Design and analysis of a micro pressure sensor with optical fiber

We described an optical micro-electro-mechanical-system (MEMS) pressure sensor based on light intensity modulation that can be used in petrochemical and oil well area. The idea is to use light for transmission to replace electrical signals. Utilizing bulk micromachining technology of silicon, a membrane is obtained for sensing pressure and reflecting the light. The intensity of reflected light shifts when the membrane deforms caused by the loaded pressure. The intensity shift of reflected light can be measured by the photoelectric detection circuit that converts light intensity to voltage, so the loaded pressure can be gauged. The micro machining technology minimizes sensor size. Optical fiber is used to conduct light which makes the sensor be isolated from electricity. The sensor has been fabricated and encapsulated and the photoelectric detection circuit has been completed. The measurement range is 0~20MPa and the experimental sensitivity is 7.2mV/MPa.