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.

In this paper, a method of generating true random numbers obeying multiple distribution characteristics is proposed. First, two resistance-capacitance (RC) self-excited oscillation circuits are used to generate two jittered, periodically unstable square wave signals, and then a high-precision and high-frequency quartz crystal oscillator is used to sample and measure these two jittered signals to obtain their periods. Due to the randomness of the external environment, there is Gaussian white noise in the circuit, so the periods of these two signals are random variables subject to the Gaussian distribution. Finally, we use a field-programmable gate array (FPGA) to perform secondary processing on these two random signals, which can generate true random number sequences that conform to the distribution characteristics of Gaussian distribution, Poisson distribution, 0-1 distribution, uniform distribution, etc. The random numbers generated by the circuit can be applied to the field of intelligent control related to automatic control and machine learning. This method uses a physical entropy source to generate high-quality true random sequences, which are easy to build, low in circuit cost, and small in size. The experimental results show that the method is low-cost, highly reliable and easy to integrate, providing an effective solution for the generation of true random numbers in electronic systems.

In order to improve the accuracy of pulse laser ranging based on time-of-flight (TOF), this paper proposes a laser ranging method based on double threshold echo pulse prediction correction. By using two high-speed comparators with different thresholds to detect the pulse-echo signal, the initial TOF, pulse width, and edge rate can be obtained. These three parameters are combined with statistical functions to accurately predict the peak position of the echo pulse and obtain the corrected TOF. Finally, the accurate measurement distance is calculated. In the aspect of improving ranging accuracy, this method overcomes the shortcoming that the traditional TOF pulse laser rangefinder has large errors in measuring targets with different reflectivity. This method only uses two high-speed comparators and a monostable trigger more than traditional TOF laser ranging systems. Adding these simple circuits can greatly improve the accuracy of laser ranging. The system structure is simple and the cost is low. Experimental results show that this method can achieve accurate distance measurement, and the measurement error is significantly reduced. This method can greatly improve the performance of the TOF laser rangefinder.

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.