Multi-beam optical phase array for long-range LiDAR and free-space data communication

Abstract

We present a multi-beam optical fiber phased array (OPA) with simultaneous light detection and ranging (LiDAR) and free-space optical communication (FSO) data transmission functions. The OPA component can achieve a stable phase and a high turning speed. First, the 55-element OPA is phase-locked through the stochastic parallel gradient descent (SPGD) algorithm to maintain the high light intensity of the main beam in real time. The OPA with a 5 × 11 beam array achieved a wide field of view (FOV) of 58°×32°, a single beam array steering angle of0.48°, and a steering speed of 40 MHz. Subsequently, this OPA was used to detect targets within a range of approximately 2 km, and we theoretically verified that two-dimensional coherent frequency-modulated continuous wave (FMCW) LiDAR could extract the target characteristics. In addition, a free-space optical communication link of up to 3 km was also demonstrated, with a data rate of 8 Gbps. The proposed system easily increases the array-to-MHz steering speed and yields a high-power output.