How to Extend Your Network Transmission Distance?

To face the need for long-haul, high-capacity transmission, experts come up with several DWDM projects including DWDM Mux Demux, EDFA amplifier (erbium-doped fiber amplifier) and DCM module (dispersion compensation module) to expand network capacity and enhance the signal power, which can greatly extend the optical network reach. Do you have the need to deploy a longer fiber optical transmission link? If yes, you can just build a DWDM system with the DWDM projects mentioned above. This paper will introduce three solutions that utilize these DWDM components to extend the optical network transmission distance. Hope these DWDM solutions would be useful for you.

Using DWDM Mux Demux for Long Transmission up to 50 km

DWDM technology plays an important role in building long-haul transmission system, which enables multiple signals with different wavelengths to be transmitted through only one single fiber. To build a long system with DWDM technology, the DWDM Mux Demux is an indispensable component that features low insertion loss and polarization-dependent loss. By using the DWDM Mux Demux in your network, the signal transmission distance can be extended to up to 50 km. To better know the advantage of DWDM Mux Demux, here offers an example that uses two 8 channel DWDM Mux Demux for extending the optical fiber link.

8 channel DWDM Mux Demux for Long transmission

From the figure, we can learn that at the transmit side, eight kinds of signals from different fiber links are multiplexed into an integrated signal by the 8 channel DWDM Mux. Then the integrated signal is transmitted over the single mode fiber (SMF) and the maximum transmission distance can be up to 50 km. At the receiver side, the signal will be demultiplexed into individual signals with their original wavelengths by the 8 channel DWDM Demux and then transmitted to another eight different fiber links. Just by using the DWDM Mux Demux, a 50km long-haul transmission can be simply achieved.

Adding EDFA Amplifier for Transmission Longer Than 50 km

As we know, the longer the transmission distance is, the higher the fiber loss will be. Hence, except for the DWDM Mux Demux, you are suggested to add an EDFA amplifier to the long fiber link if the transmission distance is longer than 50 km. What’s the function of EDFA amplifier? It is mainly designed to amplify the signal power, which enables longer transmission. As shown in the following figure, you can learn that the only difference is the EDFA amplifier in the SMF, compared to the first solution.

EDFA and 8 channel DWDM Mux Demux for Long transmission

When the integrated signal multiplexed by the 8 channel DWDM Demux is transmitted over the SMF, it would become too weak in the transmission process to be transmitted. Then the EDFA amplifier should be placed there to boost the signal power, supporting the transmission longer than 50 km. Once the long transmission is realized, the signal will be also split by the 8 channel DWDM Demux, like the first solution. In short, DWDM Mux Demux and EDFA amplifier are highly suggested if you want to deploy a DWDM system longer than 50 km.

Adding DCM Module for Transmission up to 200 km

With the use of EDFA amplifier, the DWDM fiber link can be extended to 200 km. However, the signal quality is always unsatisfied due to the optical dispersion in long transmission, especially in CATV systems. To meet high requirements of the signal quality in these long transmission systems, an additional optical component, DCM module are needed in the long fiber link, as deployed in the figure below.

DCM, EDFA and 8 channel DWDM Mux Demux for Long transmission

From the figure, we can learn it is a long-haul point-to-multipoint CATV system. To extend the transmission distance, 8 channel DWDM Mux Demux, EDFA amplifier are used. Except for that, a DCM module is added to enhance the skew signal for ensuring the whole transmission quality. With the use of DCM module, the accumulated chromatic dispersion issue is solved, without dropping and regenerating the wavelengths on the long fiber link. Thereby, a high-performance 200km system can be reached.


DWDM projects including DWDM Mux Demux, EDFA amplifier and DCM module are key optical components to support long-haul transmission systems. If you want to deploy a long transmission system up to 50 km, then the DWDM Mux Demux is needed. For transmission longer than 50 km, both the DWDM Mux Demux and EDFA amplifier are required for boost the signal power. But once the transmission distance is about 200 km, you should additionally add the DCM module to enhance the signal quality.


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