ACCURATE FABRICATION OF ANAMORPHIC MICROLENSES AND EFFICIENT COLLIMATION OF TEMPERED UNSTABLE-RESONATOR DIODE-LASERS

Highly precise f/0.9 refractive anamorphic microlenses have been fabricated in GaP substrates by mass-transport smoothing of etched multiple-mesa structures. Astigmatic outputs from tapered unstable-resonator lasers have been collimated to a nearly round beam of near diffraction-limited 0.43-degrees divergence. Initial good efficiencies (as high as 35%) have been obtained in coupling the laser output into a single-mode fiber. These lenses are highly promising for realizing simple compact optical systems that exploit the high power capability of tapered lasers.