Are low- and high-loss glass–ceramic optical fibers possible game changers?

The transparency of optical fibers is one of the most sought-after properties for this optical waveguide, the paradigmatic example being fibers for long-haul telecommunications. This transparency is achieved by eliminating absorbing centers and heterogeneities. So, the idea of deliberately introducing nanoparticles into the core of a fiber seems to go against the usual doxa, given the light scattering they induce. Such fibers, mainly based on silica glass, were first designed to modify luminescence properties to develop fiber lasers and amplifiers. For such applications, light scattering must be limited. However, over the last five years, light scattering has proved to be a valuable property for sensor applications. This review article is an opportunity to review the state of the art in nanoparticle-containing optical fibers, and to highlight their potential for laser and sensor applications.