Optical wavelengths refer to the light channels that transmit data in fibre optic networks. Learn all about optical wavelengths, their different types, and how leasing wavelengths can supercharge your business network.
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What are optical wavelengths?
In fibre optic networks, optical wavelengths refer to the different channels of light used to transmit data. It’s the distance between the peaks or troughs of the light waves used for each channel and is typically measured in nanometres (nm) or billionths of a metre.
The light signal is divided into multiple channels with different frequencies and wavelengths, each transmitting a different data stream. This way, you can transmit up to 88 or more data streams on a single fibre optic cable.
Main types of optical wavelengths
In fibre optic networks, wavelengths are classified by how they divide the light. Optical networks use a technology called Wavelength Division Multiplexing (WDM) to create multiple channels on a single fibre. There are two main types of WDM: CWDM and DWDM.
CWDM
Coarse Wavelength Division Multiplexing (CWDM) typically uses eight active wavelengths per fibre but can support up to 18 channels or more. It’s generally used for short-range networks and can be more cost-effective than DWDM.
DWDM
Dense Wavelength Division Multiplexing (DWDM) uses precision lasers to create up to 88 channels or more per fibre. Typically used in core networks or other high capacity applications, DWDM is a good option for businesses transmitting large data volumes over longer distances.
DWDM optical wavelengths
The table above shows the nominal wavelengths of a typical 88-channel DWDM system.
What are nominal wavelengths?
Nominal wavelengths refer to the centre wavelength of each data channel, as set by the International Telecommunications Union (ITU).
For example, in the DWDM optical wavelengths table above, channel 43.5 has a nominal wavelength of 1542.54nm, which is spaced 0.4nm from channel 43 (1542.94). By standardising nominal wavelengths, the ITU ensures that optical network components are compatible and interoperable worldwide.
What are long-haul wavelengths?
Long-haul wavelengths are the light wavelengths used to transmit over long-distance optical networks. Typically, fibre networks use DWDM wavelengths on the C-band (around 1530-1565nm), and some operators use the L-band (around 1565-1625nm) to maximise capacity on their optical systems.
DWDM supports a higher number of channels and higher data rates than CWDM, providing ample capacity for long-haul optical networks.
In addition, DWDM allows you to amplify the signal using devices like erbium-doped fibre amplifiers (EDFA), massively extending its range. While CWDM is suitable for distances up to 80km (50 miles), DWDM can support networks over hundreds or thousands of kilometres using amplification techniques.
What are the benefits of optical wavelengths?
Optical wavelengths provide high capacity connectivity that’s ideal for communication service providers, data centres, financial services, media and other enterprises transmitting high data volumes.
DWDM-enabled optical networks can provide:
- High capacity: Diverse wavelengths make the most of existing fibre networks, providing more channels, greater bandwidth and speeds up to 400Gbps carried over wavelengths with a potential capacity of 1.6Tbps in the latest vendor technologies.
- Low latency: Optical networks typically have much lower latency than other types of L2 services.
- Easy scalability: Add new channels by simply adding new wavelengths, allowing upgrades without significantly changing the network architecture
- Security: Optical networks can support encryption and ‘dedicated’ wavelengths, which provide exclusive channels for your business to run mission-critical applications.
By leasing optical wavelengths, you only pay for the capacity you need now and scale as you grow. You avoid the upfront costs of building infrastructure and hiring personnel to manage your network.
Optical wavelengths for your business
At Neos Networks, we’re helping businesses nationwide transform their networks with Optical Wavelengths delivering speeds up to 400Gbps.
If you’re looking to upgrade your network to meet the exploding demand for bandwidth, get in touch. We’ll be happy to design a cost-effective optical wavelength solution for your digital future.
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Optical wavelengths FAQs
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How do optical wavelengths enhance the efficiency of fibre optic networks?
Optical wavelengths boost network capacity by allowing multiple data streams to be transmitted simultaneously over a single fibre, each carried on its own wavelength of light. This enables far higher throughput and more efficient use of fibre infrastructure by multiplying the usable bandwidth without adding new physical cables.
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What is the role of Wavelength Division Multiplexing in optical networks?
Wavelength Division Multiplexing (WDM) is a core technology that increases the capacity of fibre optic networks by splitting a single light signal into multiple wavelength channels on one fibre. There are two main types: Coarse Wavelength Division Multiplexing (CWDM), which uses wider spacing for fewer channels over shorter distances, and Dense Wavelength Division Multiplexing (DWDM), which enables many more channels for high-capacity, long-distance transmission.
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Can optical wavelengths be reassigned or reconfigured dynamically?
Modern optical networks can reroute and reassign wavelengths dynamically using ROADMs, without any physical changes to the fibre. Capacity can then be shifted in real time to where it’s needed most, keeping the network efficient as demand changes.
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What are ROADMs?
ROADMs (Reconfigurable Optical Add-Drop Multiplexers) are devices that control how wavelengths are added, dropped or routed through a fibre network. With ROADMs in place, operators can adjust traffic paths remotely, improving flexibility and making it easier to manage network capacity.
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What limits the distance an optical wavelength can travel?
Distance is limited by attenuation, dispersion and noise as the optical signal travels through the fibre, gradually reducing signal strength and quality. To overcome this, networks use optical amplification and regeneration to restore signal integrity and extend reach over longer distances.
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What are typical use cases for optical wavelength services?
Optical wavelength services are commonly used for data centre interconnects (DCI), core network connectivity and high capacity transport between sites. They’re also ideal for data‑intensive applications such as cloud computing, AI workloads, financial trading and media delivery, where high bandwidth and low latency are critical.
