提出了一种基于超高分辨率光谱分析实现周期性光信号频域中相位分布的测量方法.在已测得待测信号高分辨率光谱的情况下,利用马赫泽德调制器载波抑制效应调制激光器产生双泵浦,激发高非线性光纤中的受激布里渊散射效应形成有源双滤波器.用泵浦激光器在测量波长范围内进行连续扫描,得到包含待测信号相位信息的拍频信号,经数据采集和处理后得到待测信号频域上的相对相位信息.实验给出了速率为5Gb/s,字长为31bit的周期性光信号在频域上的相对相位分布信息,证明了这种有源双滤波器的频率响应特性可以满足相位测试的需要.

基于经典的色散理论建立的单振子光谱分析模型，通过理论推导，借助计算机辅助处理，提出了一种比较简捷直观的只利用垂直透射光谱对薄膜光谱进行分析的方法.利用这种方法分析了直流溅射制备的ZnO薄膜的透射光谱，计算出了薄膜在透明振荡区的折射率色散关系以及厚度等参量，并对分析方法给出了验证.

We present the all-fiber system for supercontiuum (SC) generation with picosecond pulses. By launching 1.6-ps pulses from pulsed erbium-doped fiber laser (EDFL) into a section of photonic crystal fiber (PCF), the spectral broadening is observed. The bandwidth of 237 nm (at 20 dB level) is achieved.

The xNb2O5-(15-x)La2O3-40B2O3-45BaO (x=5, 7.5, 12.5 mol%) glasses doped with Eu3+ ions in 1 mol% are fabricated by the melting method. The Fourier transform infrared (FTIR) spectra, phonon side-band spectra, emission and excitation spectra of the glasses are measured. The crystal field parameter and coordination number of Eu3+ ions in the glasses are obtained according to the splitting of their 5D0-7F1 levels. The intensity parameters 'Omega'2 and 'Omega'4 of Eu3+ ions for optical transition are calculated from their emission spectra in terms of reduced matrix U(t) ('lambda'=2, 4, 6) character for optical transitions. The results indicate that the intensity parameters 'Omega'2 and 'Omega'4 increase with the increase of Nb2O5 content, suggesting that the symmetry becomes lower, the band of Eu and O atoms becomes stronger and the covalence increases with the increase of Nb2O5 content.

A novel quantitative analysis method of multi-component mixture gas concentration based on support vector machine (SVM) and spectroscopy is proposed. Through transformation of the kernel function, the seriously overlapped and nonlinear spectrum data are transformed in high-dimensional space, but the high-dimensional data can be processed in the original space. Some factors, such as kernel function, range of the wavelength, and penalty coefficient, are discussed. This method is applied to the quantitative analysis of natural gas components concentration, and the component concentration maximal deviation is 2.28%.

A real-coded genetic algorithm (RGA) for fiber Bragg grating (FBG) distributed sensing is presented. The distributed strain fields along the fiber Bragg grating sensor (FBGS) are real coded into genes, and the concept of elitism and simulated annealing are also included in this algorithm. Compared with the binary coded genetic algorithm, this method is more simple and efficient. Only with the reflect spectrum of distributed FBGS, the strain fields distribution can be exactly demodulated even in the regions with significant strain gradients. The algorithm is a promising method for demodulating the distributed FBGS, which can be used for structural failure analysis and structural damage identification.

This letter describes a novel optical method for wavelength fine-selection in the optical spectrum analysers (OSAs) for dense wavelength division multiplexing (DWDM) applications. The proposed new method employs a 'refractive optical lever' system consisting of a rotating optical wedge prism. A new OSA system based on Littman-type monochromator is proposed and the wavelength selection accuracy and resolution of OSA that has included such an optical lever system have been improved by a factor of 20 to 100 depending on the wedge angle and offset orientation angle of the optical wedge prism. This proposed 'refractive optical lever' may also simplify the rotation mechanism of the mirror in the commercially available OSAs.

We investigate the emission spectra of a Ξ-type three-level atom interacting with a single-mode optical field in an ideal cavity filled with a Kerr medium and discuss the structure of emission spectrum when the optical field is initially in a pure number state and a coherent state, respectively. It is shown that the structure of emission spectrum depends not only on the photon number distribution, but also on the strength of incident field and the coupling of Kerr medium to the field.