Abstract

The basic design concept for several types of fiber optic interconnecting device consists of a pair of graded-index (GRIN) rod lenses mounted so that an interface occurs between the lenses. The collimating lens transforms the divergent output of the input fiber into collimated light which passes through the interface plane and enters the focusing lens. The focusing lens intercepts the collimated light which has transited the interface plane between the lenses and reimages it onto the input end of the output fiber. Adhesives have been used to attach fibers to GRIN lenses. There are two basic problems with adhesives. First, when they are cured, there is invariably shrinkage or growth which results in some movement of the fiber with respect to the lens. Any misalignment results in an increase in signal loss through the joint. Second, adhesives have a relatively high coefficient of thermal expansion with respect to glass and this limits the useful temperature range over which the joints can be used without suffering unacceptable signal losses.

© 1992 Optical Society of America