Division of C-band and L-band in WDM

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Key words: WDM, C-band, L-band, O-band

In optical communication,  wavelength of 1260-1620nm is most suitable for transmission in optical fibers.

ITU-T divides the frequency bands above 1260nm into O, E, S, C, L and U bands

WDM wavelength division multiplexing band type:

O-band: The O-band is 1260-1360 nm. In O-band, the signal distortion (due to dispersion) is minimal.

E-band: E-band (extended wavelength band)1360-1460 nm). The E band is mainly used as an extension of the O band, but has few applications.

S-band: S-band (Short-wavelength Band), short-wave band: 1460-1530 nm, lower loss than O-band, S-band is used as PON (passive optical network) system.

C-band: The C-band (Conventional Band) ranges from 1530 nm to 1565 nm. Optical fiber shows the lowest loss in the C-band, has a greater advantage in long-distance transmission systems, and is commonly used in many metropolitan, long-distance, ultra-long-distance and subsea optical transmission systems combined with WDM and EDFA technology.

L-band: L-band (Long-wavelength Band), 1565-1625 nm, is the second lowest loss wavelength Band, often used when the C-band is insufficient to meet bandwidth requirements. The DWDM system extends upwards to the L-band.

The two transmission Windows of C-band and L-band have the smallest transmission attenuation loss, so the signal light in the DWDM system is usually chosen in the C-band and L-band.

In addition to the O-band to L-band, there are two other bands, namely 850 nm band and U band (ultra-long band: 1625-1675 nm). The 850 nm band is the dominant wavelength for multimode fiber optic communication systems, incorporating VCsels (vertical cavity surface-emitting lasers). The U-band is mainly used for network monitoring.

WDM technology can be divided into CWDM and DWDM according to different wavelength modes. The wavelength range specified by the ITU for CWDM (ITU-T G.694.2) is 1271 to 1611 nm; DWDM channels are more densely spaced, using C-band (1530 nm-1565 nm) and L-band (1570nm-1610nm) transmission Windows. Ordinary WDM generally uses 1310 and 1550nm wavelengths.

Fiberwdm has many years of manufacturing experience in the optical communication industry, independent research and development and production of WDM products, fully used in data centers, power communications, railway communications, radio and television networks, metropolitan area networks and 4G/5G networks and other scenarios, FWDM, CWDM, CCWDM, DWDM, AAWG, ultra-mini WDM and other products for a variety of application scenarios to provide the best products and services, to meet the application needs of different customers