Stochastic computing allows a drastic reduction in hardware complexity using serial processing of bit streams. While the induced high computing latency can be overcome using integrated optics technology, the design of realistic optical stochastic computing architectures calls for energy efficient switching devices. Photonics Crystal (PhC) nanocavities are $\mu m^2$ scale devices offering 100fJ switching operation under picoseconds-scale switching speed. Fabrication process allows controlling the Quality factor of each nanocavity resonance, leading to opportunities to implement architectures involving cascaded gates and multi-wavelength signaling. In this report, we investigate the design of cascaded gates architecture using nanocavities in the context of stochastic computing. We propose a transmission model considering key nanocavity device parameters, such as Quality factors, resonance wavelength and switching efficiency. The model is calibrated with experimental measurements. We propose the design of XOR gate and multiplexer. We illustrate the use of the gates to design an edge detection filter. System-level exploration of laser power, bit-stream length and bit-error rate is carried out for the processing of gray-scale images. The results show that the proposed architecture leads to 8.5nJ/pixel energy consumption and 512ns/pixel processing time.

中文翻译：

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使用光子晶体纳米腔的光学随机计算架构

随机计算允许使用位流的串行处理来大大降低硬件复杂性。虽然可以使用集成光学技术来克服所引起的高计算延迟，但现实的光学随机计算体系结构的设计要求使用节能开关设备。光子晶体（PhC）纳米腔是1微米级的设备，可在皮秒级的开关速度下提供100fJ的开关操作。制造过程允许控制每个纳米腔共振的品质因数，从而带来实现包含级联门和多波长信号的架构的机会。在本报告中，我们研究了随机计算环境下使用纳米腔的级联门架构设计。我们提出了一种传输模型，其中考虑了关键的纳米腔器件参数，例如质量因数，谐振波长和开关效率。使用实验测量值对模型进行校准。我们提出了异或门和多路复用器的设计。我们说明了如何使用门来设计边缘检测滤波器。系统对激光功率，位流长度和误码率进行了系统级研究，以处理灰度图像。结果表明，所提出的架构导致8.5nJ /像素的能耗和512ns /像素的处理时间。系统对激光功率，位流长度和误码率进行了系统级研究，以处理灰度图像。结果表明，所提出的架构导致8.5nJ /像素的能耗和512ns /像素的处理时间。系统对激光功率，位流长度和误码率进行了系统级研究，以处理灰度图像。结果表明，所提出的架构导致8.5nJ /像素的能耗和512ns /像素的处理时间。