Hybrid FMCW LiDAR System With Nonlinearity-Corrected MEMS-VCSEL for Extended 3D Imaging Range

Nonlinear laser frequency sweep and limited laser coherence length in micro-electro-mechanical-systems based vertical-cavity surface-emitting laser (MEMS-VCSEL) pose significant challenges for developing high-performance and long-distance three-dimensional (3D) imaging frequency-modulated continuous- wave (FMCW) light detection and ranging (LiDAR). Herein, we present a hybrid FMCW LiDAR system using a nonlinearity-corrected MEMS-VCSEL, featuring an ultra-wide tuning range of 7.76 nm and an extremely fast tuning rate of 38.49-GHz/µs, to address these issues. An effective and efficient digital pre-distorter, combining a single neuron and an incremental proportional integral derivative (PID) controller, corrects the nonlinearity, achieving a relative residual nonlinearity of 0.14% in just 5 iterations. Relying on the incoherent detection of the laser amplitude-modulated by a triangular frequency-chirped pulse-like train signal, the system extends the 3D imaging range to 10 m, significantly beyond the laser coherence length of 3.28 m, achieving 100 × 200-pixel 3D imaging with a precision better than 60 mm. Within the laser coherence length, the system still operates in coherent detection, capturing targets with 79 × 200 pixels and providing sub-millimeter-level lateral resolution and millimeter-level axial resolution, with a 3D imaging precision better than 24 mm. This work unveils a novel approach for breaking laser source limitations, advancing the design of high-performance and long-distance 3D imaging FMCW LiDAR.