Techniques to compensate for variations in phase over time in LIDAR systems

A light detection and ranging (LIDAR) system comprising:

• a first detector to receive an optical beam received from the target and a local oscillator (LO) beam and generate a digitally-sampled target signal;
• a fiber delay device having a known length and coupled to the optical beam source;
• a second detector coupled to the fiber delay device to generate a digitally-sampled reference signal using a reference beam transmitted through the fiber delay device;
• and
• circuitry coupled with memory and including instructions which, when executed, cause the circuitry to:
• estimate one or more phase impairments in the LiDAR system using the digitally-sampled reference signal to produce one or more estimated phase impairments, wherein the one or more phase impairments include variations in phase over time;
• correct for the one or more phase impairments in the LiDAR system to produce one or more corrected signals;
• and
• calculate at least one of a range and a velocity of a target based on the corrected signals.

A light detection and ranging (LIDAR) system comprising:

• a first detector to receive an optical beam received from a target and a local oscillator (LO) beam and generate a digitally-sampled target signal;
• a fiber delay device having a known length and coupled to an optical beam source;
• a second detector coupled to the fiber delay device to generate a digitally-sampled reference signal using a reference beam transmitted through the fiber delay device;
• and
• a processing device coupled with memory and including instructions which, when executed, cause the processing device to:
• estimate one or more phase impairments in the LIDAR system using the digitally-sampled reference signal to produce one or more estimated phase impairments, wherein the one or more phase impairments include variations in phase over time;
• correct for the one or more phase impairments in the LIDAR system to produce one or more corrected signals;
• and
• calculate at least one of a range and a velocity of a target based on the corrected signals.