Optical near-field study of photonic crystal tapers.
A scanning near-field optical microscopy study is undertaken on photonic crystal tapers. These tapers are used to couple a 3 microm wide multimode dielectric waveguide to a single-line defect monomode photonic crystal waveguide. Two kinds of taper, with or without a localized defect, are compared. Higher transmission efficiency is obtained when a defect is utilized. The near-field study at 1550 nm shows experimentally that this defect prevents leaky resonant states to appear in the taper and thus permits a decrease in out-of-plane losses. These observations are supported by band diagram calculations.
Institut des Nanotechnologies de Lyon (INL), CNRS, UMR 5270, Université de Lyon, INSA-Lyon, Bât Blaise Pascal, 7 avenue Jean Capelle, Villeurbanne F-69621, France.
Delphine
D
Néel
Taha
T
Benyattou
Pablo
P
Sanchis
Javier
J
Martí
Wim
W
Bogaerts
Pieter
P
Dumon
Roel
R
Baets