Grating waveguide combiner for optical engine

A method of manufacturing an optical engine, the method comprising:

• bonding a plurality of laser diodes directly or indirectly to a base substrate;
• coupling at least one laser diode driver circuit to the laser diodes, in operation the at least one laser diode driver circuit selectively drives current to the laser diodes;
• bonding a plurality of collimation lenses to the base substrate proximate the plurality of laser diodes;
• bonding a cap comprising at least one wall and at least one optical window to the base substrate, the at least one wall, the at least one optical window, and at least a portion of the base substrate together delimit an interior volume sized and dimensioned to receive at least the plurality of laser diodes and the plurality of collimation lenses, the bonding of the cap to the base substrate providing 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 light emitted from the laser diodes through the collimation lenses to exit the interior volume;
• and
• bonding a grating waveguide combiner proximate the optical window of the cap, the grating waveguide combiner comprising a plurality of input grating couplers and at least one output grating coupler, in operation, the grating waveguide combiner receives a plurality of beams of light at the respective plurality of input grating couplers and combines the plurality of beams of light to provide a collimated aggregated beam of light at the output grating coupler.