Skip to main content

What is fractional QAM?

Extend the lifespan of your optical network

Today’s cloud and internet content providers urgently need to achieve more with their existing regional, long-haul and submarine infrastructure. Communication service providers are also looking to increase the capacity of their deployed optical transport networks to handle data creation growth rates increasing at around 20% every year. The introduction of higher line rates is one of the most common strategies to increase the transport capacity of existing optical infrastructure. In DWDM networks with coherent technology, using higher modulation orders, with a higher number of bits per symbol, will increase the transport capacity per wavelength but at the cost of wavelength reach. With typical QAM modulation schemes, increments can only be in integer and fixed steps, which leads to significant performance steps and inefficient utilization of the available bandwidth. Fractional QAM technology eliminates these steps and allows users to maximize the capacity-reach performance of their existing transport network infrastructure.

Ultra-flexible modulation

With fractional QAM enabling ultra-flexible modulation, a legacy fixed grid optical line system is no longer a barrier to high-speed wavelengths.
Dramatic bandwidth increases are now possible without expensive optical line system upgrades.

Balancing capacity and distance

Operators can now significantly reduce cost per Gigabit mile in brownfield and subsea scenarios.

Optimizing legacy networks with fractional QAM modulation

Fractional QAM modulation boosts network capacity even over legacy DWDM networks, ensuring the lowest cost per Gbit/s for any link. Coherent transponders with typical QAM modulation use a limited range of bit-per-symbol and symbol-rate options. But these discrete steps often fail to achieve the ideal balance between capacity and reach. Fractional QAM modulation technology leverages the many small increments in between, enabling more options to suit a far more comprehensive range of fiber conditions. This means that, for any traffic demand over any distance, data is transmitted with the lowest spectral occupation. Likewise, for a fixed spectral slot (say 50GHz or 100GHz) on any given lightpath, fractional QAM maximizes the transmitted capacity.

Ultra-flexible coherent transport

With fractional QAM technology, enabling massive capacity increase is simple and cost-effective.

A new level of efficiency

With ultra-flexible coherent interfaces featuring fractional QAM, our FSP 3000 TeraFlex™ open optical terminal offers unprecedented network efficiency. An extensive installed base and numerous trials with commercial metro, data center interconnect, and long-haul networks have proven that dramatic bandwidth increases are now possible without expensive optical line system upgrades. Fractional QAM gives users more options beyond classical QAM steps, which leads to a higher capacity and reach performance and a lower cost per Gbit over any type of infrastructure. What’s more, FSP 3000 TeraFlex™ offers client flexibility and enables smooth network upgrades from 10GbE to 100GbE and 400Gbit/s Ethernet. With our FSP 3000 TeraFlex™, service providers and data center operators can now address a broad range of applications with minimum inventory sprawl and market-leading capacity, reach and power efficiency.

Do you need more information?

Contact our team