Open AccessOptical micro‐electro‐mechanical‐system pressure sensor based on light intensity modulation
Author(s) -
Zhao Yulong,
Li Cun,
Hao Mengmeng,
Cheng Rongjun,
Fan Xiaole,
Chen Pei
Publication year - 2015
Publication title -
micro and nano letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.25
H-Index - 31
ISSN - 1750-0443
DOI - 10.1049/mnl.2015.0189
Subject(s) - diaphragm (acoustics) , materials science , light intensity , optoelectronics , microelectromechanical systems , pressure sensor , photoelectric effect , optics , silicon , intensity modulation , voltage , surface micromachining , intensity (physics) , optical modulator , fabrication , acoustics , electrical engineering , vibration , phase modulation , mechanical engineering , engineering , medicine , physics , alternative medicine , pathology , phase noise
An optical micro‐electro‐mechanical‐system pressure sensor based on light intensity modulation is described. The idea is to use light for signal transmission to replace electrical signal, which isolates the sensor from electrical signals, so that it is quite suitable in flammable and combustible areas such as petrochemical and oil well. The sensor is composed of silicon diaphragm and optical system. The silicon diaphragm is fabricated from bulk micromachining technology and Si 3 N 4 film is deposited on diaphragm for reflecting light. In the optical cable, one fibre conducts source light to the diaphragm and the other fibres conduct the reflected light back to photoelectric detection circuit. When pressure is applied on the sensor, the diaphragm will deform causing the intensity shift of reflected light. Photoelectric detection circuit converts the intensity of reflected light to voltage. The voltage is proportional to reflected light intensity and, in turn, to the deformation of silicon diaphragm, so that pressure can be measured. Deformation of silicon diaphragm is acquired by finite element method. Sensor's optical features are also analysed. Sensor prototype has been fabricated and encapsulated. The measurement range is 0–20 MPa and experimental sensitivity is −7.2 mV/MPa.