All-fiber drop-pass filters with fiber Bragg gratings

We introduce new fiber grating devices, called here all-fiber drop-pass filters. Excellent controllability of the relative drop and pass power and wavelength tunability for the drop-pass filters, which consist of an all-fiber Mach-Zehnder interferometer (MZI), a phase controller and one or two fiber gratings, have been demonstrated. The experimental data on the relative drop and pass power at different phases agree well with the theoretical values.