title: Microienses to improve LED-to-fiber optical coupling and alignment tolerance.
abstract: The performances of four refractive concentrators in enhancing LED source-to-multimode fiber coupling are compared on the basis of improvement of coupling efficiency and relaxation of source-fiber mechanical alignment tolerances. For a core-to-source area ratio of 1.9 and a parabolic index, 0.23-N.A. fiber, experiments indicated a coupling improvement factor over butt coupling of up to 1.6, and alignment tolerance improvement factors of up to 10 (axial) or 5 (lateral) by use of an appropriate concentrator. An experimentally verified ray trace numerical simulation was used to examine the effects of fiber N.A., core area, and concentrator refractive index.
authors.forename: J G
authors.initials: JG
authors.lastname: Ackenhusen