title: Fabrication and analysis of a directional coupler written in glass by nanojoule femtosecond laser pulses.
abstract: A directional coupler written in a glass sample by the focused 400-nm output from a 25-fs oscillator is reported. The coupler is single mode; the splitting ratio is 1.9 dB at 633 nm. A refractive-index profile of the waveguide with a magnitude of Dn = 4.5 x 10(-3) was retrieved from a near-field mode pattern.
authors.forename: A M
authors.initials: AM
authors.lastname: Streltsov
authors.forename: N F
authors.initials: NF
authors.lastname: Borrelli