空气导光型光子晶体光纤特性及研究进展

介绍了空气导光型光子晶体光纤的概念、结构和导光原理,详细讨论了它的优越特性及其在光通信系统中的广阔的应用前景。

新式导光型电梯按钮的设计

介绍了一种新式导光型电梯按钮的设计。提出了新式导光型电梯按钮的主要技术指标．分析了实现新式导光型电梯按钮的功能的电路设计原理，同时描述了新式导光型电梯按钮的结构设计、外观设计以及该电梯按钮的主要特点。

HC-PCF的传输特性及其应用

简要介绍了光子晶体的原理,由此引出光子带隙型光子晶体光纤的概念、结构、导光机理及其制备,着重分析空气导光型光子晶体光纤的传输特性,并用时域有限差分(FDTD)法仿真了三角形结构空气导光型光子晶体的色散特性,最后展望其应用前景。

Photolytic Model of Six Degradable Mulch Plastic Films

[Objective] This study aimed to solve the mulch plastic film pollution problems in Xinjiang, in order to provide reliable theoretical basis for the research on the degradation mechanism of biodegradable plastic films. [Method] The effect of illumination intensity on the decomposition of decomposable mulching films was investigated through simulating the field condition in laboratory. Regression analysis was employed to fit the processes of film decompositions. [Result] The weight loss ratios of different types of plastic films were closely related with the illumination. There was no sundry produced during the degradation process, but the weight was reduced, indicating that degradation produced gas, thus, ultraviolet rays had destructive effect on mulch plastic films. Different types of plastic films showed significant differences in the degradation speeds, and under the same conditions, the degradation speed of S4# with the induction period of 30 d was the fastest. With the extension of uv illumination time, the degradation became cumulative degradation process. [Conclusion] Under the uv rays, the weight loss ratio and illumination hours is regarded as a positive correlation relationship. The significant inspection shows that the data fitted degradation model can be described by the logistic model of Y = a/（1＋b×e -ct）, and all the parameters show significant differences （P0.01）.

A High-Efficiency Fiber-to-Waveguide Coupler with Low Polarization Dependence Using a Diluted Waveguide in InP Substrate with a 1.55μm Wavelength

We propose a fiber-to-waveguide coupler for side-illuminated p-i-n photodiodes to obtain high responsivity and low polarization dependence that is grown on InP substrate and is suitable for surface hybrid integration in low cost modules. The fiber-to-waveguide coupler is based on a diluted waveguide,which is composed of ten periods of undoped 120nm InP/80nm InGaAsP （1.05μm bandgap） multiple layers. Using the semi-vectorial three dimensional beam propagation method （BPM） with the central difference scheme,the coupling efficiency of fiber-to-waveguide under different conditions is simulated and studied,and the optimized conditions for fiber-to-waveguide coupling are obtained. For TE-like and TM-like modes,the calculated maximum coupling efficiency is higher than 94% and 92% ,respectively. The calculated polarization dependence is less than 0. ldB,showing good polarization independence.

Calculation of Valence Subband Structures for Strained Quantum-Wells by Plane Wave Expansion Method Within 6×6 Luttinger-Kohn Model

The valence subband energies and wave functions of a tensile strained quantum well are calculated by the plane wave expansion method within the 6×6 Luttinger Kohn model.The effect of the number and period of plane waves used for expansion on the stability of energy eigenvalues is examined.For practical calculation,it should choose the period large sufficiently to ensure the envelope functions vanish at the boundary and the number of plane waves large enough to ensure the energy eigenvalues keep unchanged within a prescribed range.

The Usage of Two Dielectric Function Models

This paper presents an overview of the history, modifications, characteristics, and applications of two well known dielectric function models ——the Forouhi-Bloomer model and the Tauc-Lorentz model——which have been widely used for the extraction and parameterization of optical constants in semiconductors and dielectrics. Based on analysis of their inherent characteristics and comparison via demonstrative examples, deeper and wider usage of the two models is predicted.

Drude Weight, Optical Conductivity of Two-Dimensional Hubbard Model at Half Filling

We study the Drude weight D and optical conductivity of the two-dimensional （2D） Hubbard model at half filling with staggered magnetic flux （SMF）. When SMF being introduced, the hopping integrals are modulated by the magnetic flux. The optical sum rule, which is related to the mean kinetic energy of band electrons, is evaluated for this 2D Hubbard Hamiltonian. Our present result gives the dependence of the kinetic energy, D and the optical conductivity on SMF and U. At half filling D vanishes exponentially with system size. We also find in the frequency dependence of the optical conductivity, there is δ-function peak at ω ≈ 2｜m｜U and the incoherent excitations begin to present themselves extended to a higher energy region.

Scattering loss in optical waveguide with trapezoidal cross section

To get the scattering loss of the trapezoidal core waveguide,a new analysis model is presented based on the perturbation equivalent method and modified effective-index method.Firstly,the trapezoidal core waveguide is successfully equivalent to the rectangular one with both restricting the same optical field energy by adopting the perturbation method,Then,the equivalent rectangular core waveguide is decomposed into two slab waveguides by employing the modified effective-index method,The trapezoidal core waveguide scattering theory model is established based on the slab waveguide scattering theory.With the sidewalls surface roughness in the range from 0 to 100 nm in the single model trapezodial core waveguide,optical simulation shows excellent agreement with the results from the scattering loss model presented.The relationship between the dimension and side-wall roughness with the scattering loss can be determined in the trapezoidal core waveguide by the scattering loss model.

Characteristic Analysis of Diffraction from the Restricted Output End Surface of Single Mode Planar Waveguide

As for single mode symmetric step refractive index structure dielectric planar optical waveguide, when its output end is restricted, the diffractive field distribution is derived. It can be expressed as the convolution between the Dirac function and the Sinc and Lorenz functions. It is helpful to deepen the recognition of the restricted diffraction. The characteristic of the diffractive field is discussed. The variational curve of the full angle width at half maximum intensity of central bright fringe versus the half width of slit is presented by numerical calculation, and the fitting curve with the exponential function is close to it.

Analysis of reflection coefficient for coated optical waveguide devices

From an ordinary condition,using a full three-dimensional model theory and an infinite perturbation expansion method,an exact solution of the reflection coefficient for the coated narrow stripe-geometry optical waveguide devices has been derived.All six components and the vector property of the electromagnetic field have been considered.The results are suitable for the symmetric and asymmetric waveguides.

A traffic model of optical networks based on time-space complexity and traffic grooming

This paper researched the traffic of optical networks in time-space complexity,proposed a novel traf-fic model for complex optical networks based on traffic grooming,designed a traffic generator GTS(gener-ator based on time and space)with 'centralized+distributed' idea,and then made a simulation in Clanguage.Experiments results show that GTS can produce the virtual network topology which can changedynamically with the characteristic of scaling-free network.GTS can also groom the different traffic andtrigger them under real-time or scheduling mechanisms,generating different optical connections.Thistraffic model is convenient for the simulation of optical networks considering the traffic complexity.

Quantum size effects in InP inner film fiber

Based on the semiconductor amplifiing properties and the structure of optical fiber wave guide an InP inner fiber is developed.The InP inner film fiber can be employed as a small size,broadband,and ultra-short fiber amplifier. The quantum size effects of the fiber are emphatically investigated in the work. Using the experimental data,we compare the effective mass approximation （EMA） with effective pararneterization within the tight binding （EPTB） models for the accurate description of the quantum size effects in InP. The results show that the EPTB model provides an excellent description of band gap variation over a wide range of sizes. The Bohr diameter and the effective Rydberg energy of InP are calculated. Finally,the amplifiing properties of the InP inner film fiber are discussed due to the quantum size effects.

A Derivative Recovery Spectral Volume Model for the Analysis of Constituents Transport in One-Dimensional Flows

The treatment of advective fluxes in high-order finite volume models is well established, but this is not the case for diffusive fluxes, due to the conflict between the discontinuous representation of the solution and the continuous structure of analytic solutions. In this paper, a derivative reconstruction approach is proposed in the context of spectral volume methods, for the approximation of diffusive fluxes, aiming at the reconciliation of this conflict. Two different reconstructions are used for advective and diffusive fluxes： the advective reconstruction makes use of the information contained in a spectral cell, and allows the formation of discontinuities at the spectral cells boundaries; the diffusive reconstruction makes use of the information contained in contiguous spectral cells, imposing the continuity of the reconstruction at the spectral cells boundaries. The method is demonstrated by a number of numerical experiments, including the solution of shallow-water equations, complemented with the advective-diffusive transport equation of a conservative substance, showing the promising abilities of the numerical scheme proposed.

STUDY ON RECTANGULAR WAVEGUIDE GRATING SLOW-WAVE STRUCTURE WITH COSINE-SHAPED GROOVES

This paper focuses on a new rectangular waveguide grating Slow-Wave Structure (SWS) with cosine-shaped grooves and studies the propagation characteristics of the wave in the SWS. By using the approximate field-matching conditions,the dispersion equation and the coupling impedance of this circuit are obtained. The dispersion curves and coupling impedances of the fundamental wave are calculated and the influences of the various geometrical dimensions are discussed. The results show that the bandwidth of the cosine-shaped groove SWS is much wider than that of rectangular-shaped groove one. And reducing the groove width can broaden the frequency-band and decrease the phase-velocity,while increment of the groove-depth can also decrease phase-velocity. For above cases,the coupling impedance is more than 16Ω. The present analysis will be helpful on further study and design of the RF systems used in millimeter wave Traveling Wave Tube (TWT).

Mathematical modeling of output power in RF-excited CO_2 waveguide lasers

Theoretical analysis model has been established for CO 2 laser to describe the process of dynamic emission in the electrooptically Q switched laser .The electron excitation and the energy transfer of vibration level and the rotational relaxation of rotational levels are described. The comparison between this model and a set of coupled rat equations model are discussed.

Spectra analysis and O_2 evolution for TiO_2 photocatalyst compounded with indirect transition semiconductors

The photo absorbing, photo transmitting and photoluminescence performances of WiO2 photocatalysts compounded with V2O5 or WO3 were investigated by UV-Vis spectra, transmitting spectra, and PL spectra, respectively. The energy band structures of TiO2 photocatalysts were analyzed. The photocatalytic activities of the TiO2 photocatalysts were investigated by splitting of water for 02 evolution. The results indicate that the band gaps of WO3 and V205 are about 2.8 and 2.14 eV, respectively, and the band gap of rutile TiO2 is about 3.08 eV. Speeds of water splitting for 2%WO3-TiO2 and 8%V2O5-TiO2 photocatalysts are 420 and 110 μmol/（L.h）, respectively, under UV light irradiation. V2O5 and WO3 compounded with suitable concentration can improve the photocatalytic activity of TiO2 with Fe3＋ as electron acceptor.

Construction of Type I Aggregation-Induced Emission Photosensitizers for Photodynamic Therapy via Photoinduced Electron Transfer Mechanism

Photodynamic therapy(PDT)as a non-invasive anticancer modality has received increasing attention due to its advantages of noninvasiveness,high temporospatial selectivity,simple and controllable operation,etc.PDT mainly relies on the generation of toxic reactive oxygen species(ROS)by photosensitizers(PSs)under the light irradiation to cause cancer cell apoptosis and death.However,solid tumors usually exhibit an inherent hypoxic microenvironment,which greatly limits the PDT efficacy of these high oxygen-dependent conventional type II PSs.Therefore,it is of great importance to design and develop efficient type I PSs that are less oxygen-dependent for the treatment of hypoxic tumors.Herein,a new strategy for the preparation of efficient type I PSs by introducing the photoinduced electron transfer(PET)mechanism is reported.DR-NO_(2) is obtained by introducing 4-nitrobenzyl to(Z)-2-(5-(4-(diethylamino)-2-hydroxybenzylidene)-4-oxo-3-phenylthiazolidin-2-ylidene)malononitrile(DR-OH)with aggregation-induced emission(AIE)feature.The AIE feature ensures their high ROS generation efficiency in aggregate,and the PET process leads to fluorescence quenching of DR-NO_(2) to promote triplet state formation,which also promotes intramolecular charge separation and electron transfer that is conducive for type I ROS particularly superoxide radicals generation.In addition,DR-NO_(2) nanoparticles are prepared by nanoprecipitation to possess nanoscaled sizes,high cancer cell uptake,and excellent type I ROS generation ability,which results in an excellent performance in PDT ablation of MCF-7 cancer cells.This PET strategy for the development of type I PSs possesses great potential for PDT applications against hypoxic tumors.

Photo-electrochemical water splitting system with three-layer n-type organic semiconductor film as photoanode under visible irradiation

A three-layer structure of n-type organic semiconductors （PTCDA/PTCDA：PCBM/PCBM） is successfully identified as pho- toanode for photoelectrochemical water oxidation during the overall splitting of water into hydrogen/oxygen in a nearly stoi- chiometric ratio （H2：O2 = 2：1） under visible irradiation （2 〉 420 nm）. A possible charge separation mechanism under visible light illumination was also proposed.

Recent progress on mixed-anion type visible-light induced photocatalysts

Environmentally friendly soft chemical processes, including solvothermal/hydrothermal process and mechanochemical process,for the synthesis of mixed anion type visible-lightinduced photocatalysts are introduced in this review paper. Titania and strontium titanate based anion doped photocatalysts can be effectively prepared at such low-temperature as below 200 ℃. Especially,the mechanochemical process is a useful method for the synthesis of various mixed ions doping functional materials at low temperatures. The mixed anion type photocatalytic compounds consisted of N/O, N/F/O, S/O, N/C/O, show excellent visible light absorption ability and photocatalytic activities, indicating the potential applications in environmental purifications. Full-spectra active long wavelength light induced photocatalyst, full-time active photocatalyst system and infrared radiation(IR) shielding multifunctional photocatalysts will be introduced also.