Next-generation reconfigurable optical add/ drop multiplexers (ROADMs) will perform an important role in simplifying network operation but optical component vendors making the core component - the wavelength-selective switch (WSS) - on which such ROADMs will be based should expect a limited return for their efforts.
"[Component suppliers] are going to be under extreme constraints on pricing and cost"
Sterling Perrin, Heavy Reading
That is one finding from an upcoming report by market research firm, Heavy Reading, entitled: "The Next-Gen ROADM Opportunity: Forecast & Analysis".
"We do see a growth opportunity [for optical component vendors]," says Sterling Perrin, senior analyst and author of the report. “But in terms of massive pools of money becoming available, it's not going to happen; it is a modest growth in spend that will go to next-generation ROADMs."
That is because operators’ capex spending on optical will grow only in single digits annually while system vendors that supply the next-generation ROADMs will compete fiercely, including using discounting, to win this business. "All of this comes crashing down on the component suppliers, such that they are going to be under extreme constraints on pricing and cost," says Perrin. The report will quantify the market opportunity but Heavy Reading will not discuss numbers until the report is published.
Next-generation ROADMs incorporate such features as colourless (wavelength-independence on an input port), directionless (wavelength routing to any port), contentionless (more than one same-wavelength light path accommodated at a port) and flexible spectrum (variable channel width for signal rates above 100 Gigabit-per-second (Gbps)).
Networks using such ROADMs promise to reduce service providers' operational costs. And coupled with the wide deployment of coherent optical transmission technology, next-generation ROADMs are set to finally deliver agile optical networks.
Other of the report’s findings include the fact that operators have been deploying colourless and directionless ROADMs since 2010, even though implementing such features using current 1x9 WSSs are cumbersome and expensive. However, operators wanting these features in their networks have built such systems with existing components. "Probably about 10% of the market was using colourless and directionless functions in 2010," says Perrin.
Service providers are requiring ROADMs to support flexible spectrum even though networks will likely adopt light paths faster than 100Gbps (400Gbps and beyond) in several years' time.
The need to implement a flexible spectrum scheme will force optical component vendors with microelectromechanical system (MEMS) technology to adopt liquid crystal technology – and liquid-crystal-on-silicon (LCoS) in particular - for their WSSs (see Comments). "MEMS WSS technology is great for all the stuff we do today - colourless, directionless and contentionless - but when you move to flexible spectrum it is not capable of doing that function," says Perrin. "The technology they (vendors with MEMS technology) have set their sights on - and which there is pretty much agreement as the right technology for flexible spectrum - is the liquid crystal on silicon." A shift from MEMS to LCoS for next-generation ROADM technology is thus to be expected, he says.
Perrin also highlights how coherent detection technology, now being installed for 100 Gbps optical transmission, can also implement a colourless ROADM by making use of the tunable nature of the coherent receiver. "It knocks out a bunch of WSSs added to the add/ drop," says Perrin. "It is giving a colourless function for free, which is a huge advantage."
Perrin views next-gen ROADMs as a money-saving exercise for the operators, not a money-making one. "This is hitting on the capex as well as the opex piece which is absolutely critical," he says. "You see the charts of the hockey stick of bandwidth growth and flat venue growth; that is what ROADMS hit at."
The Heavy Reading report will be published later this month.
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