Agilent design software improves optical link performance

Agilent Technologies Inc. (NYSE: A) has introduced a physics-based software model for its opto model library that it says quickly and accurately solves the challenges posed by signal distortion in vertical cavity surface emitting lasers (VCSELs) used in rack-to-rack optical links.

Oct 29th, 2013

Agilent Technologies Inc. (NYSE: A) has introduced a physics-based software model for its opto model library that it says quickly and accurately solves the challenges posed by signal distortion in vertical-cavity surface-emitting lasers (VCSELs) used in rack-to-rack optical links.

The new VCSEL model, available in the Advanced Design System (ADS) 2013 Transient Convolution Element and SystemVue 2013 AMI Modeling Kit, is used both for modeling optoelectronic components and designing them into equipment.

In earlier years, rack-to-rack digital signals propagated tens or even hundreds of meters across CAT-5 twisted pair or coaxial copper cables with little distortion. However, at today’s data rates, rising and falling edges degrade after travelling only a few meters. Laser technologies like VCSELs have reduced the cost of optoelectronics to the point where fiber-optic cables are now replacing traditional copper cabling for spans over about 10 m in the multi-gigabit regime.

Up to now, simulation tools used to design these nonlinear devices required engineers to learn a new method of analysis. With the new VCSEL model, however, Agilent is leveraging a technique that high-speed digital engineers will already be familiar with—the input/output buffer information specification (IBIS) AMI flow. Senior Agilent engineers contributed this innovative model to document BIRD-156 of the IBIS Open Forum. BIRD-156 extends the AMI flow to allow both electrical and optical repeater links to be modeled and was incorporated in the recently ratified IBIS version 6.0. Agilent co-authors will present a paper, “Modeling, Extraction and Verification of VCSEL Model for Optical IBIS AMI,” at DesignCon 2014, to be held in January in Santa Clara.

With the VCSEL model, SystemVue 2013 now offers model builders, such as optoelectronic component vendors, a tool that supports the evolution of IBIS and can be used to build rack-to-rack opto link models, Agilent says. The models run in ADS, the tool that consumers of these optical components, such as data center and telecom equipment manufacturers, use to design optical subsystems into their hardware. SystemVue 2013 also features an enhanced model for the clock/data recovery circuitry found in both optical and electrical retimers.

“With our previous opto model library release we added a simpler class of VCSEL model with frequency-independent behavior,” said Colin Warwick, product manager for high-speed digital design at Agilent EEsof EDA. “With this release, we’re adding not only a physics-based, frequency-dependent model that uses rate equation techniques, but also a tool to fit the rate equation parameters to measured data, ensuring an accurate model.”

Agilent’s Advanced Design System 2013 and SystemVue 2013 are available now. Pricing depends on configuration.

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