Fiber ring resonator based slow-light and high sensitivity gas sensing technology

•A novel high sensitivity gas concentration sensing method using slow light technology based on fiber ring resonator is proposed and demonstrated for the first time. The parameters of fiber ring resonator are optimized for slow light generated and gas sensing, and the optimal parameters are obtained. Finally, the gas absorption coefficient where slow light was generated in the system reached to 2.41, which increased by 6.73 times compared with that of the traditional method, that is the sensitivity is increased by 6.73 times.•The proposed theory and method open a new idea in the field of sensing application utilizing slow light technology, but also, for gas concentration sensor have a positive effect.

A high sensitivity gas sensing technology based on fiber ring resonator slow-light is proposed and demonstrated in this paper. Slow-light produced by coupled resonator induced transparency in a fiber ring resonator has been studied theoretically and experimentally. Influences of parameters, such as cycle numbers, coupling ratio of couplers, ring loss and coupler additional loss, on slow-light characteristics of the fiber ring resonator were analyzed theoretically and numerically in detail. The delay time of slow-light in the fiber ring resonators has been measured using time domain measuring method, and the maximum delay time of 34.18 ns at wavelength of 1531.63 nm has been obtained, which is in accord with theoretical analysis. The gas absorption coefficient at the wavelength of 1531.63 nm where slow-light generated reached 2.41, which increased by 6.73 times the figure for the traditional method. It is the first time to measure gas concentration by using slow-light in fiber ring resonators, and the method is simple in structure and easy to implement.