Development Of Narrow Linewidth Semiconductor Fiber Laser Control System

With the rapid development of laser technology,its application is more and more widely.Because of its high conversion efficiency,good beam quality,compact structure and high reliability,the semiconductor laser has a high share in the market of the laser.In recent years,the market demand of narrow linewidth fiber laser is increasing,which is widely used in the field of coherent detection,gravitational wave detection,coherent synthesis and so on.The narrow linewidth semiconductor fiber laser is more stringent than the other lasers.In this paper,a high power narrow linewidth fiber laser control system is developed.This paper introduces the working principle of narrow linewidth fiber laser diode control system development process and system and main structure,anti-jamming and so on several of the hardware circuit design,software programming and system are discussed in detail.And the system uses a modular design,the control system is mainly composed of the core control unit,the LD temperature control unit,the LD current drive unit,the host computer,etc..In order to improve the flexibility and reliability of the system design,the design of the control chip with a high degree of integration of the Plath Psoc5 LP series products.The chip integrates a large number of digital and analog devices,including A/D conversion module,D/A conversion module,comparator and programmable logic module,etc..In order to achieve high precision temperature control,LD temperature control unit uses TEC and H bridge circuit as the hardware part,and uses PID algorithm to realize the accurate closed-loop control.LD current drive unit adopts voltage controlled constant current source circuit structure to realize the current stability,and then combined with analog switch circuit structure,the drive module can work in continuous or quasi continuous state.In view of the unexpected burst and anti-jamming of the laser system,the protection circuit structure design,electromagnetic compatibility and the whole machine wiring are discussed in detail.In this paper,the prototype of the narrow linewidth fiber laser control system has been applied to the high precision measurement,laser radar and other equipment.The laser has multiple modes of operation,and through the host computer and the serial instruction,output power and output mode can conveniently and accurately control the fiber laser,in the quasi continuous mode in real time to modify the frequency and duty ratio.When the laser operating state is abnormal,the protectionsystem will generate alarm function and corresponding protection measures.Based on the analysis of optical parameters,the laser control system designed in this paper can meet the requirements of high precision control of narrow linewidth fiber lasers.Through the experiments of high and low temperature and aging,the laser control system designed in this paper can operate normally in the environment of 0-40 degrees Celsius for a long time.