Vitesse chipset enhances high-density 40G/100G optical systems

SAN DIEGO, USA: Vitesse Semiconductor Corp., a leading provider of advanced IC solutions for Carrier and Enterprise networks, has announced the industry’s first complete chipset solution for line cards, CXP, and CFP optical transceivers used in next-generation servers, routers, and OTN transport equipment.

In the ultra-broadband era it is estimated that internet traffic doubles every two years. Network equipment manufacturers meet this increased bandwidth demand by deploying high density 40 Gigabit Ethernet (GbE) and 100 GbE solutions based on 4x10G and 10x10G optical wavelengths.

By offering a reference design with its 40G/100G chipset, Vitesse provides module and system OEMs an accelerated, cost-effective development path for building scalable, compact, high-performance optical systems and delivers on the highly anticipated benefits of integrated electronics with optics called Photonic Integrated Circuits (PICs).

Vitesse’s chipset (VSC8248, VSC7978, VSC7986, and VSC7987) supports packing Nx10G un-cooled DMLs of different wavelengths into a very compact area, critical for 40GBase-LR4, ER4 or 10x10G PIC applications for 10km and 40km. It also extends optical links up to 120km without costly optical dispersion compensation, improving link margin in excess of 3dB. Additionally, the chipset meets and exceeds the 40 GbE and 100 GbE IEEE P802.3ba/D3.0 draft standard in areas such as optical stressed receiver sensitivity test and transmit jitter specifications.

The reference design consists of a transmit optical sub-assembly (TOSA) tightly integrated with Vitesse’s low power VSC7986 Directly-Modulated-Laser (DML) drivers, CyOptics lasers, and a Color-Chip System-on-GlassTM (SOG) optical Multiplexer (Mux).

The TOSA eliminates the need for costly bias-T networks and can save as much as 70 percent on laser driver power when compared to alternative implementations. In the receive direction, the reference design comprises a receive optical sub-assembly (ROSA), including a Color-Chip SOGTM optical Demultiplexer (Demux), integrated with Vitesse’s VSC7987 limiting and VSC7978 transimpedance amplifiers.

The limiting approach works well in single mode and multimode fiber for short reach applications, as well as for the datacenter market targeting parallel interconnections such as 12x QDR InfiniBand at 120 Gbps and for 100 GbE.

For single mode and multimode fiber supporting various data rates, protocols, longer link distances, and more challenging applications with difficult optical impairments, the reference design utilizes Vitesse’s VSC7878 linear transimpedance amplifier in the ROSA and its VSC8248 with advanced FlexEQ electronic dispersion compensation (EDC) technology on the line card or in the CFP module.

The VSC8248 is the industry’s first truly integrated quad full-duplex device with EDC functions on all channels. The highly flexible transmit-path with three-tap output driver supports the optimization of output signal transmission across printed circuit board material and connectors while meeting stringent SONET/SDH jitter generation requirements.

In addition to the high-performance EDC receivers and flexible transmit output drivers, the chip has a complete set of build-in-self-test (BIST) functions including pattern generator, checker, and loopback capability at both line and client sides. The VSC8248 also integrates Vitesse’s VScope embedded waveform viewing technology which enables production testing along with remote diagnostics after system deployment.

“We are pleased to work with leading optical module and component vendors such as ColorChip and CyOptics in the development of next-generation high density and high-performance 40G and 100G solutions,” said Raymond Fontayne, senior product marketing manager for Vitesse. “The fully functional reference design proves the interoperability with market leading sub-systems and components, and shortens time-to-market for our OEM customers.”

ColorChip’s transmit and receive PICs include efficient coupling of CWDM DFB lasers into one single mode fiber and provide high-performance channel demultiplexing with very low pass-band loss and high out-of-band rejection. Meeting the most stringent international standards, the PICs are Telcordia qualified and compliance-tested.

“With continued innovation and close collaboration with Vitesse, we continue to enhance the performance of our PIC offerings,” said Eli Arad, vice president of research and development for ColorChip.

“We have worked closely with Vitesse on multiple optical front end designs over the years,” said Kou-Wei Wang, vice president and general manager of the InP OEM Business at CyOptics. “Their PMD and EDC-capable products provide excellent performance with lower power and small size enabling the integration necessary for high density 40G/100G systems.”