Study of C_2H_2 optic-fiber monitoring system on spectrum absorption

摘要

We report our research on the development of optical fiber trace gas sensors for environmental applications. A novel optical fiber sensor for monitoring acetylene (C_2H_2) gases is described. Through studying the measure theory, we use the Beer-Lambert law to monitor the gas. And after analyzing the C_2H_2 spectrum, we select Distributed Feedback Laser Diode (DFB LD) as light source. Comparing many kinds' sensor detection head, the gas absorbing cell with tail fiber can have good coupling with optical fiber and improve the coupling stability. In the data processing system, signals are distilled by lock-in amplifiers and then harmonic measure technology processes that distilled faint signals. After the all, the electronic signals are transmitted into computer to process, alarm and display. We design the instrument who can remote and on-line measuring acetylene. Through theory analysis and system experiment, the design of the system is practicable, and has a better precision and some apply foreground.