Temperature insensitive optical MEMS pressure sensor using long period gratings on a circular diaphragm

We present design and simulation of temperature insensitive optical MEMS pressure sensor using long period gratings on a circular diaphragm. The sensor consists of a curved waveguide with two identical long period gratings located on circular diaphragm. When pressure is applied on the diaphragm, the pitch of the gratings changes and hence there is a shift in the corresponding Bragg wavelength. As temperature shifts the Bragg wavelength of the two gratings equally, the error due to temperature change on pressure sensitivity is eliminated. Long period gratings provide higher pressure sensitivity compared to Bragg gratings but with a limited pressure range.