title: Single-mode fiber with a plano-convex silicon microlens for an integrated butt-coupling scheme.
abstract: A single-mode fiber with plano-convex silicon microlens is proposed for butt-coupling between single-mode fibers and high-index-contrast waveguides with fine mode-field diameter. The lensed fiber has two specific features, high focusing power, and null working distance. The theoretical focus-spot diameter at the endface of the lensed fiber is calculated to be as small as 0.56 microm at a wavelength 1.55 microm. A simple fabrication method for the lensed fiber employing chemical etching and rf-sputtering is presented. Experiments showed that the mode-field-diameter of a single-mode fiber was successfully contracted from 10.5 to 1.3 microm with the lensed fiber.
authors.affiliation: Graduate School of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya 321-8585, Japan. kazuos@cc.utsunomiya-u.ac.jp
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shiraishi
authors.forename: Makoto
authors.initials: M
authors.lastname: Kagaya
authors.forename: Koichi
authors.initials: K
authors.lastname: Muro
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Yoda
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kogami
authors.forename: Chen S
authors.initials: CS
authors.lastname: Tsai