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Entries in Coherent (29)

Tuesday
Oct102017

Acacia announces a 1.2 terabit coherent module

Acacia Communications has given first details of its AC1200 coherent optical module, capable of transmitting up to 1.2 terabits of data. The custom coherent transceiver is being aimed at applications ranging from linking data centres to long-haul and even sub-sea transmissions and was announced at the recent ECOC show held in Gothenburg.

Channel capacity and link margin can be maximised by using the fractional QAM scheme. Source: Acacia.

The company is facing increasing market competition. Ciena has teamed up with Lumentum, NeoPhotonics, and Oclaro, sharing its high-end coherent DSP expertise with the three optical module makers. Meanwhile, Inphi has started sampling its 16nm CMOS M200, a 100- and 200-gigabit coherent DSP suitable for CFP2-ACO, CFP-DCO, and CFP2-DCO module designs.

The AC1200 is Acacia’s response, extending its high-end module offering beyond a terabit to compete with the in-house system vendors and preserve its performance lead against the optical module makers.

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Friday
Sep152017

Has coherent optical transmission run its course?

Feature: Coherent's future

Three optical systems vendors share their thoughts about coherent technology and the scope for further improvement as they look two generations ahead to symbol rates approaching 100 gigabaud   

Optical transmission using coherent detection has made huge strides in the last decade. The latest coherent technology with transmitter-based digital signal processing delivers 25x the capacity-reach of 10-gigabit wavelengths using direct-detection, according to Infinera.

Since early 2016, the optical systems vendors Infinera, Ciena and Nokia have all announced new coherent digital signal processor (DSP) designs. Each new generation of coherent DSP improves the capacity that can be transmitted over an optical link. But given the effectiveness of the latest coherent systems, has most of the benefits already been achieved?

 

Source: Infinera

“It is getting harder and harder,” admits Kim Roberts, vice president, WaveLogic science at Ciena. “Unlike 10 years ago, there are no factors of 10 available for improvement.”

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Thursday
Jun222017

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

Part 2: Coherent developments

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.   

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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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