The rise of integrated quantum photonics

Taposhree Dutta, Atefe Safinezhad, Mariia Zhuldybina +5 more

Integrated photonics in quantum technology.

Stefano Paesani

Mathias Van Regemortel, Vincenzo Ardizzone, Eugenio Maggiolini +3 more

Strong light-matter coupling between a guided electromagnetic mode and an excitonic semiconductor transition gives rise to exciton-polaritons with optical nonlinearities far exceeding those of conventional photonic platforms. Utilizing these nonlinearities in the few-particle regime, where quantum signatures such as photon antibunching, sub-Poissonian statistics and non-trivial inter-mode correlations become accessible, is a central goal of integrated quantum photonics. Yet, a quantitative theoretical framework connecting realistic waveguide parameters to measurable non-classical photonic output is absent. Here, we present a comprehensive framework for predicting and benchmarking quantum photon statistics in polaritonic integrated circuits, using state-of-the-art experimentally achieved device parameters for (Al)GaAs waveguide platforms. By mapping the pulsed nonlinear waveguide dynamics onto a bosonic quantum circuit representation that explicitly incorporates dissipation, we identify experimentally accessible quantum signatures across two circuit configurations: a single waveguide in a free-space interferometric configuration and a fully integrated multimode coupled-waveguide circuit. We further show that slow-light engineering of the polariton dispersion offers a practical route to amplifying the effective nonlinearity, pushing quantum signatures beyond Gaussian statistics.

Carsten Schuck

Superconducting Nanowire Single Photon Detectors (SNSPD) have set leading performance benchmarks in terms of detection efficiency, low noise operation, speed, and timing accuracy. Besides scaling up the numbers of individually addressable nanowire detector channels, integration with nanophotonic functionalities as well as optical and electrical multiplexing will be key to advance single photon counting applications, such as quantum key distribution, optical quantum information processing and simulations of sampling problems. Here we show how integration of SNSPDs with nanophotonic circuit components gives rise to novel use cases. We combine highperformance waveguide-integrated SNSPDs with nano-electromechanical phase-shifters, high speed electro-optic modulators, sub-wavelength grating structures, directional coupler networks, on-chip delay lines and highly efficient and broadband 3D-interconnects to optical fibers, achieving crucial active and passive functionalities for integrated quantum photonics. We showcase the capabilities and practical relevance of photonic integrated SNSPD solutions for the example of high-rate quantum key distribution receivers.

Krishna Thyagarajan