Point-to-Point DWDM Architecture Using 100G Coherent Optics Over Dual Fiber

Background

It is widely acknowledged that DWDM systems are the preferred solution over long-haul transmission networks. To overcome the dispersion and attenuation caused in the long-distance links as well as improve the system performance, the selection and deployment of applicable DWDM components becomes vitally imperative. Recently, one of our clients came across some problems in 100G DWDM network deployment and required for a solution for 60km dual fiber transmission.

Challenge

Though there are 2 pairs of fiber links at present, more channels for traffic transmission are potentially needed in the future.For the fact that the total loss across the optical path should be less than 28dB but the whole link loss for the 60 km link is nearly 24dB and the client has already got 1+1 OLP, how many amplifiers are needed and where the amplifier should be placed become issues.In addition, our client requires extra instruments for optical monitoring.

Solution

To ensure normal running of the two traffic channels and the potentially more channels in the future, two 16CH DWDM MUX/DEMUXs are deployed, which are possible to support up to 16×100G traffic transmission.

Owing to the distance limitation of QSFP28 modules, 100G transponders are used to convert QSFP28 to 100G coherent CFP so as to realize 100G data transmission over a longer distance.

In each link, a booster amplifier (BA) is installed behind the DWDM MUX/DEMUX and the pre-amplifier (PA) is placed before the DWDM MUX/DEMUX with the consideration of the link loss and insertion loss of OLP.

To keep the transceiver modules working properly with the output power of 100G DWDM modules limited in a range from -3dBm to -15dBm, some optical attenuators are equipped.

With the aim of monitoring two fiber bidirectional links, a customized OTDR and 1×4 OSW optical switches are used so that client can manually switch or automatically monitor optical paths.

Conclusion

In this case, FS helps the client build up a scalable 100G DWDM solution using FS FMT series products and customized DWDM components, assuring high-performance bandwidth and the link security.