ROC: A Reconfigurable Optical Computer for Simulating Physical Processes
ROC: A Reconfigurable Optical Computer for Simulating Physical Processes
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DOI：
10.1145/3380944
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发表时间：
2020-03-01
影响因子：
1.6
通讯作者：
El-Ghazawi, Tarek
中科院分区：
文献类型：
--
作者：
Anderson, Jeff;Kayraklioglu, Engin;El-Ghazawi, Tarek
由于摩尔定律和登纳德缩放定律的终结，我们正在进入处理器的新时代。由于电阻和电容充电的设备和电路相关挑战，计算系统日益面临功率和性能挑战。需要非冯诺依曼架构来通过创新的后摩尔定律架构来支持未来的计算。为了使这些新兴架构具有高性能和超低功耗，可以使用光子支持片上并行计算和节点间通信。为此，我们引入了 ROC，一种可以求解偏微分方程（PDE）的可重构光学计算机。 PDE 求解器构成了目前在超级计算机上执行的许多传统科学和工程模拟问题的基础。所提出的引擎不是迭代地解决问题，而是使用电阻网格架构在单次迭代（一次性）中求解偏微分方程。物理底层硬件不使用实际的电路，而是使用硅光子网格来模拟此类结构，该网格将光分成单独的路径，使其能够像可编程电阻一样增加或减少光功率。获得 PDE 解的时间仅取决于光子通过编程网格的飞行时间，对于毫米级紧凑型集成光子电路，该飞行时间约为 10 皮秒。数值验证的实验结果表明，在多种配置下，当考虑到速度、功耗和尺寸时，ROC 可以比最先进的 GPU 实现几个数量级的改进。此外，它的精度约为当前数值求解器的 90%。因此，ROC 可以成为一种可行的可重构近似计算机，当用纳米级光子集总元件替换硅光子构建块时，有可能获得更精确的结果。
Due to the end of Moore's law and Dennard scaling, we are entering a new era of processors. Computing systems are increasingly facing power and performance challenges due to both device- and circuit-related challenges with resistive and capacitive charging. Non-von Neumann architectures are needed to support future computations through innovative post-Moore's law architectures. To enable these emerging architectures with high-performance and at ultra-low power, both parallel computation and inter-node communication on-the-chip can be supported using photons. To this end, we introduce ROC, a reconfigurable optical computer that can solve partial differential equations (PDEs). PDE solvers form the basis for many traditional simulation problems in science and engineering that are currently performed on supercomputers. Instead of solving problems iteratively, the proposed engine uses a resistive mesh architecture to solve a PDE in a single iteration (one-shot). Instead of using actual electrical circuits, the physical underlying hardware emulates such structures using a silicon-photonics mesh that splits light into separate pathways, allowing it to add or subtract optical power analogous to programmable resistors. The time to obtain the PDE solution then only depends on the time-of-flight of a photon through the programmed mesh, which can be on the order of 10's of picoseconds given the millimeter-compact integrated photonic circuit. Numerically validated experimental results show that, over multiple configurations, ROC can achieve several orders of magnitude improvement over state-of-the-art GPUs when speed, power, and size are taken into account. Further, it comes within approximately 90% precision of current numerical solvers. As such, ROC can be a viable reconfigurable, approximate computer with the potential for more precise results when replacing silicon-photonics building blocks with nanoscale photonic lumped-elements.