Systems and Applications in Optical Fiber Sensor Technology The essential technology which underpins developments in optical fiber sensors continues to expand, and continues to be driven to a very large extent by advances in optoelectronics which have been produced for the ever-expanding optical com­ munications systems and networks of the world. The steps forward in the technol­ ogy, often accompanied by a reduction in the price of associated components, have been, and continue to be, adapted for use in a wide variety of optical fiber sensor systems. These include, for example, the use of photoinduced gratings as fiber sensor components, coupled with the wider availability of shorter wavelength lasers, bright luminescent sources and high-sensitivity detectors which have opened up new possibilities for both novel fiber optic sensor applications and new sensing systems. This is to be welcomed at a time when, coupled with integrated optic miniaturized devices and detectors, real possibilities of systems integration, at lower cost and increased utility, can be offered. The fiber laser, and the expansions of the types and availability of the doped fiber on which it is based, offer further examples of the integration of the essential components of advanced optical sensor systems, fitted for a new range of applications.