Performance Analysis and Design Optimization of an Intracavity Absorption Gas Sensor Based on Fiber Ring Laser

An intracavity absorption gas sensor based on fiber ring laser using erbium-doped fiber (EDF) as the gain media was proposed in this paper. A theoretical model for analyzing the effects of the EDF and the system parameters on the performance of this gas sensor was established using coupled rate equations and propagation equations. The system performances of various parameters were simulated and compared. Relations between optimal parameters and desirable performances were found. We also investigated a number of specific cases and suggested practical choices of their parameters. Experiments with two cavity losses were conducted to test the system sensitivity enhancement and the SNR. The general trends of experimental results agreed with the theoretical prediction and sensitivity enhancement factors of 50-65 were achieved, showing the ability to realize trace gas detection.