Integrated bound-mode spectral/angular sensors
An occupancy sensor covering a wide field in an integrated chip is disclosed. The occupancy sensor includes an array of grating coupled waveguide sensors wherein continuous wave (cw) signals monitor an ambient light field for dynamic changes on times scales of seconds, and high frequency signals map in three-dimensions of the space using time-of-flight (TOF) measurements, pixel level electronics that perform signal processing; array level electronics that perform additional signal processing; and communications and site level electronics that interface with actuators to respond to occupancy sensing.
1 . A 2-D optical sensor array comprising:
a semiconductor substrate;
a plurality of pixels including at least a first pixel and a second pixel, wherein each of the pixels comprise:
a waveguide disposed on the semiconductor substrate that supports a single transverse electric (TE) and a single transverse magnetic (TM) waveguide mode;
one or more collection areas that couple incident light into the single TE and the single TM waveguide modes;
one or more transmission regions that allow propagation of the incident light that is coupled and collected in the collection area to one or more detection areas;
the one or more detection areas couples a portion of the light propagating through the one or more transmission regions to one or more detectors integrated into the semiconductor substrate;
a contact area where signals from the one or more detectors associated with the one or more pixels are collected; and
electronics for processing the signals that are collected to provide information on angular and spectral characteristics of the light incident onto one or more pixels of the plurality of pixels.
2 . The sensor array of claim 1 , wherein the one or more collection areas are structured as an array of 1-D gratings with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detector areas located perpendicular to grating lines of the array of 1-D gratings on two sides of each of the collection areas.
3 . The sensor array of claim 1 , wherein the one or more collection areas are structured as an array of 2-D rectilinear grating patterns with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detection areas located on four sides of each of the collection areas.
4 . The sensor array of claim 1 , wherein the one or more collection areas are structured as an array of 1-D gratings with different pitches and an array of different baffles above the collection areas to restrict an angular acceptance of each collection area.
5 . The sensor array of claim 2 , wherein the one or more collection area are structured as an array of 1-D gratings with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detection areas located perpendicular to grating lines of the array of 1-D gratings to both sides of each collection area, wherein the 1-D gratings are longitudinally chirped to adjust an angular/spectral coupling.
6 . The sensor array of claim 3 , wherein the one or more collection area are structured as an array of 2-D gratings with varying pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detector areas located at all four sides of the collection area, wherein the 2-D gratings are longitudinally chirped to adjust an angular/spectral coupling.
7 . The sensor array of claim 1 , wherein the one or more collection areas are structured as a curvilinear grating that focuses the light coupled into the waveguide along a propagation region.
8 . The sensor array of claim 1 , wherein the one or more collection areas are structured as a superposition of multiple curved gratings with different or varying pitches and different or varying foci providing multiple detection regions.
9 . The sensor array of claim 1 , wherein the one of more transmission regions of one or more pixels of the plurality of pixels are tapered to concentrate the light coupled into the waveguide into a single mode rectilinear waveguide portion, and wherein one or more wavelength selective add/drop filters are positioned along the single mode rectilinear portion to provide spectral information.
10 . The sensor array of claim 9 , wherein the wavelength selective add/drop filters are whispering gallery resonators.
11 . The sensor array of claim 1 , wherein:
the waveguide comprises a cladding comprising SiO 2 ;
the cladding comprising a bottom portion that has a thickness to allow low loss propagation of the light collected in the collection area and a top portion that is structured to provide coupling to incident light;
the waveguide comprises a waveguide core that comprises Si 3 N 4 ; and
the waveguide core has a thickness that allows only a single TE and a single TM mode to propagate in the transmission region.
12 . An ambient light control system comprising:
one or more ambient light sources;
a 2-D sensor array as in claim 1 ;
electronics to combine one or more detector outputs from one or more pixels of the plurality of pixels to provide angular and spectral information on ambient light incident onto the detector; and
a controller to adjust angular and spectral characteristics of the ambient light to specification.
13 . The ambient light control system of claim 12 , wherein:
each of the one or more ambient light sources broadcasts an ID at a frequency beyond human optical perception;
each of the one or more detection areas of the one or more pixels has sufficient bandwidth to resolve the IDs of the one or more light sources; and
the ID information is used to simplify the requirements on the 2-D sensor array.
14 . A method of determining information on angular and spectral characteristics of ambient light using an optical sensor array, the method comprising:
receiving incident ambient light with one or pixels of a plurality of pixels, wherein each pixel comprises a waveguide disposed on the semiconductor substrate that supports a single transverse electric (TE) and a single transverse magnetic (TM) waveguide mode; one or more collection areas that couple incident light into the single TE and the single TM waveguide mode; one or more transmission regions that allow propagation of the incident light that is coupled and collected in the one or more collection areas to one or more detection areas; the one or more detection areas that couples a portion of the light propagating through the one or more transmission regions to one or more detectors integrated into the semiconductor substrate; a contact area where signals from the one or more detectors associated with the one or more pixels are collected; and electronics for processing the signals that are collected to provide information on angular and spectral characteristics of the light incident onto one or more pixels of the plurality of pixels; and
outputting the information on angular and spectral characteristics of the light.
15 . The method of claim 14 , wherein the one or more collection areas are structured as an array of 1-D gratings with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and the one or more detection areas located perpendicular to grating lines of the array of 1-D gratings on two sides of each of the one or more collection areas.
16 . The method of claim 14 , wherein the one or more collection areas are structured as an array of 2-D rectilinear grating patterns with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detection areas located on four sides of each of the one or more collection areas.
17 . The method of claim 14 , wherein the one or more collection areas are structured as an array of 1-D gratings with different pitches and an array of different baffles above the collection area to restrict an angular acceptance of each of the one or more collection areas.
18 . The method of claim 17 , wherein the one or more collection area are structured as an array of 1-D gratings with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detection areas located perpendicular to grating lines of the array of 1-D gratings to both sides of each of the one or more collection area, wherein the 1-D gratings are longitudinally chirped to adjust an angular/spectral coupling.
19 . The method of claim 17 , wherein the one or more collection area are structured as an array of 2-D gratings with different pitches to allow coupling to different aspects of the light incident onto the one or more collection areas of one or more pixels of the plurality of pixels, and transmission regions and detection areas located at all four sides of the one or more collection areas, wherein the 2-D gratings are longitudinally chirped to adjust an angular/spectral coupling.
20 . The method of claim 14 , wherein the one or more collection areas are structured as a curvilinear grating that focuses the light coupled into the waveguide along a propagation region.