Optics Communications最新文献

{"title":"The enhancement of high-order-harmonic generation in two-color laser field in fibonacci quasicrystals","authors":"Hai-Yan Sun,&nbsp;Ai-Yuan He,&nbsp;Guang-Xian Xiao,&nbsp;Chang-Long Xia","doi":"10.1016/j.optcom.2025.132135","DOIUrl":"10.1016/j.optcom.2025.132135","url":null,"abstract":"<div><div>High-order harmonic generation (HHG) from the Fibonacci quasicrystal system is investigated by solving the time-dependent Schrödinger equation (TDSE). The Fibonacci quasicrystal (FQ) has a fractal structure and appears many intersections on the band structure, which may provide more possible channels for HHG than that from crystals. Our simulation shows that the electron ionization is weaker for the top valence band (VB) states than that for the states from fractal energy bands in the middle of valence bands for a two-color field scheme. This is very different for electron excitation from the one-color scheme in Fibonacci quasicrystals or crystals. Compared with the one-color field scheme, the intensity of HHG is enhanced by <span><math><mrow><mn>3</mn><mo>∼</mo><mn>4</mn></mrow></math></span> orders in the case of the two-color field scheme. HHG from crystals could also be enhanced by two-color scheme, but the enhancement of the electron excitation usually comes from the states near the top of VB or resonance excitation channels. The fractal bands in FQ not only increase the ionization channels but also promote the generation of backscattering, thereby enhancing the electron distribution on the conduction band. Time-dependent population imaging (TDPI) is simulated to describe the microscopic dynamics of electrons and multiple channels from the intersection of fractal bands are proposed to explain the physical mechanism. The fractal band structure provides more sources of interference paths and may provide more information in harmonic spectra from the quasicrystal system for further investigation.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132135"},"PeriodicalIF":2.2,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical solving of dissipative solitons and Turing patterns in the Lugiato-Lefever equation using squared-operator iteration method","authors":"Gaoyan Cheng ,&nbsp;Xiankun Yao","doi":"10.1016/j.optcom.2025.132170","DOIUrl":"10.1016/j.optcom.2025.132170","url":null,"abstract":"<div><div>This study develops the squared-operator iteration method to numerically solve dissipative solitons and Turing patterns in the Lugiato-Lefever equation. We analytically derive dissipative soliton solutions with a nonzero background and employ Fourier series expansion to obtain the discrete spectrum, along with the corresponding solutions of Turing patterns. These advances address a critical limitation of conventional squared-operator iteration method implementations. Linear stability analysis further examines the stability of these solutions under finite perturbations. Overall, this research provides an efficient and reliable approach for investigating nonlinear phenomena in the Lugiato-Lefever equation.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132170"},"PeriodicalIF":2.2,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast path loss calculation of W2A-OWC based on the grid cell collective photon refraction method","authors":"Wendong Liao ,&nbsp;Chengye Cai ,&nbsp;Yufan Zhang ,&nbsp;Haipeng Wang ,&nbsp;Qingrui Chen ,&nbsp;Tianhao Zhang ,&nbsp;Xiaoxu Ma ,&nbsp;Yuxin He ,&nbsp;Xiaoqi Hu ,&nbsp;Shaoda Yuan ,&nbsp;Baokang Chen ,&nbsp;Zejun Zhang ,&nbsp;Jing Xu","doi":"10.1016/j.optcom.2025.132168","DOIUrl":"10.1016/j.optcom.2025.132168","url":null,"abstract":"<div><div>The simulation speed of traditional Monte Carlo (MC) methods for water-to-air (W2A) optical wireless communication (OWC) is limited by the dynamic property of sea surfaces and the large number of photons required. This study aims to accelerate the simulation process by analyzing the channel characteristics. Two major optimizations of the MC algorithm for W2A-OWC are introduced. Firstly, the bicubic interpolation method is introduced to enhance the resolution of sea surface modeling. Secondly, the sea surface height difference iteration method (SSHIM) is proposed to calculate photon refraction points rapidly. Based on these advances, this study proposes an innovative path loss simulation method based on the grid cell collective photon refraction (GCCPR) method. The proposed method is verified in three simulation scenarios: sea surface energy distribution, receiving plane energy distribution and received optical power (ROP). The highest Pearson correlation coefficient between the proposed method and MC simulation is 89.62 % for the receiving plane energy distribution, and the calculation speed of the proposed method can be more than 1000 times faster than the MC simulation. Finally, the feasibility of the proposed method is validated through experiments with regular and irregular two-dimensional (2D) waves. In a stable environment with only wave fluctuations, the proposed method can quickly calculate the change of energy distribution on the receiving plane caused by sea surface fluctuations.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132168"},"PeriodicalIF":2.2,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144536005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Luminescence properties and application of near-infrared Er3+-doped bismuth germanate laser glass","authors":"Fang Tan ,&nbsp;Dexiao Chen ,&nbsp;Songsong Ge ,&nbsp;Chengao Jiang ,&nbsp;Yanke Zhang ,&nbsp;Zhitao Zhang ,&nbsp;Shunfa Cui ,&nbsp;Zhuang Leng","doi":"10.1016/j.optcom.2025.132167","DOIUrl":"10.1016/j.optcom.2025.132167","url":null,"abstract":"<div><div>Er³⁺-doped bismuth germanate laser materials were prepared using the conventional high-temperature melt-quenching method. The results of both the DSC and XRD analyses demonstrate that bismuth germanate glasses exhibit optimal thermal stability and a good amorphous phase. In a subsequent analysis, the internal topology of the laser glass was deduced through the integration of Raman spectroscopy. This analysis revealed that the incorporation of H₃BO₃ and Al₂O₃ could enhance the thermodynamic properties of the glass. The J-O theory calculations yielded the following parameters: intensity parameter Ω₂ = 6.49 × 10⁻²⁰cm², quality factor χ = 1.00, spontaneous radiation probability A_rad = 449.40 s⁻¹, and fluorescence lifetime τ_rad = 2.23 ms. The data demonstrate superiority over other glass systems. In order to study the luminescence characteristics of Er³⁺ in the near-infrared band, the absorption and emission cross sections as well as the gain coefficient curves were calculated based on the absorption and emission spectra. Meanwhile, the microscopic energy transfer coefficient C_D-A (1.34 × 10⁻³⁸ cm⁶/s) for the CR process between Er³⁺ was calculated according to Dexter's theory. In addition, the laser glass prepared in this paper was applied in a multi-core photonic crystal fiber, and the inter-core crosstalk XT (−56.8 dB), the effective mode-field area A_<em>eff</em> (363 μm²), and the photovoltaic field strengths were quantitatively computed and analyzed by the beam propagation method (BPM) and the finite element method (FEM). The results show that bismuth germanate glass is an excellent gain medium for realizing high-quality laser emission of Er³⁺ in the near-infrared band.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132167"},"PeriodicalIF":2.2,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance enhancement of 3D-GS-CAP based on improved swarm intelligence algorithm and spherical Fibonacci grid in VLC system","authors":"Tianshuo Wang ,&nbsp;Jie Ma ,&nbsp;Jia Lu ,&nbsp;Jianfei Liu ,&nbsp;Xiangye Zeng ,&nbsp;Yang Wang","doi":"10.1016/j.optcom.2025.132161","DOIUrl":"10.1016/j.optcom.2025.132161","url":null,"abstract":"<div><div>This paper proposes an optimization scheme for three-dimensional geometrically shaped carrier-less amplitude phase (3D-GS-CAP) modulation based on the multi-strategy improved honey badger algorithm (MIHBA) and the spherical Fibonacci grid (SFG), with its performance experimentally verified in a visible light communication (VLC) system. To reduce the geometric complexity of artificial constellation design, the scheme uses the uniform distribution of the spherical surface and the swarm intelligence algorithm to optimize the three-dimensional (3D) spherical surface. Aiming at the problem that the HBA algorithm is prone to local optimality, four improvement strategies are proposed in this paper to optimize the 3D constellation distribution and improve the anti-noise ability of the signal. In addition, in order to solve the high computational complexity of existing optimization algorithms, SFG is introduced innovatively in this paper. The universality of the method to constellation points makes it efficient to optimize under different orders without complicated parameter adjustment. The experimental results show that when the bit error rate threshold is 5E^-4, the maximum Vpp operating range of 3D-MIHBA is extended by 59.98 % and the bias current is increased by 23.4 mA compared with the traditional 3D-CAP-16 signal. This shows that the scheme enhances the anti-noise capability of the system and greatly improves the flexibility of constellation optimization under low complexity.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132161"},"PeriodicalIF":2.2,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lateral mode selection of a novel laser structure with surface tapered distributed Bragg reflectors","authors":"Yongle Zhan ,&nbsp;Qiong Qi ,&nbsp;Cong Xiong ,&nbsp;Suping Liu ,&nbsp;Xiaoyu Ma ,&nbsp;ZhenWu Liu ,&nbsp;Ting Wang ,&nbsp;Shuang Hao ,&nbsp;Wang Xing","doi":"10.1016/j.optcom.2025.132160","DOIUrl":"10.1016/j.optcom.2025.132160","url":null,"abstract":"<div><div>This study proposes a theoretical model and optical simulation framework to achieve single lateral mode operation in broad-area mesa lasers by integrating surface narrow distributed Bragg grating (DBR) reflectors. By introducing an effective grating confinement factor (Γ_{<em>g,eff</em>}) to refine the coupling coefficient formula for buried heterostructure gratings, we systematically analyze the impact of grating parameters—etching depth (d_<em>g</em>), width (W_<em>g</em>), and filling factor (γ)—on the coupling coefficients (κ) and reflectivity of TE₀₀ and TE₀₁ modes. Key relationships between modal discrimination (MD) and grating parameters, as well as cavity length (L), are established. We propose a novel surface tapered DBR structure with varying W_<em>g</em>, which enhances MD notably compared to uniform gratings, while maintaining high TE₀₀ reflectivity. This work provides a design paradigm for high-power, single-lateral-mode lasers, bridging the gap between broad-area mesa scalability and spectral purity requirements in applications such as atomic clocks and precision navigation systems.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132160"},"PeriodicalIF":2.2,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CMA-ES enhanced optimization of optical nonlinear activation functions","authors":"Tao Jia,&nbsp;Ziling Fu,&nbsp;Rui Jiang,&nbsp;Zunliang Zou,&nbsp;Li Yang,&nbsp;Shuo Wang,&nbsp;Ningxin Jiao,&nbsp;Guanjie Zhao,&nbsp;Zhi Wang","doi":"10.1016/j.optcom.2025.132145","DOIUrl":"10.1016/j.optcom.2025.132145","url":null,"abstract":"<div><div>The development of all-optical and electro-optical neural networks represents a rapidly growing field of research. In this field, optimization and reconfigurability of optical nonlinear activation functions (ONAF) devices are crucial. In this work, we propose an optimization framework for MZI and MRR-based ONAF devices using the Covariance Matrix Adaptation Evolution Strategy (CMA-ES). By incorporating this approach into the optimization of artificial neural networks (ANNs), the root mean square error (RMSE) of the fitted optimization functions can reach as low as −86.0 dB. We also present a theoretical analysis of electro-optical (E/O) modulation in directional couplers (DC), enabling reconfigurable power coupling coefficients. Additionally, we investigate an alternative MRR configuration where output light is coupled with MZI from the drop port instead of the through port, leading to optimal performance. This setup allows for the implementation of several activation functions including Parametric ReLU, which attains 100 % training accuracy and 99.1 % validation accuracy in the MNIST handwritten digit recognition task. Our findings provide new insights into the design and optimization of optical activation devices for integrated photonic neural networks.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132145"},"PeriodicalIF":2.2,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144513793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Classical analogues of the quantum-mechanical Moshinsky effect: “Stretching” and “freezing” of gradient interference effects for rectangular-shaped laser pulses in dispersion-decreasing optical fibers","authors":"T.L. Belyaeva ,&nbsp;L. Morales-Lara ,&nbsp;R. Peña-Moreno ,&nbsp;V.N. Serkin","doi":"10.1016/j.optcom.2025.132096","DOIUrl":"10.1016/j.optcom.2025.132096","url":null,"abstract":"<div><div>We study classical optical analogues of the transient quantum mechanical Moshinsky effect, also known as “diffraction in time”, which can be observed in the linear propagation dynamics of rectangular-shaped super-Gaussian laser pulses and beams. We find critical field gradients at the pulse fronts and beam edges, at which the Fresnel-type diffraction patterns completely fill the flat top of the super-Gaussian field profile, and their interference leads to the linear dispersive/diffractive “self-focusing” effect. We show that the dependencies of both the “self-focusing length” and the corresponding effective “gain” on the steepness of the field gradients demonstrate a tendency towards saturation. We highlight that the accuracy of quasioptical computational modeling based on the Schrödinger-type equations must always be controlled by the principal conservation laws in both ordinary space/time and the Fourier spectral domains. In particular, we demonstrate that significant Fresnel-type diffraction patterns arising in the linear dynamics of super- Gaussian pulses and beams are accompanied by their completely stationary Fourier spectral distributions calculated with an accuracy up to 8 orders of magnitude. Since the considered optical analogues of the quantum-mechanical Moshinsky effect manifest themselves only at the rather small distances compared to the dispersion and diffraction lengths, we concentrate on possible experimental realizations of these features in nonautonomous systems, a typical example of which is represented by the optical fiber with group velocity dispersion decreasing along the fiber length. We reveal that dispersion-decreasing optical fibers provide a unique opportunity to slow down (“stretch”) the formation of the Moshinsky-type dispersion patterns at the flat tops of super-Gaussian pulses and even “freeze” the linear gradient interference “self-focusing” of the central parts of rectangular-shaped laser pulses.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132096"},"PeriodicalIF":2.2,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of efficient asymmetric subwavelength grating coupler for plasmonic interconnect circuits","authors":"Zhenyuan Huang ,&nbsp;Zhiqing Zhang ,&nbsp;Canran Zhang,&nbsp;Yijing Xu,&nbsp;Qilong Wang","doi":"10.1016/j.optcom.2025.132102","DOIUrl":"10.1016/j.optcom.2025.132102","url":null,"abstract":"<div><div>This paper studies the design of asymmetric subwavelength grating coupling structures aimed at enhancing the unidirectional coupling efficiency of plasmonic grating couplers. Based on uniform symmetric grating couplers, a chirped cut-off grating coupler with parameters that vary according to a fixed rule is designed. Then, by innovatively defining the grating arrangement rules using hexadecimal coding and incorporating the genetic algorithm, a structurally random binarized asymmetric grating coupler is designed. The optimal binarized grating coupler obtained after 500 iterations achieves a unidirectional coupling efficiency of 60.38% for SPPs in the 1550 nm wavelength band.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132102"},"PeriodicalIF":2.2,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the contribution of electromagnetic nearfield gradients in TERS","authors":"Amirhassan Khodadadi ,&nbsp;Kevin Fiederling ,&nbsp;Stephan Kupfer ,&nbsp;Stefanie Gräfe","doi":"10.1016/j.optcom.2025.132154","DOIUrl":"10.1016/j.optcom.2025.132154","url":null,"abstract":"<div><div>Tip-enhanced Raman spectroscopy (TERS) extends the spatial resolution of conventional Raman far beyond the diffraction limit by merging the advantages of both surface-enhanced Raman spectroscopy (SERS) and scanning probe microscopy (SPM). While most theoretical models focus on either electromagnetic (EM) enhancement or chemical (CM) effects – and typically consider only the component of the polarizability tensor normal to the substrate (<em>α</em>_<em>zz</em>) – we present a fully quantum-mechanical approach that accounts for all components of the polarizability tensor, allowing to evaluate the impact of spatial inhomogeneity in the electromagnetic nearfield on the Raman response. These may become particularly pronounced for Raman modes which are, for symmetry reasons, dark in the field enhancement direction normal to the substrate (here the <em>z</em>-direction). By scanning a single metal atom mimicking a plasmonic tip at various positions above a flat planar sample molecule, we demonstrate how the tip-molecule interactions shift the electronic transitions and thereby modify the resonance Raman response. In particular, some off-diagonal components (<em>α</em>_<em>xy</em>, <em>α</em>_<em>yx</em>) become crucial for activating certain vibrational modes that are absent for the isolated molecule. Decreasing the tip-sample distance reveals how the <em>z</em>-directed charge-transfer states enhance TERS signals out of the molecular plane. Overall, our findings underscore the need to include different components of the polarizability tensor and to account for both EM and CM contributions for an accurate description of TERS spectra.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"591 ","pages":"Article 132154"},"PeriodicalIF":2.2,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}