100-gigabaud optics usher in the era of terabit transmissions

•  NeoPhotonics has unveiled a coherent modulator and receiver that operate at over 100 gigabaud.

Telecom operators are in a continual battle to improve the economics of their optical transport networks to keep pace with the relentless growth of IP traffic.

One approach is to increase the symbol rate used for optical transmission. By operating at a higher baud rate, more data can be carried on an optical wavelength.

Ferris Lipscomb

Alternatively, a higher baud rate allows a simpler modulation scheme to be used, sending the same amount of data over greater distances. That is because the fewer constellation points of the simpler modulation scheme help data recovery at the receiver.

NeoPhotonics has detailed two optical components - a coherent driver-modulator and an intradyne coherent receiver (micro-ICR) - that operate at over 100 gigabaud (GBd). The symbol rate suits 800-gigabit systems and can enable one-terabit transmissions.

NeoPhotonics’ coherent devices were announced to coincide with the ECOC 2020 show.

Click to read more ...

Telecoms embraces 400ZR optics for IP-over-DWDM

Verizon Media has trialled 400-gigabit coherent pluggable optics to improve the delivery of video content to subscribers.

Tomas Maj

Verizon Media added a 400ZR QSFP-DD module from Inphi to a switch already using 100-gigabit optics to upgrade its content delivery network.

Adding dense wavelength-division multiplexing (DWDM) optics to a switch enables it to send IP traffic (IP-over-DWDM) directly without needing a separate DWDM data centre interconnect box and additional client-side optics to link the two platforms (see diagram).

“Verizon Media, showing leadership outside the hyperscalers, is moving to IP-over-DWDM,” says Tomas Maj, senior director, marketing, optical interconnect at Inphi. “It shows the maturity of the ecosystem and the confidence of more and more operators in IP-over-DWDM and 400ZR.”

Click to read more ...

Is traffic aggregation the next role for coherent?

Ciena and Infinera have each demonstrated the transmission of 800-gigabit wavelengths over near-1,000km distances, continuing coherent's marked progress. But what next for coherent now that high-end optical transmission is approaching the theoretical limit? Can coherent compete over shorter spans and will it find new uses?

The first of several articles addressing what next for coherent.

Part 1: XR Optics

“I’m going to be a bit of a historian here,” says Dave Welch, when asked about the future of coherent.

Interest in coherent started with the idea of using electronics rather than optics to tackle dispersion in fibre. Using electronics for dispersion compensation made optical link engineering simpler.

Dave Welch

Coherent then evolved as a way to improve spectral efficiency and reduce the cost of sending traffic, measured in gigabit-per-dollar.

“By moving up the QAM (quadrature amplitude modulation) scale, you got both these benefits,” says Welch, the chief innovation officer at Infinera.

Click to read more ...

II-VI shrinks an optical line system into an OSFP module

II-VI has developed an optical line system that fits inside a pluggable module. 

The advent of coherent pluggable modules implementing the 400ZR standard allows switches and routers to be linked across separate data centres. Now, with a pluggable optical line system, a dedicated line-system platform is no longer needed to send the 400ZR signals over a fibre. 

Sanjai ParthasarathiIn turn, the network operating system on the switch manages the optical line system directly such that a separate optical management software layer is no longer needed.

“We have shrunk an entire pizza-box line system into a small pluggable,” says Sanjai Parthasarathi, chief marketing officer at II-VI.

Indeed, one customer refers to the II-VI pluggable product - dubbed the OSFP-LS - as a ‘zero-rack-unit’ platform.

Click to read more ...

NeoPhotonics talks 400ZR, 600G, 800G and Lidar

Many companies that prepared for the OFC show in March had their plans thwarted due to the COVID-19 pandemic. 

OFC did take place in San Diego despite all the hardships. But company withdrawals meant technology demonstrations were scrapped, press releases went unissued and stories left untold.

Ferris Lipscomb

Intel and Ranovus, for example, planned to fanfare their first co-packaged optics designs at OFC. Demonstrations to interested parties did occur but at their offices instead.

Equally, 800-gigabit coherent technologies from Ciena and Infinera would have been showcased at the show, as would industry organisations' interoperability demonstrations. 

NeoPhotonics announced in January that it was sampling 400-gigabit coherent pluggable offerings in the CFP2 and OSFP form factors.

At OFC it was to show a QSFP-DD module implementing the 400ZR OIF coherent standard, thereby completing its 400-gigabit coherent portfolio. 

“A lot of the planned demos involved inter-operation in customer switches with other modules,” says Ferris Lipscomb, vice president of marketing at NeoPhotonics. “Many of these demos are now being done in San Jose [its HQ in California] for customers coming individually.”

Click to read more ...

Acacia unveils its 400G coherent module portfolio

Acacia Communications has unveiled a full portfolio of 400-gigabit coherent optics and has provided test samples to customers, one being Arista Networks.

Delivering a complete set of modules offers a comprehensive approach to address the next phase of coherent optics, the company says. 

Tom WilliamsThe 400-gigabit coherent designs detailed by Acacia are implemented using the QSFP-DD, OSFP and CFP2 pluggable form factors.

Collectively, the pluggables support three performance categories: the 400ZR standard, OpenZR+ that is backed by several companies, and the coherent optics specification used for the Open ROADM multi-source agreement (MSA). 

“These are challenging specifications,” says Tom Williams, vice president of marketing at Acacia. “Even the 400ZR, where the objective has been to simplify the requirements.” 

Click to read more ...

Nokia buys Elenion for its expertise and partnerships

Nokia will become the latest systems vendor to bolster its silicon photonics expertise with the acquisition of Elenion Technologies. 

The deal for Elenion, a privately-held company, is expected to be completed this quarter, subject to regulatory approval. No fee has been disclosed.

Kyle Hollasch

“If you look at the vertically-integrated [systems] vendors, they captured the lion’s share of the optical coherent marketplace,” says Kyle Hollasch, director of optical networking product marketing at Nokia. “But the coherent marketplace is shifting to pluggables and it is shifting to more integration; we can’t afford to be left behind.”   

Click to read more ...