Research On Driving And Control Technology Of Optical Phased Array All-solid-state Lidar

Chip-based optoelectronic integrated OPA(optical phased array)can realize laser beam scanning without any mechanical rotating parts.It is a new beam pointing control technology.The research and development of all-solid-state radar technology based on OPA are not only widely used in the civil field,but also of great significance in the military field.At present,the research on OPA chip design and OPA solid-state lidar abroad has reached the stage of the optical path and circuit integration,while China is still in the stage of theoretical research and optical path design exploration of OPA,and the gap is very huge.The research of this paper is of great significance to break through the core technology of OPA all-solid-state lidar and seize the commanding height of domestic lidar.This paper focuses on a series of OPA chips developed by us to design the corresponding driving and control circuits,build the silicon-based OPA all-solid-state lidar system,and carry out the following research work:1.According to the working principle of OPA,the corresponding driving and control circuit is developed to drive the OPA chip for high-speed and wide-range angle scanning.According to the characteristics of optical phase control of multi-channel OPA chip,a method using FPGA(field-programmable gate array)internal parallel RAM(random access memory)array technology is proposed to realize the rapid control of the optical phase of each channel of OPA.The circuit adopts the existing integrated circuit chip and FPGA,and the phase configuration time is no more than 8?s.The control speed is the fastest in the known literature,which can meet the phase configuration speed requirements of thermal optical and electro-optical OPA.The system is used to verify the main performance indexes of our OPA chip.The system has high universality and strong scalability and meets the requirements of high-speed scanning of OPA all-solid-state lidar.2.A pulse-phase laser ranging method based on FPGA digital mixing is proposed.Combined with a single FPGA chip and a simple laser transmitting and receiving circuit,the accurate laser ranging based on a purely digital system is realized.The system has the advantages of simple structure,low cost,and easy system integration and implementation.Compared with the pulse laser ranging method using commercial TDC(time to digital converter)chip,the ranging error is significantly reduced(the error is increased from 5cm to 3cm),and the accuracy is significantly better than that of commercial TDC chip.This method can be applied to the scanning and imaging of laser radar to obtain high-precision ranging data.3.In order to further improve the accuracy of pulse laser ranging,a pulse laser ranging method based on echo delay trigger is proposed.The echo signal is delayed by a simple delay unit.In a fixed time window,the delay pulse triggers the laser transmitter to generate pulses in turn.At the same time,the counter records the number of echoes received in the time window,and finally calculates the actual distance.In terms of improving ranging accuracy,this method overcomes the difficulty that traditional TOF(time of flight)laser ranging requires high time resolution TDC.This method can be realized by using one FPGA,delay unit,and simple laser transmitter and receiver.The system structure is simple and the cost is low.The measurement error of this method is within 5mm,which improves the accuracy of pulse laser ranging from centimeter level to millimeter level.When this method is applied to the lidar system of static target measurement,the depth image with millimeter accuracy can be obtained.4.A method of realizing laser ranging and communication simultaneously based on DPIM(dual pulse interval modulation)is proposed.This method realizes laser ranging and communication simultaneously for the first time.In the communication process,the transmission of the binary data bits is realized by continuously sending two laser pulses.The time interval of double pulses is used to characterize the value of this bit,and then the laser ranging is realized according to the TOF principle.This method enables the lidar to have the communication function at the same time and can be applied to the field of “vehicle dialogue” and lidar anti-jamming.It provides an effective solution for the popularization of lidar and the application of multiple lidars on the same occasion.5.OPA chip is used as a scanning element to realize space multi-target optical communication.By controlling the optical phase of the OPA chip,the rapid scanning of the outgoing beam and accurate aiming of different receiving targets are realized.DPIM technology is used to input the double pulse laser signal with data information into an OPA chip to realize information transmission with multiple receiving targets.The experimental results show that the system can realize the rapid and accurate aiming of communication targets,and can transmit information to targets in different positions without distortion.The system is used to realize OPA lidar space communication networking and solve the technical problem of "one to many" space optical communication.6.Combine OPA scanning driving technology,laser ranging technology,and imaging technology,realize the integration of OPA all-solid-state lidar,finally realize the lidar imaging function,and realize the design and development of OPA solid-state lidar prototype.