The Theoretical Research Of Moire Fiber Grating Used In OWDM Systems

With the abrupt increase of the information and the rapid development of optical communication technique,it' s necessary to make full use of the broad-bandwidth advantage of the fibers. Then,optical Wavelength-division- multiplexing (WDM) has been brought out. In the OWDM systems,there are a lot of active components and passive components with excellent characteristics,which make multiple optical signals transmit simultaneously without interaction in the same fiber and perform its function by the light,such as optical signal interchange multiplexing/demultiplexing etc . Moire fiber grating (MFC) is a new kind of passive components. Because of its especial features,it can be used in OWDM systems,operated in all light,and is considered promising. In the paper,the general method analyzing the characteristics of fiber grating has been used to research the effect of the MFC parameters on its character,some good results gotten.It' s very useful for them to design practical product to suit the needs of OWDM systems. The main parts are as follows:1) At the base of the fabrication methods,the photosensitivity of optical fiber and the UV laser sources are introduced simply,the diffraction characteristics of phase mask are analyzed to get the distribution of refractive index in fiber grating,referent the paper[4] (delivered).2) The coupled-mode equation analyzing the characteristics of fiber grating is deduced step by step. Two methods-the transfer matrix metod and the Runge-Kuttar method are compared,which are often used to solve the coupled-mode equation. The analysis in this paper demonstrates the power of the transfer matrix method,which can get the features of aperiode fiber grating fastly,referent the papers[1-2](published).3) In terms of the theoretical mode of MFC,the effect of MFC parameters on its features-chirped Moire fiber grating and Moire fiber grating formed by two uniform fiber grating with different central wavelengths,is discussed individually. By comparison between the two kinds of MFC,chirped Moire fiber grating is better for OWDM,referent the paper[3] (to be published).