ECCS-EPSRC Micromechanical Elements for Photonic Reconfigurable Zero-Static-Power Modules

集成光子学在过去十年中得到了跨越式的发展，并且已经看到了远远超出最初设想的电信领域的广泛应用。例如，光子学初创公司Lightmatter和PsiQuantum最近筹集的资金表明，集成光子学有望在人工智能和量子计算的硬件开发中发挥关键作用。尽管取得了所有这些进展和前景，但有一个关键问题尚未解决。光子学要实现其在规模和能效方面的承诺，就需要使用高品质因数谐振器，这种设备可以使光以低损耗长时间循环。虽然在减少光子器件中的传播损耗方面已经取得了很大的进展，但是即使在现有技术的铸造工艺中也存在固有的制造变化，使得不可能设计名义上相同的器件来实现任何给定的功能。这意味着必须使用一些用于制造后补偿和调谐的方法。虽然目前存在几种这样的调谐方法，但它们都需要大的稳态能耗（热调谐）或大的片上占用面积（MEMS调谐）。理想地需要的是一种允许谐振器的频率在制造后被调谐的机构，其中调谐机构既小占地面积又有效（零静态能量耗散）。该项目旨在通过利用可以在两个稳定状态之间翻转以诱导调谐的机械可调谐结构来实现这一目标。我们将发展可切换、数位（逐步）、非挥发性（无静态功率耗散）的微机械调谐元件，以在制造后调整整合式光子共振器的共振波长。这些调谐元件将被选择性地和永久地切换以将谐振器数字地调谐成彼此对准，从而消除了应用持续的、谐振器特定的调谐以补偿制造变化的需要。我们将证明，这些机械可编程元件可以在最先进的铸造工艺中设计和制造，并且还显示了从室温到4K的操作稳定性。我们的主要目标是表明，通过使用这种调谐方法，我们可以将“有效”制造变化减少约10倍，并实现围绕高Q谐振器设计的新一代集成光子器件。

Integrated photonics has developed by leaps and bounds over the past decade and has seen widespread application far beyond the originally envisioned domain of telecommunications. For instance, the recent funding rounds raised by photonics startups Lightmatter and PsiQuantum, point to the fact that integrated photonics is expected to play a key role in the development of hardware for both artificial intelligence and quantum computing.In spite of all this progress and promise, there is one key problem that has remained unaddressed. For photonics to realise its promise, both in terms of scale and energy efficiency, it requires the use of high quality factor resonators, devices in which light can circulate for long periods with low-loss. While there has been great progress in reducing the propagation loss in photonic devices, the inherent fabrication variation present even in state of the art foundry processes, makes it impossible to design nominally identical devices for implementing any given function. This means that some method for post fabrication compensation and tuning must be utilised. While several such approaches for tuning currently exist, all of them either require large steady state energy consumption (thermal tuning) or large on-chip footprint (MEMS tuning). What is ideally needed is a mechanism that allows a resonator's frequency to be tuned post-fabrication where the tuning mechanism is both small footprint and efficient (zero static energy dissipation). This project is designed to address this goal by exploiting mechanically bistable structures that can be flipped between two stable states to induce the tuning. We will develop switchable, digital (step-by-step), nonvolatile (no static power dissipation) micromechanical tuning elements for adjusting the resonant wavelength of integrated photonic resonators after fabrication. These tuning elements will be selectively and permanently switched to digitally tune resonators into alignment with each other, eliminating the need to apply a persistent, resonator-specific tuning to compensate for fabrication variations. We will demonstrate that these mechanically bistable elements can be designed and fabricated in a state of the art foundry process, and also show the stability of operation from room temperature down to 4K. Our main goal is to show that by using this tuning method, we can reduce the 'effective' fabrication variation by ~10x, and enable a new generation of integrated photonic devices, designed around high-Q resonators.