Optical Network Design and Implementation

The ITU Grid

The ITU-T established a set of standards for telecommunications that drives all optical WDM systems today. All land-based DWDM systems follow this standard. The ITU-T has been engaged in standardization initiatives to enable international interoperability of various WDM systems. The introduction of the ITU-T G.694.1 frequency raster has made it easier to integrate WDM with older but more standard SONET systems. The ITU G.694.1 and G.694.2 standard replaces the earlier G.692 specification. The G.694.1 recommendation specifies a frequency grid for DWDM applications. The frequency grid, anchored to 193.1 THz or 1552.52 nm, supports a variety of channel spacing of 12.5 GHz (0.1 nm), 25 GHz (0.2 nm), 50 GHz (0.4 nm), and 100 GHz (0.8 ...