Method and device for tunable optical filtering

Abstract

An optical device includes an optical splitter having a resonant structure including at least a resonator, the optical splitter being adapted to receive at an input port a WDM optical signal and to output at first and second output ports, respectively, a first and a second portion of the optical signal, the second portion including the channels spaced by an integer multiple of the WDM frequency spacing; an optical combiner adapted to receive at first and second input ports, respectively, the first and the second portions and adapted to output them at an output port; a first optical path optically connecting the first output port to the first input port; a second optical path optically connecting the second output port to the second input port; and an optical filter optically coupled to the second optical path, wherein the optical combiner includes at least a resonator.

1 . An optical device comprising:
 an optical splitter having an input port, a first output port, and a second output port, said optical splitter being adapted to output at said first and second output ports, respectively, a first and a second portion of said optical signal, said second portion comprising the channels lying on a second sub-grid of optical frequencies and the first portion comprising the remaining channels lying on a first sub-grid;   an optical combiner having a first input port, a second input port, and an output port and adapted to receive at said first and second input ports, respectively, the first and the second portion and to output the first and second portions at said output port;   a first optical path optically connecting the first output port of the optical splitter to the first input port of the optical combiner and capable of propagating said first portion;   a second optical path optically connecting the second output port of the optical splitter to the second input port of the optical combiner and capable of propagating said second portion; and   an optical filter optically coupled to the second optical path and capable of filtering a channel within said second portion propagating through the second optical path.