Frequency-interleaved parallel FMCW LiDAR with narrow detection bandwidth.

Frequency-modulated continuous-wave (FMCW) LiDAR enables high-precision ranging and velocity measurement through coherent detection. Parallelization based on optical frequency combs can increase imaging rate; the required detection bandwidth in conventional architectures scales proportionally with the number of channels, further imposing stringent requirements on sampling and real-time processing. Here, we propose a frequency-interleaved (FI) parallel FMCW LiDAR with narrow detection bandwidth. By exploiting the frequency sparsity of the beat signals, multi-channel beat signals are coherently detected using a single photodetector with significantly reduced detection bandwidth and interleaved within a shared spectral window. An Amplitude-Frequency-Logic-Time matching de-frequency-interleaved algorithm is further developed to identify channel-specific beat signals. In 7-channel FI parallel FMCW LiDAR experiments, the total PD electrical 3-dB detection bandwidth is only 400 MHz, and the ranging precision of 0.29 mm is achieved. The reduced bandwidth also lowers sampling requirements and computational complexity, providing a scalable approach for high-imaging-rate coherent LiDAR systems.