Long-haul DWDM Transmission With Optical Line Protection

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Long-haul DWDM Transmission With Optical Line Protection

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By FS Project Designer2019-07-11

Kujtesa

Industry: IT Services

Location: Kosovo

Background

DWDM network helps maximize the use of existing fibre and optimize the network investment. Our client Kujtesa, an IT company from Kosovo, decided to expand the capacities of their optical transmission link over 79km and planned for a 120km backup path for future scalability.

Challenge

The client needed to improve their network infrastructure and desired to build a more reliable and scalable network. The problems they encountered including:

1, How to establish link protection while achieving future capacity expansion?

2, How to reduce optical loss and ensure enough reserve budget for reliable and stable transmission over long distance transmission?

Solution

FS engineers planned to deploy a 40CH DWDM system with optical line protection to feed the customer’s current and future growth demands for networking capacities.

4 Channels Multi-Rate WDM Converter (Transponder), 8 SFP/SFP+ Slots, Up to 11.3G Rate, Pluggable Module for FMT Multi-Service Transport Platform

£630.00

Customised Pre-Amplifier DWDM EDFA

£1,000.00

40KM DCF-based Passive Dispersion Compensation Module, 4.2dB Low Loss, LC/UPC, Pluggable Module for FMT Multi-Service Transport Platform

£658.00

40 Channels C21-C60, with Monitor Port, 3.0dB Typical IL, LC/UPC, Dual Fibre DWDM Mux Demux, FMU 1U Rack Mount

£1,392.00

LC/UPC Single Mode Fixed Fibre Optic Attenuator, Male-Female, 7dB

£2.40

The OEOs are used to convert the 1G and 10G optical signals into the corresponding DWDM wavelengths. And 1+1 optical line protection switch (OLP) is deployed to create a backup path. When the main optical fibre fails, the protective line will continue to deliver the signal. Therefore, the whole transmission will be more reliable.
To reduce the optical loss on the primary path, the booster amplifier (OBA) is used to increase the power of the transmitted light. The pre-amplifier (OPA) is applied for amplifying the weak optical signal. In addition, several optical attenuators are used to ensure the optical power in a stable and desired level. In this solution, the optical loss on primary link could be 21dB and there will be 5dB for reserve budget, while the optical loss of backup path could be 34dB, with 4dB reserve budget.

Note that dispersion compensation modules (DCMs) should be used on both sides for dispersion compensation in optical fibre transmission. For the current transmission, a 40km DCM is needed, while an 80km DCM should be used for the future link.

Conclusion

FS 40CH DWDM solution not only feeds the current transmission need, but also prepares well for future expansions. And with OLPs on both sides, the signal can be boosted and protected across the whole link, which improves the network stability.