The Design And Implementation Of Low Noise High Stability Diode Laser Current Source

With the development of laser technology, semiconductor laser (LD) is widely usedin scientific research、medical、communications、defense and other fields because of itshigh conversion efficiency, good color, easy integration, ease of modulation equaladvantages. LD is a semiconductor laser which use current injection as an incentive, itsoperating characteristics and service are largely determined by the reliable laser drivepower. The traditional constant current source is often used linear regulation and analogcontrol, which make the current source low conversion efficiency、anti-interference abilityis poor、poor reliability、and unable to provide intelligent man-machine interface. A lownoise and high stability diode laser drive current source have been described, which isdeveloped according to the operating characteristics of the laser.Firstly, in order to improve the intelligence and controllable of the system, wepropose the use of C8051F021microcontroller as the control core. During the workingprocess there is software to replace some of the hardware implementation the functions,reduce the amount of hardware, increase of integration, and make the whole system moreflexible and easy to modify.Secondly, we have designed hardware circuit of the system. The circuit design usinga top-down modular design method, the entire circuit is divided into the power circuit、constant current drive circuit、data acquisition circuit、protection circuit, microcontrollerperipheral interface circuit and other circuits.Thirdly, we have designed software of the system. The software design mainlyincluding system initialization、to achieve the drive of the semiconductor laser by usingPWM increase their own less、realization of the A/D converter、to achieve data transfer byusing IIC communication, etc. In order to prevent excessive current or excessive voltagecaused LD damage, in the software design process keep real-time monitoring of theoperating current and operating voltage when during the LD working process, we alsotake preventive measures to against program runaway and crash.Finally, we do a series tests to our successful development current source. Mainly contains the power supply ripple test、current source frequency response test、currentsource noise test and current source stability test. Experiments show that the design of thecurrent source achieved a good effect in the application.