Modular three-dimensional optical sensing system

Abstract

Examples of a three-dimensional (3D) optical sensing system for a vehicle include a modular architecture. Light can be transmitted to an optical signal processing module, which can include a photonic integrated circuit (PIC) that can create one or more signals with tailored amplitude, phase, and spectral characteristics. The plurality of optical signals processed by the optical signal processing module can be sent to beam steering units distributed around the vehicle. The steering units can direct a plurality of optical beams towards targets. The return optical signal can be detected by a receiver PIC including an array of sensors and using a direct intensity detection technique or a coherent detection technique. The return optical signal can be converted into an electrical signal by the array of sensors, which can then be processed by the electronic signal processing unit, and information about the location and speed of the targets can be quantified.

1 . A photonic circuit comprising:
 a focal plane array of grating couplers in two dimensions, at least one of the grating couplers being configured to receive a frequency chirped light beam and emit the frequency chirped light beam towards a refractive optical element configured to direct the frequency chirped light beam towards a target region: and   one or more optical switches configured to adjust a position of the frequency chirped light beam in the two dimensions within the target region by selecting grating couplers in the focal plane array of grating couplers.   
     
     
         2 . The photonic circuit of  claim 1 , wherein:
 the one or more optical switches are configured to select which ones of the grating couplers in the focal plane array of grating couplers are to receive light from a waveguide.   
     
     
         3 . The photonic circuit of  claim 1 , wherein:
 the focal plane array of grating couplers includes a first group of grating couplers having a first orientation and a second group of grating couplers having a second orientation different from the first orientation.   
     
     
         4 . The photonic circuit of  claim 1 , wherein:
 the one or more optical switches include a Mach Zehnder switch configured to select at least one of the grating couplers in the focal plane array of grating couplers.   
     
     
         5 . The photonic circuit of  claim 1 , wherein:
 the one or more optical switches include a ring-based switch configured to select at least one of the grating couplers in the focal plane array of grating couplers.   
     
     
         6 . The photonic circuit of  claim 1 , wherein:
 the one or more optical switches include a phase shifter configured to use a thereto-optic effect.   
     
     
         7 . The photonic circuit of  claim 1 , wherein:
 the one or more optical switches include a junction configured to operate in a depletion mode.   
     
     
         8 . The photonic circuit of  claim 1 , wherein:
 the one or more optical switches include a junction configured to operate in an injection mode.   
     
     
         9 . The photonic circuit of  claim 1 , wherein:
 the frequency chirped light beam has a wavelength in a range from 1300 nanometers to 1600 nanometers.   
     
     
         10 . The photonic circuit of  claim 1 , wherein:
 the focal plane array of grating couplers and the one or more optical switches are monolithically integrated with:
 a continuous wave light source coupler configured to provide light from a light source; 
 a splitter configured to split the light into at least a first portion and a second portion; 
 a first modulator configured to in-phase modulate the first portion of the light; 
 a second modulator configured to quadrature modulate the second portion of the light; and 
 an output coupler configured to form the frequency chirped light beam based on the in-phase modulated first portion of the light and based on the quadrature modulated second portion of the light. 
   
     
     
         11 . A method comprising:
 receiving, by at least one grating coupler in a focal plane array of grating couplers in two dimensions, a frequency chirped light beam;   emitting, by the at least one grating coupler in the focal plane array of grating couplers, the frequency chirped light beam towards a refractive optical element configured to direct the frequency chirped light beam towards a target region; and   adjusting, by one or more optical switches, a position of the frequency chirped light beam in the two dimensions within the target region by selecting grating couplers in the focal plane array of grating couplers.   
     
     
         12 . The method of  claim 11 , wherein:
 the adjusting of the position of the frequency chirped light beam includes selecting which ones of the grating couplers in the focal plane array are to is receive light from a waveguide.   
     
     
         13 . The method of  claim 11 , wherein:
 the focal plane array of grating couplers includes a first group of grating couplers having a first orientation and a second group of grating couplers having a second orientation different from the first orientation.   
     
     
         14 . The method of  claim 11 , wherein:
 the adjusting of the position of the frequency chirped light beam includes causing a Mach Zehnder switch to select at least one of the grating couplers in the focal plane array of grating couplers.   
     
     
         15 . The method of  claim 11 , wherein:
 the adjusting of the position of the frequency chirped light beam includes causing a ring-based switch to select at least one of the grating couplers in the focal plane array of grating couplers.   
     
     
         16 . The method of  claim 11 , wherein:
 the one or more optical switches include a phase shifter configured to use a thermo-optic effect.   
     
     
         17 . The method of  claim 11 , wherein:
 the one or more optical switches include a junction configured to operate in a depletion mode.   
     
     
         18 . The method of  claim 11 , wherein:
 the one or more optical switches include a junction configured to operate in an injection mode.   
     
     
         19 . The method of  claim 11 , wherein:
 the frequency chirped light beam has a wavelength in a range from 1300 nanometers to 1600 nanometers.   
     
     
         20 . The method of  claim 11 , further comprising:
 providing, by a continuous wave light source coupler, light from a light source;   splitting, by a sputter, the light into at least a first portion and a second portion;   in-phase modulating, by a first modulator, the first portion of the light;   quadrature modulating, by a second modulator, the second portion of the light; and   forming, by an output coupler, the frequency chirped light beam based on the in-phase modulated first portion of the light and based on the quadrature modulated second portion of the light.