WDM (Wave length Division Multiplexing) is really a transmission technology that utilizes just one optical fiber to concurrently transmit multiple optical carriers of various wavelengths in optical fiber communications. Once the wave length of sunshine differs, the transmission reduction in the fiber can also be different. To be able to lessen the fiber loss, it’s important to obtain the most appropriate transmission wave length. Following a lengthy duration of exploration and testing, light having a wave length of 1260nm~1625nm has got the tiniest dispersion signal distortion with low loss, the most appropriate for transmission in optical fiber.
The wave length of fiber could be split into several bands, each band can be used being an independent funnel to deliver predetermined wave length. Based on the ITU-T standards, singlemode fiber using the band over 1260nm is split into O/E/S/C/L/U
What’s O band?
The O band may be the original band with wave length from 1260 to 1360nm. The O-band may be the first wave length band utilized in optical communications ever, and also the signal distortion (because of dispersion) is minimal.
What’s E band?
The E-band (extended wave length band: 1360-1460 nm) may be the least common of those bands. The E-band is principally employed for the development from the O-band, but it’s rarely used, due to the fact many existing optical cables show high attenuation within the E-band and also the manufacturing process is extremely energy-intensive, therefore the use within optical communication is restricted.
What’s S band?
The optical fiber reduction in the S-band (Short-wave length Band, 1460-1530 nm) is gloomier compared to reduction in the O-band. The S-band can be used as numerous PON (passive optical network) systems.
What’s C band?
The C-band (Conventional Band) varies from 1530 nm to 1565nm to represent the traditional band. Optical fiber shows the cheapest reduction in the C-band and occupies a sizable advantage in lengthy-distance transmission systems. It is almost always utilized in many urban centers coupled with WDM, lengthy-distance, ultra-lengthy-distance and submarine optical transmission systems and EDFA technology. Because the transmission distance becomes longer, and fiber optic amplifiers are utilized rather of optical-to-electronic-to-optical repeaters, the C-band becomes increasingly more important. Using the creation of DWDM (Dense Wave length Division Multiplexing) that enables multiple signals to talk about just one fiber, using the C-band continues to be expanded.
What’s L band?
The L-band (Lengthy-wave length Band, 1565-1625nm) may be the second cheapest-loss wave length band, and it is frequently used once the C-band is inadequate to satisfy the bandwidth needs. Using the wide accessibility to b-doped fiber amplifiers (EDFAs), DWDM systems have expanded upward towards the L-band, and were initially accustomed to expand the capability of terrestrial DWDM optical systems. Now, it’s been brought to submarine cable operators to complete exactly the same factor-to grow the entire capacity of submarine cables.
Because of its low transmission attenuation loss, C-band and L-band is generally selected to make use of within the DWDM system. Aside from the O-band and L-band, there’s two other artists, 850nm band and also the U band (ultra-lengthy band: 1625-1675 nm). The 850nm band may be the primary wave length from the multimode optical fiber communication system, which mixes VCSEL (Vertical Cavity Surface Emitting Laser). The U frequency band is principally employed for network monitoring.
WDM technology could be split into WDM, CWDM, DWDM based on different wave length modes. The wave length range stipulated by ITU for CWDM (ITU-T G.694.2) is 1271 to 1611nm, but thinking about the attenuation from the 1270-1470nm band within the application, this guitar rock band of 1470~1610nm is generally used. The funnel space of DWDM is much more closeness, so pick the C-band (1530 nm-1565 nm) and L-band (1570 nm-1610 nm) transmission home windows. Ordinary WDM generally uses 1310 and 1550nm wavelengths.
Using the development of FTTH applications , the C-band and L-band will have an more and more natural part in optical transmission systems.