| Aiming at the temperature detection problem in space optics expernment,a fiber-optic temperature sensor structure based on Fabry-Perot(F-P)cavity interference is proposed.The quartz glass material is selected as the F-P cavity,and the reflectivity of the F-P cavity is changed with temperature.The principle is to measure the temperature.The sensor system has the feature of being directly embedded in the optical path.Firstly,the thesis conducts relevant theoretical analysis and derivation,and builds a sensor test system.The reflected light is used as temperature sensing light,and transmitted light is used as experimental light for space optical experiment.The paper analyzes the experimental results theoretically and summarizes an empirical formula.The calculation shows that the mean square error between the calculated value of the empirical formula and the measured value of the actual temperature control system is s=0.055 ?,which can satisfy the general spatial optical optics.The needs of the experiment.The temperature sensor has the advantages of simple structure,high efficiency,low manufacturing cost,and no electromagnetic interference;compared with the fiber grating temperature sensor,no complicated packaging,pasting and the like process are required,and no special demodulation device is required,which is the temperature of the space optical experiment.Detection provides convenience and has important application value.The main content of this paper is:(1)A fiber-optic temperature sensor structure based on F-P cavity interference and a temperature measurement principle using the reflectivity of F-P cavity with temperature are proposed.Based on the theoretical analysis,the influence of the thickness,surface flatness and coating coefficient of the quartz phase plate on the reflectivity is analyzed.The parameters such as the thickness,surface flatness and coating coefficient of each batch of quartz phase plate are carefully examined and selected.The quartz phase plate required for the experiment was used for subsequent heating experiments.(2)Under the condition that the coating coefficients of both sides are the same,the theoretical calculation of the reflectivity of the selected quartz phase plate is obtained,and the maximum and minimum reflectances are obtained.Aiming at the thermal expansion and refractive index change caused by the change of ambient temperature of quartz glass materials,a heating temperature control system was designed to conduct preliminary heating experiments on quartz phase plates,and the maximum and minimum transmittances were selected in theoretical calculation.Quartz phase plate in the range to prepare for the construction of the experimental system(3)Using a quartz phase plate,an optical circulator,a dichroic prism and other devices to fabricate a fiber optic temperature sensor,and using a temperature control heating system to build a temperature sensor test system.The test results were obtained by recording the reflected light power of the quartz phase plate.The results show that the error between the temperature sensor and the standard temperature is controlled within 0.1 ?.(4)The above temperature sensor is embedded in the space optical experiment system,and the specific application is carried out in the test experiment of multi-stage quarter-wave plate phase with temperature change. |
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