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Entries in Coherent (27)

Thursday
Jun222017

The OIF’s 400ZR coherent interface starts to take shape

The Optical Internetworking Forum’s (OIF) group tasked with developing two styles of 400-gigabit coherent interface is now concentrating its efforts on one of the two.

When first announced last November, the 400ZR project planned to define a dense wavelength-division multiplexing (DWDM) 400-gigabit interface and a single wavelength one. Now the work is concentrating on the DWDM interface, with the single-channel interface deemed secondary. 

Karl Gass"It [the single channel] appears to be a very small percentage of what the fielded units would be,” says Karl Gass of Qorvo and the OIF Physical and Link Layer working group vice chair, optical, the group responsible for the 400ZR work.

The likelihood is that the resulting optical module will serve both applications. “Realistically, probably both [interfaces] will use a tunable laser because the goal is to have the same hardware,” says Gass.   

The resulting module may also only have a reach of 80km, shorter than the original goal of up to 120km, due to the challenging optical link budget.

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Monday
Nov282016

DIMENSION tackles silicon photonics’ laser shortfall

Ambitious European project seeks to combine lasers, electronics and photonics, all on one chip

Several companies and research institutes, part of a European project, are developing a silicon photonics process that combines on-chip electronics and lasers. Dubbed Dimension (Directly Modulated Lasers on Silicon), the silicon photonics project is part of the European Commission’s Horizon 2020 research and innovation programme.

 

 The Dimension process showing the passive photonics, dielectric material, BiCMOS circuitry, and the on-chip lasers and modulators. The indium phosphide material is shown in red. Source: Dimension.

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Wednesday
Nov252015

COBO looks inside and beyond the data centre 

The Consortium of On-Board Optics is working on 400 gigabit optics for the data centre and also for longer-distance links. COBO is a Microsoft-led initiative tasked with standardising a form factor for embedded optics.

Established in March 2015, the consortium already has over 50 members and expects to have early specifications next year and first hardware by late 2017.

 

Brad Booth

Brad Booth, the chair of COBO and principal architect for Microsoft’s Azure Global Networking Services, says Microsoft plans to deploy 100 gigabit in its data centres next year and that when the company started looking at 400 gigabit, it became concerned about the size of the proposed pluggable modules, and the interface speeds needed between the switch silicon and the pluggable module.

“What jumped out at us is that we might be running into an issue here,” says Booth.

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Wednesday
Oct142015

ECOC 2015 Review - Part 1

Part 1: Line side announcements

  • Several companies announced components for 400 gigabit optical transmission
  • NEL announced a 200 gigabit coherent DSP-ASIC
  • Lumentum ramps production of its ROADM blades while extending the operating temperature of its tunable SFP+

 

400 gigabit

Oclaro, Teraxion and NeoPhotonics detailed their latest optical components for 400 gigabit optical transmission using coherent detection.

Oclaro and Teraxion announced 400 gigabit modulators for line-side transmission; Oclaro’s based on lithium niobate and Teraxion’s an indium phosphide one.

NeoPhotonics outlined other components that will be required for higher-speed transmission: indium phosphide-based waveguide photo-detectors for coherent receivers, and ultra-narrow line-width lasers suited for higher order modulation schemes such as dual-polarisation 16-quadrature amplitude modulation (DP-16-QAM) and DP-64-QAM.

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Thursday
May212015

OIF moves to raise coherent transmission baud rate

The Optical Internetworking Forum (OIF) has started modulator and receiver specification work to enhance coherent optical transmission performance. The OIF initiative aims to optimise modulator and receiver photonics operating at a higher baud rate than the current 32 Gigabaud (Gbaud).

"We want the two projects to look at those trade-offs and look at how we could build the particular components that could support higher individual channel rates,” says Karl Gass of Qorvo and the OIF physical and link layer working group vice chair, optical.  

Karl Gass

The OIF members, which include operators, internet content providers, equipment makers, and optical component and chip players, want components that work over a wide bandwidth, says Gass. This will allow the modulator and receiver to be optimised for the new higher baud rate.

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Tuesday
Nov252014

NeoPhotonics to expand its tunable laser portfolio 

Part 1: Tunable lasers

NeoPhotonics will become the industry's main supplier of narrow line-width tunable lasers for high-speed coherent systems once its US $17.5 million acquisition of Emcore's tunable laser business is completed. Gazettabyte spoke with Ferris Lipscomb of NeoPhotonics about Emcore's external cavity laser and the laser performance attributes needed for metro and long haul.   


Key specifications and attributes of Emcore's external cavity laser and NeoPhotonics's DFB laser array. Source: NeoPhotonics.

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Tuesday
Mar182014

Acacia uses silicon photonics for its 100G coherent CFP

Acacia Communications has revealed the innards of its 100 Gig coherent pluggable module for metro networks. The AC-100 CFP combines a low-power DSP-ASIC with a silicon-photonics-based optics chip. The CFP's reach is 80km to 1,200km, and its power consumption is 24-26W, well within the pluggable's maximum power profile of 32W.

 

The power consumption of the AC-100 CFP, and its main components, and the target power consumptions of the components needed for a digital CFP2. Source: Gazettabyte

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