Synchronous micromechanically resonant programmable photonic circuits

Programmable photonic integrated circuits (PICs) are emerging as powerful tools for the precise manipulation of light, with applications in quantum information processing, optical range finding, and artificial intelligence. The leading architecture for programmable PICs is the mesh of Mach-Zehnder interferometers (MZIs) embedded with reconfigurable optical phase shifters. Low-power implementations of these PICs involve micromechanical structures driven capacitively or piezoelectrically but are limited in modulation bandwidth by mechanical resonances and high operating voltages. However, circuits designed to operate exclusively at these mechanical resonances would reduce the necessary driving voltage from resonantly enhanced modulation as well as maintaining high actuation speeds. Here we introduce a synchronous, micromechanically resonant design architecture for programmable PICs, which exploits micromechanical eigenmodes for modulation enhancement. This approach combines high-frequency mechanical resonances and optically broadband phase shifters to increase the modulation response on the order of the mechanical quality factor $Q_m$, thereby reducing the PIC's power consumption, voltage-loss product, and footprint. The architecture is useful for broadly applicable circuits such as optical phased arrays, $1$ x $N$, and $N$ x $N$ photonic switches. We report a proof-of-principle programmable 1 x 8 switch with piezoelectric phase shifters at specifically targeted mechanical eigenfrequencies, showing a full switching cycle of all eight channels spaced by approximately 11 ns and operating at >3x average modulation enhancement across all on-chip modulators. By further leveraging micromechanical devices with high $Q_m$, which can exceed 1 million, our design architecture should enable a new class of low-voltage and high-speed programmable PICs.Comment: 18 pages, 5 figures, 5 supplementary figure

High-speed photonic crystal modulator with non-volatile memory via structurally-engineered strain concentration in a piezo-MEMS platform

Numerous applications in quantum and classical optics require scalable, high-speed modulators that cover visible-NIR wavelengths with low footprint, drive voltage (V) and power dissipation. A critical figure of merit for electro-optic (EO) modulators is the transmission change per voltage, dT/dV. Conventional approaches in wave-guided modulators seek to maximize dT/dV by the selection of a high EO coefficient or a longer light-material interaction, but are ultimately limited by nonlinear material properties and material losses, respectively. Optical and RF resonances can improve dT/dV, but introduce added challenges in terms of speed and spectral tuning, especially for high-Q photonic cavity resonances. Here, we introduce a cavity-based EO modulator to solve both trade-offs in a piezo-strained photonic crystal cavity. Our approach concentrates the displacement of a piezo-electric actuator of length L and a given piezoelectric coefficient into the PhCC, resulting in dT/dV proportional to L under fixed material loss. Secondly, we employ a material deformation that is programmable under a "read-write" protocol with a continuous, repeatable tuning range of 5 GHz and a maximum non-volatile excursion of 8 GHz. In telecom-band demonstrations, we measure a fundamental mode linewidth = 5.4 GHz, with voltage response 177 MHz/V corresponding to 40 GHz for voltage spanning -120 to 120 V, 3dB-modulation bandwidth of 3.2 MHz broadband DC-AC, and 142 MHz for resonant operation near 2.8 GHz operation, optical extinction down to min(log(T)) = -25 dB via Michelson-type interference, and an energy consumption down to 0.17 nW/GHz. The strain-enhancement methods presented here are applicable to study and control other strain-sensitive systems

Multiplexed control of spin quantum memories in a photonic circuit

A central goal in many quantum information processing applications is a network of quantum memories that can be entangled with each other while being individually controlled and measured with high fidelity. This goal has motivated the development of programmable photonic integrated circuits (PICs) with integrated spin quantum memories using diamond color center spin-photon interfaces. However, this approach introduces a challenge in the microwave control of individual spins within closely packed registers. Here, we present a quantum-memory-integrated photonics platform capable of (i) the integration of multiple diamond color center spins into a cryogenically compatible, high-speed programmable PIC platform; (ii) selective manipulation of individual spin qubits addressed via tunable magnetic field gradients; and (iii) simultaneous control of multiple qubits using numerically optimized microwave pulse shaping. The combination of localized optical control, enabled by the PIC platform, together with selective spin manipulation opens the path to scalable quantum networks on intra-chip and inter-chip platforms.Comment: 10 pages, 4 figure

Nanoelectromechanical control of spin-photon interfaces in a hybrid quantum system on chip

Atom-like defects or color centers (CC's) in nanostructured diamond are a leading platform for optically linked quantum technologies, with recent advances including memory-enhanced quantum communication, multi-node quantum networks, and spin-mediated generation of photonic cluster states. Scaling to practically useful applications motivates architectures meeting the following criteria: C1 individual optical addressing of spin qubits; C2 frequency tuning of CC spin-dependent optical transitions; C3 coherent spin control in CC ground states; C4 active photon routing; C5 scalable manufacturability; and C6 low on-chip power dissipation for cryogenic operations. However, no architecture meeting C1-C6 has thus far been demonstrated. Here, we introduce a hybrid quantum system-on-chip (HQ-SoC) architecture that simultaneously achieves C1-C6. Key to this advance is the realization of piezoelectric strain control of diamond waveguide-coupled tin vacancy centers to meet C2 and C3, with ultra-low power dissipation necessary for C6. The DC response of our device allows emitter transition tuning by over 20 GHz, while the large frequency range (exceeding 2 GHz) enables low-power AC control. We show acoustic manipulation of integrated tin vacancy spins and estimate single-phonon coupling rates over 1 kHz in the resolved sideband regime. Combined with high-speed optical routing with negligible static hold power, this HQ-SoC platform opens the path to scalable single-qubit control with optically mediated entangling gates

Scalable photonic integrated circuits for programmable control of atomic systems

Advances in laser technology have driven discoveries in atomic, molecular, and optical (AMO) physics and emerging applications, from quantum computers with cold atoms or ions, to quantum networks with solid-state color centers. This progress is motivating the development of a new generation of "programmable optical control" systems, characterized by criteria (C1) visible (VIS) and near-infrared (IR) wavelength operation, (C2) large channel counts extensible beyond 1000s of individually addressable atoms, (C3) high intensity modulation extinction and (C4) repeatability compatible with low gate errors, and (C5) fast switching times. Here, we address these challenges by introducing an atom control architecture based on VIS-IR photonic integrated circuit (PIC) technology. Based on a complementary metal-oxide-semiconductor (CMOS) fabrication process, this Atom-control PIC (APIC) technology meets the system requirements (C1)-(C5). As a proof of concept, we demonstrate a 16-channel silicon nitride based APIC with (5.8$\pm$0.4) ns response times and -30 dB extinction ratio at a wavelength of 780 nm. This work demonstrates the suitability of PIC technology for quantum control, opening a path towards scalable quantum information processing based on optically-programmable atomic systems

Priority research questions in atopic dermatitis : an International Eczema Council eDelphi consensus

Recent advances in understanding the complex pathogenesis of atopic dermatitis (AD, also known as eczema or atopic eczema), coupled with the development of new treatments, have led to increased interest from multiple stakeholders. There is a need to prioritize areas for research to inform a coordinated approach to advancing science and patient care

Favorable outcome of juvenile dermatomyositis treated without systemic corticosteroids.

OBJECTIVE: To describe the course of patients with juvenile dermatomyositis (JDM) treated effectively without systemic corticosteroids. STUDY DESIGN: A retrospective study of 38 patients with JDM treated at a tertiary care children\u27s hospital identified 8 patients who had never received corticosteroids. Disease presentation and course, pharmacologic, and ancillary treatments were recorded. RESULTS: Patients in the no corticosteroid group were followed for a median of 2.8 years (range, 2.1 to 9.5 years). Treatment was primarily with intravenous immunoglobulin (IVIG) (75%) and methotrexate (50%), with favorable response in all. No serious treatment complications were observed; headaches were reported by 3 patients receiving IVIG. Two patients had a myositis flare after discontinuing all medications for more than 1 year; complete resolution of symptoms was observed after either 1 or 2 further doses of IVIG. Two patients had calcinosis (at 1 and 9 years of disease); however, no patient had joint contractures, muscle atrophy, lipodystrophy, or functional limitations. CONCLUSIONS: Systemic corticosteroids can be avoided in a select group of patients with JDM. Alternative agents such as methotrexate and IVIG may be prescribed to effectively treat JDM and prevent complications