In a nutshell? i cannot seem to find a lot of information online about these. Could someone please help?
It depends on the type of sensor. The most popular is probably the diaphragm design. They are basically just a regular fiber with a diaphragm on the end that is normal to the fiber. Light is sent to the end of a fiber via a fiber coupler and received by a photodiode/phototransistor. As the pressure increases, the diaphragm deforms and causes more light from the fiber to deflect thereby lowering the return intensity/optical path.