- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Optical solitons of the paraxial wave dynamical model in kerr media and its applications in nonlinear optics
摘要： The solitons and other solutions illustrate nondiffractive and nondispersive spatio-temporal localized packets of wave propagating in the media of optical Kerr. In this paper, solitons, elliptic function and other solutions of dimensionless time-dependent paraxial wave model are constructed via employing three mathematical techniques, namely, the improved simple equation technique, exp(?Φ(ζ))-expansion technique and modified extended direct algebraic technique. These wave solutions have key applications and help to understand the physical phenomena of this wave model. By giving appropriate parameter values, different types of solitons structures can be depicted graphically. Several precise solutions and computations have proved the straightforwardness, consistency and power of the these techniques.
关键词： Exp(?Φ(ξ))-expansion method,solitons,Improved simple equation method,elliptic and periodic solutions,paraxial wave model,modified extended direct algebraic method
更新于2025-09-23 15:19:57
-
A Fast Analysis Method for Blue-Green Laser Transmission through the Sea Surface
摘要： The fast estimation of blue-green laser transmission characteristics through the fluctuating sea surface, such as refraction angles and transmittance, is very important to correct operating parameters, detection depth and anti-detection warning in airborne Light Detection and Ranging (LiDAR) applications. However, the geometry of the sea surface is changed by complex environment factors, such as wind and wave, which significantly affect the rapid acquisition of the blue-green laser transmission characteristics. To address this problem, a fast analysis method is provided to rapidly compute the blue-green laser transmittance and refraction angles through the fluctuating sea surface driven by different wind directions and speeds. In the method, a three-dimensional wave model driven by the wind was built to describe the wave spatial distribution varying with time. Using the wave model, the propagation path of the scanning laser footprint was analyzed using the proposed meshing method, thus the transmittance and refraction angles of the optical path can be fast obtained by using parallel computing. The simulation results imply that the proposed method can reduce the time consumption by 70% compared with the traditional analytical method with sequential computing. This paper provides some statistical laws of refraction angles and transmittance through the fluctuating sea surface under different wind conditions, which may serve as a basic for fast computation of airborne LiDAR transmission characteristics in complex environments.
关键词： blue-green laser,sea surface,refraction angles,wave model,transmission characteristics,transmittance,airborne LiDAR
更新于2025-09-23 15:19:57
-
Simulation and design of a compact GaAs based tunable dual-wavelength diode laser system
摘要： We present our design of a compact, integrated and tunable dual-wavelength diode laser system emitting around 785 nm, which is of interest for several applications like Raman spectroscopy and the generation of THz radiation. To achieve a more compact device compared to previous GaAs based designs two etch depths are realized, leading to shallowly etched ridge waveguides in regions were optical gain is applied and deeply etched waveguides used to enable compact integrated waveguide components. The device parameters are optimized using a numerically efficient simulation tool for passive waveguides. Subsequently, the entire laser system is further analyzed applying a sophisticated traveling-wave equation based model for active devices giving access to internal intensity and carrier density distributions. It is shown that active laser simulations are crucial to deduce critical and performance limiting design aspects not accessible via an all-passive simulation.
关键词： Tunable laser diodes,Dual-wavelength laser,Traveling-wave model
更新于2025-09-16 10:30:52
-
[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) - Time Domain Traveling Wave Model of a Hybrid Laser for Silicon Photonics Applications
摘要： Integration of lasers sources in Silicon Photonics (SiPh), realised trough different techniques, became very appealing for applications in the ever growing field of intra/inter chip data data interconnects and optical communications. We implemented a Time Domain Traveling Wave (TDTW) model based on a set of Partial Differential Equations (PDE) for the slowly varying envelope of the electric field, the medium polarization and the charge carriers density in order to describe the dynamics of a new generation of hybrid laser based on III-V Reflective Semiconductor Optical Amplifier (RSOA) and SiPh external mirror with narrow effective reflectivity bandwidth (< 10GHz) similar to that considered in [2, 3]. The effect of the SiPh mirror can be taken into account by cascading the transmission matrices associated with all its passive sections (namely spot-size-conveter, phase control sections, ring resonators etc...) and including the result in frequency dependent boundary conditions for the PDE problem. Differently from standard rate equation models for semiconductor lasers, our approch correctly reproduce the RSOA gain/refractive index dependence from frequency and carriers density that represent peculiar features of radiation-matter interaction in semiconductor media and play a fundamental role in determining the hybrid laser dynamical behaviour. After computing the TW (Traveling wave) solutions for typical narrow reflectivity bandwidth designs, we numerically showed how for realistic values of the linewidth enhancement factor α (namely α > 2) stable single frequency lasing emission not always occurs at the reflectivity peak (TW0 solution in Fig. 1), but on the red part of the SiPh mirror reflectivity resonance curve around the point of maximum reflectivity slope (TW1 solution in Fig. 1a and Fig. 1b). The fact that this point also coincides with that of minimum optical linewidth, where negative feedback regime reduces instantaneous frequencies fluctuations, and the additional numerical evidence that the interval of TW stability decreases with increasing output power indicate that phase-amplitude coupling mediated by the α-factor may be at the origin of the observed TW instability. It also follows that by a suitable tuning of a phase section in SiPh circuit it is possible to stabilize hybrid laser emission by placing a TW solution on the point of maximum reflectivity slope.
关键词： hybrid laser,Partial Differential Equations,linewidth enhancement factor,Silicon Photonics,Time Domain Traveling Wave model,Reflective Semiconductor Optical Amplifier
更新于2025-09-12 10:27:22
-
MODELLING AND SIMULATION OF P-I-N QUANTUM DOT SEMICONDUCTOR SATURABLE ABSORBER MIRRORS
摘要： Semiconductor saturable absorber mirror (SESAM) based on InAs quantum dot (QD) is important in designing fast mode-locked laser devices. A self-consistent time-domain material travelling-wave (TDTW) model for the simulation of self-assembled QD-SESAM is developed. The 1-D TDTW model takes into consideration the time-varying QD optical susceptibility, refractive index variation resulting from the intersubband free-carrier absorption, homogeneous and inhomogeneous broadening. The carrier concentration rate equations are considered simultaneously with the travelling wave model. The model is used to analyze the characteristics of 1.3-μm p-i-n QD InAs-GaAs SESAM. The ?eld distribution resulting from the TDTW equations, in both the SESAM absorbing region and the distributed Bragg re?ectors, is obtained and used in ?nding the device characteristics including the modulation depth and recovery dynamics. These characteristics are studied considering the e?ects of QD surface density, inhomogeneous broadening, the number of QD absorbing layers, and the applied reverse voltage. The obtained results, based on the assumed device parameters, are in good agreement, qualitatively, with the experimental results.
关键词： Travelling-wave model,Quantum dot,Modulation depth,Semiconductor saturable absorber mirror,Recovery dynamics
更新于2025-09-11 14:15:04
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Swell Wavelength Variation Across the Ocean Based on SAR Wave Mode Data
摘要： This paper presents the wavelength trend of a swell propagating across the ocean along a great circle path. Hindcast WW3 wave model data are used for finding the storm sources that are the starting points for a swell. We search the SAR swell observation sequences from ASAR wave mode Level 2P data. It is shown that the wavelength of a swell will increase when propagating from a storm source. When a swell propagates far beyond 10000 km, the wavelength may decrease because shorter wind seas are introduced by the local wind in the westerlies from the other hemisphere. The wavelength can be approximately regarded as constant beyond 4000 km from the storm source.
关键词： SAR,wave model,wave mode,swell,wavelength
更新于2025-09-09 09:28:46
-
Deep-subwavelength control of acoustic waves in an ultra-compact metasurface lens
摘要： Space-coiling acoustic metasurfaces have been largely exploited and shown their outstanding wave manipulation capacity. However, they are complex in realization and cannot directly manipulate acoustic near-fields by controlling the effective path length. Here, we propose a comprehensive paradigm for acoustic metasurfaces to extend the wave manipulations to both far- and near-fields and markedly reduce the implementation complexity with a simple structure, which consists of an array of deep-subwavelength-spaced slits perforated in a thin plate. A semi-analytical approach for such a design is established using a microscopic coupled-wave model, which reveals that the acoustic diffractive pattern at every slit exit is the sum of the initial transmission and the secondary scatterings of the coupled fields from other slits. For proof-of-concept, we examine two metasurface lenses for sound focusing within and beyond the diffraction limit. This work provides a feasible strategy for creating ultra-compact acoustic components with versatile potentials.
关键词： acoustic metasurfaces,sound focusing,microscopic coupled-wave model,wave manipulation,deep-subwavelength
更新于2025-09-09 09:28:46