Fiber Bragg gratings

Following the realization of low loss optical waveguides in the 1960s, optical fibers have been developed to the point where they are now synonymous with modern telecommunication and optical sensor networks. A major drawback to the evolution of optical fiber-based networks has been the reliance on bulk optics for conditioning and controlling the guided light beam. The necessity of coupling light out of the waveguides to perform, for example, reflection, diffraction and filtering (spatial, polarization etc) is an inherently lossy process. Moreover, coupling light in and out of fiber significantly increases the number of high quality, bulk-optic components, often requiring stringent tolerance on optical alignment–thus necessarily making conceptually simple systems complicated and expensive in practice. Replacing a bulk optic mirror or beam splitter with a fiber equivalent can dramatically increase system stability and portability, whilst reducing overall size; pushing laboratory-based experiments into real world environments. The most successful fiberized technology to date is the optical fiber laser and amplifier and fused tapered coupler. The intrinsic low loss nature of these components and compatibility with integrated-optic waveguide structures has made them indispensable to the continued development of optical systems as a whole.