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：
[Li, YD; Liu, LS] Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430070, Peoples R China.
通讯机构：
[Li, YD] H;Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430070, Peoples R China.
关键词：
J/psi photoproduction;quark fragmentation
摘要：
The J/psi, photoproduction via resolved photon process at HERA is studied. it turns out that the J/psi production is dominated by the leading order production process in low p(t) range (p(t) < 4 GeV), while in the high p(t) range (p(t) > 4 GeV), it is dominated by the fragmentation processes. The difference of J/psi cross section caused by using GRV and DO photon structure functions is large, especially in the large negative rapidity range. Hence it is possible to use the J/psi photoproduction process to probe the parton distribution of photon and proton, as well as to test the gluon and heavy quark fragmentation of J/psi, from the perturbative QCD.
作者机构：
Department of Physics, Central China Normal University, Wuhan, China;Department of Solid State Electronics, Huazhong University of Science and Techndogy, Wuhan, China;[Li, YP] Department of Physics, University of Science and Technology of China, Hefei, China;[Huang, XT; Qi, SR; Li, XJ] Department of Physics, Central China Normal University, Wuhan, China<&wdkj&>Department of Solid State Electronics, Huazhong University of Science and Techndogy, Wuhan, China
通讯机构：
[Huang, XT] C;CENT CHINA NORMAL UNIV,DEPT PHYS,WUHAN 430070,PEOPLES R CHINA.
摘要：
<正> Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy （STM） system, and the problems have attracted almost all STM scientists’ attention. In 1992, Kenkre proposed the new programme which describes the behaviour of the electrons moving in the STM tunnelling by the method of exciton dynamics, and the programme not only breaks through the restrictions of Tersoff-Hamann theory, but also can be applied conveniently to discussing the effects of the tip structure, adsorbate structure, substrate structure, temperature, tunneling voltage, and the degree of coherence of elec-
