Am. Streltsov et Nf. Borrelli, Fabrication and analysis of a directional coupler written in glass by nanojoule femtosecond laser pulses, OPTICS LETT, 26(1), 2001, pp. 42-43
A directional coupler written in a glass sample by the focused 400-nm outpu
t from a 25-fs oscillator is reported. The coupler is single mode; the spli
tting ratio is 1.9 dB at 633 nm. A refractive-index profile of the waveguid
e with a magnitude of Deltan = 4.5 x 10(-3) was retrieved from a near-field
mode pattern. (C) 2001 Optical Society of America OCIS codes: 220.4000, 32
0.7130, 320.7160, 230.7370.