Design Of Microbend Fiber Optic Pressure Sensor Detection System

The optical fiber sensing technology developed so far, with its unique features, it is taken seriously by people and widely applicated. Along with the rapid development of manufacturing industry and optical theory continuously updating, many different modulation type of optical fiber sensing technology appear constantly. Among them, type of light intensity modulation appear firstly, it's theory areach mature.this kind of optical fiber sensor have the features that less demanding on the components, flexibility in design and high sensitivity, it is satisfactory for ordinary living and industrial measurement requirements.The main work of the paper is study of pressure sensing system based on the micro-bending loss. First, This paper analysis of microbending fiber optic sensing principle, and the distance of each tooth in microbent mechanism is determined according to fiber parameters and principle of microbending loss. Pressure is generated by place heavy objects on the microbending device, The weight of objects reflect outside pressure. Considering the location of the placed object can affect results of pressure measurements. This paper build a supporting device that can excluding the impact of location factors. Second, Based on the above facilities, pressure dectecting system that can stable measure and display the size of the weight of external heavy objects is designed. Detecting system chiefly consist of hardware circuit and sofeware,it's hardware circuit contain the section of stable light emission, weak intensity receiving, signal amplifying, signal filter, data processing display and transmission.the part of data processing display and transmission include STC89C52RC single-chip computer and its peripheral circuits. The measurement result is display by LCD and upper machine PC.At last,In order to calibration the ralationship between voltage and weight,PC interface and procedures is designed.Beside the calibration and display function, PC need to perform senting calibration results into single-chip computer function,for single-chip computer can query and display weight value according to detected voltage,and achieve the purpose of measuring without PC.In this paper,the sensing performance of this system is tested by experiment,the results is found in reasonable area,and this design have achieved desired results.