Wavelength-division multiplexing isolation filter using concatenated chirped long period gratings

We propose the use of concatenated chirped long period gratings as an efficient wavelength-division multiplexing (WDM) isolation filter. The proposed filter not only works in the transmission mode but also has almost equispaced pass bands with high isolation at the stop bands. The filter has negligible dispersion effects in the pass band, which should make such a device suitable for use in WDM fiber optic communication links.