Optical Integrated Sensing and Communication Lidar Based on RBPSK-FMCW Joint Waveform and Optical Phased Array

Optical integrated sensing and communication (ISAC) Light detection and ranging (Lidar) has attracted significant attention as a promising complement to radio frequency ISAC Radar in next-generation wireless networks. However, existing solutions suffer from critical tradeoff between Lidar waveform and communication modulation, resulting in low data rate and insufficient sensing capability. Meanwhile, the integration and scanning range of system are severely restricted by discrete optical devices. Hereby, this study addresses these challenges by developing a novel ISAC Lidar system based on RBPSK-FMCW joint waveform and silicon photonics optical phased array (OPA) chip. Firstly, a reduced BPSK (RBPSK) based phase-noise reduction method is proposed for frequency modulated continuous wave (FMCW) joint waveform design to effectively alleviate the adverse phase-noise impact on beat signal induced by the conventional BPSK. Secondly, a pilot strategy of segmented modulation is also proposed to enable accurate signal synchronization for the data demodulation. Through the RBPSK FMCW waveform design, both precise target detection and high speed optical wireless communication (OWC) can be achieved. Thirdly, a silicon-based integrated OPA with non-uniform-width waveguide array design is employed to eliminate the optical crosstalk and grating lobes, thereby expanding the scanning range of ISAC Lidar system. Experiment results show that simultaneous distance and velocity measurements, as well as OWC at different steering angles are demonstrated, achieving a maximum data rate of 14.4 Gbps, signal-to-noise ratio (SNR) of 18.03 dB and distance resolution of 1.496 cm over a 21-m free-space optical transmission.