Research Initiation: Volume Holographic Optical Interconnection

光学互连元件可以潜在地充当电气布线的强大替代品，因为光子缺乏电子的相互作用性质。因此，光子互连提供最小的信号劣化、对寄生（电容性或电感性）负载的抗扰性以及对EMI的不敏感性，以及其他优点。当前的光学互连主要基于光纤、薄膜全息类型的平面配置或可以执行矩阵-向量或矩阵-矩阵乘法的光学空间光调制器。然而，使用薄全息图的方案的互连能力受到全息图的面积的限制，并且操作效率受到膜厚度的窄相互作用区域的限制。另一方面，基于空间光调制器的光互连系统复杂且体积庞大。本文的工作是对最近提出的利用光折变晶体的三维光子互连进行理论和实验研究。这些新的配置是基于体积（而不是平面）全息几何。它们的操作涉及由大量全息光栅提供的复合布拉格反射机制;光栅由光学输入本身根据规定的互连图案在体积内生成。

Optical interconnecting elements can potentially act as a powerful alternative to electrical wiring, because photons lack the interactive nature of electrons. As a result, photonic interconnections offer minimal signal deterioration, immunity to parasitic (capacitive or inductive) loading, and insensitivity to EMI, amongst other advantages. Current optical interconnects are based primarily on optical fibers, on planar configurations of the thin-film holographic type or on optical spatial light modulators which can perform matrix- vector or matrix-matrix multiplications. However, the interconnection capacity of schemes using thin holograms is restricted by the area of the hologram and the operating efficiency is limited by the narrow interaction region of the film thickness. On the other hand, optical interconnection systems based on spatial light modulators are complicated and bulky. The work projected here is a theoretical and experimental investigation of a recently proposed three-dimensional class of photonic interconnections utilizing photorefractive crystals. These novel configurations are based on volume (rather than planar) holographic geometries. Their operation involves a composite Bragg- reflection mechanism provided by a large multiplicity of holographic gratings; the gratings are generated inside the volume by the optical inputs themselves according to a prescribed interconnection pattern.