Programmable interferometric circuits are at the heart of integrated quantum photonic processors. While the lithium niobate-on-insulator platform has the potential to advance integrated quantum photonics due to its strong nonlinearity and tight mode confinement, the demonstration of reconfigurable two-photon interference has not yet been achieved. Here, we design, fabricate and characterize the building block of such interferometric networks in the form of a 2 × 2 Mach–Zehnder Interferometer. We use a thermo-optic phase shifter to achieve stable performance with a power consumption of Pπ=44.4 mW and sub-microsecond switching times. We demonstrate the effectiveness of our device for quantum applications by measuring single-photon routing with up to 34 dB extinction ratio. We show Hong-Ou-Mandel interference with fully tunable visibilities reaching a maximum value of 97.4±1.0% . As part of large scale quantum photonic circuits, this building block will facilitate reconfigurable and tunable photonic processing units integrated alongside non-classical light sources.

中文翻译：

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绝缘体上铌酸锂光子集成电路中的片上可调谐量子干涉


可编程干涉电路是集成量子光子处理器的核心。虽然绝缘体上铌酸锂平台由于其强非线性和紧模式限制而具有推进集成量子光子学的潜力，但尚未实现可重构双光子干涉的演示。在这里，我们以 2 × 2 马赫-曾德尔干涉仪的形式设计、制造并表征了此类干涉网络的构建模块。我们使用热光移相器来实现稳定的性能，功耗为 Pπ=44.4 mW，开关时间为亚微秒。我们通过测量消光比高达 34 dB 的单光子路由来证明我们的设备在量子应用中的有效性。我们展示了红欧曼德尔干涉，其能见度完全可调，最大值达到 97.4±1.0%。作为大规模量子光子电路的一部分，该构建模块将促进可重构和可调谐的光子处理单元与非经典光源集成。