Based on the characteristics of magneto-optical switch, such as fast switching speed, high reliability, and low cross talk, a time division multiplexing solid-state lidar based on a fiber magneto-optical switch is proposed. First, the working principle and properties of the time division multiplexing solid-state lidar based on a fiber magneto-optical switch are discussed and examined, and the performance indexes of the magneto-optical switch related to the performance of lidar are tested, including delay time, switch rising edge time, insertion loss, and return loss. Then, a time division multiplexing solid-state lidar system was constructed based on the 1 × 8 optical fiber magneto-optical switch. A time-of-flight (ToF) ranging technology was used to quickly achieve three-dimensional (3D) imaging of the lidar by switching the optical path to the fiber channel at various locations of the two-dimensional beam array. Finally, the 3D point cloud map of the measured object was built in the experiment to confirm the system's all-solid-state 3D imaging capability. The scanning frequency of 510.3 Hz and angular resolution of 0.36° are achieved, and the angular resolution is increased to 0.18° by the microjitter translation platform. The developed technique has advantages over micro-electro-mechanical system (MEMS) and optical phased array beam imaging technology, including low cost, high energy utilization, and good beam quality.
Fig. 1. Structure and imaging principle of all-solid-state lidar based on magneto-optical switch. (a) Diagram of all-solid-state time division multiplexing lidar system based on magneto-optical switch; (b) schematic of the position coordinate (dx, dy) of the optical fiber array relative to the optical axis of the lens and the spatial position coordinate (r, θ, s) of the detection target point P; (c) schematic of improving beam angular resolution by dithering the lens or fiber array
Fig. 3. Four targets (toy car model) at different distances away from the all-solid-state time division multiplexing lidar system based on magneto-optical switch are sensed. (a) Photo of the experiment showing four toy cars placed 1.93, 3.25, 4.54, 5.46 m, respectively, away from the lens; (b) time domain relation diagram of echo signal and reference signal of four toy cars in different positions; (c) 3D point cloud of four toy cars in different positions (total of 8 detection points)
Fig. 4. Three-dimensional sensing of cube box sensed by all solid-state time division multiplexing lidar system based on magneto-optical switch. (a) Photo of the experiment showing cube box 3D imaging; (b) 3D point cloud of cube box
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