Directly written waveguide for coupling of laser to photonic integrated circuit

A wearable heads-up display (WHUD), comprising:

• a support structure that in use is worn on the head of a user;
• a laser projector carried by the support structure, the 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;
• a photonic integrated circuit bonded to the base substrate proximate the optical window of the cap, 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 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
• a waveguide medium disposed between the optical window of the cap and the photonic integrated circuit, the waveguide medium comprising at least one directly written waveguide that is operative to couple the plurality of beams of light emitted by the plurality of laser diodes from the optical window of the cap to the input facets of the photonic integrated circuit;
• 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.