How 96-Channel 50GHz DWDM Makes Better Use of C-Band Fiber

When an optical network needs to support more services, adding new fiber routes is not always the most practical way to increase capacity. Existing single-mode fiber can carry multiple independent signals when different services are assigned to separate wavelengths within the same optical spectrum.

Dense Wavelength Division Multiplexing (DWDM) takes this concept further by using closely spaced wavelength channels. Instead of allocating a separate fiber pair to every optical service, numerous channels can be combined onto the same physical fiber route and separated at the receiving end.

A high-density configuration such as the DWDM 96 dual fiber 2U is designed for this type of optical transport architecture. Developed by Infinol Technology (Shenzhen) Co., Ltd., the system uses a 96-channel AAWG MUX/DEMUX configuration based on the 50GHz ITU-T G.694.1 wavelength grid.

With channels from C14/H14 through C61/H61, the system provides a structured way to utilize the C-band for high-density point-to-point optical transmission.

Why 50GHz Spacing Enables Higher Channel Density

Channel spacing determines how many wavelengths can be arranged within a particular portion of the optical spectrum.

The system uses a 50GHz channel interval, equivalent to approximately 0.4nm in the C-band. Compared with a wider wavelength grid, this narrower spacing allows more channels to be positioned within the available spectral range.

For the 96-channel configuration, the wavelength plan extends approximately from 1566.31nm to 1528.38nm, covering the C14/H14 through C61/H61 channels according to the ITU-T G.694.1 50GHz grid.

The advantage of this arrangement is not simply the ability to advertise a higher channel count. It provides a method for assigning different optical services to separate wavelength positions while allowing those services to use the same physical fiber infrastructure.

For networks facing increasing traffic but limited fiber availability, this can provide another approach to capacity planning.

How the AAWG MUX/DEMUX Handles Closely Spaced Wavelengths

A dense wavelength system requires an optical filtering technology capable of distinguishing neighboring channels accurately.

The system uses AAWG (Arrayed Waveguide Grating) technology with a FAT-TOP design. This passive optical technology is used to combine multiple wavelength signals at the transmitting side and separate them at the receiving side.

During multiplexing, individual wavelength channels enter their corresponding input ports. The AAWG structure combines these signals into a common line output. The resulting composite optical signal can then travel through the shared fiber route.

At the remote location, the demultiplexer reverses the process by separating the wavelength channels and directing each one toward its designated output.

Because the channels are closely spaced, optical filtering characteristics become especially important. The system specifies center wavelength accuracy of ±0.05nm and passband ripple of ≤0.75dB.

The specified -1dB passband is ≥0.18nm, while the -3dB passband is ≥0.28nm. These parameters provide engineers with reference points for evaluating the usable spectral region around each channel.

96 Channels Across a Dual-Fiber Point-to-Point Link

The fiber architecture is another important consideration when designing a DWDM system.

The 96-channel configuration uses a dual-fiber bidirectional arrangement, providing separate physical paths for the two transmission directions. One fiber can carry the optical traffic in one direction, while the second fiber handles the reverse direction.

Multiple wavelength channels can operate over these shared fiber paths rather than requiring an independent fiber pair for every service.

For example, several optical services can be assigned different DWDM wavelengths. The MUX combines the signals at the originating site, the fiber route transports the composite signal, and the DEMUX at the remote location separates the wavelengths again.

This architecture can be considered for applications such as data centers, cloud infrastructure, telecommunications networks, financial systems, broadcast networks, government communications, and other high-capacity optical environments.

The physical fiber remains shared, while wavelength allocation provides separation between individual services.

Optical Loss Needs to Be Included in the Link Budget

Higher channel density does not eliminate the need for careful optical power planning.

The specified insertion loss of the 96-channel DWDM configuration is ≤7.0dB, while the specified link loss is ≤14dB. These figures should be evaluated together with the other losses present in the complete transmission path.

A passive MUX/DEMUX does not amplify or regenerate an optical signal. Its primary function is wavelength combination and separation. Consequently, the available optical power must account for fiber attenuation, connectors, splices, optical switches, amplifiers, and other passive components.

For longer-distance transmission, additional optical equipment may be required. DWDM amplifiers can be incorporated where optical amplification is needed, while dispersion compensation modules can be considered when chromatic dispersion becomes a relevant factor.

The appropriate configuration depends on the actual transmission distance, transceiver specifications, fiber characteristics, and required optical margin.

Channel Isolation Becomes More Important as Density Increases

With 96 wavelength channels occupying a relatively compact spectral region, maintaining separation between neighboring channels is essential.

The system specifies adjacent channel isolation of ≥25dB and non-adjacent channel isolation of ≥30dB, with total crosstalk specified at ≥25dB.

Channel isolation indicates how effectively the optical filtering system keeps energy associated with one wavelength from affecting another channel.

This becomes particularly relevant when multiple services share the same fiber. Each service may use different transceivers or carry different traffic, so maintaining appropriate wavelength separation helps preserve the intended optical channel structure.

For this reason, a DWDM MUX/DEMUX should not be evaluated only by its channel count. Channel spacing, wavelength accuracy, passband behavior, insertion loss, and isolation all contribute to the practical performance of a dense wavelength system.

Monitoring Access for Optical Network Maintenance

Large optical networks can become difficult to troubleshoot when many wavelengths share the same transmission path. A dedicated monitoring interface can provide additional visibility without requiring engineers to disconnect the primary traffic path.

The 96-channel system includes a dedicated monitor port that can be used for optical link monitoring or optical power measurement.

During maintenance, engineers can use the monitoring path to inspect optical conditions and help identify potential problems within the transmission system.

For example, if one wavelength experiences abnormal performance, monitoring information can help narrow the investigation toward the transceiver, fiber route, passive component, or optical power level.

This type of access is particularly useful in high-density deployments because multiple services may be traveling through the same physical infrastructure. Troubleshooting one channel should ideally avoid unnecessary disruption to unrelated traffic.

A 2U Rackmount Format for Centralized Deployment

Physical installation becomes increasingly important when a network uses a large number of optical channels.

The product is available in a 2U rackmount configuration measuring approximately 88 × 440 × 230mm, with a net weight of about 4.5kg.

The standard interface configuration uses LC/UPC connectors and includes the optical monitoring port.

A 2U enclosure allows the MUX/DEMUX to be integrated into a standard equipment rack alongside other transmission and optical management equipment. This can make fiber routing and equipment organization more structured in centralized facilities.

Such a format can be suitable for data centers, telecommunications rooms, transmission sites, and other environments where optical components need to be installed within standardized rack infrastructure.

What Applications Can Use a 96-Channel DWDM Platform?

The combination of high channel density and shared fiber transmission makes 96-channel DWDM relevant to networks where spectral efficiency is an important design consideration.

Potential application environments include:

• Data center interconnection

• Cloud network infrastructure

• Telecommunications transmission

• Financial communication networks

• Broadcast and television systems

• Government optical networks

• High-capacity enterprise links

• Long-distance optical transport

The MUX/DEMUX itself provides the passive wavelength layer, while the rest of the network can be built around compatible optical transceivers, amplifiers, dispersion compensation equipment, switches, and transmission systems.

The final configuration should always be based on the required distance, service type, wavelength allocation, fiber route, and optical power budget.

Working With a Supplier for Different Optical Configurations

A DWDM deployment may require more than a standard 96-channel configuration. Projects can differ in wavelength selection, connector type, rack format, transmission architecture, and supporting optical equipment.

Infinol Technology (Shenzhen) Co., Ltd. develops and supplies active and passive optical communication products, including DWDM and CWDM equipment, optical transceivers, SFP and QSFP products, DAC and AOC cables, and MPO/MTP solutions.

The company also supports OEM and ODM requirements for optical communication products. This can be relevant for network projects that require specific interfaces, configurations, or integration requirements rather than a single standardized product.

When evaluating a supplier, engineers can therefore consider both the individual MUX/DEMUX specifications and the supplier's ability to support the wider optical network architecture.

Key Points to Check Before Deployment

Before integrating a 96-channel DWDM MUX/DEMUX into an optical network, several technical parameters should be reviewed.

Wavelength compatibility: Confirm that all optical transceivers correspond to the selected ITU-T G.694.1 wavelength channels.

Channel spacing: Verify the 50GHz grid and ensure that the connected equipment is compatible with the selected wavelength plan.

Passband performance: Check the center wavelength accuracy, passband ripple, and -1dB/-3dB passband specifications.

Optical loss: Include MUX/DEMUX insertion loss and link loss when calculating the complete optical budget.

Channel isolation: Review adjacent and non-adjacent isolation when multiple high-density channels are deployed.

Transmission architecture: Confirm whether the planned network uses the appropriate dual-fiber point-to-point arrangement.

Monitoring: Determine whether the monitor port can support the maintenance and optical power monitoring requirements of the network.

Rack integration: Check the available rack space and interface requirements for the 2U enclosure.

These checks can help engineers identify potential compatibility and link-budget issues before installation.

Making Better Use of Existing C-Band Fiber

The practical purpose of a high-density DWDM system is to increase the amount of information that can be transported over existing fiber infrastructure by using the optical spectrum more efficiently.

With a 50GHz channel grid, 96 available wavelength channels, AAWG filtering, defined isolation characteristics, and a dual-fiber point-to-point architecture, the system provides a structured platform for carrying multiple optical services through shared fiber resources.

The DWDM 96 dual fiber 2U also combines the wavelength layer with a rackmount enclosure and dedicated monitor port, allowing it to fit into centralized optical transmission environments.

When paired with compatible transceivers and, where required, amplifiers, dispersion compensation modules, and other optical equipment, a high-density DWDM MUX/DEMUX can form an important passive layer within a network designed to expand capacity while continuing to make efficient use of existing C-band fiber.

www.infinol.com
Infinol Technology (shenzhen) Co., Ltd​

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