A multiple mode pre-loadable fiber optic pressure and temperature sensor includes
a generally cylindrical structure having at least one compression element, a fiber
optic having a Bragg grating in contact with one side of the compression element,
a diaphragm in contact with the other side of the compression element, and a fluid
port in fluid communication with the diaphragm. According to preferred aspects
of the, a groove is provided in at least one compression element for receiving
the fiber optic. The sensor is pre-loaded by straining the diaphragm over the adjacent
compression element when the cover is attached. The compression element in contact
with the diaphragm preferably has a contoured surface contacting the diaphragm
and the diaphragm is stretched to match that contour. By varying the contour of
the compression element and the thickness of the diaphragm, the dynamic range of
the sensor can be changed. The preferred diaphragm has a variable thickness and
is made as an integral part of the structure. The sensor can be operated in normal,
reverse, or differential mode.
