Mach-Zehnder Optical Fiber Sensor Based On Peanut-Shaped Structure

In this era of rapid development of big data,artificial intelligence,and block-chain networks,unprecedented advances have been made in the development of electronic circuit devices and optical fiber sensors as a medium for the data information collection,transmission and analysis.The fiber optic sensor based on the Mach-Zehnder interference principle designed and manufactured in this paper is characterized by its unique features such as a particularly simple manufacturing process,a very strong fender resistance,a high degree of environmental change sensitivity and a very short response time has become increasingly popular and hot in the research of carrier circuits and fiber optic devices.This paper will be arranged and described in the following layout format:1.Various types of optical fiber sensors were analyzed theoretically according to different structures and application fields.At the same time,the software and hardware system components of the femtosecond laser,the fiber optic microfabrication principle and the fiber optic micro-taper technology were introduced.The relationship between the pore diameter and the femtosecond laser energy was analyzed theoretically.The research on temperature,strain,refractive index of Mach-Zehnder sensor was studied.And the principle of temperature and strain measuring simultaneously was summarized.The principle of temperature and refractive index measuring simultaneously was studied.2.Using the femtosecond laser micromachining technology,a built-in double-hole peanut-shaped sensor with ultra-small size,high temperature sensitivity,and high strain sensitivity was designed and implemented for the first time based on the micro-taper technology.The sensor in temperature sensitivity reached 60.46 pm/°C,which is 5 times higher than FBG(Fiber Bragg Grating),and the strain sensitivity reached 3.25 pm/??,which is more than 3 times of FBG.3.Two kinds of polarization-maintaining fiber sensors and fine-core fiber sensors based on cone-and-peanut cascade structure were designed and manufactured.The temperature and strain characteristics of these two sensors were studied experimentally and according to the sensitivity coefficient matrix,the temperature and strain parameters were measured simultaneously.The sensitivity to the temperature of the polarization-maintaining fiber sensor reached 51.383 pm/°C,which is 4 times higher than that of the FBG and the strain sensitivity was-1.5 pm/??.The sensitivity of the fine-core fiber sensor to the temperature reached 32.6 pm/°C,which is higher than that of the ordinary Mach-Zehnder interferometer and the strain sensitivity reached-2.2321 pm/??.The maximum strain tolerance of the sensor when performing the strain experiment was 1600 ?? indicating that the sensor has a strong structure,high strength,and is not easily damaged.4.Two kinds of polarization-maintaining fiber sensors and fine-core fiber sensors based on spherical-peanut cascade structure were designed and manufactured.The temperature and refractive index parameters of the two sensors were studied experimentally and the temperature and refractive index parameters were measured simultaneously with the sensitivity coefficient matrix.The temperature sensitivity of the polarization-maintaining fiber sensor was 19.5 pm/°C,and the refractive index sensitivity reached 242.105 nm/RIU,which is more sensitive than the LPFG(Long Period Fiber Grating).And the structure size is more dominant.The sensitivity of the fine-core fiber sensor to temperature reached 148.22 pm/°C,which is 12 times higher than the FBG,and the refractive index sensitivity reached-43.651 nm/RIU.