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How does DWDM technology work?

Telecommunication networks today employ optical technology to transport the enormous amounts of data we consume, often across large distances. It is for this reason that networks are predominately built using fiber optic cable. In order to maximize the transmission capacity of these cable assets, a technology known as wavelength division multiplexing (WDM) was developed that is a fundamental for dense wavelength division multiplexing. i.e. DWDM technology, the most popular variant. Essentially, DWDM squeezes data traffic into many distinct optical channels, using different wavelength bands, or ‘colors’ of light. With the latest flexgrid and C+L technology, DWDM systems can carry 30-40 Tb/s across a single fiber pair, depending on the length of the fiber stretch itself. 

Since its introduction in late 90’s, DWDM has played an important role in optical networking, dramatically increasing data capacity and utilization of the physical fiber. Simply explained, DWDM technology is based on the combination and transmission of multiple optical signals, with dedicated wavelengths simultaneously using the same fiber cable. This means that DWDM uses single mode fiber to carry multiple light waves of different frequencies. Because of its simplicity and efficiency, DWDM technology is a key component of the Internet backbone, providing almost unlimited transmission capacity and scalability.  

DWDM technology squeezes data traffic into many distinct optical channels, using different wavelength bands, or ‘colors’ of light.

Why we use DWDM

DWDM is used in both terrestrial and subsea networks, and other scenarios, including data center to data center links. Apart from meeting high-capacity requirements, DWDM also delivers required levels of quality and security. This technology is especially suitable and cost-effective for long distance transmission, i.e., long-haul networking. 


Arelion uses the term Wavelengths to describe all services using the DWDM network irrespective of interface/framing. Wavelength services can be handed over as Ethernet over DWDM/EoDWDM (XXGE), SDH (STM-XX) or OTN (OTU-X).

Arelion’s Wavelength offerings, based on the DWDM technology and underpinned with software-defined flexibility, are scalable and easily upgradeable. We provide transport of heavy data loads that require high transport capacity and flexibility. Our Wavelength services support all applications, from voice and video to storage across different customer sites, on a global scale. Customers can also choose between different options to build their network and connect key sites, from single links to a redundant ring topology.  

Additionally, we offer a dual-link service option, with our highest level of availability for the most critical applications. This provides two fully diverse routes between the same endpoints. 

DWDM chart

The latest, beta-released option that Arelion introduced in 2021. This is a new and innovative way of monitoring fiber patches between Arelion’s network and customer equipment (this service does not include monitoring of active 3rd party tails). See the DWDM chart below.

Technical highlights
Wavelengths service options: single, protected and dual links

1 GE

10 GE

100 GE

400 GE 


STM 16/ OC 48

STM 64/ OC 192

ODU capacity


OTU 2e



Security highlights

When you need the highest level of security for critical data, our highest level of availability, the dual-link service option provides two fully diverse routes between the same end points.

Secure by design features
NOC situated in a well secured and connected building with multiple power sources
Physical and logical security from design to deployment
Network-wide Acceptable Use Policy (AUP)
Customer Service authentication procedures
Clear customer data handling policies

Build your core network

It is the 21st century, the number of people on Earth is reaching 8 billion, and we are experiencing the network connectivity’s flowering time connecting the entire planet. In parallel, we are going through many challenges, like pandemics, energy crises and instable economies.

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