Applications of GRIN-rod lenses in optical fiber communication systems

Graded-refractive-index-rod lenses (GRIN-rod lenses) have a number of features that make them particularly suitable for use in optical devices for manipulating and processing the optical signals in fiber communication systems. Such lenses can be cemented directly to the other elements of a device, thus giving a structure that is compact, solid, stable, and rugged. They also have significantly smaller aberrations than equivalent simple homogeneous lenses, and this results in lower insertion losses. Designs for various GRIN-rod lens devices, including connectors, attenuators, directional couplers, switches, isolators and wavelength-division multiplexers are reviewed. A consistent set of loss estimates is provided for all the device designs considered.