The beam with orbital angular momentum is a present domestic and foreign research key direction.Its application and development will bring the profound influence in the optical communication field. The research progress of the beam with orbital angular momentum and encoding information as light's OAM for free-space optical communication were reviewed and the existing design method,w rking principle,effecting factors,mechanism and description methods of encoding information as light's OAM were discussed. Based on these analysis,the prospect of future development in the encoding information as light's OAM for freespace optical communication were also forecasted.

The optical and electron paramagnetic resonance(EPR)parameters of ZnS:V3+ crystal are correlated with the local structure of the ionic cluster. According to Sugano-Tanabe's scheme,complete energy matrix(45×45)of d2/8 electron system is constructed. EPR parameter formulae are deduced from spin Hamiltonian theory. Meanwhile,the relationship between crystal parameter and the local structure of ionic cluster in Td symmetry is obtained via point-dipolar model. Based on the semi-self-consitent-field(semi-SCF)d-orbital model and the complete energy matrix diagonalization procedure(CDP),the optical spectra and g factor of ZnS:V3+ are uniformly explained from the local structure. The calculated results agree well with the experimental findings. Calculated results show that,the optical and EPR spectra of ZnS:V3+ can be well understood in the framework of crystal field theory.

The reflection and transmission characteristics are analyzed theoretically when circularly polarized light is incident upon the surface of a chiral negative refraction medium. Normalized reflected and transmission power curves vs incident angle,and Brewster angle curves vs the cbirality parameter are plotted. When the incident angle is larger than the critical angles of two eigen waves,the total internal reflection occurs. Due to the negative refraction of one eigenwave in the chiral medium,the polarization state of the reflected waves caused by the incidence of right or left circularly polarized light is very different from that in the common medium. The reflected waves are linearly polarized with different polarization direction when the light is incident at the Brewster angle.

In order to improve the accuracy of straightness measurement,a sub-pixel edge detection algorithm using an operator named Sobel-Guass fitting was presented in the measurement system based on CCD image using laser beam as straight datum. At first,edge was thinned based on Sobel operator,and then the precision of the image edge location was further improved through Gauss function fitting and interpolation at the gradient direction. At last,the geometrical parameter was attained precisely to subpixel by best circular least-square fitting. Consequently,the precision of measurement system was improved about an order. The experimental results demonstrated that the position accuracy of edge can reach 0.1 pixel after thinned by pixel,and the position accuracy of laser spot center is better than 0.03 pixel.

An eigenvector method(EM)is given to calculate the optical field in laser with flowing saturable gain media. Flowing staturable gain media is equivalent to a thin gain sheet just near inside the big mirror of laser resonators cavity. And transit matrix of EM is obtained on the basis of this model. The calculated results show that the flowing saturable gain media has a negative effect on the optical field distribution. It causes the optical field distribution inclines along the direction of gas flowing. The results are in good agreement with other methods.

The stimulated Brillouin scattering(SBS)effect is easy to be observed in optical system because of the huge power of laser in ICF experiment. To avoid its damage,phase modulator is used to increase the threshold of the SBS effect. Simulation is used to discuss the situation of laser pulse after amplitude modulator,phase modulator and filter. Corresponding to the experimental result of 4.3 GHz(0.23 ns in time domain)fluctuation on the top of the pulse,it is obtained that lack of high frequency part of the laser pulse causes the fluctuation with the frequency of phase modulator,while the unbalanced sidebands make this effect easy to be observed. The influence of the shape,bandwidth and mismatch of the filter on the pulse fluctuation are also discussed. Furthermore,a way to suppress the high frequency fluctuation is proposed. When the filter detunes with the center wavelength of the laser,a Gaussian filter is better for small bandwidth,whereas ideal filter is better for bigger bandwidth situation

The wavelength of semi-conductor laser diode(LD)varies with the temperature. Meanwhile,the output power also drifts according to the temperature and the used time. Therefore,it is quite necessary to control the temperature of semi-conductor LD. Concerning the characteristics of thermostat controller for LD,the theories of PID control and fuzzy control were analyzed. By combing SIMULINK2.1 and FuzzylogicTool-box,the computer simulation design for the self tuning PID parameters control system was implemented. The result shows that this method is simple and easy to operate and can be applied to some other small-sized temperature control systems as well.

The quantum pure state and mixed state are the most important quantum states in quantum information. They are the foundation of studying density operator,quantum entanglement and quantum decoherence. The two states' definition and innate differences are given in quantum theory. The observable effect for quantum pure states' mutually phase is the most important characteristics in quantum interference. The transformation from quantum pure state to mixed state is analyzed through measurement of mechanic quantity ■z,■s and ■n,by quantum mechanics methods. The result shows that the measurement of mechanical quantity is anisotropic in the quantum pure state but for quantum mixed state is isotropic.

Quantum thermal entanglement of two next nearest-neighbor qubits in a four-qubit isotropic Heisenberg XY model consisting of spin 1/2 and spin S in a homogeneous external magnetic field B was investigated by concurrence measure of entanglement. The results show that the external magnetic field can induce the thermal entanglement of two next nearest-neighbor qubits. The amplitude of thermal entanglement is dependent on the spin S,temperature T and homogeneous external magnetic field B. As a result,it is feasible to control thermal entanglement by adjusting the value of external magnetic field B. When S is sufficiently large,the threshold temperature above which there is no thermal entanglement may also be very high. The feature can be used in high-temperature entanglement of condensed matter systems and it will be useful in the research of quantum information in solid systems.

The depolarizing channel is one of the basic quantum channels. For simplicity and generality,quantum channels with two senders and one receiver are considered to discuss the capacity of the quantum depolarizing channel. Two different capacity regions,classical-quantum region and quantum-quantum region,are deduced in theory for the quantum depolarizing channels with two senders and one receiver. The first region is comprised of the rates at which it is achievable for one sender to transmit classical information,while the other to send quantum information. The other region consists of the rates at which each sender sends quantum information. At the same time,the performance of the quantum multiple access depolarizing channel is analyzed.

Hardware-software HW-SW co-synthesis is a key step of future design of embedded systems which consists of two NP-complete problems. So it is a really hard and challenging task to optimiza-tion algorithms. A new hybrid evolutionary algorithm,called hybrid quantum probabilistic coding genetic algorithm(HQGA),is proposed to implement the co-synthesis of large scale multiprocessor embedded systems. In HQGA,a heuristic algorithm is combined with the quantum probabilistic coding genetic algorithm(QGA)to enhance the performance on the hard task. The experimental results show that HQGA has better performance than both HA and QGA on large scale HW/SW co-synthesis problems.

A scheme for quantum information transfer is proposed based on the large-detuned interaction between atom and cavity field. In this scheme the quantum information can be transferred into each other between an atom and a cavity field,many entangled atoms and a cavity field,many atoms and many cavity fields respectively.

A general scheme for controlled teleportation of an arbitrary single-qubit state with four-qubit cluster state is proposed. For an arbitrary single-qubit state,the sender Alice performs the Bell-state measurement on her qubits and the controllers also need take the Bell-state measurement. The receiver David can reconstruct the unknown signal state by performing appropriate unitary operations on his particle if he cooperates with all the controllers.

In order to gain the propagation characteristics of two-dimensional triangular lattice photonic crystal in THz range,the band gap structure and density of photon states were calculated by plane wave expansion method(PWM). It was found that the maximum photonic band gap was observed when f =0.9069 in E polarization and f = 0.7364 in H polarization,and the maximum absolute photonic band gap was gained when f=0.8358.It was found that large photonic band gap can be obtained by increasing D-value of dielectric constant. The photonic band structure was also shown by the photonic density of states. This result provides theoretic basis for the development of THz devices.

Combining anti-synchronization with lag synchronization,a novel kind of inverse lag synchronization is proposed. Moreover,based on state observer,a response system is constructed. The error system is global asymptotically stable at the origin by using the pole placement technique,and inverse lag synchronization occurs. The Chen's system and Chua's circuit are used as illustrative examples for verification.With the preconcerted eigenvalues,the synchronized response system is obtained via the pole placement technique. Numerical simulations verify the effectiveness of the proposed method.

Analyses show that the linewidth of emission spectra of EDFA determines the 4f shell electronic correlation. It influences the electronic dipole-dipole interaction and the resonantly enhanced nonlinearity of erbium ions. Si-EDFAs and Te-EDFAs,with different emission linewidths,correspond to different level of resonantly enhanced nonlinearities. Comparison of crosstalk induced by four-wave mixing and cross-phase modulation in Si-EDFAs and Te-EDFAs is carried out using semiclassical theory. The results show that Te-EDFA corresponds to much smaller crosstalk than Si-EDFA,and therefore is more appropriate for DWDM communications.

The ultraviolet laser micro-processing system was self-developed. Effective working area of the system was 120 mm x120 mm and its minimum linewidth was 80 μm. The Nd∶YAG ultraviolet laser,XY shake lens and F-Theta lens were designed,and ultraviolet laser in 355 nm with maximum average output power of 2.13 W was achieved with the power fluctuation less than 7% in 1 h. The maximum scan angle of XY shake lens was ±28°,and response speed was less than 0.35～0.5 ms. The field angle of the F-Theta lens was ±25°,and focal length was 250 mm. In the end,some problem in the system was analyzed.

A specific spectrometer system with mini-invasion fiber probe was used to obtain the optical parameters of brain tissue within C6 gliomarbearing rats in vivo and real time,and demonstrate the feasi-bility of using optical parameters to identify tumor and help clinical diagnosis. The optical parameters of C6 glioma tissue and normal brain tissue were measured by the specific system. Reducing scattering coefficient(μ＇s)and oxygen saturation(SO2)were recorded in vivo for C6 glioma-bearing rats' brain tissues and normal brain tissue. The experiment results show that μ＇s and SO2 can display some valuable information,such as the location and pathology grade of C6 glioma. μ＇s and SO2 measured by near infrared spectroscopy can beused for glioma quantification and lay the foundation for clinical application.

Combining simple genetic algorithms with simulated annealing,a new genetic simulated annealing algorithms is obtained with the characteristics of global searching and optimum. This method is used to fit experimental data to bidirectional reflectance distribution function(BRDF)statistical model in order to obtain more light scattering information of rough surface from satellite. And we also get the 3D BRDF distribution of the sample plane. The results are in accordance with experimental data.

In OCDMA systems,the cross correlation of address codes is a crucial parameter which can directly affect the performance of the codes. Research of the distribution of the correlation becomes important work. Using strict algebraic operation and statistical analysis,a tiny modification on Kwong's distribution formula of PC is proposed. According to the same methods and means,a new distribution formula of EQC is also proposed. Based on this new distribution formula,the error probabilities corresponding to different combination of codes are compared. Finally it is concluded that using the address codes of EQC without user 0 can improve the performance effectively.

The interaction between the femtosecond solitons was numerically studied with source chirp under quintic nonlinear effect. The results show that under quintic nonlinear effect,when the source chirp is small,two solitons attract to collide and then repulse straight each other. With the increase of source chirp,more collisions happen. The farther increase of the source chirp leads to the split of solitons. The larger the source chirp,the more serious the split. In addition,the interactions between femtosecond solitons with source chirp are suppressed by unequal amplitude method to some extent.

Elliptical-hole photonic crystal fibers exhibit high birefringence. It gives rise to an adequate difference in coupling lengths for the two orthogonal polarizations. Highly birefringent two-core photonic crystal fibers can separate the two orthogonal polarizations from each other. Plane-wave expansion method(PWE)is applied to analyze the coupling lengths for x-polarization and y-polarization. A polarization splitter based on elliptical-hole rectangular-lattice two-core photonic crystal fibers is designed. Full-vectorial beam propagation method(BPM)is employed to analyze the performance of splitter. Numerical simulations demonstrate that it is possible to obtain a 1.055-mm-long polarization splitter. The splitting ratio is better than-16 dB and a bandwidth of 270 nm.

The measurement of nonlinear coefficient of microstructure fiber based on self-phase modulation(SPM)is experimentally demonstrated. A semiconductor laser with 1.6 ps hyperbolic secant shape pulses at a repetition rate of 10 GHz is used as light source. After amplified by the EDFA,the pulses are injected into an 80-m-long dispersion-flattened microstructure fiber. The output spectra of the pulses are broadened due to SPM. By measuring the peak power of the input pulse and the output spectrum,nonlinear coefficient of microstructure fiber can be calculated. This measurement method is simple and accurate,and the error between our experimental result and the measurement result supplied by the fiber producer is within 1%.