SEARCH LiDAR: single-emitter-and-receiver CDMA-Hadamard LiDAR for parallel ranging

We propose and experimentally demonstrate a cost-efficient and scalable LiDAR architecture that enables hybrid solid-state parallel ranging using a single emitter and receiver. The system integrates code-division multiple access (CDMA) temporal modulation with Hadamard matrix-based spatial encoding, forming a dual-modulation framework referred to as SEARCH LiDAR (single-emitter-and-receiver CDMA-Hadamard LiDAR). To address the limitations of conventional mechanical scanning and costly parallel systems, we first implement a hybrid solid-state scanning method via wavelength tuning and CDMA encoding. Building upon this, we realize parallel ranging by introducing a secondary spatial modulation layer using an S-matrix (a type of binary Hadamard matrix). Experimental results confirm the feasibility of the 1D SEARCH LiDAR concept and further suggest a future extension toward fully solid-state 2D scanning using optical switch-array devices. 3D imaging under varying noise conditions demonstrates the superior robustness of the proposed system, particularly in low SNR, due to the combined benefits of CDMA and Hadamard encoding. This work provides a practical path toward low-cost, high-performance LiDAR suitable for next-generation autonomous perception systems.