Hyperscalers' needs drive a new class of coherent DSP

Coherent digital signal processors (DSPs) companies have supported two families of coherent chips for some time. That's because no single coherent DSP can meet all the market's requirements.

The coherent DSP used for highest-performance optical transmissions must include advanced coding techniques, forward error correction, and a high symbol rate to send as much data as possible on a single wavelength and maximise reach.

Helen Xenos at NGON & DCI World

In contrast, a DSP for coherent pluggable modules needs to be power-efficient and compact to meet the optical module's power envelope and size constraints; a 400ZR QSFP-DD and a CFP2-DCO 400ZR+ being examples.

According to Ciena, now there is a need for a third category of coherent DSP for 1.6 terabit-per-second (Tbps) and 3.2Tbps transmissions over short distances for next-generation switch routers.

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ADVA and II-VI’s coherent partnership

• ADVA and II-VI have jointly developed a 100-gigabit coherent DSP
• Both companies plan to use the 2.0-2.5W, 7nm CMOS Steelerton DSP for a 100 ZR QSFP28 module
• II-VI’s ASIC design team engineered the DSP while ADVA developed the silicon photonics-based optics. 

ADVA and II-VI have joined forces to define a tiny coherent digital signal processor (DSP) that fits inside a QSFP28 optical module.

Christoph Glingener

The Steelerton DSP can send a 100-gigabit dense wavelength-division multiplexing (DWDM) transmission over 80-120km, carrying wireless backhaul and access traffic.

“It is backhaul of broadband, it is backhaul of mobile, and it definitely moves outdoors,” says Christoph Glingener, CTO at ADVA.

The module also serves metro networks with its 300km reach using optical amplification.

II-VI and ADVA now join such established coherent players as Ciena, Huawei, Infinera, Nokia as well as Marvell, NEL, and Acacia, now part of Cisco.

Effect Photonics announced at OFC earlier this year its coherent market entry with its acquisition of the Viasat DSP team. 

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