A compact single channel dropping filter for wavelength division multiplexe
d systems with high selectivity has been realized in planar waveguide techn
ology, It consists of a cylindrical microresonator between a pair of parall
el mono-modal waveguides. From the first experimental results and simulatio
ns it can be concluded that an add/drop device is feasible with a free spec
tral range that allows operation with a large number of wavelengths in the
third telecommunication window. (C) 1999 Published by Elsevier B.V. All rig
hts reserved.