Multiple emitter laser diode assembly with graded-index fiber microlens

摘要

The multiple emitters laser diode assembly comprises a laser diode bar for emitting a laser beam. The laser diode bar comprises a plurality of emitters aligned with respect to each other in a same plane of emission. A graded-index elongated fiber microlens is transversely set at a given distance in front of the laser diode bar for controlling the divergence of the beam. The microlens has an axis of symmetry substantially intersecting the optical axis of each emitter. A mount is provided for positioning the microlens with respect to the laser diode bar. Alternatively, the assembly may comprise a laser diode array for emitting the beam. The laser diode array comprises a plurality of substantially parallel rows of emitters with a substantially regular period between them. An array of graded-index elongated fiber microlenses is positioned substantially parallel to the rows. Each microlens corresponds to one of the rows for collimating the beam generated thereby. The GRIN fiber microlens shows less alignment sensitivity than ordinary fiber lens or aspherical fiber lens when used in a multiple emitters laser diode assembly. The GRIN lens further has the advantage of collimating a laser diode bar or array with a high degree of quality while minimizing phase aberration and distortion in the collimated transmitted beam.