Patent ID: 7266299

Claim:
A tunable add/drop-drop and continue module, comprising: a branching unit for optical signals, wherein each optical signal comprises a plurality of optical transmission channels; an insertion unit; and first and second tunable optical filters, arranged in series between the branching unit and insertion unit, wherein the first optical filter has a lower reflection attenuation and a higher transmission attenuation than the second optical filter, wherein, during the transmission of one of the plurality of transmission channels, the first optical filter is tuned to a pass frequency range that is between two optical transmission channels that neighbor the one transmission channel, and wherein the pass frequency of the second optical filter is tuned to a frequency range of the one transmission channel, said second optical filter reflecting a portion of the signal in the one transmission channel received from the first optical filter, and passing the remaining portion of the signal in the one transmission channel to effect a drop-and-continue functionality for the channel within the module.