Spatio-spectral control of coherent nanophotonics.

Fast modulation of optical signals that carry multidimensional information in the form of wavelength, phase or polarization has fueled an explosion of interest in integrated photonics. This interest however masks a significant challenge which is that independent modulation of multi-wavelength carrier signals in a single waveguide is not trivial. Such challenge is attributed to the longitudinal direction of guided-mode propagation, limiting the spatial separation and modulation of electric-field.

Emergent Self-Adaptation in an Integrated Photonic Neural Network for Backpropagation-Free Learning.

Plastic self-adaptation, nonlinear recurrent dynamics and multi-scale memory are desired features in hardware implementations of neural networks, because they enable them to learn, adapt, and process information similarly to the way biological brains do. In this work, these properties occurring in arrays of photonic neurons are experimentally demonstrated. Importantly, this is realized autonomously in an emergent fashion, without the need for an external controller setting weights and without explicit feedback of a global reward signal.

Erratum: Interlaboratory study on SbS interplay between structure, dielectric function, and amorphous-to-crystalline phase change for photonics.

[This corrects the article DOI: 10.1016/j.isci.

Partial coherence enhances parallelized photonic computing.

Advancements in optical coherence control have unlocked many cutting-edge applications, including long-haul communication, light detection and ranging (LiDAR) and optical coherence tomography. Prevailing wisdom suggests that using more coherent light sources leads to enhanced system performance and device functionalities. Our study introduces a photonic convolutional processing system that takes advantage of partially coherent light to boost computing parallelism without substantially sacrificing accuracy, potentially enabling larger-size photonic tensor cores.

Scalable and efficient grating couplers on low-index photonic platforms enabled by cryogenic deep silicon etching.

Efficient fiber-to-chip couplers for multi-port access to photonic integrated circuits are paramount for a broad class of applications, ranging, e.g., from telecommunication to photonic computing and quantum technologies.

Biohybrid Photonic Platform for Subcellular Stimulation and Readout of In Vitro Neurons.

Targeted manipulation of neural activity via light has become an indispensable tool for gaining insights into the intricate processes governing single neurons and complex neural networks. To shed light onto the underlying interaction mechanisms, it is crucial to achieve precise control of individual neural activity, as well as a spatial read-out resolution on the nanoscale. Here, a versatile photonic platform with subcellular resolution for stimulation and monitoring of in-vitro neurons is demonstrated.

High-quality factor TaO-on-insulator resonators with ultimate thermal stability.

Experiments in photonics, laser optics, and quantum technology require low-loss, thermal, and mechanical stability. While photonic integrated circuits on monolithic chips achieve interferometric stability, important nanophotonic material systems suffer from propagation loss, thermal drift, and noise that prevent, for example, precise frequency stabilization of resonators. Here we show that tantalum pentoxide (TaO) on insulator micro-ring resonators combine quality factors beyond 1.

Event-driven adaptive optical neural network.

We present an adaptive optical neural network based on a large-scale event-driven architecture. In addition to changing the synaptic weights (synaptic plasticity), the optical neural network's structure can also be reconfigured enabling various functionalities (structural plasticity). Key building blocks are wavelength-addressable artificial neurons with embedded phase-change materials that implement nonlinear activation functions and nonvolatile memory.

An electroluminescent and tunable cavity-enhanced carbon-nanotube-emitter in the telecom band.

Emerging photonic information processing systems require chip-level integration of controllable nanoscale light sources at telecommunication wavelengths. Currently, substantial challenges remain in the dynamic control of the sources, the low-loss integration into a photonic environment, and in the site-selective placement at desired positions on a chip. Here, we overcome these challenges using heterogeneous integration of electroluminescent (EL), semiconducting carbon nanotubes (sCNTs) into hybrid two dimensional - three dimensional (2D-3D) photonic circuits.

In-memory photonic dot-product engine with electrically programmable weight banks.

Electronically reprogrammable photonic circuits based on phase-change chalcogenides present an avenue to resolve the von-Neumann bottleneck; however, implementation of such hybrid photonic-electronic processing has not achieved computational success. Here, we achieve this milestone by demonstrating an in-memory photonic-electronic dot-product engine, one that decouples electronic programming of phase-change materials (PCMs) and photonic computation. Specifically, we develop non-volatile electronically reprogrammable PCM memory cells with a record-high 4-bit weight encoding, the lowest energy consumption per unit modulation depth (1.

Scalable High-Precision Trimming of Photonic Resonances by Polymer Exposure to Energetic Beams.

Integrated photonic circuits (PICs) have seen an explosion in interest, through to commercialization in the past decade. Most PICs rely on sharp resonances to modulate, steer, and multiplex signals. However, the spectral characteristics of high-quality resonances are highly sensitive to small variations in fabrication and material constants, which limits their applicability.

High-speed thin-film lithium niobate quantum processor driven by a solid-state quantum emitter.

Scalable photonic quantum computing architectures pose stringent requirements on photonic processing devices. The needs for low-loss high-speed reconfigurable circuits and near-deterministic resource state generators are some of the most challenging requirements. Here, we develop an integrated photonic platform based on thin-film lithium niobate and interface it with deterministic solid-state single-photon sources based on quantum dots in nanophotonic waveguides.

Ultrafast quantum key distribution using fully parallelized quantum channels.

The field of quantum information processing offers secure communication protected by the laws of quantum mechanics and is on the verge of finding wider application for the information transfer of sensitive data. To improve cost-efficiency, extensive research is being carried out on the various components required for high data throughput using quantum key distribution (QKD). Aiming for an application-oriented solution, we report the realization of a multichannel QKD system for plug-and-play high-bandwidth secure communication at telecom wavelengths.

Scaling waveguide-integrated superconducting nanowire single-photon detector solutions to large numbers of independent optical channels.

Superconducting nanowire single-photon detectors are an enabling technology for modern quantum information science and are gaining attractiveness for the most demanding photon counting tasks in other fields. Embedding such detectors in photonic integrated circuits enables additional counting capabilities through nanophotonic functionalization. Here, we show how a scalable number of waveguide-integrated superconducting nanowire single-photon detectors can be interfaced with independent fiber optic channels on the same chip.

Low-Divergence hBN Single-Photon Source with a 3D-Printed Low-Fluorescence Elliptical Polymer Microlens.

Efficiently collecting light from single-photon emitters is crucial for photonic quantum technologies. Here, we develop and use an ultralow fluorescence photopolymer to three-dimensionally print micrometer-sized elliptical lenses on individual precharacterized single-photon emitters in hexagonal boron nitride (hBN) nanocrystals, operating in the visible regime. The elliptical lens design beams the light highly efficiently into the far field, rendering bulky objective lenses obsolete.

Cryo-compatible opto-mechanical low-voltage phase-modulator integrated with superconducting single-photon detectors.

Photonic integrated circuits (PICs) have enabled novel functionality in quantum optics, quantum information processing and quantum communication. PICs based on Silicon Nitride (SiN) provide low-loss passive components and are compatible with efficient superconducting nanowire single-photon detectors (SNSPDs). For realizing functional quantum photonic systems, the integration with active phase-shifters is needed which is challenging at the cryogenic temperatures needed for operating SNSPDs.

An integrated photonics engine for unsupervised correlation detection.

With more and more aspects of modern life and scientific tools becoming digitized, the amount of data being generated is growing exponentially. Fast and efficient statistical processing, such as identifying correlations in big datasets, is therefore becoming increasingly important, and this, on account of the various compute bottlenecks in modern digital machines, has necessitated new computational paradigms. Here, we demonstrate one such novel paradigm, via the development of an integrated phase-change photonics engine.

Interlaboratory study on SbS interplay between structure, dielectric function, and amorphous-to-crystalline phase change for photonics.

Antimony sulfide, SbS, is interesting as the phase-change material for applications requiring high transmission from the visible to telecom wavelengths, with its band gap tunable from 2.2 to 1.6 eV, depending on the amorphous and crystalline phase.

Single-photon detection and cryogenic reconfigurability in lithium niobate nanophotonic circuits.

Lithium-Niobate-On-Insulator (LNOI) is emerging as a promising platform for integrated quantum photonic technologies because of its high second-order nonlinearity and compact waveguide footprint. Importantly, LNOI allows for creating electro-optically reconfigurable circuits, which can be efficiently operated at cryogenic temperature. Their integration with superconducting nanowire single-photon detectors (SNSPDs) paves the way for realizing scalable photonic devices for active manipulation and detection of quantum states of light.

Efficient self-imaging grating couplers on a lithium-niobate-on-insulator platform at near-visible and telecom wavelengths.

Lithium-niobate-on-insulator (LNOI) has emerged as a promising platform in the field of integrated photonics. Nonlinear optical processes and fast electro-optic modulation have been reported with outstanding performance in ultra-low loss waveguides. In order to harness the advantages offered by the LNOI technology, suitable fiber-to-chip interconnects operating at different wavelength ranges are demanded.

All-optical phase control in nanophotonic silicon waveguides with epsilon-near-zero nanoheaters.

A wide variety of nanophotonic applications require controlling the optical phase without changing optical absorption, which in silicon (Si) photonics has been mostly pursued electrically. Here, we investigate the unique light-matter interaction exhibited by epsilon-near-zero (ENZ) materials for all-optical phase control in nanophotonic silicon waveguides. Thermo-optic all-optical phase tuning is achieved using an ENZ material as a compact, low-loss, and efficient optical heat source.

Optoelectromechanical phase shifter with low insertion loss and a 13π tuning range.

We present an on-chip optoectromechanical phase shifter with low insertion loss and low half-wave voltage using a silicon nitride platform. The device is based on a slot waveguide in which the electrostatic displacement of mechanical structures results in a change of the effective refractive index. We achieve insertion loss below 0.