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As it is known to all, optical multiplexers are components specifically designed for wavelength division multiplexing (WDM) systems. The optical multiplexer couples two or more wavelengths into the same fiber, while the optical demultiplexer separates a multiplicity of wavelengths in a fiber and directs them to many fibers (see figure 1). If a multiplexer is placed and properly aligned back-to-back with a demultiplexer, it is clear that multiple wavelengths exist in the area between them. This presents an opportunity for an enhanced function—optical add drop multiplexer.
An optical add drop multiplexer (OADM) is a device used in wavelength division multiplexing systems for multiplexing and routing different channels of light into or out of a single mode fiber (SMF). This is a type of optical node, which is generally used for the construction of optical telecommunications networks. “Add” and “drop” here refer to the capability of the device to add one or more new wavelength channels to an existing multi-wavelength WDM signal, and/or to drop/remove one or more channels, passing those signals to another network path (see Figure 2). In Figure 2, F1 signifies a filter that drops wavelength λ1 and allows all other wavelengths to pass through, while M1 signifies a multiplexer that multiplexes all wavelengths.
The explosive growth of the Internet and high bandwidth application has created capacity demands exceeding traditional TDM limits. To meet growing demands for bandwidth, wavelength division multiplexing (WDM) has been developed that multiplies the capacity of a single fiber. This cutting-edge WDM technology when combined with optical add drop multiplexers enables carriers to adopt optically-based transmission optical networks that will meet faster transmitted and high bandwidth demand.
Wavelength selective optical add/drop multiplexer is required for adding and dropping a particular WDM channel at each subscriber’s node in the WDM based optical access networks. Add/drop multiplexer used in WDM based optical networks will have a good reflection characteristic, a temperature stability, a narrow spectral bandwidth, and a low implementation cost. At present, OADM has been investigated based on WDM technology for high speed performance. Under this technology, the bit error rate for added and dropped channels at different fiber link lengths has been decreased. OADM has a key role in moving toward the goal of all-optical networks, no conversion of the signal from optical to electrical takes place. Moreover, OADM is one of the key components for WDM equipment in passive optical ring network. It is used for selectively dropping and inserting signals into a transparent DWDM equipment and CWDM modules.
The OADM based on WDM technology is moving the telecommunications industry closer to the development of optical networks. Fiberstore, a leading supplier and manufacturer in the optical industry, has a large number of WDM products including DWDM Mux/Demux, CWDM SFP transceiver, fiber Mux Demux and CWDM multiplexer, etc. For more information, welcome to visit Fiberstore.