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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Wideband and Continuously Tunable Microwave Photonic Phase Shifter Based on an Active InP/InGaAsP Microring Resonator
摘要： We propose and experimentally demonstrate a wideband and continuously tunable microwave photonic (MWP) phase shifter based on an active InP/InGaAsP microring resonator (MRR) incorporating two semiconductor optical amplifiers (SOAs) and a phase modulator (PM). By tuning the gain provided by the SOAs, the loss in the ring cavity can be compensated and the extinction ratio of a resonance is decreased to nearly 0 dB, while maintaining the optical phase shift range within the resonance bandwidth. A theoretical analysis is performed. The key advantages of using the proposed MRR to achieve a microwave phase shifter are that the power variation at the output of the phase shifter is minimized during phase tuning and the microwave phase can be continuously tuned by tuning the PM in the MRR theoretically. The proposed phase shifter is experimentally demonstrated. A continuously tunable microwave phase shift over a phase tuning range of 291° from 5 GHz to 20 GHz by tuning the injection current to the PM is implemented. The microwave power variation is lower than 5 dB.
关键词： integrated optics devices,ring resonators,phase shift
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Active Metasurface Devices for Terahertz Wave Front Modulation
摘要： Terahertz (THz) radiation, which is sandwiched between the infrared and microwave in the electromagnetic spectrum, has become more and more attractive due to its special properties. Compared with the quick development of THz sources and detectors, THz functional devices are lagging behind, especially the devices for wave front modulation. Metasurface, a kind of artificial materials, is enable effective manipulation of the amplitude, phase and polarization state of electromagnetic waves with subwavelength spatial resolution. It has been used for ultrathin planar lenses, complex light field generation, spin orbital angular momentum coupling, and metasurface holograms. However, the function of this kind of metasurface based devices are fixed once they are fabricated, the spatial THz modulation which can dynamically modulate the wave front of THz radiation is demand in high resolution THz imaging and THz communication. In this presentation, we present a novel approach for generating arbitrary wave fronts of a THz beam by dynamically creating metasurface structures through illuminating a super thin silicon wafer with femtosecond laser, which is spatially modulated to result in an array of reconfigurable subwavelength resonators. The wave front of the THz beam is then determined by forming spatial profiles of the Pancharatnam-Berry scattering phase by dynamically controlling the resonator orientation. Proof-of-concept experiments demonstrate that streaming holographic images and lenses of variable focal length can be realized in real time. The theoretical expectations and experimental results are shown in Fig. 1, the generated patterns are matching with the theoretical exceptions. The reconfigurable scheme demonstrated here is convenient and fast, and may lead to advances in a host of THz applications.
关键词： Pancharatnam-Berry scattering phase,reconfigurable subwavelength resonators,wave front modulation,metasurface,Terahertz
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Electro-Optic Frequency Comb Generation in Lithium Niobate Whispering Gallery Mode Resonators
摘要： Optical frequency combs (OFCs) are light sources whose spectra consists of equally spaced frequency lines in the optical domain [1]. They have great potential for improving high-capacity data transfer, all-optical atomic clocks, spectroscopy, and high-precision measurements [2]. In contrast to the traditional third-order nonlinearity based OFC generation methods, we present a new approach which is based on second-order non-linear effects in a whispering gallery mode (WGM) resonator made of lithium niobate (LN) [3,4]. Our system is composed of a resonant hybrid structure comprising an optical LN disk resonator and a microwave copper cavity. The hybrid structure enables highly efficient nonlinear mixing of photons. In this scheme, two continuous waves, one in the optical domain ((cid:2033) = 193 THz) and another in the microwave region (Ω = 8.9 GHz) couple within a LN WGM resonator [5]. The second-order non-linearity of LN leads to frequency comb generation via cascaded symmetric sum and difference frequency generation [6]. In our experiment, the optical pump power is coupled into the WGM by using a standard prism coupling method that is based on frustrated total internal reflection (Fig. 1 (a)). The microwave power is coupled using a coaxial probe coupled attached to the 3-D copper cavity specifically designed to have the microwave cavity resonance to be equal to the optical free spectral range of the LN resonator, required for efficient phase matching. In addition, the cavity design also provides a very good spatial overlap between the microwave and optical modes by confining the microwave field to the rim of the LN disk. In our proof-of-concept experimental demonstration we observe a 1.6 THz long frequency comb centred around 193.5 THz more than180 comb lines by using only 20 dBm of microwave power. Compared to previously reported OFCs generation schemes, this method has two major advantages: inherent phase stability, and better power efficiency. The power efficiency when measured in terms of pi-voltage of the modulator is 25 times better than a commercial Thorlabs modulator.
关键词： second-order non-linearity,whispering gallery mode resonators,electro-optic frequency comb generation,Optical frequency combs,lithium niobate
更新于2025-09-12 10:27:22
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Dual-Band High <i>Q</i> -Factor Complementary Split-Ring Resonators Using Substrate Integrated Waveguide Method and Their Applications
摘要： In modern microwave telecommunication systems, especially in low phase noise oscillators, there is a need for resonators with low insertion losses and high Q-factor. More specifically, it is of high interest to design resonators with high group delay. In this paper, three novel dual-band complementary split-ring resonators (CSRRs) featuring high group delay etched on the waveguide surface by using substrate integrated waveguides are investigated and proposed. They are designed for a frequency range of 4.5–5.5 GHz. Group delay rates for the first, second, and third resonators were approximated as much as 23 ns, 293 ns, and 90 ns, respectively. We also proposed a new practical method to develop a wide tuning range SIW CSRR cavity resonator with a small tuning voltage in the second resonator, which leads to about 19% and 1% of tuning frequency band in the first and second bands, respectively. Finally, some of their applications in the design of filter, diplexer, and low phase noise oscillator will be investigated.
关键词： complementary split-ring resonators,low phase noise oscillator,group delay,substrate integrated waveguide,high Q-factor
更新于2025-09-11 14:15:04
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Configurable Perforated Air-Filled Substrate Integrated Waveguide (AFSIW) For Generic High-Performance Systems on Substrate
摘要： In this article, the patent pending configurable perforated air-filled substrate integrated waveguide (PAFSIW) is presented. First, a theoretical and experimental study of the proposed PAFSIW topology is introduced. Specifically, it is demonstrated that a low-cost Hi-Tg FR4 PAFSIW transmission line can handle over 190 W (up to 1340 W, determined from extrapolation of the experimental results) of continuous wave (CW) power at 20 GHz with an enhanced thermal dissipation compared with its AFISW counterpart. Then, configurable phase shifters, resonators, and filters based on the PAFSIW transmission line sections are introduced. Those components are fabricated using the conventional printed circuit board (PCB) and the through-hole mounting (THM) process to demonstrate the PAFSIW versatility and fabrication-tolerance robustness. The proposed PAFSIW extends the capabilities of the high-performance AFSIW technological platform as it provides genericity, manufacturing process robustness, and an alternative to improve thermal dissipation. The authors expect its implementation in highly configurable microwave- and millimeter-wave circuits for future generic systems on substrate.
关键词： systems on substrate,filters,power-handling,cavities,Air-filled substrate integrated waveguides (AFSIWs),transmission lines,resonators,configurability,phase shifters
更新于2025-09-11 14:15:04
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3-D Printed Bandpass Filters With Coupled Vertically Extruded Split Ring Resonators
摘要： The additive manufacturing process of multimaterial extrusion offers performance advantages using functional materials including conductors while making accessible the third dimension in the design of electronics. In this work, we show that the additional geometrical freedom offered by this technique can be exploited for the design and realization of filters made of 3-D resonators that exhibit enhanced characteristics. The coupling properties of 3-D grounded square split ring resonators (SRRs) are initially explored. We demonstrate by simulations and experiments that SRRs with finite height display significantly stronger coupling compared to equivalent thin printed circuit structures. The observed trend can be exploited for designing filters with wider operational bandwidths for a given footprint, or miniaturized layouts and enhanced compatibility with fabrication limits for minimum feature size and spacing without performance degradation. This concept is demonstrated by presenting results of full-wave simulations for sample bandpass filters with identical footprint but formed by coupled 3-D square SRRs of different heights, showing that filters with taller resonators exhibit increasingly wider bandwidths. Two filter prototypes with center frequencies at 1.6 and 2.45 GHz are manufactured by multimaterial 3-D printing. The measured characteristics of these prototypes are found to be in good agreement with numerical simulations taking into account the effect of the lossier metallic and dielectric materials used in 3-D printing and confirm the predicted larger bandwidth of the filters made of 3-D SRRs with marginally higher insertion losses.
关键词： Additive manufacturing,resonance,split-ring resonators,filter design,fused deposition modeling (FDM),3-D printing,direct digital manufacturing (DDM),electromagnetic coupling
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Spontaneous Symmetry Breaking, Oscillations, and Chaotic Regimes in Bidirectionally-Pumped Ring Resonators
摘要： Spontaneous symmetry breaking has been recently demonstrated experimentally in bidirectionally-pumped dielectric microresonators [1,2]. This process is mediated by cross-phase modulation due to the Kerr nonlinearity. We present comprehensive analytical and dynamical models for this symmetry breaking, with novel results in both time-dependent and time-independent cases, including chaos. The time-dependent system is described by the following pair of dimensionless coupled equations: ˙e1,2 = ?e1,2 ? [1 + i(|e1,2|2 + 2|e2,1|2 ? Δ)]e1,2, wherein ?e1,2 are the (clockwise or counterclockwise) electric ?eld amplitudes sent to the cavity, e1,2 are the (clockwise or counterclockwise) electric ?eld amplitudes coupled into the cavity, and Δ is the normalised detuning of the laser with respect to the non-Kerr-shifted cavity resonant frequency. Above a symmetry-breaking threshold, in which the stationary amplitudes of the two ?elds are different from each other, the system is strongly susceptible to oscillations [3], implying periodic energy exchange between the two modes. Above a theoretically-determined value of input power, oscillations develop with observable amplitudes (see Fig. 1 for typical ranges of instability). At still higher values of input power, we observe more complicated time-dependent behaviour: the onset of period-doubling, whereby much more complicated waveforms, and ?nally chaos, emerge [3]. Numerical integration of Eqs. (1) con?rms the ranges of instability and frequencies of oscillation [3]. In addition to being of fundamental interest, this theory is relevant for many applications, such as optical diodes and logic gates, as well as opening up the possibility of constructing an all-optical oscillator. The rich time-dependent behaviour exhibited by this system suggests applicability to other devices, such as scramblers and random number generators, all within a compact form factor, such as a microresonator. Note that many of the results presented here are general with respect to changes in the coef?cients of self- and cross-phase modulation in Eqs. (1).
关键词： Spontaneous symmetry breaking,bidirectionally-pumped ring resonators,chaotic regimes,oscillations
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Fast Photon Storage in a Fiber-Based Atom-Cavity System
摘要： Miniaturized ?ber-based optical resonators are emerging as a robust and scalable technology for realizing ?ber-based quantum networks. First demonstrated in [1], these cavities have been integrated with a variety of emitters, e.g. atoms, ions and solid-state systems, to build single-photon quantum interfaces. Our system consists of a single 87Rb atom coupled to a high bandwidth (κ = 2π×40 MHz (cid:2) γ), single-sided ?ber Fabry-Perot cavity (FFPC), Fig. 1(a). The unique system of four in-vacuum lenses, with their focal points coinciding with the ?ber-cavity center, provides the necessary optical access for 3D-cooling and trapping, addressing and high resolution ?uorescence imaging of the atoms, Fig. 1(b). For the D2-transition of 87Rb, the strongly coupled atom-cavity system shows a sixfold Purcell broadening and 90% emission into the cavity mode [2]. Here we present deterministic generation and storage of fast photon pulses. For single-photon generation the atomic state is prepared in F = 1 ground state. A π?polarized classical control laser pulse creates a single photon in the cavity mode with an ef?ciency of ～80%, Fig. 1(c). The pulse shape of the emitted single photon can be tailored by the temporal shape of the control pulse on a time scale lower than the atomic excited state lifetime of ～26 ns, Fig. 1(d). For the storage of fast (short) coherent light pulses, the atomic system is prepared in the |F = 2, m f = ?2(cid:4) state by optical pumping. The temporally shaped input coherent laser pulse at the single-photon level incidents on the cavity mirror while a π?polarized control classical laser pulse with an optimized temporal pro?le, dresses the atom-cavity system such that the storage ef?ciency of the input pulse is maximised. We store photon pulses with a temporal width down to 10 ns with an overall ef?ciency of ～5%.
关键词： 87Rb atom,single-photon quantum interfaces,photon storage,fiber Fabry-Perot cavity,fiber-based optical resonators,quantum networks
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Sixth-Order 2D Microring Optical Filter with Sharp Transmission Zero
摘要： Microring resonators have been shown to be extremely versatile elements for constructing high-order optical filters. By coupling multiple microring resonators together, high-order optical transfer functions with flat-top passband and sharp skirt roll-offs can be realized. However, most coupled microring optical filters to date are based on the 1D serially-coupled configuration (also known as CROW filters), which can only realize transfer functions with all poles and no transmission zeros. The inability of the 1D configuration to realize transmission zeros limits the rate of skirt roll-off that can be achieved in the filter spectrum. In contrast, the 2D coupling configuration provides multiple pathways of light through the lattice, which can result in complete destructive interference of the transmitted light at certain frequencies. By positioning these transmission nulls near the edge of the passband, filter spectra with very sharp skirt roll-offs can be realized, which are important for applications requiring separation of two closely spaced wavelengths, such as in dense WDM communication systems, fluorescence spectroscopy and nonlinear pump-and-probe experiments.
关键词： 2D coupling configuration,optical filters,transmission zeros,microring resonators
更新于2025-09-11 14:15:04
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Nonlinear operation of resonant sensors based on weakly-coupled resonators: theory and modeling
摘要： This theoretical work investigates the properties of nonlinearly-operated weakly-coupled resonators (WCRs) for resonant sensing applications. We propose an analysis framework for mutually injection-locked oscillators (MILOs) and to nonlinear mode-localized oscillators restoring and damping simplifying assumptions, three sensor architectures are investigated and compared, highlighting several common features such as: (i) the insensitivity of the amplitude ratio output metric to the A-f effect, (ii) the instability of one oscillation state above a threshold amplitude. These results are illustrated and validated using transient simulations. Their range of validity is then discussed with respect finite bandwidth, finite perturbations, measurement noise and nonlinear dissipation-fluctuation.
关键词： resonant sensing,mutually injection-locked oscillators,weakly-coupled resonators,mode-localized oscillators,nonlinear operation
更新于2025-09-11 14:15:04