Quantum sensors have the potential to transform numerous applications across a broad range of fields from precision timing to electro-magnetic field sensing, medical imaging, gravimetry, to inertial sensing. Despite promising performances in laboratory experiments, quantum sensors have yet to be widely deployed in real-world applications at large scale. The large-scale adoption of quantum sensors has been hampered by the high SWaP-c and their sensitivity to environmental factors. Photonic integrated circuits have emerged as an enabling technology for quantum sensors to reduce SWaP-c, enhance fieldability, and add enhanced functionality. Honeywell has developed state-of-the-art capabilities in Silicon Nitride (SiN) and other photonics platforms, to enable low-swap quantum sensors ranging from atomic clocks, Rydberg electromagnetic field sensors, and NV diamond magnetometers among others. In this talk we will give an overview of how Honeywell is using photonic integrated circuits to enable a variety of quantum sensing and timing technologies for aerospace applications. Low-loss SiN waveguides can be used to deliver light to the quantum system in a compact form factor, produce high Q-optical cavities for narrow-linewidth lasers, tunably filter frequency components, or to generate optical combs. Mode-matched edge couplers can efficiently transfer light from fiberto- chip or chip-to-chip. Other photonic platforms such as diamond or thin-film lithium niobate (TFLN) can be integrated with a SiN platform in either hybrid or heterogenous configurations to enable quantum magnetometry and laser frequency tuning or modulation in ultra-compact form factors. We will discuss the advantages and remaining challenges for using photonic integrated circuits to advance quantum sensors to the point where they can be adopted in mainstream applications.
Quantum sensors have the potential to transform numerous applications across a broad range of fields from precision timing to electro-magnetic field sensing, medical imaging, gravimetry, to inertial sensing. Despite promising performances in laboratory experiments, quantum sensors have yet to be widely deployed in real-world applications at large scale. The large-scale adoption of quantum sensors has been hampered by the high SWaP-c and their sensitivity to environmental factors. Photonic integrated circuits have emerged as an enabling technology for quantum sensors to reduce SWaP-c, enhance fieldability, and add enhanced functionality. Honeywell has developed state-of-the-art capabilities in Silicon Nitride (SiN) and other photonics platforms, to enable low-swap quantum sensors ranging from atomic clocks, Rydberg electromagnetic field sensors, and NV diamond magnetometers among others. In this talk we will give an overview of how Honeywell is using photonic integrated circuits to enable a variety of quantum sensing and timing technologies for aerospace applications. Low-loss SiN waveguides can be used to deliver light to the quantum system in a compact form factor, produce high Q-optical cavities for narrow-linewidth lasers, tunably filter frequency components, or to generate optical combs. Mode-matched edge couplers can efficiently transfer light from fiberto- chip or chip-to-chip. Other photonic platforms such as diamond or thin-film lithium niobate (TFLN) can be integrated with a SiN platform in either hybrid or heterogenous configurations to enable quantum magnetometry and laser frequency tuning or modulation in ultra-compact form factors. We will discuss the advantages and remaining challenges for using photonic integrated circuits to advance quantum sensors to the point where they can be adopted in mainstream applications.
Laser-cooled atoms are a key quantum medium for atomic clocks, precision metrology, and atom interferometers, and they hold strong potential to advance quantum technologies for position, navigation, and timing. Realizing this potential requires moving cold-atom systems beyond laboratory environments. Integrated photonic chips provide a path forward by improving reliability and reducing size, weight, and power consumption, enabling portable and compact quantum sensors for real-world applications. This review surveys recent progress in laser-cooled atomic platforms, with a focus on the key components that enable on-chip integration of cold-atom systems. We discuss on-chip laser stabilization and linewidth-narrowing techniques, enhanced photon–atom coupling at the chip scale, miniaturized high-vacuum chambers, and the integration of on-chip magnetic coils for cold-atom sensing. Together, these developments are critical to the deployment of chip-scale cold-atom devices in both fundamental atomic physics and practical sensing applications. We conclude with an outlook on next-generation integrated cold-atom platforms and their potential impact on quantum technologies.
Diamond NV centers have transformed quantum sensing by enabling precise measurement of magnetic and electric fields, temperature, pressure, and strain, all within a reliable solid-state platform, at room temperature, down to the nanoscale. These capabilities position NV-based sensors as alternatives to cryogenic SQUIDs or atomic gas systems, with transformative potential across biomedical imaging, autonomous navigation, and industrial non-destructive testing (NDT). Despite promising prototypes—such as fiber-integrated endoscopes, CMOS-compatible sensors, and microfluidic chips—the development of widescale applications is hampered due to challenges in diamond micro/nanofabrication and photonic integration. Our group addresses these limitations through diamond processing techniques and hybrid material platforms. We develop methods for fabricating quantum-grade diamond nanostructures, including nanopillars optimized for neuronal electric field sensing and other photonic cavity applications. Additionally, we explore the integration of NV-rich diamond membranes within photonic systems to improve the spin photon interaction and efficient conversion of the pump beam. Collaborating with industry partner Kwantek, we also work on a compact fiber-endoscope prototype enabling NDT in constrained environments. These innovations will improve the state-of-the-art NV magnetometry to reduce system footprint and cost, critical for future industrialisation.
Photonic molecules are systems of coupled optical resonators, or of deliberately coupled modes within one resonator, whose collective states have engineered frequencies, lifetimes and optical access. Integration on silicon, silicon nitride, thin-film lithium niobate and hybrid platforms has turned them from spectroscopic objects into circuit elements for filtering, frequency conversion, nonlinear light generation, lasing and sensing. This review covers the physics and the state of the art of integrated photonic molecules. We first introduce the temporal coupled-mode description of a two-resonator molecule and the quantities used to characterize it: mode splitting, linewidth and their ratio. We then review each platform: thermally tuned and photonic-crystal molecules in silicon for compact spectral processing, spectrometry and sensing; low-loss silicon nitride molecules for soliton and parametric generation, squeezed light and narrow-linewidth Brillouin lasing; and electro-optic molecules in lithium niobate and hybrid stacks for programmable two-level dynamics, frequency shifting, comb generation and transduction. Non-Hermitian and active molecules, including exceptional-point devices and coupled lasers, are treated separately. Comparison tables collect the reported metrics together with their operating conditions. We close with the open problems of calibration, stability and packaging and with prospects in microwave photonics and quantum technologies.
The realization of quantum networks capable of distributing quantum information over kilometer scale distances is key to maximizing the potential of quantum information technology. Implementing this technology requires both the ability to generate remote entanglement between quantum memory nodes, requiring an efficient spin-photon interface, and the ability to efficiently scale the classical optical control and multiplexing optics within a given node. In this work, we develop integrated photonics platforms in diamond and thin film lithium niobate to address both of these issues. Together, these platforms provide the necessary ingredients to create large scale quantum networking technology. For the quantum network nodes, we extend previous results combining diamond nanophotonic resonators with the silicon-vacancy defect as a quantum networking platform. We demonstrate, for the first time, quantum entanglement between SiV quantum memories across 35km in a deployed fiber network. We also develop additional functionalities within the SiV platform including the incorporation of deterministic strain to increase defect yield and deterministic single photon generation with the SiV. In order to enable the scalable control and multiplexing of individual SiV centers necessary for realizing practical quantum network nodes, we develop a state-of-the-art electro-optics platform operating at visible wavelengths using thin film lithium niobate. We develop an understanding of fabrication induced losses at visible wavelengths in the platform and a variety of key devices in the platform including high-bandwidth, low-drive voltage amplitude and phase modulators, as well as high-efficiency off chip couplers. Utilizing this platform we perform ultra-high efficiency electro-optic frequency shifting, achieving a 15 GHz frequency shift with over 50% efficiency. Finally, using our measured device performance, we discuss and model how these devices can effectively multiplex SiV-based quantum nodes. Thus through these two platforms we have demonstrated the necessary ingredients to realize large-scale quantum network nodes.
Hybrid-integrated photonic circuits play a crucial role in recent quantum technologies. However, deterministic and alignment-tolerant methods are still lacking, and their development is crucial for accelerating the scalable fabrication of quantum systems. In this study, we demonstrate alignment-tolerant coupling between diamond and silicon nitride waveguides using the deterministic transfer-printing method. To validate this approach, we also demonstrate the capability of on-chip quantum sensing using nitrogen vacancy centers in diamond waveguides. These results pave the way for compact packaging of highly sensitive quantum sensors based on photonic integrated circuits.
Photonics is poised to play a unique role in quantum technology for computation, communications and sensing. Meanwhile, integrated photonic circuits-with their intrinsic phase stability and high-performance, nanoscale components-offer a route to scaling. However, each integrated platform has a unique set of advantages and pitfalls, which can limit their power. So far, the most advanced demonstrations of quantum photonic circuitry has been in silicon photonics. However, thin-film lithium niobate (TFLN) is emerging as a powerful platform with unique capabilities; advances in fabrication have yielded loss metrics competitive with any integrated photonics platform, while its large second-order nonlinearity provides efficient nonlinear processing and ultra-fast modulation. In this short review, we explore the prospects of dynamic quantum circuits-such as multiplexed photon sources and entanglement generation-on hybrid TFLN on silicon (TFLN/Si) photonics and argue that hybrid TFLN/Si photonics may have the capability to deliver the photonic quantum technology of tomorrow.