Diode-laser to optical fiber coupling system with biaxial optical power

Abstract

A coupling system for enhanced light coupling between a laser diode and an optical fiber that includes a laser diode having an emitting surface for generating an asymmetric beam with a fast axis that is more divergent than an orthogonal slow axis thereof, an optical fiber having an input end and a delivery end, a first microlens mounted on the input side surface of the fiber, and a second microlens disposed between the laser diode and the first microlens. The input end of the optical fiber includes a beveled end surface disposed at an oblique angle with respect to a longitudinal axis of the optical fiber, and a light input side surface opposing the beveled end surface and aligned with the emitting surface of the laser diode to capture the beam emitted therefrom. The angle of the beveled surface is selected such that the beam entering the input side surface from the laser diode is total internally reflected by the beveled surface along the longitudinal axis of the fiber. The first microlens is mounted on the input side surface of the fiber in a manner to have optical continuity therewith for focusing light into the fiber and having a focal power along an axis perpendicular to the longitudinal axis of the fiber. The second microlens has a focal power along the fast axis of the beam.