chapter  13
24 Pages

Radiation Effects on Optical Fibers and Fiber-Based Sensors

Applications ....................................................................... 365 13.4.2 For Fiber-Based Sensors ................................................................... 365

13.4.2.1 The Fiber Bragg Gratings (FBGs) .....................................366 13.4.2.2 Fibers as Dosimetry Systems .............................................366 13.4.2.3 Distributed Sensors ............................................................ 367

13.5 Multiscale Modeling from Ab Initio to System Levels: Recent Progress .... 368 13.6 Conclusions ................................................................................................... 370 References .............................................................................................................. 371

The presence of ionizing or nonionizing radiation appears as a severe constraint for most of the electronic components and circuits when the total ionizing dose* (TID) exceeds 1 kGy(SiO2) [1]. Such TID levels are encountered in natural environments, such as space, or in the artificial manmade environments associated with nuclear power plants and/or high-energy physics facilities [2]. Radiation induces a variety of transient or permanent effects that can alter the device functionality or sometimes, depending on the technology vulnerability level and irradiation conditions, lead to the complete loss of its functionality. Optical fibers and fiber-based devices have been shown since the ’70s to be more radiation-tolerant than most of the electronic technologies, in addition to their other intrinsic advantages, such as their electromagnetic immunity, low weight, high multiplexing capacity, and high temperature resistance [3]. Then, this photonic technology was first routinely used for data transfer in radiation environments instead of copper cables, becoming later key parts of more complex systems or subsystems in physics facilities, such as the plasma diagnostics for fusion facilities [4]. More recently, optical fibers revealed exceptional advantages for the development of new classes of sensors [5]. These new optical fiber sensors (OFS) use the fiber material scattering properties as sensing phenomenon when the reflectometry technique offers high spatial resolution over large fiber distances. Today’s Brillouin or Raman-based sensors allow monitoring strain and temperature changes over dozens of kilometers with resolution below 1 m along one fiber link [6] whereas Rayleigh-based sensors offer an exceptional resolution of less than 1 mm over 70 m of fiber [7]. More complex techniques are under development to increase even more the sensor performances in terms of resolution, sensitivity, and discrimination between the two measurands.