title: Wavelength division with three-dimensional couplers fabricated by filamentation of femtosecond laser pulses.
abstract: Refractive-index changes can be induced by filamentation of 800-nm, 1-kHz femtosecond laser pulses in silica glass. Two-dimensional translation of a 40-microm-long filament leads to the formation of a curved waveguide because of bending by the previously induced refractive-index change. The fabrication of 2-mm directional couplers to split the coupled beam into 1:1 at a wavelength of 632.8 nm is demonstrated. The realization of three-dimensional directional couplers and wavelength division in the output from the couplers is also demonstrated.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka, 565-0871 Japan. watanabe@photonics.mls.eng.osaka-u.ac.jp
authors.forename: Wataru
authors.initials: W
authors.lastname: Watanabe
authors.forename: Taishi
authors.initials: T
authors.lastname: Asano
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamada
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Itoh
authors.forename: Junji
authors.initials: J
authors.lastname: Nishii