Micro pressure sensors play a crucial rote in pressure measurement in narrow spaces, especially in the medical field. Traditional pressure sensors are limited in small space applications due to their large size. The advantages of miniaturized pressure sensors are highlighted. The measurement of pressure within the organism during clinical diagnosis and minimally invasive surgery can provide doctors with necessary diagnostic information, decision support, and guidance for treatment. Real time monitoring of internal pressure is a key factor in determining the :success or failure of treatment, especially in cardiovascular surgery, head injury recovery, and urologicat intervention. With the development of Micro Electro Mechanical Systems (MEMS) technology and the improvetnent of medical standards, various types of miniaturized pressure sensors have begun to enter the field of biology, including electronic pressure sensors and fiber optic sensors. Electronic sensors, including piezoelectric, resistive, and capacitive pressure sensors, have complex structures and are not resistant to electromagnetic interference, which limits their applications in the medical field. Compared with traditional electronic sensors, fiber optic sensors have received widespread attention due to their small size, simple structure, high sensitivity, corrosion resistance, and resistance to electromagnetic interference. At present, most of the reported fiber optic sensors are based on fiber Bragg grating and Fabry Perot. The core component of fiber optic Fabry Perot sensors is the Fabry Perot cavity, and its preparation process is mainly divided into manual single preparation and MEMS technology batch preparation. Single prepared sensors are produced in one go, with poor consistency and difficulty in mass production. By contrast, the MEMS technology can not only improve sensor consistency but also reduce costs to achieve large-scale production. A micro fiber optic Fabry Perot sensor based on MEMS technology is designed and prepare. The sensor has the characteristics of high sensitivity and hatch manufacturing. Based on the research of hiocompatible materials, Silicon-On-Insulator (SOD and BF33 glass were selected as sensor sensitive materials on insulating substrates. The etched SOI device layer is made of monocrystattine silicon as a sensitive membrane, and the etching depth is used as the initial cavity length of the micro Fabry Perot cavity. It is then bonded together with BF33 glass through anodic bonding technology to form a vacuum sealed micro Fabry Perot cavity array on the bonding surface. Monocrystalline silicon and BF33 glass form two reflective surfaces in a miniature Fabry Perot cavity. The incident light enters the cavity and undergoes double beam interference. When the external pressure changes, the sensitive membrane deforms, resulting in a change in the length of the Fabry Perot cavity. The signal is transmitted to the demodulation system through optical fibers to determine the change in external pressure. By using femtosecond laser fine cutting technology to independently separate the sensor unit, and using a micro displacement platform under a microscope to integrate the fiber and sensor head, the overall outer diameter and the high of a single sensor is only 400 mu m and 220 mu m, respectively. We built a signal demodulation experimental platform and conducted detailed tests on the pressure characteristics of the sensor. The test results show that within the gas pressure range of 0 similar to 50 kPa, the pressure sensitivity of the sensor can reach 18. 5 nm/kPa, with a tnaximum nonlinearity of 0.47N, a repeatability of 0.18%, a hysteresis of 0.18%, and a small cross sensitivity coefficient within the range of human temperature changes. In summary, the sensor designed and prepared in this paper with advantages such as small size, high sensitivity, electromagnetic compatibility, biocompatibitity, and strong stability, provide enormous commercial conversion vatue in the fields of biomedical and medical science.
