60km 10G Multi-Site Chain Network on DWDM

Background

There are usually more than two sites in the realistic DWDM network. And it is a very trivial work to design a DWDM network with multiple sites. One FS client needs to build a 10G DWDM chain network which runs about 60km from A to G across several sites, among which there are two sites need to add and drop data.

Challenge

• Active devices such as EDFA can be only installed in sites A and G.

• There are several sites in the whole link. Thus it is difficult to keep the whole link’s optical power balance.

Solution

To maximum the existing fiber capacity for current use, the 40CH C21-C60 DWDM Mux/Demux is placed at both ends of the link which are Sites A and G, and wavelength from C37-C60 is occupied to satisfy the data transmission from A to G. An 8CH OADM with wavelength of C21-C28 is used for data adding and dropping on Site B. And Wavelengths C29-C36 is designed for Site G data adding and dropping with an 8CH OADM.

To ensure reliable transmission, a PA (O13/G20) and a BA (O20/G20) are used on both site A and Site G to ensure there is enough safety margin. The 7db attenuator added before the BA is to adjust the optical power around +4dB thus to protect BA from damage by too much optical power. The 10db attenuator added behind the PA is to ensure the RX power around -13db to -20db.

Moreover, sites B and F also need to use fiber optic attenuators to keep the optical power of the added wavelengths in the proper range.

Conclusion

In this case, we help our client build an efficient 10G 40CH DWDM network which uses only one existing fiber to transmit various business services. This solution not only solves the multiple-site transmission challenge but also reduces the deployment cost and cover future growth to the maximum.