Planar lightwave wavelength blocker

摘要

A method and apparatus are disclosed for filtering an input wavelength-division multiplexed (WDM) signal comprised of N wavelength channels. The disclosed wavelength blocker includes a demultiplexer for producing a plurality of demultiplexed output signals from the input WDM signal and a multiplexer for producing an output WDM signal. A shutter array selectively passes each of the N wavelength channels using a plurality of shutters. The demultiplexer is coupled to the multiplexer using a plurality of waveguides having approximately equal length, in order to reduce multipath interference. Each of the N wavelength channels are selectively passed or blocked using a thermo-optic or electro-optic control signal to control the state of the corresponding shutter. Crosstalk can be reduced using dilation techniques that position two shutters in series, especially where the shutters are thermo-optic Mach-Zehnder switches. Wavelength-selective cross connects and wavelength add-drop multiplexers are also disclosed that employ the novel wavelength blockers.