| The characteristic absorption of methane is an effective method to measure the concentration of methane. In this method, A tunable laser is needed to trace the absorption peak of methane, Distributed Feedback Laser is one of the tunable lasers. In order to match the wavelength of laser to the absorption peak of methane, it is very important to make research on current drive and temperature control of DFB laser. At present, temperature controllers and current drivers are mostly separated, their functions are quite perfect, but they are expensive, the ratio of performance to price is cheaper In order to improve their performance and reduce their price, the DFB laser drive and temperature control system have been developed in dissertation. The structure of the system is simple, the current driver and temperature controller are united together. The system can meet the requirement of methane concentration measurement.Based on the principle of DFB Laser, this paper first analyzes many factors which affect the stability of DFB Laser, then discusses in detail the significance and theoretic basis of designing the current driver and temperature controller system; Finally, designs circuit driver and temperature controller system of DFB Laser, compiles corresponding processing and display software, and obtains some experiment results. The results indicate that driver and temperature controller system works reliably.In the design of DFB laser driver, LSCI (max3669) was adopted, the protective circuit was added; As for design of temperature controller of DFB laser, we adopt Platinum thermometer as temperature sensor, select the thermoelectric cooler (TECI-12704) as conduct device (LSCI (max1969) controlled the thermoelectric cooler instrument. In addition, the temperature data collecting and analyzing system were designed. The system samples temperature control data at 10Hz sampling frequency, then saves, analyses, and processes the data, finally, gets respond waveform of system. |
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