OPTIMIZATION OF THE COUPLING BETWEEN A TAPERED FIBER AND A P-I-N PHOTODIODE

With increasing information flow, direct illumination of the photodiod e intrinsic layer from the end of a fibre becomes a necessity. The act ive area size of the photodiode is much smaller than the spot size in the fibre. This paper proposes an optimized scheme for direct coupling between the fibre and the device. Different fibre extremities are inv estigated. It is shown that optical coupling could be optimized with a n acid-etched taper ended by a lens of 13 mu m diameter or by a pulled and melted fibre with certain conditions of profiles.