光纤白光干涉仪等臂长技术研究

介绍了几种光纤干涉仪等臂长技术,比较了各自的优缺点和适用范围,对光纤干涉仪的平衡有较大的参考价值。     

Measurements of Time-Varying Characteristics of Optical Signals and Inhomogeneities of Tested Substances with Additional Phase Modulation

The problem of investigation of the amplitude and phase structure of a time-varying probing optical signal and the structure of time-varying inhomogeneities of a substance tested by this signal is considered. The analysis is concerned, in particular, with determination of the structure of signals and processes with resolution in the pico- and femtosecond range. The scheme used for the analysis is based on registration of four spatially separated spectra of the studied radiation. The spectra are formed in a four-channel scheme with a twin-wave Michelson interferometer and a spectral device. Modulators based on electrooptical crystals (perovskites) are placed in the channels. The sum spectra are formed: without modulators, with the effect of either of the modulators, and with both of them affecting the radiation. The effect of the studied substance implies either modulating the radiation (in this case it is described by multiplication) or redistributing the radiation (then it is described by convolution).     

Andreev-Fano Effect in a Hybrid Normal-Metal/Superconductor Interferometer

We report on a new type of Fano effect, named as Andreev-Fano effect, in a hybrid normal-metal/supeeconductor (N/S) interferometer embedded with a quantum dot. Compared with the conventional Fano effect, AndreevFano effect has some new features related to the characteristics of Andreev reflection. In the Iinear response regime, the line shape is the square of the conventional Fano shape, while in the nonlinear transport, a sharp resonant structure is superposed on an expanded interference pattern, which is qualitatively different from the conventional Fano effect. The phase dependence of the hybrid N/S interferometer is also distinguished from those of all-N or all-S interferometers.     

Implementation of a Nonzero-order Joint Transform Correlator Using Interferometric Technique

The implementation of a nonzero-order joint transform correlator using the double port Mach-Zehnder interferometric technique is proposed and demonstrated. This approach provides on-line processing for directly removing the zero-order components of a joint power spectrum in one step and performs the nonzero-order optical correlation. Experimental results are presented and discussed.     

Analysis of a Young–Michelson tandem interferometer

In a Young–Michelson tandem interferometer a Michelson interferometer is illuminated through a pair of Young slits. The pattern produced by this set-up is analyzed theoretically. The consequences of small misalignments and uncompensated arms in the Michelson interferometer are studied. The effects of the spatial and temporal partial coherence of the source are also explored. Experimental results using a laser source are shown to be in good agreement with the predicted theoretical calculations.     

用迈克耳逊干涉仪测量气体折射率的误差的研究

研究在用迈克尔逊干涉仪测量气体折射率时存在的系统和方法误差，提出了误差修正方法。     

在线滤波技术在光纤马赫-德尔交叉复用器中的应用

为构造出与理想梯形滤波器接近的滤波形状，在单级光纤马赫-德尔交叉复用器的基础上，引入在线滤波技术；通过增加干涉级数和调整2对干涉臂的干涉长度和耦合器的耦合比，实现了逼近宽带陡沿的滤波输出。通过与梯形滤波器傅里叶展开式的比较，计算得到了器件的最佳参数，器件的滤波性能以及温度稳定性相对于单级结构得到了明显提高。根据理论计算，成功制作出通道间隔为50GHz的样品器件。其输出为-0.5dB，带宽大于0.185nm，相邻通道隔离度大于30dB，满足了DWDM系统指标要求。     

Acousto-optic mode coupling of partially coherent light in two-mode optical fibers

An acoustic pulse propagating on a two-mode fiber can act as a beam splitter in a scanning interferometer. When this device is employed in white-light interferometry, the effects of distributed coupling and dispersive interferometer arms need to be considered. A theory suitable for treating acousto-optic interaction of partially coherent light in a moving interaction region was developed. It was found that differential optical dispersion should be negligible and the acoustic pulse length short. Also the coherence time should be short but long compared to the intermodal group delay difference over a pulse length. Experiments with long acoustic pulses were performed, and fairly good agreement with theory was obtained.     

Phase Measurement Algorithm in Wavelength Scanned Fizeau Interferometer

Wavelength scanned interferometry allows the simultaneous measurement of top surface shape and optical thickness variation of a transparent object consisting of several parallel surfaces. Interference signals from these surfaces can be separated in frequency space, and their phases are detected by discrete Fourier analysis. However, these signal frequencies are shifted from the detection frequency by the refractive index dispersion of the object and a nonlinearity of the wavelength scanning. The Fourier analysis is sensitive to the detuning of the signal frequency and suffers from the multiple-beam interference noise. Conventional error-compensating algorithms cannot be applied to an object consisting of more than three reflecting surfaces. We derive a new 2N-1 sample error-compensating algorithm, which allows the phase detection of any order of harmonic frequency among the interference signals. The new algorithm suppresses the effect of signal frequency detuning as well as the multiple-beam interference noise and can be applied to the measurement of complex objects consisting of more than three reflecting surfaces.