Abstract: An optical add/drop multiplexer (OADM) adapted to route optical signals having at least two different bit rates. The OADM has at least two sets of DWDM channels with channels in a first set having a first bandwidth value, e.g., suitable for the transmission of signals having a bit rate of 10 Gb/s, and channels in a second set having a second bandwidth value, e.g., suitable for the transmission of signals having a bit rate of 40 Gb/s. In one embodiment, the frequencies of the channels from the first set are interleaved with the frequencies of the channels from the second set, and the OADM has first and second optical branches adapted to process optical signals corresponding to the first and second sets, respectively. Initially, the OADM may be configured to process 10-Gb/s signals using the first optical branch only while leaving the second optical branch unutilized.

Abstract: An optical add/drop multiplexer (OADM) adapted to route optical signals having at least two different bit rates. The OADM has at least two sets of DWDM channels, e.g., with channels in a first set having a first bandwidth value suitable for the transmission of 10-Gb/s signals and channels in a second set having a second bandwidth value suitable for the transmission of 40-Gb/s signals. The first and second sets occupy two different spectral bands and the first set has two subsets of interleaved channels. In one embodiment, the OADM has first and second optical branches adapted to process optical signals corresponding to first and second groups of channels, respectively. The first group includes a first subset from the first set while the second group includes the second set and a second subset from the first set. Advantageously, OADMs of the invention may be used to create independent processing paths for different groups of channels. As a result, a communication system having those OADMs can be upgraded, e.g.