Research And Realization Of Pulse-DFB Laser Driver Circuit Based On FPGA

The With the continuous development of semiconductor laser technology,in which the DFB distributed feedback laser has been more widely used.DFB lasers biggest feature is having excellent spectral purity,his spectral line-width that can be done 1MHz,side mode suppression ratio SMSR up to 40-50 dB.Because of its excellent color and convenient package in the field of optical fiber communications,gas detection,medical applications,laser atomic physics systems,film magnetometer,precision measurement,etc.has been widely used,and therefore the development of DFB driving circuit has a certain practical significance.Firstly,the principle of the semiconductor laser and output characteristics were analyzed for DFB laser characteristics presents a wide range of FPGA-based tunable pulsed laser driving circuit.The modular design of the drive circuit design,including FPGA pulse signal generating circuit for converting the pulse shaping circuit,pulse current drive circuit,a laser thermostat circuit and power circuit section.First,by generating circuit Xilinx Spartan-6 LX9 PFGA development platform designed pulse signal,using FPGA internal PLL frequency multiplier module will signal an external crystal phase-locked to 500 MHz,and the pulse repetition frequency of the signal pulse width by setting divider,combined with the internal FPGA ODDR double 1GHz clock unit to achieve the equivalent of twice the clock,the output resolution adjustable pulse width 1ns pulse signal.Then through the high-speed comparator for pulse shaping,the polarity and the amplitude of the pulse signal level suitable for driving the pulse signal driving circuit composed of MOS transistors.By MOS-Driver circuit for driving MOS transistors constituting the pulse current drive circuit.Since the wavelength,the temperature of the laser power instability,one design based on PID automatic temperature control circuit ensures that the temperature stability of the laser work environment.The power supply EMC design principles of the PCB entire driver circuit,and program the entire system design,and finally the system signal testing and data analysis.The receiving system through the USB serial data,to achieve the pulse parameters and temperature parameters of control.Can be achieved digitally controlled stepper is 1ns,a width of 10ns-1000 ns,repetition frequency of 100Hz-1MHz wide range of pulse drive signal.TEC temperature control portion may set the maximum operating voltage of 5V,the maximum operating current of 3A.Real-time temperature lock indication signal detection warning,avoid DFB laser burned.