Research Of Fiber Fabry-Perot Sensor Based On Coronary Fractional Flow Reserve Detection

Cardiovascular disease is one of the three causes of death in modern human society.Coronary fractional flow reserve(FFR)is a relatively new cardiovascular disease assessment technique.In the case of maximal myocardial congestion,it measures the distal and proximal pressures of a narrow coronary artery and uses their ratio to determine the extent to which the stenotic lesion limits the maximum blood flow to determine whether the stenotic lesion causes myocardial ischemia.Using F-P cavity pressure sensing principle for FFR detection can improve its detection sensitivity,and can perform multi-parameter measurement to achieve accurate lesion diagnosis.The use of optical fiber to detect FFR can improve the high cost of cardiovascular disease detection,difficult operation and cause human discomfort.It is of great significance.This paper proposes a thin film fiber-optic F-P cavity sensor for FFR measurement,which has the advantages of high sensitivity,simple fabrication and low cost.Firstly,a large number of domestic and foreign related literatures were read,and the research status of FFR measurement and fiber F-P cavity sensor was analyzed.Aiming at the shortcomings,a thin film fiber F-P cavity sensor was used to detect FFR.Then,the measurement principle of FFR and the detection principle of fiber F-P cavity sensor are analyzed.The theoretical model of FFR measurement by fiber F-P cavity sensor is constructed based on the theory of film elastic mechanics.And using the finite element software COMSOL to model and analyze it,using the gold film to simulate the best film thickness of 300nm.Under different pressures,the most suitable film material is aluminum by using different materials to simulate.The effect of the change in cavity length on the drift of the reflection spectrum is drawn by MATLAB software.Then,an offset fiber F-P cavity stress sensor was fabricated by etching with hydrofluoric acid solution and applied to the tensile force measurement experiment.The fabrication method of the offset fiber F-P cavity sensor is introduced.It is found that the sensitivity and misalignment distance of the sensor are linear in a certain range.The larger the offset distance,the higher the sensitivity of the sensor,and the best offset distance is about 4 um.The offset fiber F-P cavity sensor has a high linearity of 99.38%and a high sensitivity of 5.4 nm/N,and the experimental repeatability is very high.Finally,the fabrication method of thin film fiber F-P cavity sensor was introduced.The F-P cavity fabrication platform,experimental measurement system and self-designed sensing device were introduced in detail.Hydraulic test results of sensor made of organic material film,melt-cut sensor,and sensor made of metal aluminum film under different effective areas was analyzed.The most suitable sensor is made by aluminum film with an effective diameter of 1 mm.The sensitivity of the sensor is 0.7533nm/KPa.The linear fitting degree is good,and the sensor stability is high.The PC software for real-time monitoring is designed and used for hydraulic real-time monitoring.The experimental results are good.The protection device of the fiber F-P cavity sensor is designed to play the role of guiding and protection.A dynamic hydraulic measuring system and a narrow simulation device is designed.