Co-Package Technology Platform for Low-Power and Low-Cost Data Centers

We report recent advances in photonic–electronic integration developed in the European research project L3MATRIX. The aim of the project was to demonstrate the basic building blocks of a co-packaged optical system. Two-dimensional silicon photonics arrays with 64 modulators were fabricated. Novel modulation schemes based on slow light modulation were developed to assist in achieving an efficient performance of the module. Integration of DFB laser sources within each cell in the matrix was demonstrated as well using wafer bonding between the InP and SOI wafers. Improved semiconductor quantum dot MBE growth, characterization and gain stack designs were developed. Packaging of these 2D photonic arrays in a chiplet configuration was demonstrated using a vertical integration approach in which the optical interconnect matrix was flip-chip assembled on top of a CMOS mimic chip with 2D vertical fiber coupling. The optical chiplet was further assembled on a substrate to facilitate integration with the multi-chip module of the co-packaged system with a switch surrounded by several such optical chiplets. We summarize the features of the L3MATRIX co-package technology platform and its holistic toolbox of technologies to address the next generation of computing challenges

Photo-induced Changes In The Complex Index Of Refraction In Conjugated Polymer/fullerene Blends

We report steady-state photo-induced absorption (PIA) and photo-induced reflectance (PIR) in films of poly[2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylene vinylene] (MEH-PPV) and poly[2,5-bis cholestanoxy-1,4 phenylene vinylene] (BCHA-PPV) blended with fullerenes. Absorption from the metastable charge-transferred state is probed by PIA; the modulated absorption spectrum causes changes in the real part of the index of refraction, Δn, which can be measured directly by PIR. The charge transfer gives rise to pronounced features in Δn, including vibrational structure in the mid-infrared, and broad spectral windows with negative Δn in the mid- and near-infrared. Our measurements over a wide spectral range (0.05 eV–1.9 eV) allow quantitative comparison of Δn obtained from PIR with that obtained from Kramers–Kronig transformation of the PIA data. We find good agreement throughout the infrared, indicating that our method for measuring Δn is useful as an analytical tool for optical characterization and for prediction of optical spectral ranges for nonlinear optical response

Rack-scale disaggregated cloud data centers: The dReDBox project vision

For quite some time now, computing systems servers, whether low-power or high-end ones designs are created around a common design principle: the main-board and its hardware components form a baseline, monolithic building block that the rest of the hardware/software stack design builds upon. This proportionality of compute/memory/network/storage resources is fixed during design time and remains static throughout machine lifetime, with known ramifications in terms of low system resource utilization, costly upgrade cycles and degraded energy proportionality. dReDBox takes on the challenge of revolutionizing the low-power computing market by breaking server boundaries through materialization of the concept of disaggregation. Besides proposing a highly modular software-defined architecture for the next generation datacentre, dRedBox will specify, design and prototype a novel hardware architecture where SoC-based microservers, memory modules and accelerators, will be placed in separated modular server trays interconnected via a high-speed, low-latency opto-electronic system fabric, and be allocated in arbitrary sets, as driven by fit-for-purpose resource/power management software. These blocks will employ state-of-the-art low-power components and be amenable to deployment in various integration form factors and target scenarios. dRedBox aims to deliver a full-fledged, vertically integrated datacentre-in-a-box prototype to showcase the superiority of disaggregation in terms of scalability, efficiency, reliability, performance and energy reduction which will be demonstrated in three pilot use-cases. © 2016 EDAA