Fiber optic sensors, thanks to their size, flexibility and survivability advantages, continue to gain popularity as effective alternatives to conventional transducers. Two types have emerged as leaders in meeting the changing needs of industrial customers: single-point and multiplexed optical fiber sensors. Single-point sensors, such as the extrinsic Fabry-Perot interferometer, find use as pressure, strain and temperature sensors. Multiplexed devices, such as grating-based sensors, are an important, more recent, player in market.