Ciena advances coherent technology on multiple fronts

• Ciena has unveiled the industry’s first coherent digital signal processor (DSP) to support 1.6-terabit wavelengths
• Ciena announced two WaveLogic 6 coherent DSPs: Extreme and Nano
• WaveLogic 6 Extreme operates at a symbol rate of up to 200 gigabaud (GBd) while the Nano, aimed at coherent pluggables, has a baud rate from 118-140GBd

Part 1: WaveLogic 6 coherent DSPs

Helen Xenos

Ciena has leapfrogged the competition by announcing the industry’s first coherent DSP operating at up to 200GBd.

The WaveLogic 6 chips are the first announced coherent DSPs implemented using a 3nm CMOS process.

Ciena’s competitors are - or will soon be - shipping 5nm CMOS coherent DSPs. In contrast, Ciena has chosen to skip 5nm and will ship WaveLogic 6 Extreme coherent modems in the first half of 2024.

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Deutsche Telekom explains its IP-over-DWDM thinking

Telecom operators are always seeking better ways to run their networks. In particular, operators regularly scrutinise how best to couple the IP layer with their optical networking infrastructure.

The advent of 400-gigabit coherent modules that plug directly into an IP router is one development that has caught their eye.

Placing dense wavelength division multiplexing (DWDM) interfaces directly onto an IP router allows the removal of a separate transponder box and its interfacing.

IP-over-DWDM is not a new concept. However, until now, operators have had to add a coherent line card, taking up valuable router chassis space.

Werner Weiershausen

Now, with the advent of compact 400-gigabit coherent pluggables developed for the hyperscalers to link their data centres, telecom operators have realised that such pluggables also serve their needs.

BT will start rolling out IP-over-DWDM in its network this year, while Deutsche Telekom has analysed the merits of IP-over-DWDM.

"The adoption of IP-over-DWDM is the subject of our techno-economical studies," says Werner Weiershausen, senior architect for the transport network at Deutsche Telekom.

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Lumentum talks switching & signalling developments

In detailing some of its recent product announcements and the associated optical networking trends, Lumentum provides useful pointers to watch out for at the upcoming OFC virtual conference and exhibition event in June.

Brandon Collings

Lumentum detailed recently its high-bandwidth coherent driver modulator (HB-CDM) that operates at a symbol rate up to 96 gigabaud (GBd).

"Lumentum is working with a decent number of network equipment makers (NEMs) on their high-performance coherent offerings using the HB-CDM component," says Brandon Collings, CTO of Lumentum.

The 96GBd device supports modulation formats from dual polarisation quadrature phase-shift keying (DP-QPSK) to 64-ary quadrature amplitude modulation (DP-64QAM) and when used with an appropriate coherent digital signal processor (DSP), the device supports up to 800-gigabit wavelengths.

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