D.W. Dolfi

Demonstration of a compact low-power 250-Gb/s parallel-WDM optical interconnect

In this letter, we demonstrate error-free operation of a 12-fiber /spl times/4-wavelength /spl times/5.21-Gb/s parallel-wavelength-division-multiplexed (PWDM) optical link. The 250-Gb/s transmitter and receiver assemblies each have a 5/spl times/8-mm footprint and consume a combined power of 1.5 W. To our knowledge, this is the first publication of a fully functional PWDM optical interconnect as well as the highest demonstrated bandwidth per unit area and bandwidth per unit power consumption for any multiple-channel fiber-optic interconnect. This technology is intended for short-distance high-bandwidth-density applications such as multiprocessor computer backplanes.

Parallel optical interconnects

Summary form only given. Due to the increasing demand for high-bandwidth applications, multi-processor systems and communication systems are demanding very low cost, high-bandwidth optical interconnects. We present results on a 12-channel parallel optical link module (PONI Project) with each channel operating at a bit rate up to 2.5 GBd providing an aggregate bit rate up to 30 GBd. Each parallel optical link module is either a 12-channel transmitter module or a 12-channel receiver module with dimensions of 35 mm/spl times/16 mm/spl times/10 mm.

The PONI-1 parallel-optical link

A low-cost, surface-mountable parallel-fiber optical link, which employs passive mechanical alignment of its optical elements, is described. The optical links are fabricated as separate transmitter and receiver modules comprised of 8 or 12 channels operating at a maximum rate of 1.25 GBd per channel. The electro-mechanical platform is constructed using materials and techniques originally developed for fabricating tape ball grid array (TBGA) IC packages. Electrical I/O is provided via a 6/spl times/10 solder ball array on 50 mil centers. The modules are designed to operate off of a 3.3 V supply voltage, and to interface with a variety of fiber ribbon connectors.

500-Gbps Parallel-WDM Optical Interconnect

This paper describes a 500-Gbps parallel wavelength-division multiplexed (PWDM) optical interconnect where 48 channels of 10.42-Gbps data are transmitted over a parallel 12-fiber ribbon with 4 wavelengths per fiber. The transmitter and receiver are each chip-scale packages with a footprint of 5 mm times 8 mm and a combined power consumption of 3 W. This work is motivated by the continually increasing bandwidth needs of short-distance computer processor interconnects, which are demanding optical solutions that maximize bandwidth per unit area, power consumption, and cost

Parallel optical interconnect at 10 Gb/s per channel

In many high-end systems, there is a growing need to replace copper interconnects with optical interconnects for link lengths up to 600 meters. 12-channel parallel-optical interconnects with each channel operating at a data rate up to 10 Gb/s are designed, assembled, and demonstrated. This is achieved using bottom-emitting 990-nm VCSELs and bottom-illuminated photodetectors (PDs) flip-chip bonded directly to 12-channel transmitter and receiver integrated circuits, respectively. Results show a 12-channel parallel-optical transmitter module operating at a data rate of 10 Gb/s per channel with all 12 channels operating simultaneously. In addition, a 12-channel parallel-optical receiver module with each channel operating at a data rate up to 10 Gb/s with all channels operating simultaneously is demonstrated. A BER <10/sup -12/ is measured on a single channel operating at a data rate of 10 Gb/s with all 12 channels operating simultaneously after transmission over 100 meters of 50-/spl mu/m core standard multimode ribbon fiber.

The PONI optoelectronic platform

The PONI platform is designed with a keen awareness of trade-offs. The optical alignment tolerance is at the heart of the tradeoffs because it is generally the cost limiting factor that also determines the maximum performance. For example, modules designed for 50 /spl mu/m multimode optical fiber are expected to have lower package costs.

Next-generation parallel-optical data links

Parallel-optical data links are now available and designed into many next-generation telecom/datacom central-office switches and routers. A line of products from Agilent Technologies is based upon a new platform and components developed at Agilent Laboratories. These links cost less per channel than serial links and allow about six times higher I/O density. The current generation of twelve-channel modules operates at 2.5 GBd over distances up to 600 m on optimized multimode fiber. These improvements will enable the continued exponential growth rate of Internet capacity over the next couple of years. In order to progress further up this growth curve, next-generation parallel-optical data links are expected to operate at 10 GBd. A research and development project at Agilent Labs is focussing on next-generation parallel-optical data links. It is called Parallel Optics for SuperHighways or POSH. This name is intended to reflect the continuing role that parallel optics will play in the future network of data communications superhighways.

Multi-channel optical interconnects for short-reach applications

As data rates have increased over time, fiber-optic lis have replaced those in copper media at successively shorter and shorter distances. In this paper we will examine the factors that have driven this trend, and investigate current and future short reach optical interconnect technologies. Finally, we will look at the issues, and potential solutions, that will determine how and when optics will continue its migration path down to the PC board and backplane level.

Parallel-WDM for multi-Tb/s optical interconnects

This article presents a promising approach for multi-Tb/s optical interconnects. This approach is contained in the MAUI project, which develops a parallel multiwavelength optical subassembly (PMOSA) that uses PWDM to gain the component-density advantages of two-dimensional parallel optics and the connector and cabling density advantages of CWDM. In the MAUI approach, a standard multimode 12-fiber ribbon is used with 4 wavelengths transmitted through each fiber, for a total of 48 optical channels.

Direct integration of dense parallel optical interconnects on a first level package for high-end servers

The direct integration of dense 48-channel parallel multiwavelength optical transmitter and receiver subassemblies directly onto a first level package using a flex lead attach has been demonstrated. Such an approach, at 10 Gb/s/channel would provide a linear edge bandwidth density of 300 Gb/s/cm. By attaching dense multichannel optical subassemblies directly onto an MCM, the performance limitations of the connectors and node card wiring can be avoided and the total bandwidth off the MCM can be increased while also enabling longer distance and higher speed signaling. This approach involves only a modest modification to the bent-flex approach commonly used for parallel optical modules intended for board mounting but enables a significant density and performance improvement for this application.