- 标题
- 摘要
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- 实验方案
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Online Degradation Detection/Prediction Method for Current Transfer Ratio of Photo-Coupler Installed in Digitally-Controlled Switching Mode Power Supply
摘要： The software-implemented degradation detection/prediction of the current transfer ratio (CTR) of a photo-coupler installed in a digitally-controlled switching mode power supply was studied. The photo-coupler is one of the key devices in an isolated power supply circuit, which transmits a voltage/current signal to a controller though the isolation gap. If the CTR of the photo-coupler degrades to halfway between the normal value and the threshold of the hardware protection circuit, overvoltage/current may be supplied continuously to the load circuit and possibly cause a severe failure. By comparing the theoretical pulse width modulation (PWM) duty, which is calculated from the input/output voltage and the pre-measured power supply circuit e?ciency, and the applied PWM duty, which is calculated via feedback control, CTR degradation is detectable online. In this paper, we describe the concept of this method and verify it using both simulation and prototyping circuits.
关键词： digitally-controlled power supply,current transfer ratio,failure prediction,degradation,photo-coupler,CTR
更新于2025-09-23 15:21:01
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A New 4 ?? 4 Rectangular Waveguide Short-Slot Coupler in 3D Printed Technology at Ku-Band
摘要： This paper presents a novel design of an eight-port directional coupler with a very compact structure and simple manufacturing, working in the Ku frequency band. One of the main goals of the design was to ease the manufacturing with a simple structure: the coupler consisted of four rectangular waveguide input ports, four rectangular waveguide output ports, and a central coupling region with only H-plane variation. A prototype was fabricated using additive manufacturing, with a combination of 3D printing and silver coating metallization. The obtained performance showed a theoretical bandwidth of 6.6% with 20 dB return loss for the input/output ports. Good agreement between simulations and measurements was obtained, validating the proposed coupler as a good trade-off for low cost 3D printing, compactness, and high performance for systems requiring a high number of ports as in phase arrays or Butler matrices.
关键词： rectangular waveguide,Riblet-type coupler,directional couplers,additive manufacturing
更新于2025-09-23 15:21:01
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A Wideband On-Chip Directional Coupler Using a Negative Capacitance Circuit
摘要： We propose a wideband lumped element directional coupler using lossy negative capacitance (NCAP). NCAP provides a broadband resonance effect combined with passive inductors and capacitors in a circuit, enabling the coupler to exhibit wideband directivity performance. In addition, a 3-dB loss in the NCAP enhanced the bandwidth at the expense of the transmission gain, which decreased by only 0.3 dB. The proposed coupler was implemented in the IBM 7RF 180-nm CMOS technology. The size of the core chip is 1180 μm × 570 μm. The designed NCAP provides a capacitance of ?13 pF using a supply voltage of 2.7 V and a current of 9.6 mA. The coupling was designed to be ?10 dB at the center frequency of 1 GHz. The bandwidth was de?ned by the frequency range, which exhibited a directivity of more than 30 dB. The S-parameter measurements showed an absolute bandwidth ranging from 0.86 to 1.12 GHz, and a fractional bandwidth of 26%. In the bandwidth, the coupling had a 0.5-dB variation, the transmission loss was smaller than 2.14 dB, and the noise ?gures were 1.8–2.5 dB.
关键词： Broadband resonance,wideband lumped element (LE) directional coupler,negative capacitance (NCAP)
更新于2025-09-23 15:21:01
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[IEEE 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Lausanne (2018.7.29-2018.8.2)] 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Digital Silicon Photonic MEMS Phase-Shifter
摘要： We report on a 4-bit digital silicon photonic MEMS phase-shifter with sub-microsecond switching time and low power consumption (< 10 uW). The device consists of 4 digitally switched phase-shifting units, which in total enable phase shift from (cid:2)(cid:2)(cid:1)/8 to 15pi/8 in increments of (cid:2)(cid:1)/8.
关键词： Silicon Photonic MEMS,Adiabatic Coupler,Phase Control,Photonic Integrated Circuit,Optical Switch
更新于2025-09-23 15:21:01
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Input coupling systems for terahertz gyro-TWAs
摘要： Input coupling systems for THz gyrotron traveling wave amplifiers (gyro-TWAs) are presented in this paper. These form one of the most critical parts of the gyro-TWA as it feeds the low power seed signal into the interaction circuit and incorrect design can lead to cessation of the amplification. The T-junction, multihole and multiarm coupler types were simulated in CST Microwave Studio and their optimized reflection and transmission characteristics, operating at a central frequency of 0.37 THz are presented. A scaled multiarm coupler, designed to then operate at 94 GHz, was manufactured and its microwave properties measured on a vector network analyser.
关键词： CST Microwave Studio,multihole coupler,THz gyro-TWAs,T-junction,multiarm coupler,input coupling systems
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Compact Polarization Beam Splitter Based on a 3-Waveguide Directional Coupler with Broad Bandwidth Performance
摘要： Compact polarization beam splitter based on a 3-waveguide directional coupler with broad bandwidth performance
关键词： slot waveguide,directional coupler,Polarization beam splitter
更新于2025-09-23 15:19:57
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Extension of an FFT-Based Beam Propagation Method to Plasmonic and Dielectric Waveguide Discontinuities and Junctions
摘要： We adapted a fast Fourier transform-based Beam Propagation Method (FFT-BPM) to investigate waveguide discontinuities in plasmonic waveguides. The adaptation of the FFT-BPM to treat transverse magnetic (TM) fields requires the circumvention of two major difficulties: the mixed derivatives of the magnetic field and waveguide refractive index profile in the TM wave equation and the step-like index change at the transverse metal-dielectric boundary of the plasmonic guide and the transverse boundaries of the dielectric waveguide as well. An equivalent-index method is adopted to transform TM fields to transverse electric (TE) ones, thus enabling the benefit of the full power and simplicity of the FFT-BPM. Moreover, an appropriate smoothing function is used to approximate the step-like refractive index profile in the transverse direction. At the junction plane, we used an accurate combined spatial-spectral reflection operator to calculate the reflected field. To validate our proposed scheme, we investigated the modal propagation in a silicon waveguide terminated by air (like a laser facet in two cases: with and without a coating layer). Then we considered a subwavelength plasmonic waveguide (metal-insulator-metal MIM) butt-coupled with a dielectric waveguide, where the power transmission efficiency has been calculated and compared with other numerical methods. The comparison reveals good agreement.
关键词： butt-coupler,plasmonics,FFT-BPM,sensors,plasmonic waveguide,bi-directional BPM,photonics,reflection formalism,TM fields,optical propagation
更新于2025-09-23 15:19:57
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MINIATURIZATION OF TRANS-DIRECTIONAL COUPLED LINE COUPLERS USING SERIES INDUCTORS
摘要： A miniaturized trans-directional (TRD) coupled line coupler comprises series inductors and capacitor loaded coupled lines is proposed in the paper. Series inductors are added to the periodically loaded coupled lines for further miniaturization of volume. A novel equivalent circuit is presented and theoretically analyzed. Test circuits for the miniaturized and conventional 3-dB TRD couplers were designed to operate at 1.6 GHz and fabricated using printed circuit board (PCB) technology. Samples have been measured, and comparisons in terms of volume, schematic simulation results and measurement results between the miniaturized and conventional 3-dB TRD couplers have been made to validate the proposed structure. Results show that the proposed miniaturized TRD coupler achieves a size reduction of 47.6% compared to the conventional TRD coupler with similar performances.
关键词： PCB technology,trans-directional coupler,miniaturization,series inductors,coupled lines
更新于2025-09-23 15:19:57
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Efficient polymer waveguide grating coupler with directionality enhancement
摘要： Polymer is viewed as an ideal platform for integrated photonics sensing. We propose a polymer waveguide grating coupler with the enhancement of directionality. A gold film mirror beneath the grating coupler is introduced to prevent the power leakage into the substrate. A Bragg grating reflector in series with the coupler is adopted to reverse the forward diffraction light. The finite-difference time-domain method is used to theoretically investigate the dimensional parameters of grating coupler, gold film mirror, as well as the grating reflector. With both two methods, an enhanced coupling efficiency of 51.31 % can be obtained at the wavelength of 1550 nm. The 62-nm wide 1-dB bandwidth covers the C-band. The proposed design has potentials in integrated optical circuit and monolithic integrated sensors.
关键词： Polymer,Grating coupler,Bragg grating,Waveguide
更新于2025-09-23 15:19:57
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Switchable multi-wavelength linearly-polarized lasing oscillations in a figure eight EDF laser based on spatial-mode beating by means of weakly-coupled FMF
摘要： A switchable multi-wavelength figure eight Erbium-doped fiber (EDF) laser with linearly-polarized (LP) beam generation in the C-band region is proposed and experimentally demonstrated. Spatial-mode beating occurs owing to effect of multi-mode interference in the weakly-coupled few-mode fiber (FMF). A bandpass filter of multiple specific wavelengths is created by incorporating a weakly-coupled FMF with a Sagnac fiber loop. The LP modes are generated by cascaded mode-selective couplers (MSCs), which are designed and fabricated by tapering the proposed FMF with single-mode fiber (SMF). Combination of the cascaded MSCs and a simple N × 1 optical switch is employed to switch the LP modes. In experiments, the proposed fiber laser delivers versatile lasing outputs in states of single-, dual-, triple-wavelength oscillations for LP01, LP11 and LP21 modes. We investigate the stabilities for LP01, LP11, LP21 modes in 24-min. Moreover, the mode intensity profiles, optical signal-noise ratios (OSNRs) of lasing output and slope efficiencies are also measured. The proposed fiber laser has promising applications in WDM-MDM optical fiber communication systems, optical fiber sensor systems, optical instruments and spectroscopy.
关键词： Weakly-coupled FMF,Mode selective coupler,Sagnac fiber loop,Erbium-doped fiber laser
更新于2025-09-23 15:19:57