Comparative evaluation of optical waveguides as alternative interconnections for high performance packaging

Schacham, S. E.; Merkelo, H.; Hwang, Lih-Tyng; McCredie, B.D.; Veatch, M. S.; Turlik, I.

doi:10.1109/33.124193

Cited by 9 publications

(3 citation statements)

References 17 publications

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“…), the conditions that make a particular optical link superior to an equivalent electrical link, and the scalability of the OI configuration. A number of guided wave interconnect technological studies have been put forth which focus on the impact attenuation, dispersion, and fan-out have on signal transmission [45], and on the development of crosstalk models for optical waveguide arrays [4], [29], [47]. In the case of free-space optical interconnects, technological models have been put forth that allow the determination of the breakeven length for which a free-space optical link becomes superior to an electrical link in terms of power and speed considerations and interconnection density limitations [20], [21].…”

Section: Related Workmentioning

confidence: 99%

The offset cube: a three-dimensional multicomputer network topology using through-wafer optics

Lacy

Cruz-Rivera

Wills

1998

IEEE Trans. Parallel Distrib. Syst.

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Three-dimensional packaging technologies are critical for enabling ultra-compact, massively parallel processors (MPPs) for embedded applications. Through-wafer optical interconnect has been proposed as a useful technology for building ultra-compact MPPs since it provides a simplified mechanism for interconnecting stacked multichip substrates. This paper presents the offset cube, a new network topology designed to exploit the packaging benefits of through-wafer optical interconnect in ultra-compact MPP systems. We validate the offset cube's topological efficiency by developing deadlock-free adaptive routing protocols with modest virtual channel requirements (only two virtual channels per link needed for full adaptivity). A preliminary analysis of router complexity suggests these protocols can be efficiently implemented in hardware. We also present a 3D mesh embedding for the offset cube. Network simulations show the offset cube performs comparably to a bidirectional 3D mesh of equal size under uniform, hot-spot, and trace-driven traffic loads. While the offset cube is not proposed as a general replacement for the mesh topology, it leverages the benefits of through-wafer optical interconnect more effectively than a mesh by completely eliminating chip-to-chip wires for data signals. Hence, the offset cube is an effective topology for interconnecting ultra-compact MCM-level MPP systems.

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Section: Related Workmentioning

confidence: 99%

The offset cube: a three-dimensional multicomputer network topology using through-wafer optics

Lacy

Cruz-Rivera

Wills

1998

IEEE Trans. Parallel Distrib. Syst.

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“…The need to overcome limitations of electrical interconnection when the data rate exceeds several hundred Mb/s now demands the use of photonic technology over a distance of 10-100 cm. Thus, frame-level (intra-system) optical interconnection within high capacity electronic systems has seen substantial growth in the past few years[ 1,2].Planar and channel glass or polymer waveguides have been considered for optical interconnection on a module or board scale [3]. However, optical loss alone (0.1-1.0 dB/cm) would have precluded their application to the inter-board and inter-shelf, or backplane interconnection level (i.e.…”

mentioning

confidence: 99%

“…Planar and channel glass or polymer waveguides have been considered for optical interconnection on a module or board scale [3]. However, optical loss alone (0.1-1.0 dB/cm) would have precluded their application to the inter-board and inter-shelf, or backplane interconnection level (i.e.…”

mentioning

confidence: 99%

Intra-system interconnection using optical fiber fabrics

Ling

Holland

Shahid

Proceedings of LEOS '93

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While optical fiber and photonic technology is the cost-effective means for long-haul, high bandwidth communication, component cost alone has precluded the wide spread deployment of similar technologies at the frame level due to the large number of interconnections required. The need to overcome limitations of electrical interconnection when the data rate exceeds several hundred Mb/s now demands the use of photonic technology over a distance of 10-100 cm. Thus, frame-level (intra-system) optical interconnection within high capacity electronic systems has seen substantial growth in the past few years[ 1,2].Planar and channel glass or polymer waveguides have been considered for optical interconnection on a module or board scale [3]. However, optical loss alone (0.1-1.0 dB/cm) would have precluded their application to the inter-board and inter-shelf, or backplane interconnection level (i.e. over lengths up to 20 inches). Free-space optics, including holographic means of using lenses, mirrors, etc to direct optical signals requires novel physical design and will probably result in non-standard hardware packaging. Therefore, optical fiber continues to be the most widely accepted medium of transmitting optical signals. For applications within equipment, the main challenge is to develop automated manufacturing technologies dealing with short fiber lengths and to manage them as a robust, organized fabric.Using discrete wiring technology, rigid boards incorporating both electrical wires and polyimide-coated optical fibers have been demonstrated [4]. However, the ultrasonic bonding technique used damages other softer polymer coatings on optical fibers, thereby creating reliability issues. The need to use standard telecom fibers with acrylate coatings led us to develop a different manufacturing technology, which can handle a variety of optical fibers and to fabricate rigid and/or flexible optical circuits. The degree of automation achieved permits precise control both of fiber placement to form multifiber ribbons and fiber lengths to form skew-free interconnections. This is especially important as array devices become increasingly used within systems [5].To be compatible with existing electronic packaging hardware, we have focused on the development of flexible optical circuits, known as OptiFlexTM within AT&T. Such circuits represent an add-on structure that could mount within the electrical frames and cabinets. Using thin tabs that bend and flex the fibers into connector housings, we have overcome a major physical design issue of ninty-degree coupling between the circuit boards and backplane in the conventional orthogonal packaging scheme. The AT&T process begins with a CAD design using common software packages such as AutoCAD and VersaCAD on a PC platform. We have developed a set of design rules for laying out the fiber arrangement. These rules provide the proper limits on bend radius, fiber spacing, intersection angles, cross-overs, and other circuit parameters. When the layout design is complete, a custom-developed con...

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Module Level Performance Simulator for Electrical and Optical Interconnects

Guan

Pusarla

Halkias

et al. 1993

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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As speed and complexity of electronic systems increase, the interconnect density has become the critical limitation to the performance of electrical systems. The performance of computing and switching systems can be increased by optimizing the interconnect density and throughput. At the board to board level, electrical interconnects at high speeds require a bulky and expensive backplane. At the chip to chip area, the allocation of interconnects limits the performance of the chips. Electrical lossy lines limit the maximum interconnect distance due to reflections, risetime degradation, increased delay, attenuation and cross talk . Optical interconnects present the possibility of solving the interconnect problems by potentially achieving a high bandwidth and high volume density of channels. At high data rates (greater than 1 Gb/s) several channels may operate with negligible mutual interference.

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Comparative evaluation of optical waveguides as alternative interconnections for high performance packaging

Cited by 9 publications

References 17 publications

The offset cube: a three-dimensional multicomputer network topology using through-wafer optics

The offset cube: a three-dimensional multicomputer network topology using through-wafer optics

Intra-system interconnection using optical fiber fabrics

Module Level Performance Simulator for Electrical and Optical Interconnects

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