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For telecommunications, a frequency grid is a table of all the central frequencies (and corresponding wavelengths) of channels allowed in a communications system.. The most common frequency grid used for fiber-optic communication is that used for channel spacing in Dense Wavelength Division Multiplexing (DWDM) at wavelengths around 1550 nm and defined by ITU-T G.694.1. [1]
The introduction of the ITU-T G.694.1 [8] frequency grid in 2002 has made it easier to integrate WDM with older but more standard SONET/SDH systems. WDM wavelengths are positioned in a grid having exactly 100 GHz (about 0.8 nm) spacing in optical frequency, with a reference frequency fixed at 193.10 THz (1,552.52 nm). [9]
As a matter of convention, the ITU divides the radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten (10 n) metres, with corresponding frequency of 3×10 8−n hertz, and each covering a decade of frequency or wavelength. Each of these bands has a traditional name.
Fax standards T.2 – T.4, T.30, T.37, T.38 F.780.2 G.114 is an ITU Recommendation that addresses acceptable delays for voice applications, is oriented to national telecommunications, and is more stringent than what is normally applied in private voice networks.
range Wavelength range ITU designation IEEE bands [5] Full name Abbreviation [6] Below 3 Hz >10 5 km — 3–30 Hz 10 5 –10 4 km: Extremely low frequency: ELF — 30–300 Hz 10 4 –10 3 km: Super low frequency: SLF — 300–3000 Hz 10 3 –100 km: Ultra low frequency: ULF — 3–30 kHz 100–10 km: Very low frequency: VLF — 30–300 kHz ...
ITU-T Recommendation G.709 Interfaces for the Optical Transport Network (OTN) describes a means of communicating data over an optical network. [1] It is a standardized method for transparent transport of services over optical wavelengths in DWDM systems. It is also known as Optical Transport Hierarchy (OTH) standard.
G.652 is an international standard that describes the geometrical, mechanical, and transmission attributes of a single-mode optical fibre and cable, developed by the Standardization Sector of the International Telecommunication Union that specifies the most popular type of single-mode optical fiber (SMF) cable.
The range of mode field diameter permitted in G.655 is 8 to 11 μm in non-zero dispersion-shifted fibre. G.655.C fibre has a maximum PMD link design value of 0.20 ps/sqrtkm, which is the lowest value recommended by ITU-T. G.655 has the cable cut-off wavelength and cable attenuation coefficients in the C and L bands. [2]