基于DFB腔注入锁定效应的可调谐光电振荡器

提出一种基于分布反馈光注入锁定效应的可调谐光电振荡器,其环路主要由马赫曾德尔调制器、光电探测器、环形器、分布反馈激光器和射频放大器顺接而成,分布反馈激光器是系统关键器件,通过分布反馈激光器光注入锁定效应,分布反馈腔在光域实现了微波光子滤波器功能,无需传统光电振荡器必须的射频带通滤波器.同时,由于分布反馈激光器注入锁定提高了环路Q值,因此系统可采用短环路结构,从而降低了光纤因温度敏感对微波信号稳定性的影响并减小了整个系统的尺寸.另外,通过调节注入光波长和功率可改变该微波光子滤波器的中心频率,从而可实现系统的可调谐性.理论分析了该光电振荡器的原理和微波光子滤波器的调谐性,在此基础上开展了实验验证.结果表明该光电振荡器能够产生18.7～21.6 GHz的可调微波信号,在1 kHz频偏处的相位噪声为-90 dBc/Hz.     

Antiphase States in Coupled Oscillator Systems

Coupled identical oscillators with resistive couplings are investigated. Various antiphase states are observed. The bifurcation threshojds for the antiphase states of coupled van der Pol oscillators and the unstable modes of these systems at the bifurcation points are explicitly compu ted. The dependence of antiphase states on system size and coupling length is investigated in detail. General coupled limit cycle models are also investigated. The realizations of antiphase states can be explained, based on the global potential analysis.     

Ergodic Properties and Thermodynamics in Anharmonic Oscillator Systems

Ergodic properties of anharmonic oscillator systems with only a few degrees of freedom are both theoretically and numerically investigated. Statistical mechanics and thermodynamics of ergodic Hamiltonian systems are built. The Henon-Heiles systems with reflecting walls and the diamagnetic Kepler problem are studied     

The Invariant Eigen-Operator Method for?N?Harmonically Coupled Identical Oscillators

In this paper, we apply the method of “invariant eigen-operator” to study the Hamiltonian of arbitrary number of coupled identical oscillators and derive their invariant eigen-operator. The results show that, (1) for the system of arbitrary number of identical harmonic oscillators by coordinate coupling or momentum coupling, the invariant eigen operator of system always has the form of or ; (2) the energy level gap of the system has two kinds of possibilities: one is that gap only related to ω that the frequency of oscillators; another one is that gap not only related to ω that the frequency of oscillators, but also related to the number of the coupling oscillators.     

The Invariant Eigen-Operator Method for Hamiltonians with Coordinates-Coordinates Coupling Terms

In this paper, we apply the method of “invariant eigen-operator” to study the Hamiltonian of harmonic oscillator with couplings and derive their invariant eigen-operator. We first discuss decoupling of coupled harmonic oscillators with the two different quality and frequencies. And then, we propose an operator Hamiltonian to describe the linear lattice chain with Born–von Karman boundary condition. The vibrating spectrum is thus obtained. The results show that, for the system of coupled harmonic oscillators by coordinate coupling or momentum coupling, the invariant eigen operator of system always has the form of or .     

激光二极管泵浦Nd：FAP激光器

报道激光二极管泵浦的掺钕氟磷酸钙固体激光器，该器件在重复频率为１００Ｈｚ的准连续状态下运行，当耦合输出透过率为８％时，得到３１％的斜效率，比较了ＦＡＰ和ＹＡＧ这两种介质的激光器的性能，理论分析得出的两者的阈值泵浦功率的相对值与实验结果相一致，并证实ＦＡＰ是一种有前途的适合激光二极管泵浦的激光介质。     

Chaotic Solutions of a Typical Nonlinear Oscillator in a Double Potential Trap

We have obtained a general unstable chaotic solution of a typical nonlinear oscillator in a double potential trap with weak periodic perturbations by using the direct perturbation method. Theoretical analysis reveals that the stable periodic orbits are embedded in the Melnikov chaotic attractors. The corresponding chaotic region and orbits in parameter space are described by numerical simulations.     

喇曼自由电子激光振荡器

本文报道喇曼自由电子激光振荡器的研究结果。脉冲加速器电子束能量０．４ＭｅＶ，束流８００Ａ。采用满足布喇格条件的分布反馈谐振腔，取代传统的激光器反射镜。理论上进行了分析和设计，采用正弦形波结构选择振荡模式。喇曼自由电子激光振荡器实验表明，输出光谱显著变窄。频率分布半高宽度，超辐射下范围为７．５ｍｍ～９．２ｍｍ，分布腔下范围为８．６ｍｍ～８．９ｍｍ。     

MASSLESS THIRRING MODEL IN CANONICAL QUANTIZATION SCHEME

It is shown that the exact solubility of the massless Thirring model in the canonical quantization scheme originates from the intrinsic hidden linearizability of its Heisenberg equations in the method of dynamical mappings. The corresponding role of inequivalent representations of free massless Dirac field and appearance of Schwinger terms are elucidated.     

利用超混沌信号调制参数实现简并光学参量振荡器混沌同步

研究在超混沌信号调制参数作用下简并光学参量振荡器的混沌同步.计算结果表明,当调制系数在某确定的范围内使系统的最大条件李指数为负数时,两个或更多台简并光学参量振荡器在新的动力学基础上可实现同步或倒同步.同步方式与初始条件和调制系数有关.当初始条件确定的情况下,调制系数取某些值时,系统的同步方式具有突变性.     

ArF准分子激光振荡放大系统的研究

研究了ＡｒＦ准分子激光振荡放大系统，中心波长１９３ｎｍ，用一只闸流管作为开关元件，通过主充放电网络匹配，有效地解决了两台器件的放电抖动，振荡放在倍数达到约５０倍，系统单脉冲输出能量５０ｍＪ，光束发射角低于０．２０ｍｒａｄ。     

A Revisory Mathematical Model on Optically Pumped Far-Infrared Laser

In an optically pumped far-infrared laser (OPFIRL) system, the infrared (IR) pumping laser with collision broadening which was closer to the practice was considered. A more precise mathematical model was set up. When the IR pumping laser line had the Lorentz function structure, by solving the semi-classic density matrix equations, the generalized form of FIR signal gain Gs and IR pumping signal absorption coefficient Gp were obtained.     

Solitons in the Two-Dimensional Antiferromagnetic Heisenberg Model

An effective Hamiltonian of the two-dimensional antiferromagnetic Heisenberg model is derived by using the Holstein-Primakoff transformation. Three nonlinear coupled partial equations of motion are obtained. In the long-wavelength approximation, these equations, are reduced to the envelope function equations by the method of multiple scales. The amplitude functions satisfy the nonlinear Schrodinger equation. Introducing an inverse scatteriag transformation, the single-, two- and multi-soliton solutions in the two-dimensional antiferromagnetic Heisenberg model are investigated.     

1150 nm High-Power Fiber Laser Oscillator Pumped by 976 nm Laser Diode

We present an all-fiber 1150 nm Yb-doped fiber laser oscillator pumped by a 976 nm laser diode. To suppress amplified spontaneous emission and avoid parasitic laser oscillation, we propose a long-length gain fiber and a high-reflectivity output fiber Bragg grating in the fiber laser oscillator. The 1150 nm band single-mode fiber laser with output power of 20.5 W is demonstrated at room temperature. The optical-to-optical conversion efficiency ranges up to 51.6% at the maximum output. The central wavelength of the fiber laser oscillator is 1150.35 nm, and its 3 dB spectral width is 0.72 nm. No evidence of amplified spontaneous emission, residual pump light, or parasitic laser oscillation were observed in the experiments. The high-power 1150 nm fiber laser oscillator can be used as a pump source in the development of a 3 μm Ho-doped fiber laser.     

On The Spectral Zeta Function For The Noncommutative Harmonic Oscillator

The spectral zeta function for the so-called noncommutative harmonic oscillator is able to be meromorphically extended to the whole complex plane, having only one simple pole at the same point s = 1 where Riemann's zeta function ζ(s) has, and possesses a trivial zero at each nonpositive even integer. The essential part of its proof is sketched. A new result is also given on the lower and upper bounds of the eigenvalues of the noncommutative harmonic oscillator.     

On diffusion equations for dynamical systems driven by noise

A unified formalism is presented to study Hamiltonian linear systems driven by noise. With this formalism, the phase averaging approximation, valid at weak noise, is easily performed. Already known results are straightforwardly recovered and new ones are obtained. After introducing this formalism on the exactly solvable one-degree-of-freedom problem with uncorrelated noise, one studies the corresponding exponentially correlated case. The validity of the approximate results thus obtained is considered by investigating the systematic weak-disorder expansion beyond the quasilinear approximation. In particular, it is argued that this expansion behaves uniformly for weak and large correlation time. The two-degrees-of-freedom problem is completely solved at the low-disorder approximation and this result is applied to the two-channel Anderson localization problem. The invariant measure and the two positive Lyapunov exponents are computed at all coupling between the channels. For systems withn degree of freedom the phase averaging leads to a Fokker-Planck equation for the measure in action space describing the system. However, it is argued that it is not solvable except in a special case which is explicitly displayed and solved. Nevertheless, in the large-n limit, it is possible to compute the largest Lyapunov exponent. Moreover, generalized Lyapunov exponents are calculated in this limit, and they do not exhibit a dispersion: in particular, log/log1, where is the energy of the system and where the brackets denote averaging over the noise. On the other hand, it is possible to compute at weak noise the sum of all the positive Lyapunov exponents. Taking into account all these results allows more insight on the whole spectrum of Lyapunov exponents.     

An F-Twisted XYZ Model

We construct a factorizing twist for a face type model equivalent to the XYZ model. Completely symmetric expressions for the operators of the monodromy matrix are obtained.     

Multipartite Entanglement in Heisenberg Model

The effects of anisotropy and magnetic field on multipartite entanglement of ground state in Heisenberg XY model are investigated. The multipartite entanglement increases as a function of the inverse strength of the external field when the degree of anisotropy is finite. There are two peaks when the degree of anisotropy is γ=±1. When the degree of anisotropy increases further, the multipartite entanglement will decrease and tend to a constant. The threshold of the inverse strength of the external field for generating multipartite entanglement generally decreases with the increasing of qubits.     

Integrable Deformations of Heisenberg Supermagnetic Model

We construct the integrable deformations of the Heisenberg supermagnet model with the quadratic constraints （i） S2=3S - 2I, for S ∈ USPL（2/1）/S（U（2）×U（1）） and （ii） S2=S, for S ∈ USPL（2/1）/S（L（1/1）×U（1））. Under the gauge transformation, their corresponding gauge equivalent counterparts are derived. They are the Grassman odd and super mixed derivative nonlinear Schrodinger equation, respectively.