Wavelength combiner photonic integrated circuit with grating coupling of lasers

Patent metadata

Field	Value
Publication number	US-2019196197-A1
Application number	US-201816216944-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 method of manufacturing an optical engine, the method comprising:
bonding a plurality of laser diodes directly or indirectly to a base substrate; bonding a cap to the base substrate, the cap comprising at least one wall that, with the base substrate, defines 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; bonding writeable glass to the base substrate; and after bonding the writeable glass to the base substrate, writing a photonic integrated circuit into the writeable glass, the 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 plurality of input facets and wavelength multiplexes the plurality of beams of light to provide an aggregated beam of light at the at least one output facet.

2 . The method of claim 1 , further comprising:
bonding each of the laser diodes indirectly to the base substrate by bonding each laser diode to a respective chip submount; and bonding each chip submount to the base substrate.

3 . The method of claim 2 wherein bonding each laser diode to a respective chip submount comprises bonding each laser diode to a respective chip submount using a eutectic gold tin (AuSn) solder process.

4 . The method of claim 2 wherein bonding each chip submount to the base substrate comprises step-soldering each chip submount to the base substrate.

5 . The method of claim 2 wherein bonding each chip submount to the base substrate comprises bonding each chip submount to the base substrate using at least one of a reflow oven process, thermosonic bonding, thermocompression bonding, transient liquid phase (TLP) bonding, or laser soldering.

6 . The method of claim 2 wherein bonding each chip submount to the base substrate comprises bonding a chip submount that has a red laser diode bonded thereto, bonding a chip submount that has a green laser diode bonded thereto, bonding a chip submount that has a blue laser diode bonded thereto, and bonding a chip submount that has an infrared laser diode bonded thereto.

7 . The method of claim 1 , further comprising:
bonding a plurality of collimation lenses between the plurality of laser diodes and the plurality of input facets of the photonic integrated circuit, 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 the plurality of input facets of the photonic integrated circuit.

8 . The method of claim 1 wherein bonding the writeable glass to the cap comprises bonding the writable glass against at least one optical window in the cap positioned and oriented to allow beams of light emitted from the plurality of laser diodes to exit the interior volume.

9 . The method of claim 1 wherein bonding the writeable glass to the cap comprises bonding the writeable glass to the cap to form at least one optical window in the writable glass positioned and oriented to allow beams of light emitted from the plurality of laser diodes to exit the interior volume.

10 . The method of claim 1 , further comprising:
providing a coupling between at least one laser diode driver circuit and the plurality of laser diodes, in operation the at least one laser diode driver circuit selectively drives current to the laser diodes.

11 . The method of claim 10 wherein providing a coupling between at least one laser diode driver circuit and the plurality of laser diodes comprises:
bonding a plurality of electrical connections to the base substrate, each electrical connection coupled to a respective laser diode in the plurality of laser diodes;
providing a coupling between each of the plurality of electrical connections and the at least one laser diode driver circuit; and
bonding an electrically insulating cover to the base substrate over the plurality of electrical connections, wherein
bonding the cap to the base substrate comprises bonding the cap to the base substrate and the electrically insulating cover.

12 . The method of claim 11 wherein providing a coupling between each of the plurality of electrical connections and the at least one laser diode driver circuit comprises:
bonding a plurality of electrical contacts to the base substrate, each electrical contact coupled to a respective one of the plurality of electrical connections; and
providing a coupling between each of the electrical contacts and the at least one laser diode driver circuit.

13 . The method of claim 10 wherein bonding the plurality of laser diodes directly or indirectly to a base substrate comprises bonding the laser diodes directly or indirectly to a first surface of the base substrate, and bonding a cap to the base substrate comprises bonding a cap to the first surface of the base substrate, the method further comprising bonding the at least one laser diode driver circuit to a second surface of the base substrate, the second surface of the base substrate opposite the first surface of the base substrate.

14 . The method of claim 10 wherein bonding the plurality of laser diodes directly or indirectly to a base substrate comprises bonding the laser diodes directly or indirectly to a first surface of the base substrate, and bonding a cap to the base substrate comprises bonding a cap to the first surface of the base substrate, the method further comprising bonding the at least one laser diode driver circuit to the first surface of the base substrate.

15 . The method of claim 1 wherein bonding a cap to the base substrate comprises bonding a cap to the base substrate using at least one of a seam welding process, a laser assisted soldering process, or a diffusion bonding process.

16 . The method of claim 1 , further comprising:
prior to bonding the cap to the base substrate, flooding the interior volume with an oxygen rich atmosphere.

17 . The method of claim 1 , further comprising:
positioning and orienting a collimation lens to receive and collimate the aggregate beam of light from the at least one output facet of the photonic integrated circuit.

18 . The method of claim 1 , wherein laser writing the photonic integrated circuit into the writeable glass comprises laser writing a plurality of waveguides into the writeable glass, each waveguide of the plurality of waveguides being written for a respective one laser diode of the plurality of laser diodes.

19 . The method of claim 18 , wherein laser writing a plurality of waveguides into the writeable glass comprises writing a waveguide combiner into the writeable glass.

20 . The method of claim 19 , wherein writing a waveguide combiner into the writeable glass comprises writing at least one of: a directional coupler, Y-branch, whispering gallery mode, or multi-mode interface coupler.

21 . The method of claim 18 wherein laser writing a plurality of waveguides into the writeable glass comprises laser writing each waveguide of the plurality of waveguides to have 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 of the input facets

Assignees

• North Inc

Inventors

• Pierer Jörg
• James Rony Jose
• Mohrdiek Stefan
• Dykaar Douglas R
• Kiik Martin Joseph
• Haque Syed Moez

Classifications

• G02B6/124

  Geodesic lenses or integrated gratings · CPC title

• G02B6/4214

  the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device (G02B6/4246 takes precedence) · CPC title

• H04N9/3129

  scanning a light beam on the display screen (scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161) · CPC title

• G02B27/1086

  operating by diffraction only · CPC title

• H01S5/02208

  characterised by the shape of the housings · CPC title