Coupled Micro Research Articles

An Optimized Integrated Optical Coupled Micro Ring Resonator for Low Pressure Sensing

In this work, a novel Integrated-optical serially coupled microring resonator-based mechanical pressure sensor is reported. Finite-Difference-Time-Domain ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FDTD</i> ) approach is used to build, analyze, and optimize <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\mu \text{m}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\mu \text{m}$ </tex-math></inline-formula> microring resonators(MRs). These optimized <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MRs</i> are used in the design and analysis of a serially coupled microring resonator ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SCMR</i> ). The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SCMR</i> is used as a sensing element in the pressure sensor. To experience the maximum stress, the sensing element is integrated with the square-shaped mechanical diaphragm. The stress of this diaphragm is analyzed by Finite-Element-Method of COMSOL Multiphysics and the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FDTD</i> method of Ansys Lumerical simulation tool is used for the analysis of the field propagation through the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SCMR</i> . The Photo-elastic effect is the working principle of this device. The dimensions of this sensor are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$25\times 25\mu \text{m}^{2}$ </tex-math></inline-formula> . A sensitivity of 0.34nm per 0.1 MPa, FSR of 94nm, and a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q-factor</i> of 21514 are reported. The sensor can be used to measure the applied pressure range of 0 to 600 kPa. A microring resonator of radius <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\mu \text{m}$ </tex-math></inline-formula> is fabricated and characterized at an operating wavelength of 1550nm.

Soft-Clamped Phononic Dimers for Mechanical Sensing and Transduction

Coupled micro- and nanomechanical resonators are of significant interest within a number of areas of research, ranging from synchronisation, nonlinear dynamics and chaos, to quantum sensing and transduction. Building upon our work on soft-clamped membrane resonators, here we present a study on phononic dimers, consisting of two defects embedded in a phononic crystal membrane. These devices exhibit widely tunable (2-100 kHz) inter-defect coupling strengths, leading to delocalized hybrid modes with mechanical Qf-products > 10^14 Hz at room temperature,ensuring low thermomechanical force noise. The mode splitting exhibits a strong dependence on the dimer orientation within the crystal lattice, as well as the spatial separation between the two defects. Given the importance of dynamic range for sensing applications, we characterize the relevant mechanical nonlinearities, specifically the self- and cross-Duffing parameters, as well as self and cross-nonlinear dampings. This work establishes soft-clamped resonators with engineered spatial and spectral multi-mode structure as a versatile mechanical platform both in the classical and quantum regimes. Applications in microwave-to-optical transduction and magnetic resonance force microscopy are particularly attractive prospects.

Spin-Phonon Interfaces in Coupled Nanomechanical Cantilevers.

Coupled micro- and nanomechanical oscillators are of fundamental and technical interest for emerging quantum technologies. Upon interfacing with long-lived solid-state spins, the coherent manipulation of the quantum hybrid system becomes possible even at ambient conditions. Although the ability of these systems to act as a quantum bus inducing long-range spin-spin interactions has been known, the possibility to coherently couple electron/nuclear spins to the common modes of multiple oscillators and map their mechanical motion to spin-polarization has not been experimentally demonstrated. We here report experiments on interfacing spins to the common modes of a coupled cantilever system and show their correlation by translating ultralow forces induced by radiation from one oscillator to a distant spin. Further, we analyze the coherent spin-spin coupling induced by the common modes and estimate the entanglement generation among distant spins.

Analysis of coupled micro rings resonators and coupled Fabry–Pérot resonators with a single physical view

Coupled micro ring resonators gained a lot of interest in recent years in the field of silicon photonics. Although it is well recognized that coupled ring resonators and coupled Fabry–Pérot resonators operate with similar physical principles, their analysis in the literature is artificially separated, often each resonator type is analysed with different physical arguments, techniques and nomenclature. As a result, coupled rings resonators and coupled Fabry–Pérot resonators appear as two different problems, and the similarity in the physical principles that govern their operation is blurred. What is more unfortunate is that the established physical intuition, familiar from Fabry–Pérot analysis, is lost in notation when dealing with coupled micro rings. Here, we argue how a lossless boundary between two dielectrics and a lossless waveguide-coupler can be viewed as a single entity: an abstract ‘boundary’ that transmits and reflects optical fields according to Stokes relations. Using this view, Fabry–Pérot and micro rings become a single type of resonator. Accordingly, we calculate effective reflection and transmission coefficients of several configurations of coupled Fabry–Pérot and rings resonators. We calculate these coefficient by the intuitive method of summing reflected fields and by the method of transfer matrix. We illustrate that the effective reflection and transmission coefficients of a coupled ring resonator is similar to 3 layers Fabry–Pérot resonator and discuss the subtle difference. It is hoped that the common nomenclature and analysis used for both types of coupled resonators will give the reader a clear and basic understanding of both types of resonators.

Unveiling 3D Deformations in Polymer Composites by Coupled Micro X-Ray Computed Tomography and Volumetric Digital Image Correlation

A new method combining micro-X-ray computed tomography (μXCT) and volumetric digital image correlation (V-DIC) in conjunction with in-situ mechanical testing was used to probe three-dimensional (3D) deformation behavior in a friction stir blind rivet (FSBR) joint of carbon fiber reinforced polymer (CFRP) composite. Intrinsic microstructural features such as fibers, pores and metal inclusions enabled accurate volumetric strain calculation of dense fiber reinforced polymer composites using V-DIC without the need for high-contrast additives. Deformation calculated with V-DIC was employed to determine variation of local mechanical properties within the FSBR altered stir-zone microstructure. Unique deformation mechanisms such as internal interfacial shear and microstructure-dependent local buckling were observed in situ. The obtained 3D microscale strain maps revealed that the deformation behavior in joint-affected zones was fundamentally different from that of the bulk composite. Combined μXCT and V-DIC were shown to be effective for understanding 3D microscale deformations in composites.

Polaritons in Defect-Containing Lattice of Coupled Micro Resonators

Polaritons in Defect-Containing Lattice of Coupled Micro Resonators

GaAs coupled micro resonators with enhanced sensitive mass detection.

This work demonstrates the improvement of mass detection sensitivity and time response using a simple sensor structure. Indeed, complicated technological processes leading to very brittle sensing structures are often required to reach high sensitivity when we want to detect specific molecules in biological fields. These developments constitute an obstacle to the early diagnosis of diseases. An alternative is the design of coupled structures. In this study, the device is based on the piezoelectric excitation and detection of two GaAs microstructures vibrating in antisymmetric modes. GaAs is a crystal which has the advantage to be micromachined easily using typical clean room processes. Moreover, we showed its high potential in direct biofunctionalisation for use in the biological field. A specific design of the device was performed to improve the detection at low mass and an original detection method has been developed. The principle is to exploit the variation in amplitude at the initial resonance frequency which has in the vicinity of weak added mass the greatest slope. Therefore, we get a very good resolution for an infinitely weak mass: relative voltage variation of 8%/1 fg. The analysis is based on results obtained by finite element simulation.

Theoretical Electromagnetic Field Calculation of a Floating Metal Wire for Inductively Coupled Micro Plasma Using a Spiral Coil

According to calculation, one of the reasons which enables inductively coupled plasma generation with low ignition power with the use of a floating metal wire is that the electrical field intensity is concentrated at the end of the floating metal wire. The electrical field intensity with the floating metal wire is not affected by the properties of the materials, such as the permeability, electrical conductivity or permittivity. It is the same result obtained through experimental ignition power data. The electrical field intensity at the upstream side increases with increments of the floating metal wire length, while the electrical field strength at the downstream side decreases with increments of the floating metal wire length. This is the possible reason for the decrease of ignition power for plasma ignition with increments of the floating metal wire length. In this paper, the function of the floating metal wire in the spiral exciting coil is investigated based on the electromagnetic field calculation using the finite element method (FEM) and is compared with the experimental results.

Novel Atmospheric Pressure Inductively Coupled Micro Plasma Source Using Floating Wire Electrode

A novel atmospheric pressure inductively coupled micro-plasma (ICMP) source is proposed. The gas flow channel is prepared inside the center of the U-shaped Cu electrode of a one-turn antenna coil. The plasma region is the center linear trench designed for the optical coupling with the slit aperture of the spectrometer. A floating wire electrode is first placed inside the trench of the gas channel without the wired connection to the power source. A glass window plate covers the gas channel allowing the optical emission from the linear trench. Under He gas flow, the plasma ignites at ∼18 W of 100 MHz very high frequency (VHF) power, and the optical emission increases with the power. Without the floating wire electrode, the plasma does not ignite even at 200 W. The floating wire electrode enhances the ignition. The characteristics of the floating wire electrode and the ICMP source are described.

Novel Atmospheric Pressure Inductively Coupled Micro Plasma Source Using Floating Wire Electrode

A novel atmospheric pressure inductively coupled micro-plasma (ICMP) source is proposed. The gas flow channel is prepared inside the center of the U-shaped Cu electrode of a one-turn antenna coil. The plasma region is the center linear trench designed for the optical coupling with the slit aperture of the spectrometer. A floating wire electrode is first placed inside the trench of the gas channel without the wired connection to the power source. A glass window plate covers the gas channel allowing the optical emission from the linear trench. Under He gas flow, the plasma ignites at ∼18 W of 100 MHz very high frequency (VHF) power, and the optical emission increases with the power. Without the floating wire electrode, the plasma does not ignite even at 200 W. The floating wire electrode enhances the ignition. The characteristics of the floating wire electrode and the ICMP source are described.

Impact of Manufacturing Variation on the Performance of Coupled Micro Resonator Array for Mass Detection Sensor

Manufacturing variation in MEMS is inevitable due to the nature of the fabrication processes. We quantify the variations and analyze its effect on the performance of a constant CMRA sensor. Finite element analysis was used to verify the effective mass and stiffness of the structure and overall performance was analyzed using lumped mass parameter model. From the results we found that the variations may cause some reduction on the CMRA performance. However, the variations may naturally stagger the mass of the constant CMRA to produce unique output signals with which any mass changes should be able to be detected.

Electromechanical Coupled Vibration for Double Coupled Micro Beams

Electromechanical Coupled Vibration for Double Coupled Micro Beams

Resonance Frequency Tuning of a Double Ring Resonator in GaInAsP/InP: Experiment and Simulation

A racetrack shaped double ring resonator (DRR) filter is demonstrated with radii of 200 µm. The double ring resonator contains two -3 dB multimode interference (MMI) couplers for I/O coupling and a -13 dB codirectional coupler in between the rings. A free spectral range of 50 GHz has been realized. A simulation model has been developed to describe the DRR. As fabrication tolerances do not allow the realization of two identical rings with required nm-circumference accuracy in the resonator, a frequency alignment of the resonator is indispensable. The resonance frequency tuning is performed thermally using platinum resistors which have been placed on top of the waveguides in both rings. An on-off ratio increase has been achieved of more than 3 dB, resulting in a total on-off ratio larger than 18 dB. The frequency alignment is inevitable in the case of multiple coupled micro ring resonators.

Coupled Micro to Macro Analysis of a Composite That Hosts Embedded Piezoelectric Actuators

A coupled micro-macromechanical approach is employed to model a fiber reinforced composite actuated by distributed piezoelectric patches. The coupled electromechanical behavior of the piezoelectric patch is formulated. The microstructures of the fiber reinforced composite and the piezoelectric composite are analyzed, and their mutual influence on the performance of the entire composite structure is estimated. Different cases of voltages, piezoelectric volume fractions and number of composite layers are studied. In-plane stresses across the composite thickness are presented to illustrate the resulting responses.