Patent ID: 7444047

Claim:
A multiplexing optical system comprising: a plurality of collimator lenses; a first condensing lens; a second condensing lens; and an optical fiber, wherein the plurality of collimator lenses collimates each of divergent laser beams that have been emitted from a plurality of semiconductor lasers arranged so that the stripe width directions of the semiconductor lasers are parallel to each other, and wherein the first condensing lens is formed by a cylindrical lens for condensing laser beams transmitted through the collimator lenses in only one of a plane including the stripe width direction of the semiconductor lasers and a plane including a direction perpendicular to the stripe width direction, and wherein the second condensing lens is formed by an anamorphic lens for condensing laser beams transmitted through the first condensing lens in the two planes in cooperation with the first condensing lens, and wherein the shapes of the anamorphic lens in the two planes are different from each other, and wherein the optical fiber is arranged in such a manner that the surface of an incident end of the optical fiber is positioned at a convergence position of the plurality of laser beams transmitted through the second condensing lens.