2 x 2 wavelength-selective cross connect capable of switching 128 channels in sets of eight

In this letter, we present an efficient 2 x 2 wavelength-selective cross connect that is serviceable without interrupting traffic. It can handle over a hundred channels in a compact fashion by operating on them in sets. The 50-GHz-spaced passbands are flat-topped with no gaps between them, and so it has high cascadability and can exhibit variable-bandwidth switching. It also can multicast.