Quantum Cascade Laser Driver in Multiple Trace Gas Monitoring

Real-time multiple trace gas monitoring instrument, based on photoacoustic spectroscopy has an important application in space capsule. The quantum cascade laser (QCL) is used in gas monitoring instrument. However, the requirement of short current pulse edge and high repetition frequency makes the design of the driver of QCL great challenge. The long current pulse edge makes QCL heat fast and widen its linewidth. On the other hand, low repetition frequency rate does not meet the requirements of gas measurement. In this work, we improve the capacitor charge-discharge pulse circuit and design a new pulse driver. The new pulse driver has short current pulse edge and high repetition frequency. Experimental results show that the driver outputs current with an amplitude greater than 1.7 amperes under a 12V DC power source and an equivalent resistor 2.73 omega; in addition, increase/decrease time is no more than 20 nanoseconds, a pulse width can be randomly adjusted, a smallest pulse width can be as low as 20 nanosecond, and a largest repetition frequency exceeds 1 MHz;