The fiber Fabry-Perot and its applications as a fiber-optic sensor element

The applications of the Fiber-Fabry-Perot (FFP) as demonstrated in the laboratory are shortly reviewed. The FFP has been used as optical spectrum analyzer, as a reference element for laser diode frequency stabilization, and as a sensing element for the measurement of temperature, mechanical vibrations, and electric and magnetic fields. A new FFP strain gauge sensor element is reported thata is made from a gradient index fiber. Its main advantages are easy coupling between light supplying and signal transmission fibers to the FFP as well as a modular configuration of the FFP sensor. A signal evaluation method is described that identifies the sign of measurand change and allows for large intensity losses on the transmission module.