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What is a wavelength (DWDM)?

1 May 20264 min read

Light travels over an optical fibre. Without any extra technology that means one light source at each end of the cable — one colour of light, so one stream of traffic. If you want to move more traffic you can take a thicker shared pipe, but then you are still sharing the road with everyone else.

A wavelength is the private road.

Wavelength multiplexing (DWDM)

With Dense Wavelength Division Multiplexing (DWDM) we let dozens of colours of light travel over the same fibre at once. Each colour — each wavelength — is a separate, completely isolated channel. Renting one of those colours is therefore like having your own cable between two data centres, without anyone digging a new one into the ground.

You connect your equipment at one end; the DWDM equipment carries your colour in a straight line to the other end. What you send over it is entirely up to you: 10 or 100 gigabit Ethernet, or another protocol that suits your application.

Why a wave instead of a shared service?

  • Fixed capacity — the full bandwidth of the wavelength is yours. What other customers do has no effect on your traffic.
  • Predictable latency — a direct optical path with minimal intermediate steps. Important for storage replication and database clusters, where every millisecond counts.
  • Full control — no agreements about VLANs or MTUs with a middleman; the channel is transparent.

When does a wavelength fit?

A wave is the right choice when a shared connection is no longer enough: a great deal of capacity between two sites, latency-sensitive applications, or simply the wish to have the channel entirely in your own hands. For smaller or more flexible needs, Ethernet transport or EVPN are often a better fit — they run over the same infrastructure, but shared and therefore cheaper.

Wavelengths at Xyphen IT

We light our leased dark fibre ourselves with our own DWDM equipment and rent out wavelengths of 10 and 100 Gbit/s between our Amsterdam core sites. The entire optical network is under our own management — a fault or a question? You speak directly to the engineer who can get to it.

Frequently asked questions

Frequently asked questions

What is the difference between a wavelength and an ordinary Ethernet connection?

An Ethernet service shares the underlying infrastructure with other traffic; a wavelength is a dedicated optical channel with a fixed capacity you share with nobody. That makes the throughput and latency of a wave entirely predictable.

Which speeds are common?

10 and 100 Gbit/s per wavelength are the standard. Dozens of wavelengths fit over the same fibre at the same time.

Do I need dark fibre for a wavelength?

No, and that is precisely the point. Whoever lights the fibre (as we do with our own DWDM equipment) rents out individual colours. You get the capacity of a dedicated connection without renting fibre or managing optics yourself.

Answer not found?

Ask an engineer directly — we usually respond within one business day.