Add More Bandwidth, Not More Fiber
By Edouard Tabet
Many industry analysts predict that new fiber deployment in Canada and the U.S. over the next five years may actually exceed the total fiber installed to date.
Closing the digital divide in rural areas is one factor driving new fiber deployment. Other drivers include cloud computing, 5G, IoT and smart cities, with many network operators laying new fiber to meet the additional bandwidth requirements of these and other applications.
But more fiber isn’t necessarily the best solution for more bandwidth. Since the 1990s, Tier-1 operators have used wavelength division multiplexing (WDM) technologies to add more bandwidth without adding more fiber.
Today, technical advances and reduced costs make WDM solutions attractive and accessible to virtually all network operators, regardless of their size and resources.
Two types of WDM are commonly used today:
- Coarse wavelength division multiplexing (CWDM) creates up to 18 widely spaced optical channels in a single fiber; driven by less sophisticated, lower cost transceivers.
- Dense wavelength division multiplexing (DWDM) creates up to 96 narrowly spaced channels in a single fiber; driven by more sophisticated, higher cost transceivers.
What’s Next? Ultra-wideband WDM (UW-WDM) will utilize an expanded range of wavelengths across the C, L and S-bands to create up to 192 channels in a single fiber, with potential throughput exceeding 100 Tbps.
Top Six Reasons for WDM
- Multiply the bandwidth and capacity of existing fiber
WDM transforms a single physical fiber into multiple virtual fibers. With DWDM, for example, it’s possible to multiplex 96 100 Gbps channels onto one fiber, increasing the capacity of each fiber from 100 Gbps to 9.6 Tbps and beyond.
- Protocol and data rate transparency
WDM channels are transparent to transmission protocols and data rates, allowing simultaneous operation of multiple services and data rates over a single fiber pair.
- Coexistence of PON standards: GPON, XGS-PON and NG-PON2
WDM enables simultaneous upstream and downstream traffic on a single fiber strand. WDM works with coexisting modules to support multiple services on a single fiber, allowing concurrent operation of GPON, XGS-PON and NG-PON2 over the existing PON infrastructure without changing the outside plant.
- 5G small cell connectivity and C-RAN optimization
Proper 5G coverage requires a massive number of small cells operating in a centralized RAN (C-RAN) architecture, typically connected over a fiber fronthaul network. WDM supports the transition to C-RAN and replaces multiple dedicated fiber runs at each small cell site with multiple WDM channels in a single fiber span.
- Simplified operations and service provisioning, faster time-to-revenue
WDM works with network management and provisioning systems to support centralized service provisioning, network reconfiguration and network operations.
- Capital efficiency and ROI
WDM technologies allow network operators to start small and scale economically. Adding capacity and bandwidth in the existing fiber plant, without adding more fiber, maximizes network ROI.
The Bottom Line
WDM allows operators to add more bandwidth without adding more fiber – saving time and money while simplifying network operations at the same time.
In a June 2022 proof-of-concept, Nokia demonstrated how to increase fiber capacity from GPON to XGS-PON to 25G and beyond by simply adding wavelengths to a single strand of glass.
Edouard Tabet,
VP, Engineering
Wirewerks
Edouard Tabet, B.ME, P. Eng., is the VP of Engineering at Wirewerks, a manufacturer of advanced optical fiber and copper structured cabling solutions. He earned his degree in Mechanical Engineering at the Université Polytechnique de Montréal and has over 20 years of industry experience.
