Fabrication and characterization of a rapid-response, ultrasensitive dual-head interferometric pressure sensor

A novel, to the best of our knowledge, dual-head Michelson interferometer-based pressure sensor with ultrahigh sensitivity and rapid response has been fabricated and optimized. The sensor consists of two diaphragm-based sensing heads, which operate on the principle of path-length variations of the interferometers due to the effect of pressure variation within the pressure channel. Pressure has been measured independently by the heads in terms of the fringe counts across two photodetectors with different sensitivities and working ranges. Head 1 had a linear working range of 0-6 psi and a sensitivity, resolution, and response time of 1295.04 fringe counts/psi, 25.74 µpsi, and 0.86 ms, respectively, which were 2.46, 2.46, and 0.86 times better than those of head 2. However, head 2 had a larger working range of 0-15 psi. Heads 1 and 2 yielded repeatable responses with negligible hysteresis and an average absolute error of 0.55% and 0.58%, respectively, compared to the predicted results. The proposed sensor has great potential for use in laboratory and industrial nonintrusive precise and fast-response pressure sensing applications.