Packaging of Components for Optical Fiber Technoidgy

ABSTRACTA number of promising tedcniques used to intercmnect two or more optical fibers and optical fibers with guided wave optical devices are reviewed. Such waveguide-to-waveguide interconnections impose severe optical and mechanical design constraints. components used in single mode infrared optical systems use fibers of five to ten microns in core diameter. This creates the need for subnicron alignment toleranc between the waveguides. Such severe toleranc requirements are satisfied, in the case of single mode fiber connectors, through the use of precision ceramic ferrules. Achieving the same performance, when interconnecting fibers and waveguide devices, is somewhat less straightforward. Several approaches are currently under study. One such approach uses precisely etched silicon V-grooves. Another approach uses self-aligned grooves or slots that are formed in the substrate material through ion-milling or laser-assisted etching. Components used in multimode fiber systems use fiber with fifty to one thousand micron core diameters, and are therefore more forgiving to misalignment. Despite this, careful design is required to achieve satisfactory performance. The misalignment penalties associated with a number of interconnect situations are illustrated and discussed in terms of alignment tolerances and fabrication difficulties.