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High-speed O-Band DWDM solutions for cost-effective metro networks

In many metro access network applications, range requirements are limited to a few tens of kilometers. For these medium-range applications, LambdaGain™ O-band DWDM transceivers and Mux/Demux modules can economically deliver up to 8 x 100Gbps services in the wavelengths between 1260 and 1360 nm, with a range of up to 40 kilometers, under ideal conditions, without additional amplifiers or dispersion compensation modules (DCMs). 

Background: 100 Gbps Grey and DWDM Optics Trade-offs

Traditional LR4 or ER4 modules can be used to implement 100 Gbps links using “grey” optics, but this approach only allows a single circuit to be implemented per fiber pair. DWDM technology can maximize the capacity of a fiber connection, and C-band NRZ/PAM4 modulation 100Gbps DWDM optics are cost-effective and low power consumption, but can only achieve distances of 2–3 kilometers. What’s needed is a DWDM solution to maximize the capacity of each fiber that can also economically reach practical distances within the metro access network. 

The O-Band Alternative: Ideal Optical Properties for Metro Networks

The O-band, or original band, offers an interesting solution to the dilemma of implementing cost-effective mid-range DWDM links. The O-band suffers from high attenuation that makes it poorly suited to long distance applications, but it offers near zero chromatic dispersion, meaning that it’s ideal for implementing cost-effective PAM4 links at typical metro access network distances. 

O-Band Capacity and Range Performance

LambdaGain QSFP28 100Gbps O-band DWDM transceivers deliver 100 Gigabit Ethernet (100GbE) optical communications over single mode fiber. With an optical link budget up to 17dB, the modules support 8 O-band wavelengths using cost-effective PAM4 modulation and direct detect demodulation. Using LambdaGain O-band DWDM mux/demux units to combine transceivers, operators can implement single and dual fiber links with up to 8, 100 Gbps circuits per fiber pair while achieving distances up to 40 kilometers, without amplification or dispersion compensation. 


Mode Of Operation  # of Services  Aggregate Bit Rate (Gbps)  Range (kms) 
Single Fiber with 4CH Mux/Demux  2  200  34 – 40 
Single Fiber with 8CH Mux/Demux  4  400  31 – 37 
Dual Fiber with 4CH Mux/Demux  4  400  34 – 40 
Dual Fiber with 8CH Mux/Demux  8  800  31 – 37 

Business Benefits

When operators need to increase the capacity of existing fiber assets, the benefits of O-band DWDM can reduce both CAPEX and OPEX. 


  • Reduced CAPEX: achieved because O-Band transceivers are a more cost-effective, high-capacity, DWDM alternative to coherent DWDM C-band optics, amplifiers, and dispersion-compensation for Metro network applications. Moreover, leveraging LambdaGain DWDM technology in the O-band, operators can cost-effectively implement metro access networks over existing fiber assets originally deployed for grey optics and/or CWDM networks, without impacting existing services. 


  • Reduced OPEX: O-band-based multiplexers and optical transceiver modules allow operators to implement high-speed IPoDWDM links over significant distances while maintaining passive infrastructure for easier management, reduced footprint, and lower energy consumption compared to transponder-based approaches.  

LambdaGainTM Solution Elements

The LambdaGain O-band DWDM solution is built around a family of low-loss O-band DWDM mux/demux units and a set of cost-effective O-band DWDM optical transceivers.  


The key elements that drive the success of the solution include: 


  • The LambdaGain O-band DWDM QSFP28 transceivers that are fully interoperable with leading industry networking equipment manufacturers (NEMs) and offer the following key features:  
  • Compliant with QSFP28 MSA, 100G Lambda MSA​ 
  • Hot Pluggable QSFP28 footprint​ 
  • O-band WDM with 400GHz Channel spacing​ 
  • Supports 106.25Gb/s(PAM4)​ 
  • APD Receiver​ 
  • 8 Wavelengths​ 
  • Max power consumption < 5.5w​ 
  • Operating Temperature: 0˚C to 70˚C​ 

QSFP28 O-band DWDM Pluggable

  • LambdaGain O-band Mux/Demux modules are fully passive and compatible with LambdaGain LGX chassis enclosures. Other key features include: 
  • Available in both dual-fiber and single-fiber configurations  
  • 400GHz spacing DWDM grid at O-Band ​ 
  • Low insertion loss​ 
  • Operating temperature: -40˚C to 85°C 

LambdaGainTM Passive O-Band DWDM Mux/Demux


Expanding capacity using 100 Gbps O-band DWDM optics and DWDM passive mux/demux modules provides a cost-effective, accelerated solution for expanding the capacity of congested metro network links. This approach aims squarely at a sweet spot of high-speed and middle-distance reach, and could be an ideal solution for a range of backhaul and data center interconnect applications, reducing both OPEX and CAPEX

Contact Us

If you are evaluating alternative transport options to increase the capacity of your metro network, and would like to know more about O-band DWDM as an alternative or complement to traditional CWDM and DWDM solutions, please contact us. 

About FONEX Data Systems inc. 

FONEX data systems inc. (FONEX), delivers optimised, purpose-built solutions for wireline and wireless telecommunications service providers across Canada, the USA, and Europe. We combine over 30 years of expertise in telecommunication architectures, standards, and trends with a leadingedge portfolio of carrier-class products to meet and exceed our customers’ business, technical and operational requirements. Find out more about FONEX here. 

Fernando Donoso

Product Marketing Manager