Abstract

Graded index (GRIN) rod lenses with their refractive index varies gradually from the center axis to the periphery are widely used in optical communications systems, fiber optic sensors and other fields that need compact and ease-of-alignment imaging and focusing elements. The GRIN rod lenses, because of their unique features such as small size, flat end face, high efficient coupling, easy processing, adjusting and aligning, coupling and composing together, are often used as connectors, switches, directional couplers, and wavelength division multiplexers and etc. As couplers or connectors, the coupling efficiency by using GRIN lenses has been discussed in a number of papers. Since the GRIN lenses have flat end face, the optical elements or fibers can be simply glued to the end faces, forming compact and mechani- cally stable coupling systems.

© 2001 Optical Society of America