Patent ID: 8594504

Claim:
An optical demultiplexing structure for demultiplexing channels from a wavelength multiplexed optical signal comprising: a first optical filter having a band-pass characteristic and operative to extract a first set of channels from an optical signal, the first set of channels including at least one channel within the pass-band of the first optical filter and not adjacent to a filtering edge of the first optical filter, and one channel adjacent each filtering edge of the first optical filter, wherein the first set of channels comprises a set of intermediate wavelength channels within a full set of channels in the optical signal; a first high/low wavelength optical splitter connected to the first optical filter and having an intersection wavelength that is within the pass-band of the first optical filter, and is configured to divide the remaining channels not extracted by the first optical filter into a second set of channels that have wavelengths lower than the wavelengths of the intermediate channels and a third set of channels that have wavelengths higher than the wavelengths of the intermediate channels; and a second optical filter having a pass-band characteristic and operative to extract a first subset of channels from the second set of channels, the first subset of channels including at least one channel within the pass-band of the second optical filter and not adjacent to a filtering edge of the second optical filter, and one channel adjacent each filtering edge of the second optical filter, such that no channel has more than one of the filtering edge adjacencies.