Study Of Fiber Optic Vehicle Information Sensing Technology Based On Cavity Ring-Down Spectroscopy

With the development of fiber technology and sensing technology,fiber cavity ring-down spectroscopy(FLRDS)originated from cavity ring-down spectroscopy(CRDS)has been widely used in physical field,chemical field and biological field for its own unique advantages.The traditional vehicle information sensing technology has been unable to keep up with the current rapid development of intelligent traffic management.Therefore,under the background of"Smart City" and intelligent transportation construction,the research of fiber vehicle information sensing technology was carried out in this article.The research is supported by the "Western Light" talent training program.This article research belongs to the field of optical fiber sensing.The main contents and innovations of this paper are as follows:Firstly,this paper analyzes the loss of passive resonant cavity and fiber,describes the sensing principle of fiber cavity ring-down spectroscopy,and discusses the technical characteristics and superiority of FLRDS.Meanwhile,according to the linear system analysis method,resonator is regarded as a "linear invariant system",which reveals the dynamic response of pulsed light in the resonator.Secondly,on the basis of theoretical analysis,a fiber vehicle information sensing system with wavelength 1550 nm is designed.The static pressure sensing experiment was carried out respectively in the laboratory and in the outdoors.The experimental results show that the system has a good response to static pressure and the force has a polynomial relationship with the term of(1/?-1/?0).In addition,the dynamic pressure sensing experiment was carried out and the influence of the speed on the dynamic weighing was analyzed.At the same time,from the theoretical model,this paper analyzes the realization of detecting the four factors of vehicle information(weight in motion,traffic statistics,vehicle speed monitoring,vehicle classification).Finally,based on the traditional FLRDS technology,a pressure sensing device combined with FLRDS technology and Sagnac effect is proposed creatively.The feasibility of the system is analyzed theoretically and the static pressure sensing experiment is carried out under the laboratory conditions.The experimental results indicate that the system has a good response to the static pressure,and the force has a cosine relationship with the term of(1/?-1/?0).The measurement accuracy of new sensor system is greatly improved.In a pressure cycle,up to 1.8 ns/N detection response can be achieved.But,at the same time,there are some shortcomings,such as interference by external signal is large,the scope of the pressure is limited and the output response is non-linear.