Multiplexing

Each computer has a port for connecting communication lines or cables to peripheral devices. Since the number of ports on the computer is limited, a multiplexer is used. They combine signals from multiple terminals and place them all on one communication line. This improves communication efficiency and increases cost effectiveness. The communication line is divided into different parts, the data from each terminal is encoded and transmitted, then received, decoded and directed to the correct part from which it originates.

Wavelength division multiplexing (WDM) is a technique for multiplexing a plurality of optical carrier signals on a single fiber. There are two general types of WDM: Coarse Wavelength Division Multiplexing (CWDM) and Dense Wavelength Division Multiplexing (DWDM). They are all very large and fast. We recommend CWDM for short distance transmission and money saving. Due to long distance and high speed, DWDM has tremendous capacity and excellent performance. You can choose the right one according to your request.

From wavelength division multiplexing (WDM) expansion, coarse wavelength division multiplexing (CWDM) is used to increase the bandwidth of the optical fiber by multiplexing several wavelengths on it. If you use 18 channels with 1270 nm to 1610 nm wavelength, you can greatly improve transfer speed. The channel width itself is 13 nm. The remaining 7 nm is used to ensure space for the next channel. This very wide channel spacing of CWDM allows the use of less expensive CWDM network components such as uncooled lasers or low quality multiplexers and demultiplexers. However, in this broad spectral range, the maximum range of CWDM placement is limited to about 60 or 80 km, as it prevents the use of an erbium-doped fiber amplifier that works optimally around 1550 nm. The maximum transmission distance is 120 km. Therefore, CWDM equipment is designed mainly for short-range communications for urban and access networks.

As well-known, CWDM (Coarse Wavelength Division Multiplexing) is a technique of multiplexing wavelengths transmitted by different optical fibers into one optical fiber and transmitting them through an optical multiplexer. This technology is very common in optical communications. But what is CWDM? There may be many people who are confused about this. This article introduces us. Initially, the term "coarse wavelength division multiplexing" was very versatile and meant various things. Often these things share the fact that the choice of channel spacing and frequency stability makes the erbium doped fiber amplifier (EDFA) unusable. Before the relatively new ITU standardization term, the general meaning of CWDM was to multiplex two (or more) signals into one fiber.