光纤分子背向散射的温度效应与分布光纤温度传感网络

本文讨论了光纤分子瑞利（Rayleigh）背向散射精细结构谱和光纤分子喇曼（Raman）背向散射光谱及其温度效应。作者从实验中发现1550nm光纤分子瑞利（Rayleigh）背向散射的温度效应强于905nm；光纤分子瑞利（Rayleigh）背向散射强度与温度近似成正比关系；作者讨论了光纤分子背向Raman散射温度效应在分布式光纤温度传感网络上的应用。

光纤分子背向散射的温度效应及其在分布光纤温度传感网络上应用研究的进展

讨论了光纤分子瑞利 (Rayleigh)背向散射精细结构谱和光纤分子喇曼 (Raman)背向散射光谱及其温度效应 ,以及在分布型光纤温度传感网络上应用研究的进展。

分子印迹光纤传感技术的应用

分子印迹聚合物(MIPs)的特异识别功能使其作为传感器的敏感材料具有很大的优势,分子印迹光纤传感器(OFS-MIPs)具有广阔的应用前景,已被广泛运用于环境、化学、医学、食品安全等领域。对OFS-MIPs的研究进展进行了综述,对光纤传感与分子印迹间的耦合方法,OFS-MIPs的应用领域以及其存在的问题进行了探讨,并对OFS-MIPs的前景进行了展望。

Controllable Optical Solitons in Optical Fiber System with Distributed Coefficients

We present how to control the dynamics of optical solitons in optical fibers under nonlinearity and dispersion management, together with the fiber loss or gain. We obtain a family of exact solutions for the nonlinear Schrfidinger equation, which describes the propagation of optical pulses in optical fibers, and investigate the dynamical features of solitons by analyzing the exact analytical solutions in different physical situations. The results show that under the appropriate condition, not only the group velocity dispersion and the nonlinearity, but also the loss/gain can be used to manipulate the light pulse.

Entangling Two Atomic Ensembles Trapped in Separated Cavities

We propose a scheme for the generation of two collections of atoms trapped in distant cavities connected by an optical fiber.The virtual photon exchange leads to the entanglement between these two atomic ensembles.During the operation the atomic system,cavity modes,and fiber are not excited,which is important in view of decoherence.

Low Distortion 1.31μm AlGaInAs/InP MQW DFB Laser Module for CATV Systems

A high power and low distortion 1.31 μm AlGaInAs/InP multiquantum well distributed feedback laser diode (MQW DFB LD) with RWG structure has been developed by MOCVD technique. The fiber output power of butterfly packaged module with optic isolator P f is more than 10 mW, threshold current is in the range of (13～20) mA, slope efficiency, E s>0.30 W/A and side mode suppression ratio, R S,M,S >35 dB. The composite second order, O C,S <-61 dBc and composite triple beat, B C,T <-65 dBc are obtained by test frequencies of (45～550) MHz with 60 PAL channels. In the test conditions the carrier to noise ratio, R C,N >51 dB.

Laser Light Scattering Study on Aggregation of Cellulose Diacetate in Acetone

We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.

Deterministic Generation of Quantum State Transfer Between Spatially Separated Single Molecule Magnets

We propose a new scheme for realizing deterministic quantum state transfer （QST） between two spatially separated single molecule magnets （SMMs） with the framework of cavity quantum eleetrodynamics （QED）. In the present scheme, two SMMs are trapped in two spatially separated optical cavities coupled by an optical fiber. Through strictly numerically simulating, we demonstrate that our scheme is robust with respect to the SMMs＇ spontaneous decay and fiber loss under the conditions of dispersive SMMs-field interaction and strong coupling of cavity fiber. In addition, we also discuss the influence of photon leakage out of cavities and show that our proposal is good enough to demonstrate the generation of QST with high fidelity utilizing the current experimental technology. The present investigation provides research opportunities for realizing QST between solid-state qubits and may result in a substantial impact on the progress of solid-state-based quantum communications network.

Measurement of the Average Molecular Weight of Cotton Cellulose Crosslinked by a Polycarboxylic Acid at Different pH Using Multiple Angle Light Scattering Photometer in a DMAc/LiCl Solvent System

Durable press finishing of cotton fabrics with polycarboxylic acid increases fabric wrinkle-resistance at the expense of its mechanical strength. Severe tensile strength loss is the major disadvantage for wrinkle resistant cotton fabrics.Tensile strength loss of cotton fabric crosslinked by a polycarboxylic acid can be attributed to depolymerization and crosslink of cellulose molecules. Measurement of the molecular weight of cotton fabric before and after crosslinked by polycarboxylic acids can offer a possibility of direct understanding of the depolymerization. In this research, amultiple angle laser light scattering photometer was used todetermine the absolute molecular weight of cotton fabric treated with BTCA at different pH and then hydrolyzed with 0. 5 M NaOH solution at 50℃ for 144 h. The results indicate that average molecular weights of cotton fabric treated with polycarboxylic acids at different pH are almost the same.

Influence of Mg Composition on Optical Properties of Exciton Confinement in Strained Wurtzite ZnO/Mg_x Zn_(1-x) O Cylindrical Quantum Dots

Based on the effective-mass approximation and variational approach, excitonic optical properties are investigated theoretically in strained wurtzite （WZ） ZnO/MgxZn1-xO cylindrical quantum dots （QDs） for four different Mg compositions： x = 0.08, 0.14, 0.25, and 0.33, with considering a three-dimensional carrier confinement in QDs and a strong built-in electric field effect due to the piezoelectricity and spontaneous polarization. The ground-state exciton binding energy, the interband emission wavelength, and the radiative lifetime as functions of the QD structural parameters （height and radius） are calculated in detail The computations are performed in the case of finite band offset. Numerical results elucidate that Mg composition has of ZnO/MgxZn1-x 0 QDs. The ground-state exciton a significant influence on the exciton states and optical properties binding energy increases with increasing Mg composition and the increment tendency is more prominent for small height QDs. As Mg composition increases, the interband emission wavelength has a blue-shift if the dot height L 〈 3.5 nm, but the interband emission wavelength has a red-shift when L 〉 3.5 nm. Furthermore, the radiative lifetime increases rapidly with increasing Mg composition if the dot height L 〉 3 nm and the increment tendency is more prominent for large height QDs. The physical reason has been analyzed in depth.

Optical fiber sensor by cascading long period fiber grating with FBG for double parameters measurement

An optical fiber sensor for strain and temperature measurement based on long period fiber grating(LPFG) cascaded with fiber Bragg grating(FBG) structure has been proposed and realized both theoretically and experimentally. Theoretical analysis shows that two microstructures with similar sensitivities cannot be used for double parameters measurement. The LPFG is micromachined by the CO_2 laser, and the FBG is micromachined by the excimer laser. For the validation and comparison, two FBGs and one LPFG are cascaded with three transmission valleys, namely FBG1 valley at 1 536.3 nm, LPFG valley at 1 551.2 nm, and FBG2 valley at 1 577.3 nm. The temperature and strain characteristics of the proposed sensor are measured at 45—70 °C and 250—500 με, respectively. The sensitivity matrix is determined by analyzing wavelength shifts and parameter response characterization of three different dips. The proposed optical fiber sensor based on LPFG cascaded with FBG structure can be efficiently used for double parameters measurement with promising application prospect and great research reference value.

Hybrid quantum private communication with continuous-variable and discrete-variable signals

The quantum key distribution(QKD) has been entering the practical application era. Subsequently, hybrid quantum private communication with discrete-variable signals, continuous-variable signals, and classic optical signals becomes inevitable in the practical scenario. In this paper, we experimentally investigated the mutual effects between the discrete-variable QKD(DVQKD) and the continuous-variable QKD(CVQKD) via a fiber channel. The experimental results show that the DVQKD will be influenced by the continuous-variable quantum signals and classic optical signals, while the CVQKD is not sensitive to the discrete-variable quantum signals.

Recent Progress in Distributed Optical Fiber Raman Photon Sensors at China Jiliang University

A brief review of recent progress in researches, productions and applications of full distributed fiber Raman photon sensors at China Jiliang University （CJLU） is presented. In order to improve the measurement distance, the accuracy, the space resolution, the ability of multi-parameter measurements, and the intelligence of full distributed fiber sensor systems, a new generation fiber sensor technology based on the optical fiber nonlinear scattering fusion principle is proposed. A series of new generation full distributed fiber sensors are investigated and designed, which consist of new generation ultra-long distance full distributed fiber Raman and Rayleigh scattering photon sensors integrated with a fiber Raman amplifier, auto-correction full distributed fiber Raman photon temperature sensors based on Raman correlation dual sources, full distributed fiber Raman photon temperature sensors based on a pulse coding source, full distributed fiber Raman photon temperature sensors using a fiber Raman wavelength shifter, a new type of Brillouin optical time domain analyzers （BOTDAs） integrated with a fiber Raman amplifier for replacing a fiber Brillouin amplifier, full distributed fiber Raman and Brillouin photon sensors integrated with a fiber Raman amplifier, and full distributed fiber Brillouin photon sensors integrated with a fiber Brillouin frequency shifter. The Internet of things is believed as one of candidates of the next technological revolution, which has driven hundreds of millions of class markets. Sensor networks are important components of the Internet of things. The full distributed optical fiber sensor network （Rayleigh, Raman, and Brillouin scattering） is a 3S （smart materials, smart structure, and smart skill） system, which is easy to construct smart fiber sensor networks. The distributed optical fiber sensor can be embedded in the power grids, railways, bridges, tunnels, roads, constructions, water supply systems, dams, oil and gas pipelines and other facilities, and can be integrated with wireless networks.

A novel polarization splitter based on three-core photonic crystal fibers

A novel polarization splitter based on photonic crystal fibers(PCFs) with three cores of high birefringence is proposed.The 45o linearly polarized light is launched into a core.After a coupling length(about 1500 μm),the xand y-polarized light beams are separated into different cores.When the light is launched into another core,the xand y-polarized light from different cores can be obtained and the degree of separation can be also adjusted.The polarization splitter is highly flexible and adjustable.The length of the polarization splitter is about 1500 μm which is just the coupling length.So it has appreciate significance of manufacturing mini-type photonic apparatus in integrated optics.

Comnutational Models for New Fiber Ootic Tweezers

This paper discusses the calculation of the trapping forces in optical tweezers using a combination of the finite differences time domain （FDTD） method and the Lorentz force on electric dipoles. The results of 2D simulations of the trapping of a circular particle by a waveguide with a circular tip are presented and discussed.

A novel polarization splitter based on octagonal dualcore photonic crystal fiber

A novel polarization splitter based on octagonal dual-core photonic crystal fiber(O-D-PCF) is proposed. The impacts of several fiber parameters on the coupling characteristics of the polarization splitter are investigated by full-vectorial finite element method(FV-FEM) in detail. Through optimizing the fiber configuration, a 4.267-mm-long polarization splitter with a bandwidth of 37 nm is achieved, and its extinction ratio(ER) is as high as 81.2 d B at the wavelength of 1.55 μm. Compared with the hexagonal dual-core photonic crystal fiber(H-D-PCF) based polarization splitter, both ER and bandwidth of the O-D-PCF based one are effectively improved.

Dual-core photonic crystal fiber polarization splitter based on lead silicate glass

A dual-core photonic crystal fiber(PCF)polarization splitter based on lead silicate glass is proposed.The characteristics of the polarization splitter are analyzed using full-vector finite element method.Compared with the silica glass PCF polarization splitter with the same structure,it is shown that the new material polarizer can realize splitting with less coupling loss and higher extinction ratio.When the wavelength is 1 550 nm and the PCF length in the beam splitter is 688μm,the coupling loss is only 0.001 9 d B,and the extinction ratio for the input core is-64.1 d B.

Imaging cellular distribution of fluorescent supramolecular nanofibers

In this study, we used the 4-nitro-2,1,3-benzoxadiazole （NBD） as an aromatic capping group for a peptide to construct the su- pramolecular nanofibers. Taking the advantage of the fluorescence property of NBD, we could directly observe the cellular distribution of the self-assembled nanofibers. We found that the distributions of the nanofibers of NBD-FFETIGGY are dif- ferent in four mammalian cells and two plant cells. The nanofibers are mainly located at the surface of two mammalian cells and one plant cell, while in the intracellular space of other cells. Different distributions of nanofibers lead to different protein binding patterns o1! the nanofibers in two different cell lines. We believe that a useful and versatile platform has been offered to the image cellular distribution of nanofibers, which can provide useful information to the biological functions of the self-assembled nanostructures.

Thermal distribution analysis of multi-core photonic crystal fiber laser

The thermal properties of photonic crystal fiber(PCF) laser with 18 circularly distributed cores are investigated by using full-vector finite element method(FEM).The results show that the 18-core PCF has a more effective thermal dispersion construction compared with the single core PCF and 19-core PCF.In addition,the temperature distribution of 18-core PCF laser with different thermal loads is simulated.The results show that the core temperature approaches the fiber drawing value of 1800 K approximately when the thermal load is above 80 W/m which corresponds to the pumping power of 600 W approximately,while the coating temperature approaches the damage value of about 550 K when the thermal load is above 15 W/m which corresponds to the pumping power of 110 W approximately.Therefore the fiber cooling is necessary to achieve power scaling.Compared with other different cooling systems,the copper cooling scheme is found to be an effective method to reduce the thermal effects.