For

telecommunications Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

, a frequency grid is a table of all the central

frequencies Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

(and corresponding

wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...

s) of channels allowed in a

communications system A communications system is a collection of individual telecommunications networks systems, relay stations, tributary stations, and terminal equipment usually capable of interconnection and interoperation to form an integrated whole. Commu ...

. The most common frequency grid used for

fiber-optic communication Fiber-optic communication is a form of optical communication for transmitting information from one place to another by sending pulses of infrared or visible light through an optical fiber. The light is a form of carrier wave that is modul ...

is that used for channel spacing in Dense Wavelength Division Multiplexing (DWDM) at wavelengths around 1550 nm and defined by

ITU-T The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...

G.694.1.ITU-T G.694.1, "Spectral grids for WDM applications: DWDM frequency grid
ITU-T website
/ref> The grid is defined relative to 193.1 THz and extends from 191.7 THz to 196.1 THz with 100 GHz spacing. While defined in frequency, the grid is often expressed in terms of wavelength, in which case it covers the wavelength range of 1528.77 nm to 1563.86 nm with approximately a 0.8 nm channel spacing. For practical purposes, the grid has been extended to cover 186 THz to 201 THz and subdivided to provide 50 GHz and 25 GHz spaced grids.

References

External links

Complete ITU grid table for 100 Ghz spacingInternational Standardization Activities on Optical Interfaces
Multiplexing ITU-T recommendations ITU-T G Series Recommendations G