Theoretical investigation on the effective coupling from laser diode to tapered lensed single-mode optical fiber

A theoretical investigation on the coupling efficiency from a laser diode a t 1.5 mu m to a single-mode optical fiber via a hemispherical lens on the e nd of the tapered section of the fiber is presented. A comparison is made b etween the drawn taper and the etched taper, and the results show that with drawn taper the coupling efficiency is insensitive to the radius of the he mispherical lens and that higher maximum coupling efficiency can be achieve d. The results are useful for the design of optimum microlens to obtain max imum coupling efficiency with yet relatively easy control in the fabricatio n process. (C) 2000 Published by Elsevier Science B.V.