Design And Implementation Of Driver Circuit For Semiconductor Pulse Seed Laser Used In MOPA

In the MOPA system, the output characteristics of high-energy pulsed laser depend on the seed source in a large extent. Thus, the design of pulsed seed source becomes one of the key technologies in MOPA pulse fiber laser. In accordance with application requirements of MOPA pulsed fiber laser to pulsed seed source, the driving circuit for the semiconductor pulsed seed source is designed and implemented in this paper, which can realize the generation of narrow pulses with adjustable parameters.According to requirements of the subject, a detailed analysis of basic working principle in the semiconductor laser is provided, and then the design target of the subject is put forward. Through the comparison of existing high-speed narrow pulse driving schemes, it's demonstrated that the driving circuit scheme with FPGA and MOSFET at the core has obvious superiority. The specific implementations of each module in the driving circuit are then discussed in details. In particular, the core fast switching module and the capacitor charge and discharge module are studies. After the detailed theoretical analysis and the simulation of Multisim circuit, the circuit design scheme is established to meet all design requirements. Finally, high-frequency characteristics of the high speed pulsed circuit is analyzed in details. Through setting reasonable PCB traces and the location of components, the unfavorable influence on the circuit is eliminated, which was affected by the circuit parasitic capacitance, parasitic inductance and so on. The making of PCB and the debugging of whole machine are accomplished.The driving circuit of semiconductor pulse seed source is proved to have a superior ability:a minimum output pulse width of 43ns,a short rising and falling time of 6ns,a repetition rate from lOHz to 1MHz,and an continuously adjustable peak current from 0 to 20A.