Research On Bwt-K85S06M Laser Drive Technology

Beacon light source plays an important role that cannot be ignored in the laser communication transmitting system, so the design of its drive circuit is also of great importance, which relates to the quality of whole communication system.The main job of this paper is to design drive circuit for BWT-K85S06M laser diode, beacon light source of Laser Communication Project, mainly including the temperature control circuit and power control circuit, the automatic control of which is conducted by the microcontroller. First the principle and characteristics of semiconductor LD and the related drive theory are analyzed, and the temperature factor is discussed that may lead to the fluctuation of laser output power, threshold current and wavelength, and the relationship between them is also discussed; then according to the requirements of laser communication project for beacon light source, we respectively design the temperature control circuit, power control circuit and the necessary protection circuit. With the digital PID algorithm, we use single-chip microcomputer software programming method to realize temperature compensation, which has made the temperature tend to be constant. With the application of negative feedback technology, the stability of constant current source has been ensured. Through the numerical control technology, the controlled variables are calculated by the single chip microcomputer, which has realized that laser drive current and output power are adjusted directly by the digital potentiometer. By the test, it turns out that the drive circuit has met the requirements of beacon light source in the laser communication project.