Zl. Liau et al., FABRICATION OF 2-SIDED ANAMORPHIC MICROLENSES AND DIRECT COUPLING OF TAPERED HIGH-POWER DIODE-LASER TO SINGLE-MODE FIBER, IEEE photonics technology letters, 7(11), 1995, pp. 1315-1317
An anamorphic microlens has been developed to couple a tapered unstabl
e-resonator laser directly to a single-mode fiber, and has demonstrate
d capability for simple, compact and efficient high-power diode laser
systems, For high collection and coupling efficiencies, the refractive
microlens has been fabricated by utilizing both sides of a GaP substr
ate, in which the first side was used to remove the astigmatism of the
laser output and the second side to focus the beam to a spot size com
parable to the fiber mode, The microlenses have been accurately formed
by using a recent technique of mass-transport smoothing of etched mul
timesa preforms, Initial fiber-coupling experiments showed powers as h
igh as 360 mW at the fiber output, and coupling efficiency as high as
29.5% has been measured at a lower power.