| 摘要 |
In accordance with the invention, a switchable optical filter comprises an optical splitter coupled to an input waveguide, one or more output waveguides and a plurality of interferometer waveguides. A multiwavelength signal from the input waveguide is split into plural identical multiwavelength split signals which are directed into the interferometer waveguides. In the interferometer waveguides, a sequence of controllable phase shifters and reflective filters reflects specific wavelength signals from a respective interferometer waveguide into the splitter and then to a respective output waveguide. In a preferred embodiment, the splitting device comprises a directional coupler, and the filter comprises a Mach-Zehnder interferometer with a mid section including an alternating sequence of a phase shifter on at least one arm and reflective filters on each arm. The filter is particularly useful as a gain equalization filter, an ADM filter and in an optical cross connect. In alternative embodiments, the splitting device can be a multimode interference coupler or a star coupler.
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