Ciena's multi-format 400G coherent QSFP-DD pluggable

Ciena showcased a working 400-gigabit Universal coherent pluggable module at the ECOC 2022 conference and exhibition in Basel, Switzerland.

Ciena is using its WaveLogic 5 Nano coherent digital signal processor (DSP) for the Universal QSFP-DD coherent pluggable module.

"We call it universal because it supports many transmission modes - interoperable and high performance; the most in the industry," says Helen Xenos, senior director of portfolio marketing at Ciena. 

A look inside Ciena's 400-gigabit Universal coherent pluggable module. TOF is the tunable optical filter. Source: Ciena

The pluggable has custom extended-performance modes and supports three industry formats: the 400ZR interoperable standard, the 400ZR+ multi-source agreement (MSA), and the OpenROADM MSA. (See tables below).

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The era of 400G coherent pluggables finally emerges

Part 1: 7nm coherent DSPs, ZR and ZR+

The era of 400-gigabit coherent pluggable modules has moved a step closer with Inphi’s announcement of its Canopus coherent digital signal processor (DSP) and its QSFP-DD ColorZ II optical module. 

NeoPhotonics has also entered the fray, delivering first samples of its 400-gigabit ClearLight CFP2-DCO module that uses the Canopus DSP.

Pranay AiyaThe ColorZ II and ClearLight modules support the 400ZR OIF standard used to link data centres up to 120km apart. They also support extended modes, known as ZR+, that is not standardised.

ZR+’s modes include 400 Gigabit-per-second (Gbps) over distances greater than 400ZR's 120km and lower data rates over metro-regional and long-haul distances.    

The announcements of the Canopus DSP and 400-gigabit pluggable coherent modules highlight the approaches being taken for ZR+. Optical module vendors are aligning around particular merchant DSPs such that interoperability exists but only within each camp.  

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WaveLogic 5: Packing a suitcase of ideas into 7nm CMOS

• Ciena’s WaveLogic 5 coherent digital signal processor family comprises the Extreme and Nano chips
• The WaveLogic 5 Extreme maximises optical capacity and transmission reach while the Nano is targeted at compact, power-conservative applications

Advancing coherent optical transmission performance to benefit its platforms; targeting the emerging coherent pluggable market opportunity; selling modules directly, and being more vertically integrated. All these aspects were outlined by Cisco to explain its intention to buy the coherent optical transmission specialist, Acacia Communications; a deal set to be completed in the spring of 2020.      

But this also fits the strategy being pursued by Ciena with its next-generation WaveLogic 5 family of coherent DSPs.

Kim Roberts

The WaveLogic 5 continues Ciena’s tradition of issuing a coherent digital signal processor (DSP) family approximately every three years: Ciena announced the WaveLogic 3 in 2012 and the WaveLogic Ai in 2016. 

Ciena has managed to maintain its three-yearly cadence despite the increasing sophistication of each generation of coherent DSP. For example, the WaveLogic 5 Extreme will support 800 gigabits-per-wavelength, double Ciena’s WaveLogic Ai that has been shipping for nearly two years. 

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Infinera’s ICE flow

Infinera’s newest Infinite Capacity Engine 5 (ICE5) doubles capacity to 2.4 terabits. The ICE, which comprises a coherent DSP and a photonic integrated circuit (PIC), is being demonstrated this week at the OFC show being held in San Diego. 

Infinera has also detailed its ICE6, being developed in tandem with the ICE5. The two designs represent a fork in Infinera’s coherent engine roadmap in terms of the end markets they will address.

Geoff BennettThe ICE5 is targeted at data centre interconnect and applications where fibre in being added towards the network edge. The next-generation access network of cable operators is one such example. Another is mobile operators deploying fibre in preparation for 5G.

First platforms using the ICE5 will be unveiled later this year and will ship early next year.

Infinera’s ICE6 is set to appear two years after the ICE5. Like the ICE4, Infinera’s current Infinite Capacity Engine, the ICE6 will be used across all of Infinera’s product portfolio.

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Coherent gets a boost with probabilistic shaping

Nokia has detailed its next-generation PSE-3 digital signal processor (DSP) family for coherent optical transmission.

The PSE-3s is the industry’s first announced coherent DSP that supports probabilistic constellation shaping, claims Nokia.

Probabilistic shaping is the latest in a series of techniques adopted to improve coherent optical transmission performance. These techniques include higher-order modulation, soft-decision forward error correction (SD-FEC), multi-dimensional coding, Nyquist filtering and higher baud rates.

Kyle Hollasch

“There is an element here that the last big gains have now been had,” says Kyle Hollasch, director of product marketing for optical networks at Nokia.

Probabilistic shaping is a signal-processing technique that squeezes the last bit of capacity out of a fibre’s spectrum, approaching what is known as the non-linear Shannon Limit.

“We are not saying we absolutely hit the Shannon Limit but we are extremely close: tenths of a decibel whereas most modern systems are a couple of decibels away from the theoretical maximum,” says Hollasch.

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