Frequency-Domain Quantum Interference with Correlated Photons from an Integrated Microresonator

Abstract

Frequency encoding of quantum information together with fiber and integrated photonic technologies can significantly reduce the complexity and resource requirements for realizing all-photonic quantum networks. The key challenge for such frequency domain processing of single photons is to realize coherent and selective interactions between quantum optical fields of different frequencies over a range of bandwidths. Here, we report frequency-domain Hong-Ou-Mandel interference with spectrally distinct photons generated from a chip-based microresonator. We use four-wave mixing to implement an active 'frequency beam-splitter' and achieve interference visibilities of 0.95 ± 0.02. Our work establishes four-wave mixing as a tool for selective high-fidelity two-photon operations in the frequency domain which, combined with integrated single-photon sources, provides a building block for frequency-multiplexed photonic quantum networks.

Few-cycle vacuum squeezing in nanophotonics

“…In nanophotonics, silicon nitride (SiN) and silica platforms have been used for many quantum photonic experiments such as entangled photon-pair generation, squeezing, error correction, and small scale Gaussian boson sampling [21][22][23][24][25]. However, their inherently weak cubic (χ (3) ) nonlinearity typically necessitates using high-Q resonators, which imposes limitations on accessible squeezing levels and bandwidths.…”

On-chip electro-optic frequency shifters and beam splitters

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Efficient and precise control of the frequency of light on gigahertz scales is important for a wide range of applications. Examples include frequency shifting for atomic physics experiments [1, 2], single-sideband modulation for microwave photonics applications [3][4][5][6], channel switching and swapping in optical communication systems [7,8], and frequency shifting and beam splitting for frequency domain photonic quantum computing [9][10][11][12][13]. However, realizing GHz-scale frequency shifts with high efficiency, low loss and reconfigurability, in particular using a miniature and scalable device, is challenging since it requires efficient and controllable nonlinear optical processes.

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“…However, realizing GHz-scale frequency shifts with high efficiency, low loss and reconfigurability, in particular using a miniature and scalable device, is challenging since it requires efficient and controllable nonlinear optical processes. Existing approaches based on acousto-optics [6, 14-16], all-optical wave mixing [10,13,[17][18][19], and electrooptics [20][21][22][23] are either limited to low efficiencies or frequencies, or are bulky, and have yet to simultaneously demonstrate the required properties mentioned above. Here we demonstrate an onchip electro-optic frequency shifter that is precisely controlled using only a single-tone microwave signal.…”

“…However, they have demonstrated high efficiency only in bulk structures that are not compatible with photonic integration. All-optical wavemixing can achieve efficient frequency conversion in the THz range in bulk media [10,13,17]. However, it requires stringent phase matching conditions, can suffer from parasitic nonlinear processes, and is difficult to control due to a nonlinear dependence on optical power.…”

Bell state analyzer for spectrally distinct photons

“…Here, all photons enter the network on a distinct available wavelength channel; to implement a BSA, two photons are spectrally isolated and measured directly with a "frequency-mismatch-erasing" operation, depicted schematically as a gray box. In principle such an operation can be realized by nonlinear-optical mixing with classical pump fields [11][12][13][14]. In our case we leverage the flexibility of a quantum frequency processor (QFP), which is capable of synthesizing arbitrary unitary transformations in discrete frequency bins [15,16].…”