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 at 1.5 mu m to a single-mode optical fiber via a hemispherical lens on the end of the tapered section of the fiber is presented. A comparison is made between 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 hemispherical lens and that higher maximum coupling efficiency can be achieved. The results are useful for the design of optimum microlens to obtain maximum coupling efficiency with yet relatively easy control in the fabrication process. (C) 2000 Published by Elsevier Science B.V.OpticsSCI(E)EI0ARTICLE1-389-9518