Negative refraction materials attracted much attention and were intensively studied since its realization in experiment. Progress in achieving negative refraction through chiral media is presented. After brief review on the fundamental theory, simulation and experimental realization of the chiral structure, its bright prospect and applicable potential are demonstrated.

Since the contribution of the spin-orbital coupling interaction of the ligand to optical and electron paramagnetic resonance (EPR) spectra can not be neglected, the optical and EPR spectra (g factors g‖、g⊥ and hyperfine structure constant A‖、A⊥ of LiHSO4:VO2+ crystal are calculated from the high-order perturbation formulas on the basis of double-spin-orbital coupling model and crystal-field theory for 3d1 ion in tetragonal symmetry. The calculated results are in good agreement with the observed values. Since the EPR parameters are sensitive to the local structure of a paramagnetic impurity center, the defect structure of V4+ center in LiHSO4 crystal is obtained. The validity of the results is discussed.

Aimed at the application of speech recognition, a new method of robust feature extraction is presented. The speech was decomposed by wavelet transformation, and then compressed by spectral compression scheme related to human hearing mask theory. Experimental results of MATLAB simulation show that high recognition rate can be obtained by using of the new feature in noise environment. It can make the best of robust characteristics of wavelet and reduce the difference between training and recognition environment.

Study of the coupled harmonic oscillator is an important problem in quantum optics, and many actual physical problems are dependent on the model of the coupled harmonic oscillator, so the easy way to solve the coupled harmonic oscillator appears to be necessary. Through structuring a formal matrix by quadratic orthogonal mathematical theory and letting the Hamiltonian diagonalization of the n-dimensional anisotropic harmonic oscillators both coordinate and momentum coupling, its eigenvalues are obtained. The energy eigenvalue of three-dimensional coupled harmonic oscillator is solved by the method. The method does not need to derive the concrete form of the transformation matrix, which make it simple and easy to calculate the results to the eigenvalue problems of the Hamiltonian with symmetrical form.

Experiments on high repetition rate all-fiber passive modelocked femtosecond laser are reported. Upon all-fiber ring cavity structure and nonlinear polarization rotation saturable absorber, stable run of high repetition rate Er-doped all-fiber modelocked femtosecond pulse is achieved. The highest repetition rate is 99.91 MHz. The spectrum FWHM is 25 nm at center wavelength of 1570 nm. The pulse duration is 194 fs. The dynamic characteristics of the all-fiber passive modelocked laser at different repetition rate are studied. The results show that the all-fiber laser can be used as an alternative compact and high stable ultrafast optical source for application in the optical frequency comb generation.

The far-field intensity distribution of 6 circular arranged coherent fiber lasers is simulated numerically and its power convergence is estimated based on Fraunhofer diffraction theory. The results show that the intensity distribution at far-field is equivalent to the product of a Gaussian envelop and the interference distribution of several planar waves. When the diameter of the arranging circle is less than 5 times of the radius of a unit laser, over 90% of the power will drop into the 86.5% power circle of the unit laser. The calculation leads to the conclusion that power convergence of the combined beam can be optimized by adjusting the arrangement, where the convergence can even exceed that of a single unit laser beam.

Er-Yb co-doped phosphate glass waveguide lasers are theoretically studied in order to understand the role of the energy transfer in Er-Yb co-doped system. The rate equations of Er-Yb codoped system coupled with the laser signal and pump photon flux equations are solved using overlapping integral method, the Er-Yb energy transfer processing is studied in detail, and the effects of Er-Yb energy transfer on the characteristics of waveguide lasers pumped by a 980 nm source are discussed. Numerical results demonstrate that effect of Er-Yb energy transfer (cross-relaxation factor) on the output power of laser is not obvious. Yb3+ ions play the role of eliminating the “cluster” of Er3+ due to high concentration and improving the pumping efficiency.

The performance of a laser diode (LD) driver is a quite important factor affecting its operating properties, thus it is significant to improve the performance of the LD driver. A novel scheme of designing the LD driver based on field programmable gate array (FPGA) is proposed. Employing FPGA as the controlling center, all the functional modules of the LD driver, including AD/DA converting, temperature PID controlling, invariably current driving, LD protection, input and output circuit, are arranged to operate together harmoniously under FPGA. The LD temperature controlling and current driving circuit based on FPGA is designed and demonstrated, and the performance test is carried out when its operating temperature is among 20℃~30℃. The experimental results show that the operating temperature stability is superior to ±0.03℃, and the driving current stability is ±0.1%.

A scheme for realizing unconventional geometric quantum logical gates with quantum dots in a microcavity, via double channel Raman interactions, is introduced. In the scheme, all of the operations are independent on the state of cavity mode, and thus insensitive to the thermal cavity field states. The total accumulated phase includes both geometric and dynamic phases, but it still depends only on global features of the process. The required quantum gates can be obtained by adjusting coupling constant and detunings. It’s relatively easy in implementation by waiving the needs of eliminating dynamic phases, and it can reach higher fidelity by avoiding the additional errors in the process of eliminating dynamic phases.

The security of differential-phase-shift quantum key distribution with weak coherent states is analyzed synthetically. Also, its security combining with decoy states is reevaluated. The expressions of key generation efficiency are given, respectively. The theoretical results indicate that differential-phase-shift quantum key distribution with decoy states is immune from the photon number splitting attacking and the sequential attacking, and its expression of key generation efficiency is identical with that proposed by Hoi-Kwong et al. The experimental data indicate that the combined system not only achieved longer transmission distance, but also improved the key generation efficiency about an order.

A quantum signature protocol based on quantum one-time pad and quantum key distribution was presented, in which the arbitrage didn’t participate in. In the process of signature, message was transformed to qubit, and the identity information of signer was attached to it. After signed, the signature message was transfered into frame structure by signer, and was transported to receiver. In the process of validation, both of communication sides must validate identity information and preserve this information each other, before the receiver wanted to obtain the information of the frame completely. Therefore the signature protocol attains the goal of non-denial.

A scheme for the entanglement swapping of entangled states with continuous variable is presented, in which the bipartite maximally entangled coherent state serves as the quantum channel. With the help of the idea of teleportation, using beam splitter and phase-shifter, entanglement swapping of tripartite entangled coherent state can be realized. In this scheme, the entanglement swapping is failure only for one measurement process. The failure probability is very small. The detail results show that the probability and the minimum of total average fidelity for successful swapping an arbitrary tripartite entangled coherent state is nearly 1 when the mean number of photons is larger than 2.

The quantization of the generalized mesoscopic RLC parallel circuit, the quantum fluctuations of the current and the voltage of each branch in vacuum state were studied. The influences on the quantum fluctuations of the dissipative resistances in the inductance and capacitance branches were discussed. The results show that the quantum fluctuations in each branch are related to the parameters of the elements and decay with time. The quantum fluctuations in the two branches are influenced by the dissipative resistances both in the decaying factor and in the coefficients. They have the same behavior in the decaying factor but having difference in the coefficients. The quantum fluctuations of the voltage are affected by the dissipative resistances in the two branches, but the quantum fluctuations of the current are not affected by them when the values of the two dissipative resistances are same.

A novel scheme for hyperchaotic secure communication based on ring coupled RC oscillators is proposed. The presented scheme uses RC oscillator-based hyperchaotic signal generators and nonlinear ring couplers, from which information encryption and decryption can be realized. Basic dynamics behaviors are investigated, including bifurcation diagram and maximum Lyapunov exponents. Furthermore, by appropriate discrete processing and variable proportion transformation of continuous time systems, this approach is designed and implemented by digital signal processor (DSP) and its hardware experimental results are also given.

Exact self-similar solution of a generalized nonlinear Schr?dinger equation with varying cubic-quintic nonlinearity, weakly nonlocality, gain and nonlinear gain was obtained. The stability of the solution was studied numerically. The results show that the self-similar solitary wave can exist and propagate in the media with or without both nonlocality and quintic nonlinearity, and that the stability of the self-similar solitary wave is drastically influenced by the degree of nonlocality and the cumulative diffraction under the condition that the phase parameter is far from ±2^{1/2}.

In previous experiments the very complicated system or high-precision and large-range spectra-analysis apparatus was used to distinguish stimulated thermal scattering (STS) and stimulated Brillouin scattering (SBS) because the frequency shift of SBS is much larger than that of STS which is a few tens MHz generally, but the shift of SBS reaches several GHz typically. It will be difficult for common laboratorial conditions. Frequency responses of STS in Cu(NO3)2 colored acetone and SBS in pure acetone were investigated experimentally. It was showed that the linewidth of SBS fluctuated random and that of STS changed regularly as pump power increased. It can become a convenient and cheap approach to distinguish STS and SBS instead of high-precision and large-range spectrometer or complicated system. This method, as far as we know, has not been reported in references.

Influence of temperature on the mean number of phonons for strong-coupling magnetopolaron in an asymmetric quantum dot are studied by using the Huybrechts’ linear combination operator and the LLP variational method. Numerical results indicate that the mean number of phonons for strong-coupling magnetopolaron decreases with increasing temperature. The changes of the mean number of phonons of magnetopolaron changing with the transverse effective confinement strength, longitudinal effective confinement strength, cyclotron frequency and the electron-phonon coupling strength are strongly related to the temperature.

Based on an excitonic basis, the intraband dynamical process and optical absorption spectrum of semiconductor superlattice in terahertz fields are investigated with the density matrix theory. The excitonic Bloch oscillation is driven by the terahertz field. The slow variation in the intraband polarization depends on the terahertz frequency. With the increase of terahertz frequency, the intraband polarization does oscillate downwards and its intensity decrease. Taking In0.52Al0.48As/InAs and Ga0.7Al0.3As/GaAsAs/GaAs superlattices for examples, because of the nonlinear effect of terahertz field and WSL excitons, their optical absorption spectra take on satellite peak structures. However, when these two superlattices in different states are compared, it’s concluded that the optical absorption spectrum anastomoses well for the strong coupling effect between the excitonic state of n0.

A new configuration of four-port channel drop filter in two dimensional photonic crystals (2D PCs) is presented. In this structure, three micro-cavities are used. Two micro-cavities are used to realize wavelength-selective reflection feedback. The other is used for resonant tunneling-based channel drop filter. Using coupled mode theory (CMT), the conditions to achieve 100% drop efficiency are derived. The simulation results by using the two dimensional FDTD method show a good agreement with the CMT results, and show that this configuration is feasible.

In a directional coupler based on photonic crystal waveguides (PCWs), the coupling coefficient can increase by reducing the refractive indexes of the rods between the two coupled PCWs. Accordingly, a shorter beating length and ultracompact device can be achieved. The distribution of odd mode intensity is nearly unaffected, but the distribution of the even mode intensity shifts to higher frequencies when the indexes are reduced. Furthermore, the beating length slope increases for a fixed frequency range, and this technique allows smaller channel spacing and more signal channels for a given total device length. The finite-difference time-domain method is used to validate the behavior that the beating length can be shortened by reducing the refractive index of the modified rods.

A new concept of self-Fourier soliton is proposed. The evolution and transmission of self-Fourier Gauss signal and self-Fourier soliton in optical fibers are studied numerically. The characteristics of signal evolution and transmission are studied analytically in both time domain and frequency domain. The results show that a class of non-self-Fourier soliton is obtained from inputting self-Fourier Gauss signals, and the amplitude of the soliton from the self-Fourier Gauss signal could be influenced by the effect of third-order dispersion on propagation. The effect of third-order dispersion also results in the time delay of the soliton and spectrum asymmetry of the soliton.

A methed to generate millimeter(mm)-wave using only one single-electrode Mach-Zehnder modulator (SD-MZM) was proposed and theoretically analysised. To generate a mixing signal, the baseband signal is mixed with the radio signal using an electric mixer. And the double-sideband(DSB) signal generated from SD-MZM drived by the mixing signal is transmited to base station(BS) over fiber. The optical carrier of the DSB signal which can be reused for uplink connection and the first-order optical sidebands of the DSB signal which generates the millimeter-wave are separated by an optical interleaver (IL) at base station(BS). The dispersion performance of the millimeter-wave is analyzed systematically by theory and simulation. According to theory and simulation results, the different delay of two first sidebands due to the fiber dispersion leads to power loss of mm-wave and the inter-symbol interference(ISI) of demodulated signals, so it limits the maximum propagation distance of mm-wave.