Multiple laser, single resonator lidar

Abstract

Various technologies described herein pertain to multiple laser, single optical resonator lidar systems. A lidar system includes a single optical resonator optically coupled to at least a first laser and a second laser. The optical resonator is formed of an electrooptic material. The first laser and the second laser are optically injection locked to the optical resonator. Moreover, a modulator applies a time-varying voltage to the optical resonator to control modulation of an optical property of the electrooptic material, which causes the first laser to generate a first frequency modulated optical signal comprising a first series of optical chirps and/or the second laser to generate a second frequency modulated optical signal comprising a second series of optical chirps. Further, front end optics transmits at least a portion of the first frequency modulated optical signal and/or the second frequency modulated optical signal into an environment from the lidar system.

What is claimed is: 
     
         1 . A lidar system, comprising:
 a first laser;   a second laser;   an optical resonator that is optically coupled to both the first laser and the second laser, the optical resonator being formed of an electrooptic material, wherein the first laser and the second laser are optically injection locked to the optical resonator;   a controller configured to selectively control operating states of the first laser and the second laser such that one of:
 the first laser is enabled and the second laser is disabled; 
 the first laser is disabled and the second laser is enabled; or 
 the first laser and the second laser are concurrently enabled; 
   a single modulator configured to apply a time-varying voltage to the optical resonator, the time-varying voltage controls modulation of an optical property of the electrooptic material, the modulation of the optical property causes:
 the first laser to generate a first frequency modulated optical signal comprising a first series of optical chirps when the first laser is enabled; and 
 the second laser to generate a second frequency modulated optical signal comprising a second series of optical chirps when the second laser is enabled; 
   a beam combiner configured to output an outputted frequency modulated optical signal based on the first frequency modulated optical signal when the first laser is enabled and the second frequency modulated optical signal when the second laser is enabled; and   front end optics configured to transmit at least a portion of the outputted frequency modulated optical signal into an environment from the lidar system.   
     
     
         2 . The lidar system of  claim 1 , the beam combiner configured to combine the first frequency modulated optical signal and the second frequency modulated optical signal to form the outputted frequency modulated optical signal when the first laser and the second laser are concurrently enabled. 
     
     
         3 . The lidar system of  claim 1 , the beam combiner configured to output the first frequency modulated optical signal as the outputted frequency modulated optical signal when the first laser is enabled and the second laser is disabled. 
     
     
         4 . The lidar system of  claim 1 , the beam combiner configured to output the second frequency modulated optical signal as the outputted frequency modulated optical signal when the first laser is disabled and the second laser is enabled. 
     
     
         5 . The lidar system of  claim 1 , the controller configured to selectively control the operating states of the first laser and the second laser based on a desired power level of the lidar system for a given time period, wherein the power level of the lidar system is based on a number of lasers concurrently enabled during the given time period. 
     
     
         6 . The lidar system of  claim 1 , the optical resonator is a whispering gallery mode (WGM) resonator. 
     
     
         7 . The lidar system of  claim 1 , the first laser and the second laser operate at a substantially similar wavelength. 
     
     
         8 . The lidar system of  claim 1 , the first laser operates at a first wavelength and the second laser operates at a second wavelength, wherein the first wavelength differs from the second wavelength. 
     
     
         9 . The lidar system of  claim 1 , the first laser and the second laser operate at one of 905 nm, 1550 nm, or 3 μm. 
     
     
         10 . The lidar system of  claim 1 , further comprising:
 a beam splitter configured to split the outputted frequency modulated optical signal into the portion of the outputted frequency modulated optical signal to be transmitted into the environment from the lidar system and a local oscillator portion of the outputted frequency modulated optical signal.   
     
     
         11 . The lidar system of  claim 10 , wherein:
 the front end optics further configured to receive a reflected optical signal, the reflected optical signal corresponds to at least a part of the portion of the outputted frequency modulated optical signal that reflected off an object in the environment;   the lidar system further comprises:
 a sensor configured to mix the reflected optical signal with the local oscillator portion of the outputted frequency modulated optical signal; and 
 processing circuitry that is configured to compute distance and velocity data of the object based on the reflected optical signal mixed with the local oscillator portion of the outputted frequency modulated optical signal. 
   
     
     
         12 . The lidar system of  claim 1 , further comprising:
 a photonics integrated circuit, wherein at least the first laser, the second laser, and the optical resonator are integrated on the photonics integrated circuit.   
     
     
         13 . The lidar system of  claim 1 , the optical property of the electrooptic material comprises an index of refraction. 
     
     
         14 . The lidar system of  claim 1  being included in an autonomous vehicle. 
     
     
         15 . A method of operating a lidar system, comprising:
 selectively enabling or disabling a first laser of the lidar system and a second laser of the lidar system such that at least one of the first laser or the second laser is enabled;   applying a time-varying voltage to an optical resonator of the lidar system, the time-varying voltage being applied to the optical resonator by a single modulator of the lidar system, the optical resonator being optically coupled to both the first laser and the second laser, the optical resonator being formed of an electrooptic material, the first laser and the second laser are optically injection locked to the optical resonator, the time-varying voltage controls modulation of an optical property of the electrooptic material;   forming an outputted frequency modulated optical signal based on a first frequency modulated optical signal comprising a first series of optical chirps generated by the first laser when enabled and a second frequency modulated optical signal comprising a second series of optical chirps generated by the second laser when enabled; and   transmitting at least a portion of the outputted frequency modulated optical signal into an environment from the lidar system.   
     
     
         16 . The method of  claim 15 , wherein forming the outputted frequency modulated optical signal comprises:
 combining the first frequency modulated optical signal and the second frequency modulated optical signal to form the outputted frequency modulated optical signal when the first laser and the second laser are concurrently enabled;   outputting the first frequency modulated optical signal as the outputted frequency modulated optical signal when the first laser is enabled and the second laser is disabled; and   outputting the second frequency modulated optical signal as the outputted frequency modulated optical signal when the first laser is disabled and the second laser is enabled.   
     
     
         17 . The method of  claim 15 , wherein the first laser and the second laser are selectively enabled or disabled based on a desired power level of the lidar system for a given time period, wherein the power level of the lidar system is based on a number of lasers concurrently enabled during the given time period. 
     
     
         18 . The method of  claim 15 , wherein the first laser and the second laser operate at a substantially similar wavelength. 
     
     
         19 . An autonomous vehicle, comprising:
 a lidar system, comprising:
 a first laser; 
 a second laser; 
 an optical resonator that is optically coupled to both the first laser and the second laser, the optical resonator being formed of an electrooptic material, wherein the first laser and the second laser are optically injection locked to the optical resonator; 
 a controller configured to selectively control operating states of the first laser and the second laser such that one of:
 the first laser is enabled and the second laser is disabled; 
 the first laser is disabled and the second laser is enabled; or 
 the first laser and the second laser are concurrently enabled; 
 
 a single modulator configured to apply a time-varying voltage to the optical resonator, the time-varying voltage controls modulation of an optical property of the electrooptic material, the modulation of the optical property causes:
 the first laser to generate a first frequency modulated optical signal comprising a first series of optical chirps when the first laser is enabled; and 
 the second laser to generate a second frequency modulated optical signal comprising a second series of optical chirps when the second laser is enabled; 
 
 a beam combiner configured to output an outputted frequency modulated optical signal based on the first frequency modulated optical signal when the first laser is enabled and the second frequency modulated optical signal when the second laser is enabled; and 
 front end optics configured to transmit at least a portion of the outputted frequency modulated optical signal into an environment from the lidar system; and 
   a computing system, comprising:
 a processor; and 
 memory that comprises computer-executable instruction that, when executed by the processor, cause the processor to perform acts comprising:
 transmitting a control signal to the lidar system to cause the controller to selectively control the operating states of the first laser and the second laser. 
 
   
     
     
         20 . The autonomous vehicle of  claim 19 , wherein the first laser and the second laser are selectively enabled or disabled based on a desired power level of the lidar system for a given time period, wherein the power level of the lidar system is based on a number of lasers concurrently enabled during the given time period.