skip to main content

Title: Microwave signal switching on a silicon photonic chip

Microwave photonics uses light to carry and process microwave signals over a photonic link. However, light can instead be used as a stimulus to microwave devices that directly control microwave signals. Such optically controlled amplitude and phase-shift switches are investigated for use in reconfigurable microwave systems, but they suffer from large footprint, high optical power level required for switching, lack of scalability and complex integration requirements, restricting their implementation in practical microwave systems. Here, we report Monolithic Optically Reconfigurable Integrated Microwave Switches (MORIMSs) built on a CMOS compatible silicon photonic chip that addresses all of the stringent requirements. Our scalable micrometer-scale switches provide higher switching efficiency and require optical power orders of magnitude lower than the state-of-the-art. Also, it opens a new research direction on silicon photonic platforms integrating microwave circuitry. This work has important implications in reconfigurable microwave and millimeter wave devices for future communication networks.

more » « less
Award ID(s):
1707641 1901844 1807890 1704085 1640227
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Nature Publishing Group
Date Published:
Journal Name:
Scientific Reports
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    Reconfigurability of photonic integrated circuits (PICs) has become increasingly important due to the growing demands for electronic–photonic systems on a chip driven by emerging applications, including neuromorphic computing, quantum information, and microwave photonics. Success in these fields usually requires highly scalable photonic switching units as essential building blocks. Current photonic switches, however, mainly rely on materials with weak, volatile thermo‐optic or electro‐optic modulation effects, resulting in large footprints and high energy consumption. As a promising alternative, chalcogenide phase‐change materials (PCMs) exhibit strong optical modulation in a static, self‐holding fashion, but the scalability of present PCM‐integrated photonic applications is still limited by the poor optical or electrical actuation approaches. Here, with phase transitions actuated by in situ silicon PIN diode heaters, scalable nonvolatile electrically reconfigurable photonic switches using PCM‐clad silicon waveguides and microring resonators are demonstrated. As a result, intrinsically compact and energy‐efficient switching units operated with low driving voltages, near‐zero additional loss, and reversible switching with high endurance are obtained in a complementary metal‐oxide‐semiconductor (CMOS)‐compatible process. This work can potentially enable very large‐scale CMOS‐integrated programmable electronic–photonic systems such as optical neural networks and general‐purpose integrated photonic processors.

    more » « less
  2. Abstract

    Large-scale generation of quantum entanglement between individually controllable qubits is at the core of quantum computing, communications, and sensing. Modular architectures of remotely-connected quantum technologies have been proposed for a variety of physical qubits, with demonstrations reported in atomic and all-photonic systems. However, an open challenge in these architectures lies in constructing high-speed and high-fidelity reconfigurable photonic networks for optically-heralded entanglement among target qubits. Here we introduce a programmable photonic integrated circuit (PIC), realized in a piezo-actuated silicon nitride (SiN)-in-oxide CMOS-compatible process, that implements anN×NMach–Zehnder mesh (MZM) capable of high-speed execution of linear optical transformations. The visible-spectrum photonic integrated mesh is programmed to generate optical connectivity on up toN = 8 inputs for a range of optically-heralded entanglement protocols. In particular, we experimentally demonstrated optical connections between 16 independent pairwise mode couplings through the MZM, with optical transformation fidelities averaging 0.991 ± 0.0063. The PIC’s reconfigurable optical connectivity suffices for the production of 8-qubit resource states as building blocks of larger topological cluster states for quantum computing. Our programmable PIC platform enables the fast and scalable optical switching technology necessary for network-based quantum information processors.

    more » « less
  3. García-Blanco, Sonia M. ; Cheben, Pavel (Ed.)
    The benefits of photonics over electronics in the application of optical transceivers and both classical and quantum computing have been demonstrated over the past decades, especially in the ability to achieve high bandwidth, high interconnectivity, and low latency. Due to the high maturity of silicon photonics foundries, research on photonics devices such as silicon micro ring resonators (MRRs), Mach-Zehnder modulators (MZM), and photonic crystal (PC) resonators has attracted plenty of attention. Among these photonic devices, silicon MRRs using carrier depletion effects in p-n junctions represent optical switches manufacturable in the most compact magnitude at high volume with demonstrated switching energies ~5.2fJ/bit. In matrix multiplication demonstrated with integrated photonics, one approach is to couple one bus straight waveguide to several MRRs with different resonant wavelengths to transport signals in different channels, corresponding to a matrix row or column. However, such architectures are potentially limited to ~30 MRRs in series, by the limited free-spectral range (FSR) of an individual MRR. We show that PC switches with sub-micron optical mode confinements can have a FSR >300nm, which can potentially enable energy efficient computing with larger matrices of ~200 resonators by multiplexing. In this paper, we present designs for an oxide-clad bus-coupled PC switch with 1dB insertion loss, 5dB extinction, and ~260aJ/bit switching energy by careful control of the cavity geometry as well as p-n junction doping. We also demonstrate that air-clad bus-coupled PC switches can operate with 1dB insertion loss, 3dB extinction, and ~80aJ/bit switching energy. 
    more » « less
  4. Nonlinear photonic circuits with the ability to generate and process signals all-optically have emerged in the past decade with superior performance to electronic chips. In particular, crystalline silicon has become a leading platform for integrated nonlinear optics. More recently, hydrogenated amorphous silicon emerged as a promising alternative to crystalline silicon due to its large nonlinearity. In this paper, we review recent research on nonlinear optical interactions in and applications of hydrogenated amorphous silicon nanophotonic devices. This new material platform enables the capability of multilayer CMOS-compatible photonic integrated circuits with low power requirements for high-speed optical signal processing. 
    more » « less
  5. A central goal in creating long-distance quantum networks and distributed quantum computing is the development of interconnected and individually controlled qubit nodes. Atom-like emitters in diamond have emerged as a leading system for optically networked quantum memories, motivating the development of visible-spectrum, multi-channel photonic integrated circuit (PIC) systems for scalable atom control. However, it has remained an open challenge to realize optical programmability with a qubit layer that can achieve high optical detection probability over many optical channels. Here, we address this problem by introducing a modular architecture of piezoelectrically actuated atom-control PICs (APICs) and artificial atoms embedded in diamond nanostructures designed for high-efficiency free-space collection. The high-speed four-channel APIC is based on a splitting tree mesh with triple-phase shifter Mach–Zehnder interferometers. This design simultaneously achieves optically broadband operation at visible wavelengths, high-fidelity switching (>40dB) at low voltages, submicrosecond modulation timescales (>30MHz), and minimal channel-to-channel crosstalk for repeatable optical pulse carving. Via a reconfigurable free-space interconnect, we use the APIC to address single silicon vacancy color centers in individual diamond waveguides with inverse tapered couplers, achieving efficient single photon detection probabilities (∼15%) and second-order autocorrelation measurementsg(2)(0)<0.14 for all channels. The modularity of this distributed APIC–quantum memory system simplifies the quantum control problem, potentially enabling further scaling to thousands of channels.

    more » « less