aggregate beam. Such optical engines may have various advantages over existing designs including, for example, smaller volumes, better manufacturability, faster modulation speed, etc. WHUDs that employ such optical engines and laser projectors are also described.

First claim

1 . A laser projector, comprising:
an optical engine, comprising:
a base substrate;
a plurality of laser diodes, each of the plurality of laser diodes bonded directly or indirectly to the base substrate;
at least one laser diode driver circuit operatively coupled to the plurality of laser diodes to selectively drive current to the plurality of laser diodes;
a cap comprising at least one wall and at least one optical window that, together with the base substrate, define an interior volume sized and dimensioned to receive at least the plurality of laser diodes, the cap being bonded to the base substrate to provide a hermetic or partially hermetic seal between the interior volume of the cap and a volume exterior to the cap, and the optical window positioned and oriented to allow beams of light emitted from the plurality of laser diodes to exit the interior volume; and
a photonic integrated circuit comprising a plurality of input facets and at least one output facet, in operation, the photonic integrated circuit receives a plurality of beams of light at the respective plurality of input facets and wavelength multiplexes the plurality of beams of light to provide an aggregated beam of light at the output facet; and
at least one scan mirror positioned to receive the aggregate beam of light output at the output facet of the photonic integrated circuit, the at least one scan mirror controllably orientable to redirect the aggregate beam of light over a range of angles.

2 . The laser projector of claim 1 , further comprising a processor communicatively coupled to the optical engine to modulate the generation of light signals.

3 . The laser projector of claim 1 , the optical engine of the laser projector further comprising:
a plurality of collimation lenses, each of the plurality of collimation lenses positioned and oriented to collimate light received from respective ones of the beams of light emitted from the plurality of laser diodes, and to output the collimated light toward to the plurality of input facets of the photonic integrated circuit.

4 . The laser projector of claim 3 wherein each of the plurality of collimation lenses is bonded to the optical window of the cap.

5 . The laser projector of claim 1 wherein the photonic integrated circuit is bonded to the optical window of the cap.

6 . The laser projector of claim 1 , the optical engine of the laser projector further comprising an optical director element disposed within the interior volume, the optical director element bonded to the base substrate proximate the plurality of laser diodes, and positioned and oriented to reflect laser light from the plurality of laser diodes toward the optical window of the cap.

7 . The laser projector of claim 1 , the optical engine of the laser projector further comprising:
a collimation lens positioned and oriented to receive and collimate the aggregate beam of light from the output facet of the photonic integrated circuit.

8 . The laser projector of claim 1 , the optical engine of the laser projector further comprising at least one diffractive optical element positioned and oriented to receive the aggregate beam of light, in operation, the at least one diffractive optical element provides wavelength dependent focus correction for the aggregate beam of light.

9 . The laser projector of claim 1 , the optical engine of the laser projector further comprising:
a plurality of chip submounts bonded to the base substrate, wherein each of the laser diodes are bonded to a corresponding one of the plurality of chip submounts.

10 . The laser projector of claim 1 wherein the plurality of laser diodes includes a red laser diode to provide a red laser light, a green laser diode to provide a green laser light, a blue laser diode to provide a blue laser light, and an infrared laser diode to provide infrared laser light.

11 . The laser projector of claim 1 wherein the at least one laser diode driver circuit is bonded to a first surface of the base substrate, and the plurality of laser diodes and the cap are bonded to a second surface of the base substrate, the second surface of the base substrate opposite the first surface of the base substrate.

12 . The laser projector of claim 1 wherein the at least one laser diode driver circuit, the plurality of laser diodes, and the cap are bonded to a first surface of the base substrate.

13 . The laser projector of claim 1 wherein the plurality of laser diodes and the cap are bonded to the base substrate, and the at least one laser diode driver circuit is bonded to another substrate separate from the base substrate.

14 . The laser projector of claim 1 wherein each of the laser diodes comprises one of an edge emitter laser or a vertical-cavity surface-emitting laser (VCSEL).

15 . The laser projector of claim 1 wherein the at least one wall of the cap comprises at least one continuous sidewall having a lower first end and an upper second end, the lower first end bonded to the base substrate, and the optical window is hermetically or partially hermetically sealed to the cap proximate the upper second end.

16 . The laser projector of claim 1 wherein the photonic integrated circuit comprises a plurality of waveguides, each waveguide of the plurality of waveguides to receive laser light from a respective laser diode of the plurality of laser diodes.

17 . The laser projector of claim 16 , wherein each waveguide of the plurality of waveguides is optimized to receive and output laser light having a wavelength corresponding to the wavelength of laser light received from the respective laser diode.

18 . The laser projector of claim 16 wherein the plurality of waveguides comprises a waveguide combiner.

19 . The laser projector of claim 18 wherein the waveguide combiner comprises at least one of: a directional coupler, Y-branch, whispering gallery mode, or multi-mode interface coupler.

20 . The laser projector of claim 16 wherein each waveguide of the plurality of waveguides includes an input facet to receive laser light from a respective laser diode of the plurality of laser diodes and an output facet to output the received laser light, a spacing between the output facets of each waveguide being smaller than a spacing between the input facets of each waveguide.

21 . The laser projector of claim 1 wherein each input facet of the plurality of input facets is a grating input coupler.

22 . The laser projector of claim 1 wherein each input facet of the plurality of input facets is a planar region with an index of refraction lower than an index of refraction of material from which the photonic integrated circuit is formed.

Assignees

• North Inc

Inventors

• Pierer Jörg
• James Rony Jose
• Mohrdiek Stefan
• Dykaar Douglas R

Classifications

• G02B2027/0134

  of stereoscopic type · CPC title

• H01S5/02224

  the gas comprising oxygen, e.g. for avoiding contamination of the light emitting facets · CPC title

• G02B6/13

  Integrated optical circuits characterised by the manufacturing method · CPC title

• H01S5/4012

  Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms · CPC title

• G02B27/141 Primary

  using dichroic mirrors · CPC title