Dielectric multilayer thin-film filters for WDM transmission systems

Dielectric multilayer thin-film (DMF) filters for a wavelength-division-multiplexing (WDM) system are discussed. It was found that a 23-layer 3-cavity bandpass-type DMF-filter made of TiO
2
and SiO
2
is most suitable for this type of system. An optical multi/demultiplexer employing this type of bandpass DMF-filter is applicable to a two-way WDM transmission system.