摘要：
A new scheme for optical trapping is presented in this paper. The method is based on a tapered fiber probe with a tip diameter less than a light wavelength. A three-dimension gradient optical field is formed within the optical near field of the fiber probe, and a particle approaching the fiber probe tip will be trapped. The evanescent electromagnetic field in the vicinity of the fiber tip is calculated by the multiple multipole method (MMP). The intensity distributions and the trapping potential of the near fields of the tip versus the longitudinal and transverse distances from the tip are analyzed respectively. The trapping force is obtained for a dielectric particle. The numerical calculating results show the availability of this method.
摘要：
FTTH/FTTC systems will be soon used in both a broadcast service and a wavelength-addressed point-to-point communication service. Optical wavelength routers will be the key devices in these systems. In this paper, we propose a new method for high-density optical routing using arrayed- waveguide gratings (AWGs), present the transmission properties of the wavelength router, and analyze the channel crosstalks and the insertion losses of the 16-channel wavelength router. The results show that the channel crosstalks are less than -18 dB, and the insertion losses are less than -6 dB. Its advantages include small volume with miniatured structure, low insertion loss, low coupling loss to fiber, and compatible with the microelectronics technology. It can be used to construct photonic integrated circuits with the waveguide laser diodes and photodetectors.
作者机构：
[Zhang, GP; Ming, H; Huang, ZM] Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhang, GP] C;Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
We propose a new method for optical trap in this paper. It is based on a tapered fibre probe with a tip size less than a Light wavelength. A three-dimension gradient optical field is formed within the optical near field of the fibre probe, and a particle approaching the fibre tip will be trapped. We calculate the evanescent electromagnetic field near the fibre tip and obtain the trapping force for a dielectric particle. The calculating results show the availability of this method.
摘要：
Based on Fresnel diffractive theory, a binary optical laser cavity is designed for a circle, flat topped fundamental mode. Instead of the traditional spherical mirrors for a laser cavity, the diffractive mode-selecting mirrors are used to optimize the amplitude and phase of the laser mode by simulated annealing algorithm. The computer simulation results show that the mode loss rate between TEM00 and TEM01 is 1:430 for a round trip in the cavity, and only the required fundamental mode is established in the laser cavity.
作者机构：
[Zhang Guoping; Huang Zhuming] Department of Physics,Central China Normal University;[Zhang Guoping; Huang Zhuming] Dept.of Basic Courses,Wuhan Institute of Chemical Technology
会议名称：
1999 International Conference on Computational Electromagnetics and Its Applications(ICCEA’99)
会议时间：
1999-11-01
会议地点：
中国北京
摘要：
<正>On the basis of the coupled-mode method, transmission properties of the tapered fiber probes which are used for the scanning near-field optical microscope (SNOM) are presented in this paper.The for
作者机构：
[Zhang, GP; Zhang, XH; Ye, JX; Li, ST] Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhang, GP] C;Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
关键词：
Mirrors;Laser resonators;Micro optics;Diffraction;Binary data;Laser applications;Near field diffraction;Quantization;Spherical lenses;Laser processing
摘要：
A novel method for mode regulation of a laser resonator is presented in this paper. The traditional spherical mirrors of the laser resonator are substituted by the micro-optic mirrors, which are produced by the binary optical technology. The phase distributions of the micro-optic mirrors may be designed carefully so that the output mode of the laser resonator is regulated as an arbitrary desired field distribution. Several mode fields, such as a fundamental-mode Gaussian distribution and a circular or rectangular uniform. intensity distribution, are analyzed in our discussion.
摘要：
A superfluorescent source used for scanning near-field optical microscope (SNOM) has been developed in this paper. The superfluorescent source originates from an amplified spontaneous emission (ASE) produced by an Er-doped fiber, with a relatively wide spectrum from 1531 nm to 1537 nm. This kind of superfluorescent fiber probe has relatively high photon flux over an ordinary probe. Different image qualities are obtained by the SNOM system with the superfluorescent source and the laser source respectively. Experimental result shows that the coherent noise of the SNOM image is dramatically reduced with the superfluorescent source.
摘要：
Passive and active fiber probes, used for the scanning near-field optical microscope (SNOM), show different image properties. For the passive fiber probe, a better optical image contrast has been obtained with a parabolic taper than with a linear taper. The reflected fields in different fiber tapers have been discussed. For the active fiber probe, an ASE (Amplified Spontaneous Emission) probe made of Er<sup>3+</sup>-doped fiber has shown a higher efficiency of several times and a lower image noise than the usual passive probe.
