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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • Mach Zehnder Interferometer
  • Convolution code
  • Lithium Niobate
  • Parity
  • Electro-optic
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • DIT University
166 条数据
?? 中文（中国） ▾

  • Low-threshold 4/5 octave-spanning mid-infrared frequency comb in a LiNbO3 microresonator

    摘要： Mid-infrared (MIR) optical frequency combs (OFCs) are ideal light sources for precision metrology and can ?nd extensive applications, especially in molecular spectroscopy and gas detection. Here the generation of mode-locked MIR frequency comb in a LiNbO3 microring through optimized slot-waveguide design is proposed. Such microcomb can span over four-?fths of an octave (ranging from (cid:24)2810 nm to (cid:24)4630 nm) with pump power as low as 50 mW, which can be applied to the 2f -3f self-referencing for fully stabilization and helpful to monolithic integration of the whole system. Further investigations on complex dynamical processes for the microcomb generation suggest that the intracavity soliton drifting caused by the third-order dispersion could be compensated by the self-steepening effect as introducing an additional drift through proper dispersion tailoring. This work could facilitate the low-threshold broadband MIR frequency comb generation technique, as well as provide a way to realize more delicate control of soliton microcombs in both temporal and spectral domain.

    关键词： mid-infrared,high-order dispersion,self-steepening,Lithium niobate,nonlinear optics

    更新于2025-09-11 14:15:04

  • Design of Linear Block Code Encoder and Decoder Using Electro-optical and All-optical Units

    摘要： In this paper novel designs for linear block code encoder and decoder using optical techniques have been proposed. The structures are designed and simulated using lithium niobate based Mach–Zehnder Interferometer (LN-MZI) and nonlinear material MEH-PPV [poly (2-methoxy-5-(28-ethylhexyloxy)-PPV)] (plasmonic) based MZI (P-MZI). The proposed LN-MZI designs offer attractive parameters such as high extinction ratio (> 35 dB) and low insertion loss (< 0.095 dB), while the proposed P-MZI designs possess a compact structure (3,020–12,375 μm2). An analytical comparison between the two design methodologies and other earlier proposed designs is presented. Each design is presented with a verified mathematical structure. Other performance parameters like contrast ratio and amplitude modulation have also been computed for the presented designs.

    关键词： electro-optic,Pockel effect,Kerr effect,error detection,syndrome bits,plasmonic,Mach–Zehnder interferometer,lithium niobate,parity,linear block code

    更新于2025-09-11 14:15:04

  • [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) - Conversion of two Photons with Different Color by a Single Waveguide for Quantum Networks

    摘要： Quantum communication would enable opportunities such as secure communication. A quantum network with quantum nodes and quantum channels is necessary for this. The realization of such a quantum network requires the ability to process, store and send photons over long distances. It is not very likely that a single physical system can accomplish all these operations. Therefore, dissimilar quantum systems have to be connected in future quantum networks. Quantum channels are likely to be based on the existing fiber network because it is already well established. The fiber network operates at telecom wavelength (1550 nm) since the losses in fibers are minimal at this wavelength. That is why quantum states at telecom wavelength are needed. Unfortunately, suitable single photon sources and quantum memories are not available at telecom wavelength. Frequency conversion provides the possibility to alter the wavelength of a single photon to another wavelength. With frequency conversion it is possible to convert the VIS/NIR single photon to telecom wavelength and transfer the state over long distances. However, quantum networks do not require single photons but rather entangled photon pairs. Quantum dots are able to generate entangled photon pairs via a biexciton cascade emission. The emitted photons of a cascaded emission usually have slightly different wavelengths. The frequency conversion of the entangled photon pair on a single device would be advantageous for building quantum nodes for real life applications. We present a frequency conversion based on a single lithium niobate waveguide with different local temperatures to convert two different wavelengths on the same chip. The setup consists of a 2100 nm pump laser and a fiber coupled input port for the two biexciton photons (894 nm and 892 nm). These three wavelengths are focused by a lens into a nonlinear crystal with two different local temperatures. Each segment converts one of the incoming wavelengths. The converted signal is coupled into an optical fiber and guided to a filter system, which removes remaining pump light and generated noise photons. A proof of principle experiment was performed with attenuated laser light, where the converted spectrum is shown.

    关键词： lithium niobate waveguide,frequency conversion,Quantum communication,entangled photon pairs,quantum network

    更新于2025-09-11 14:15:04

  • Using Er:YAG laser to remove lithium disilicate crowns from zirconia implant abutments: An in vitro study

    摘要： When implants are restored with cement-retained restorations, prosthetic retrievability can be difficult and often requires sectioning using rotary instruments. Sometimes repeated removals of a cement-retained implant crown are needed such as for treatment of peri-implantitis or immediate implant provisionalization. The purpose of this study was to evaluate the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser as a non-invasive treatment modality to remove lithium disilicate crowns from zirconia implant abutments following long-term cementation, repetitive debonding and re-cementation, and short-term retrieval.

    关键词： cement-retained restorations,zirconia implant abutments,lithium disilicate crowns,Er:YAG laser,prosthetic retrievability

    更新于2025-09-11 14:15:04

  • A review on state of health estimation for lithium ion batteries in photovoltaic systems

    摘要： Enhancing state of health (SOH) estimation accuracy and robustness for battery systems in photovoltaic (PV) systems is a feasible way to improve system performance and economics. Nevertheless, the SOH is not directly measurable and affected by a number of factors, therefore its estimation is challenging. Plenty of SOH estimation methods have been proposed for different applications, but little evaluation and discussion have been made for the SOH estimation for battery management systems in PV systems. In this paper, SOH estimation methods are categorised according to the signals that are used to extract the health indicator. Most methods are based on voltage characteristics while other signals such as temperature, ultrasound and force are also promising for SOH estimation. For each method, the basic theory, advantages and drawbacks are introduced and discussed. Then, a thorough comparison among the existing methods is conducted to provide readers with a comprehensive understanding of the development of the SOH estimation. Finally, key issues and suggestions on the SOH estimation are discussed to give novel insights to researchers and engineers.

    关键词： State of health,Photovoltaic system,Battery management system,Lithium ion battery

    更新于2025-09-11 14:15:04

  • An Integrated Photonic Electric-Field Sensor Utilizing a 1 × 2 YBB Mach-Zehnder Interferometric Modulator with a Titanium-Diffused Lithium Niobate Waveguide and a Dipole Patch Antenna

    摘要： We studied photonic electric-?eld sensors using a 1 × 2 YBB-MZI modulator composed of two complementary outputs and a 3 dB directional coupler based on the electro-optic e?ect and titanium di?used lithium–niobate optical waveguides. The measured DC switching voltage and extinction ratio at the wavelength 1.3 μm were ~16.6 V and ~14.7 dB, respectively. The minimum detectable ?elds were ~1.12 V/m and ~3.3 V/m, corresponding to the ~22 dB and ~18 dB dynamic ranges of ~10 MHz and 50 MHz, respectively, for an rf power of 20 dBm. The sensor shows an almost linear response to the applied electric-?eld strength within the range of 0.29 V/m to 29.8 V/m.

    关键词： titanium di?used optical channel waveguide,lithium–niobate electro-optic e?ect,photonic electric-?eld sensor,Y-fed balanced-bridge Mach-Zehnder interferometer (YBB-MZI)

    更新于2025-09-11 14:15:04

  • Design and Optimization of Proton Exchanged Integrated Electro-Optic Modulators in X-Cut Lithium Niobate Thin Film

    摘要： In this study, we designed, simulated, and optimized proton exchanged integrated Mach-Zehnder modulators in a 0.5-μm-thick x-cut lithium niobate thin film. The single-mode conditions, the mode distributions, and the optical power distribution of the lithium niobate channel waveguides are discussed and compared in this study. The design parameters of the Y-branch and the separation distances between the electrodes were optimized. The relationship between the half-wave voltage length production of the electro-optic modulators and the thickness of the proton exchanged region was studied.

    关键词： Mach-Zehnder,electro-optic modulator,integrated optics devices,proton exchange,lithium niobate thin film

    更新于2025-09-11 14:15:04

  • Semi-Nonlinear Nanophotonic Waveguides for Highly Efficient Second-Harmonic Generation

    摘要： Quadratic optical parametric processes form the foundation for various applications related to classical and quantum frequency conversion, and have attracted significant interest recently in on-chip implementation. These processes rely on phase matching among the interacting guided modes, and refractive index engineering is a primary approach for this purpose. Unfortunately, modal phase-matching approaches developed so far only produce parametric generation with fairly low efficiencies, due to the intrinsic modal mismatch of spatial symmetries. Here, a universal design and operation principle is proposed for highly efficient optical parametric generation on integrated photonic platforms. By breaking the spatial symmetry of the optical nonlinearity of the device, nonlinear parametric interactions can be dramatically enhanced. This principle is then employed to design and fabricate a heterogeneous titanium oxide/lithium niobate nanophotonic waveguide that is able to offer second-harmonic generation with a theoretical normalized conversion efficiency as high as 2900% W?1 cm?2, which enables the measurement of an experimental efficiency of 650% W?1 cm?2, significantly beyond the reach of conventional modal phase-matching approaches. Unlike nonlinearity domain engineering that is material selective, the proposed operation principle can be flexibly applied to any other on-chip quadratic nonlinear platform, to support ultra-highly efficient optical parametric generation.

    关键词： lithium niobate,integrated photonics,nonlinear optics,optical parametric generation

    更新于2025-09-11 14:15:04

  • Improving and Stabilizing Perovskite Solar Cells with Incorporation of Graphene in the Spiro-OMeTAD Layer: Suppressed Li Ions Migration and Improved Charge Extraction

    摘要： Perovskite solar cells (PSCs) have achieved a huge success in power conversion efficiency (PCE), while they still suffer from the long-term stability problem caused by the intrinsic sensitivity of perovskites to moisture. 2,2’,7,7’-tetrakis (N, N-di-p-methoxyphenylamine) 9,9’-spirobifluorene (Spiro-OMeTAD) is widely used as the hole transport layer (HTL) in typical PSCs; meanwhile bis(trifuoromethane)sulfonimide lithium salt (Li-TFSI) proves its necessity as an additive in the Spiro-OMeTAD HTL to improve the hole mobility. However, the Li+ ions bring in high hygroscopicity and water-uptake effect that both aggravate degradation of the Spiro-OMeTAD HTL and thereby of the perovskite layers. Here, we modify the Li-TFSI-based Spiro-OMeTAD HTL by adding reduced graphene oxide (rGO). We verify that rGO provides adsorption sites for Li+ ions and subsequently suppresses Li+ migration. The water-uptake effect originated from Li+ ions is thus relieved and detestable pinholes in HTL caused by Li+ ion migration are eliminated. Consequently, the rGO-incorporated HTL remarkably improves the device stability that maintains the initial PCEs within 3% loss after 700 h under 40% humidity; whereas the pristine devices almost lose the efficiency after 620 h. In addition, the good conductivity of the rGO favors hole transport in the Spiro-OMeTAD, resulting in a promotion in PCEs from 17.7% to 19.3% by incorporating rGO in HTL. Our work takes an insight into the function of rGO in the HTL and demonstrates an effective way of improving the efficiency and stability of PSCs simultaneously.

    关键词： Perovskite solar cells,lithium ions,moisture stability,reduced graphene oxide (rGO),charge extraction,ion migration

    更新于2025-09-11 14:15:04

  • Short-Term Photovoltaic Generation Forecasting Based on LVQ-PSO-BP Neural Network and Markov Chain Method

    摘要： The poor cycling stability is a tricky problem in the silicon-based lithium-ion batteries. Herein, we fabricate a three-dimension polyaniline/poly (acrylic acid)/phytic acid compound binder for the silicon anodes. In this binder, polyaniline-doped and gelated by phytic acid functions as a continuous electrically conductive network structure for the silicon anodes. Meanwhile, a high density of carboxyl groups provided by poly (acrylic acid) enhance the stability of the silicon electrodes by supplying strong binding ability with current collectors and silicon particles. Using this multifunctional binder in silicon anode, we succeed in manufacturing very long cycle life of larger than 1000 cycles at a current density of 4.2 A g?1.

    关键词： Si anodes,Polymer binder,Cycle,Lithium-ion battery

    更新于2025-09-11 14:15:04