Optical phased array (OPA) is a suitable device for producing emission beams in LiDAR. In order to achieve high-speed scanning control of the output beam by OPA chips, we designed and produced a 128-channel silicon-based OPA chip based on electro-optic modulation. Considering the characteristics of multi-phase control in electro-optic OPA chips, a parallel dual-port random access memory (RAM) inside a field programmable gate array (FPGA) technology is used to achieve optical phase control for each channel. The entire system is implemented by existing FPGA chips and digital-to-analog converters (DACs). To implementing the circuit system, we also built a high-speed testing environment for OPA scanning. The system was used to verify the main performance of our designed OPA chip and achieve high-speed scanning control. The test results show that our designed OPA chip and control circuit can achieve fast scanning of the emission beam. The optical phase configuration time is less than 5 μ s. This system can meet the requirements of fast scanning control for all solid-state LiDAR optical emission modules. This work lays the foundation for our subsequent development of OPA-based all solid-state LiDAR prototype.

Optical communication modulation technology and networking technology are two important technologies for constructing free-space optical (FSO) communication. In this paper, pulse width modulation (PWM) is used to realize free-space optical communication. The process of signal modulation and demodulation is implemented by means of a field programmable gate array (FPGA). An optical communication relay system is constructed to realize communication networking. The binary data bits in the communication process are converted into pulse signals of different widths, the data demodulation process is realized by sampling with a high-speed analog-to-digital converter (ADC), the data level is determined by counting the proportion of high and low voltages sampled in a pulse period. The relay system analyzes the routing target after receiving the pulse signal from the transmitter, and then sends the data to the target receiver. The experimental results show that the constructed system can achieve point-to-multipoint free-space optical communication. Additionally, using ADC to demodulate the received signal increases the stability of the free-space optical communication system. This system provides the design prototype system of FSO communication networking technology.

The pulse laser emission circuit plays a crucial role as the emission unit of time-of-flight (TOF) LiDAR. This paper proposes a nanosecond-level pulse laser diode array drive circuit for LiDAR, primarily aimed at addressing the issue of high-speed scanning drive for the laser diode array at the emission end of solid-state LiDAR. Based on the single pulse laser diode drive circuit, this paper innovatively designs a circuit that includes modules such as a boost circuit, linear power supply, high-speed gate driver, GaN field-effect transistor, and pulse narrowing circuit, realizing an 8-channel laser diode array drive circuit. This circuit can achieve a pulse laser array drive with a single channel operating frequency of greater than 100 kHz, an output pulse width of less than 5 ns, a peak power greater than 75 W, and a channel switching time that does not exceed 1 μs. A field programmable gate array (FPGA) is used to control the operation of this circuit and perform a series of performance tests. Experimental results show that this circuit has a high repetition rate, large output power, a narrow pulse width, and fast switching speeds, making it highly suitable for use in the optical emission module of solid-state LiDAR.

Frequency Modulated Continuous Wave (FMCW) Light Detection and Ranging (LiDAR) has received extensive attention, owing to its high robustness and accuracy, and its extensive applications in the automotive and robotics domains. However, mainstream demonstrations predominantly rely on high-performance yet expensive instrumentation, which poses a significant barrier to the widespread manufacturing of FMCW LiDAR systems. In this study, we introduce a novel Laser Frequency Modulation and Beat Signal Processing module (LFM-BSP) realized on a Field Programmable Gate Array (FPGA). The LFM-BSP is distinguished by its full functionality, encompassing all essential electronic operations required by FMCW LiDARs. The LFM-BSP adopts pre-distortion approach to generate linear modulation waveform of nonlinear laser source. Utilizing the waveform, a fully functional, standalone FMCW LiDAR prototype was developed based on the LFM-BSP. The prototype incorporates a 2-axis galvanometer to facilitate beam steering. Simultaneous ranging and velocimetry experiments were performed, resulting in ranging and velocimetry precision of 0.011 m and 0.059 m/s, respectively. Furthermore, the prototype’s capability in 4D point cloud imaging was evaluated. The results suggest that the LFM-BSP is highly suitable for automotive LiDAR applications, thereby offering a practical framework for the development of next-generation monolithic FMCW LiDAR systems.

A shortwave infrared Ge–Si photodetector will become the core device of the LiDAR optical receiver. In order to meet the urgent demand for photodetectors in the LiDAR field, we designed and produced a 32 × 32-pixel Ge–Si photodetector array, which was proposed and developed to meet the performance requirements of the detector array. A dark current detection system for fast scanning and detecting large-scale Ge–Si detector arrays was proposed and developed to achieve the rapid detection of dark current in each detector pixel, with a detection accuracy of less than 1 nA. The system validated the primary performance indicators of the detector array we designed, achieving rapid discrimination of the array performance and rapid localization of damaged pixels. The scanning test results showed that the average dark current of the designed detector array chip was on the nanoampere level, and the proportion of bad points was less than 1%. The consistency of the array chip was high, which meets the requirements of light detection at the receiving end of LiDAR. This work laid the foundation for our subsequent development of a LiDAR prototype system.

In this work, a regulated-voltage biasing configuration is proposed for the Ge-on-Si avalanche photodiode (APD) structure. This design incorporates an extended n-charge layer to decrease the breakdown voltage and optimizes the absorption region thickness to reduce the electron transit time. By applying three electrodes to individually modulate the electric fields in the absorption and avalanche region, respectively, both of low avalanche breakdown voltage (−8.1 V) and high bandwidth (20.4 GHz) of the surface-illuminated detector can be achieved. Meanwhile, the sensitivity of weak light detection is improved to −45 dBm. The responsivity of the APD is 60.76 A/W at 1550 nm when the voltage is biased at −13.5 V. The low voltage and improved bandwidth can meet the requirements for weak light detection and other applications demanding such sensitivity.