The Research Of High-Power Semiconductor Laser Diode Driving And Controlling Technology

With the rapid development of science and technology, the techniques of semiconductor laser diode had been applied widely in many fields such as industry, high tech and science research. Semiconductor laser diode has the excellent character of high efficiency, small size, low weight, high reliability, direct modulation, but semiconductor laser diode is a kind of device with high power density and sky-high quantum efficiency. Even weak drive current and temperature change will lead to its large change of output light power and device parameters, which directly damages the safe use of laser diode. At the same time, semiconductor laser diode is very sensitive to the temperature. The fluctuation of surrounding temperature not only leads to the fluctuation of supply current, but also makes threshold current, quantum efficiency, output wavelength and output light intensity of the laser diode change greatly. Thus higher request to the laser diode controller is put forward. Nowadays, there are two ways to improve the performance of LD. One is to improve the self device parameter of LD by new semiconductor technology. Another is to improve the performance of LD controller. The control precision of traditional laser diode controller is very low, and the operation is difficult, and cannot shift between constant current mode and constant power mode. However, the laser diode controller designed in this paper overcomes these disadvantages above, and possesses vivid technical advantage.A new 2.5A LD driver has been studied and designed. It includes constant current control, constant power control and modulation control etc. In the operate mode of constant current, the electronic negative feedback circuit is applied, which provides a effective control of output current. Thereby, the lowest current deviation and the highest output current stability are obtained. In the operate mode of constant optical power, it is hard to realize a good control of work temperature because of the change of output current. So a photodiode or other detector must be connected with the feedback circuit to control the driving current. Otherwise, 3 protective circuits (time-delay soft-start protective circuit, power-on impulse protective circuit, limit-current protective circuit) are designed to ensure LD to work efficiently, stably and chronically.In order to measure the stability of output current expediently, an automatic test system based on GPIB is designed. Its hardware is controlled by computer with GPIB and SCPI. And the software adopts VB as design flat. The whole program design is based on modular structure. The GPIB interface standard and the program control method of DMM (M2000) are introduced. Then the component modules– the program interface, rapid measurement module, continuous measurement module, storing data module and errors notice module– of the software system are set forth in detailed, focus on program manner, program flow chart and the main features etc. It is very convenient to measure and analyze the coherent data. And it is also a foundation for designing a higher precision and stability LD controller.Semiconductor laser diode is very sensitive to the temperature. The fluctuation of surrounding temperature not only leads to the fluctuation of supply current, but also makes threshold current, quantum efficiency, output wavelength and output light intensity of the laser diode change greatly. In order to ensure LD to work at the highest efficiency and the lowest power fluctuation, a new constant-temperature controller has been studied and designed. It can provide a precise and adjustable work temperature. And it includes six major components, which are voltage reference circuit, temperature measuring circuit, subtracter circuit, PID control circuit and TEC drive circuit. Its major feathers are as follows: 1. Range of control temperature is -15℃-+80℃; 2. Temperature control precision is 0.1℃; 3. short term stability is 0.02℃; 4. Long term stability is 0.05℃; 5. TEC two-way output current is±2.5A; 6. The maximum output voltage range in constant current mode is±8V; 7. The maximum power is 20W; 8. The range of limiting current is 0-2500mA. In addition, to profound research the process of control temperature in theory, the heat transport system model of constant temperature is designed and analyzed in theory.From the development trend of the semiconductor laser pulse driver to look that, the drive technology develops towards the recurrence rate to change high, the power output increases, the response time reduces, the pulse width more and more narrow direction. As a result of the LD pulse drive only then the minimum junction heating effect, speaking of many LD applications, the pulse drive type also is must. Therefore, one kind of new pulse type laser actuation power source is studied and designed. The circuit includes the ultra short pulse circuit, the pulse combs circuit, the VMOS field effect tube power enlargement circuit and the periphery auxiliary circuit. The design key point is the narrow pulse production and the switch current enlargement. The simulation experiment indicated that, output pulse rising time tr is3.458nS, fall time tf is 9.398nS, pulse width tw is 26.868nS, the output current may achieve 5.6A, and the pulse frequency is in 500Hz-50KHz adjustable continuously.The prime task in this paper is unifies the national natural sciences fund (No.60372061) project"the supervelocity initiative mode locking optical fiber laser really self-starting and investigation into stability"and the Jilin Province science development plan project (No.20040520-2)"the supervelocity initiative mode locking optical fiber laser pattern control and the investigation into stability"to complete. The paper content involves the various knowledge, including electricity, optics, and semiconductor refrigeration technology and so on, as well as negative feedback control and PID control theory. The paper research results have the positive sense to the semiconductor laser widespread application. It has solved the key question which exists in the semiconductor laser application. The practical application indicated the LD controller may guarantee the laser reliably works safely, has merit of high stable output and strong antijamming ability.