Optical coupler for LIDAR sensor
A LIDAR device for a vehicle includes an integrated chip. The integrated chip includes a substrate layer, a cladding layer, a waveguide, a scattering array, and a reflector layer. The cladding layer is disposed on the substrate layer to form an interface with the substrate layer. The waveguide is disposed within the cladding layer and configured to route an infrared optical field. The scattering array is disposed within the cladding layer between the waveguide and the interface and perturbs the infrared optical field and scatters the infrared optical field into a first beam propagating toward a surface of the cladding layer and into a second beam propagating towards the interface. The reflector layer is disposed within the cladding layer between the waveguide and the surface of the cladding layer to reflect the first beam towards the interface.
1 . A light detection and ranging (LIDAR) device for a vehicle, the LIDAR device comprising:
a cladding comprising a first surface and a second surface;
a waveguide formed in the cladding and configured to route an optical field generated from light coupled into the waveguide;
a scattering array comprising a plurality of scatterers formed in the cladding between the waveguide and the second surface, wherein the scattering array is configured to perturb the optical field and scatter the optical field into a first beam propagating toward the first surface of the cladding; and
a reflector layer disposed within the cladding between the waveguide and the first surface of the cladding, wherein the reflector layer is configured to reflect the first beam towards the second surface of the cladding.
2 . The LIDAR device of claim 1 , wherein the first beam propagating toward the first surface of the cladding contains a majority of optical power contained in the optical field.
3 . The LIDAR device of claim 1 , wherein the plurality of scatterers respectively have a parameter that is substantially uniform, the parameter comprising a thickness, a width, or a spacing of the plurality of scatterers.
4 . The LIDAR device of claim 1 , wherein the plurality of scatters respectively have a parameter that is varied respectively across the plurality of scatterers to shape the first beam to a particular shape, the parameter comprising a thickness, a width, or a spacing of the plurality of scatterers.
5 . The LIDAR device of claim 1 , wherein the scattering array is spaced apart from the waveguide by a particular spacing distance.
6 . The LIDAR device of claim 5 , wherein a strength of scattering implemented by the scattering array is controlled by the particular spacing distance and a duty factor of the plurality of scatterers.
7 . The LIDAR device of claim 1 , wherein:
the scattering array is quasi-periodic; and
the plurality of scatterers comprise silicon scatterers.
8 . The LIDAR device of claim 7 , wherein the quasi-periodic scattering array is configured to have a spacing between respective scatterers of the plurality of scatterers that is varied.
9 . The LIDAR device of claim 1 , wherein the waveguide comprises silicon nitride.
10 . The LIDAR device of claim 1 , wherein the cladding comprises an oxide that is transparent to infrared light.
11 . The LIDAR device of claim 10 , wherein the cladding comprises silicon dioxide.
12 . The LIDAR device of claim 1 , further comprising:
a substrate provided relative to the second surface of the cladding to form an interface, wherein light scattered towards the interface is at least partially reflected off of the interface to propagate toward the first surface of the cladding.
13 . The LIDAR device of claim 12 , wherein the substrate comprises silicon, and wherein the interface comprises a silicon-glass interface.
14 . The LIDAR device of claim 1 , wherein the scattering array is further configured to have a spacing between respective scatterers of the plurality of scatterers that is varied.
15 . An autonomous vehicle control system comprising:
a LIDAR device comprising:
a cladding comprising a first surface and a second surface;
a waveguide formed in the cladding and configured to route an optical field generated from light coupled into the waveguide;
a scattering array comprising a plurality of scatterers formed in the cladding between the waveguide and the second surface, wherein the scattering array is configured to perturb the optical field and scatter the optical field into a first beam propagating toward the first surface of the cladding; and
a reflector layer disposed within the cladding between the waveguide and the first surface of the cladding, wherein the reflector layer is configured to reflect the first beam towards the second surface of the cladding.
16 . The autonomous vehicle control system of claim 15 , wherein the first beam propagating toward the first surface of the cladding contains a majority of optical power contained in the optical field.
17 . The autonomous vehicle control system of claim 15 , wherein the scattering array is spaced apart from the waveguide by a particular spacing distance, and wherein a strength of scattering implemented by the scattering array is controlled by the particular spacing distance.
18 . An autonomous vehicle comprising:
a LIDAR device that includes:
a cladding comprising a first surface and a second surface;
a waveguide formed in the cladding and configured to route an optical field generated from light coupled into the waveguide;
a scattering array comprising a plurality of scatterers formed in the cladding between the waveguide and the second surface, wherein the scattering array is configured to perturb the optical field and scatter the optical field into a first beam propagating toward the first surface of the cladding; and
a reflector layer disposed within the cladding between the waveguide and the first surface of the cladding, wherein the reflector layer is configured to reflect the first beam towards the second surface of the cladding.
19 . The autonomous vehicle of claim 18 , wherein the first beam propagating toward the first surface of the cladding contains a majority of optical power contained in the optical field.
20 . The autonomous vehicle of claim 18 , wherein the LIDAR device is configured to receive a return beam that is a reflection of the first beam off of a target in an external environment.