DWDM Basics: Multiplying Capacity on a Single Fibre Pair
A single pair of optical fibres can carry far more than one 10 or 100 Gbps link. Wavelength-division multiplexing sends multiple signals at different colours of light down the same fibre — each one an independent channel.
CWDM and DWDM
- CWDM (coarse): up to 18 widely spaced wavelengths. Inexpensive passive optics, suited to shorter metro distances.
- DWDM (dense): many closely spaced wavelengths — often 40, 80 or more — in the C-band. Supports amplification for long distances and very high total capacity.
Building blocks
- Transponders or coloured optics that put each service on its own wavelength.
- Multiplexers that combine and separate wavelengths.
- Amplifiers (EDFA) that boost all channels together over long spans.
- ROADMs that add or drop wavelengths at intermediate sites without manual re-patching.
When it makes sense
- You own or lease dark fibre and need more than one or two high-speed links.
- Fibre is expensive or scarce on the route.
- You want to carry different services — Ethernet, storage, video — separately.
Plan the optical budget
Distance, splices, connectors and mux losses all add up. A proper link budget avoids surprises during commissioning.
We design and deploy optical networks over our dark and aerial fibre. Discuss your capacity needs.
