"Increasing demand for network services is driving the introduction of new transmission formats and channel management technologies that facilitate the efficient use of optical bandwidth for extremely high data rates. While the introduction of coherent techniques such as Dual-Polarization Quadrature Phase Shift Keying (DP-QPSK) enables 100Gb/s transmission within a 50 GHz channel, traffic with higher data rates, including 400 Gb/s and 1 Tbit/s signals of the future, are not expected to fit inside 50 GHz wide channels. These higher data rates require that channel spacings are flexible and can be increased to allow the use of new transmission formats. Finisar's Flexgrid® technology provides dynamic control of the channel center frequency with 6.25 GHz resolution and channel width with 12.5 GHz resolution within a Wavelenth Selective Switch (WSS), the key element in a Reconfigurable Optical Add/Drop Multiplexer (ROADM). Once deployed, channel plans are configurable 'on-the-fly', meaning that channel bandwidths can be adjusted to most efficiently carry future demands as they arise. As frequency slot edges are aligned to the 12.5 GHz ITU grid, Flexgrid offers full backwards compatibility with both the standard 100 GHz and 50 GHz ITU grids, as illustrated below. Flexgrid is available on all Finisar WSS product lines."