Generation of millimeter-wave in optical pulse carrier by using an apodized Moire fiber grating

A novel scheme is proposed to transform a Gaussian pulse to a millimeter-wave frequency modulation pulse by using an apodized Moire fiber Bragg grating in radio-over-fiber system. The relation between the input and output pulses is analyzed theoretically by Fourier transformation method and the requirements for the proposed fiber grating are presented. An apodized Moire fiber Bragg grating is designed and its characteristics are studied. It is shown that the proposed device is feasible, and the new scheme is believed to be an effective solution for the generation of millimeter-wave sub-carrier in future radio-over-fiber systems. (c) 2006 Elsevier B.V. All rights reserved.

Optical generaton of millimeter-wave pulses using a fiber Bragg grating in a fiber-optics system

A scheme is proposed to transform an optical pulse into a millimeter-wave frequency modulation pulse by using a weak fiber Bragg grating (FBG) in a fiber-optics system. The Fourier transformation method is used to obtain the required spectrum response function of the FBG for the Gaussian pulse, soliton pulse, and Lorenz shape pulse. On the condition of the first-order Born approximation of the weak fiber grating, the relation of the refractive index distribution and the spectrum response function of the FBG satisfies the Fourier transformation, and the corresponding refractive index distribution forms are obtained for single-frequency modulation and linear-frequency modulation millimeter-wave pulse generation. The performances of the designed fiber gratings are also studied by a numerical simulation method for a supershort pulse transmission. (c) 2007 Optical Society of America.

Harmonic Millimeter Wave Generation and Frequency Up-Conversion Using Optical Injection Locking and Brillouin Selective Sideband Amplification

Harmonic millimeter wave (mm-wave) generation and frequency up-conversion are experimentally demonstrated using optical injection locking and Brillouin selective sideband amplification (BSSA) induced by stimulated Brillouin scattering in a 10-km single-mode fiber. By using this method, we successfully generate third-harmonic mm-wave at 27 GHz (f(LO) - 9 GHz) with single sideband (SSB) modulation and up-convert the 2GHz intermediate frequency signal into the mm-wave band with single mode modulation of the SSB modes. In addition, the mm-wave carrier obtains more than 23 dB power gain due to the BSSA. The transmission experiments show that the generated mm-wave and up-converted signals indicate strong immunity against the chromatic dispersion of the fibers.

毫米波副载波光纤通信技术的研究进展

综述了用于下一代移动通信的光纤毫米波副载波通信技术（ROF）的研究进展。介绍了系统的基本构想和涉及的关键技术。着重介绍几种毫米波副载波光发射器以及有关光学技术的新进展，包括外调制器方法、射频上转换法、光学外差法、毫米波调制光脉冲发生器等；简要介绍了ROF接收技术、系统技术和有关应用的研究动向。

一种基于光纤光栅的毫米波副载波光纤通信方案

提出了一种采用光纤光栅滤波器获得具有一定间隔双波长成分的光脉冲光谱实现毫米波副载波光信号产生的方法。利用逆工程算法，设计了一种变迹叠栅（Moiré）光纤光栅滤波器，给出了相应的模拟结果；并在实验上初步制作了相应的光纤光栅滤波器，验证其可行性。同时基于所设计的光纤光栅和波分复用技术，提出了一种频移键控光纤-无线通信系统Radio Over Fiber系统，为下一代的高速大容量的光纤-无线通信系统系统提供一种可行的备选解决方案。

基于法布里-珀罗干涉仪的毫米波副载波光学产生方法

在光纤无线电系统(ROF)中，提出了一种利用法布里-珀罗干涉仪来实现将一个光学脉冲转换为毫米波频率调制的光学脉冲的方法。在这种方法中，毫米波调制的频率是由法布里-珀罗干涉仪的腔长来决定的，而脉冲序列振幅衰减和能量转移效率则是由法布里-珀罗干涉仪的腔镜反射率决定的。同时，文中对输出脉冲宽度的扩展所导致的脉冲间的干涉问题也进行了详细阐述。

利用脉冲重复率倍增和时域泰伯效应实现毫米波脉冲的产生

我们提出了一种新颖的利用脉冲重复率倍增和时域泰伯效应实现毫米波脉冲信号产生的光学方法。在我们的方案中，一个级联的马赫振德干涉仪被用来实现脉冲重复率倍增，一个线性的啁啾光纤光栅被用来实现时域泰伯效应。文中对这种方法的基本理论进行了分析，并给出了相应的数值模拟的结果。研究结果显示这种灵活的毫米波脉冲信号产生的方案在未来的宽带的Radio over Fiber技术将有一个很好的潜在的应用。

Narrow-Linewidth Microwave Generation Using a Self-Injected DBR Laser Diode

A novel technique for generating narrow-linewidth microwave or millimeter-wave signals is proposed. In this scheme, a delayed self-injected distributed Bragg reflector laser diode, which is tuned by a low-frequency square-wave voltage, is used to generate two correlated lightwaves simultaneously. Experiments show that the 10-dB linewidth of generated microwave signals is reduced from 147 MHz to 68 kHz utilizing the proposed self-injection technique.

Two-port calibration of test fixtures with OSL method.

The open-short-load (OSL) method is very simple and widely used, for one-port test fixture calibration. In this paper, this method. is extended to the two-port calibration of test fixtures for the first time. The problem of phase uncertainty arising in this application has been solved. The comparison between our results and those obtained with the short-open-load-thru (SOLT) method shows that the method established is accurate enough for practical applications.

Frequency limitation in calibrating microwave test fixtures

The problem of frequency limitation arising in calibration of the test fixtures is investigated in this paper. It is found that at some frequencies periodically, the accuracy of the methods becomes very low, and. the denominators of the expressions of the required S-parameters approach zero. This conclusion can be drawn whether-the test fixtures, are symmetric or not. A good agreement between theory and experiment is obtained.

Choice of calibration equations of the TSM method

For the reciprocal-test fixtures, there are six independent S-parameters to. be determined, and the thru-short-match (TSM) calibration can provide eight calibration equations. In this paper, the relation of calibration equations is investigated. It has been shown that the four equations obtained from the measurement with a transmission standard can be used simultaneously in the calibration. Experimental results show that the different choice of equations will lead to quite different solution, and the calibration accuracy can be improved by taking advantages of the established relation among the calibration equations and properly choosing calibration equations.

有机半导体中载流子迁移率的测量方法

本文简要地介绍了有机半导体中载流子迁移率的几种模型,着重阐述了测量有机半导体中载流子迁移率的各种方法的测试原理。主要有如下几种:稳态(CW)直流电流-电压特性法(steady-state DC JV),飞行时间法(time of flight,TOF),瞬态电致发光法(transient electroluminescence,transient EL),瞬态电致发光法的修正方法即双脉冲方波法和线性增压载流子瞬态法(carrier extraction by linearly increasing voltage,CELIV),暗注入空间电荷限制电流(dark injection space charge limited current,DI SCLC),场效应晶体管方法(field-effect transistor,FET),时间分辨微波传导技术(time-resolved microwave conductivity technique,TRMC),电压调制毫米波谱(voltage-modulated millimeter-wave spectroscopy,VMS)光诱导瞬态斯塔克谱方法(photoi...