Techniques for fmcw lidar system descan compensation

A method of light detection and ranging (LiDAR), comprising:

• emitting an optical beam by an optical source;
• transmitting, by a first optical lens, the optical beam to an optical window;
• reflecting a first portion of the optical beam, by the optical window, to generate a local oscillator (LO) signal, comprising disposing the LO signal to be decentered from an optical axis of an optical system on a second optical lens in front of a photodetector (PD) to increase a percentage of an overlap of the LO signal and the target return signal on the PD;
• transmitting a second portion of the optical beam to a target to scan the target to generate a target return signal;
• and
• mixing, by the PD, the target return signal with the LO signal to extract range and velocity information of the target.