CAD Development For Analyzing Step-Index Optical Fiber Characteristic

CAD (Computer-Aided Design) is one of the most outstanding technology in the 20th centry. It has many advantages such as improveing design level, shortenning the period of product development, enhancing industry competition. With the rapid progress of computer hardware and the popularization of high performance computer, CAD technology has been widely applied to many fields, for example, aviation and spaceflight, electron, machine, architecture, etc. It has gained considerable economy and social benefit. But the CAD in optical fiber communications has been developed terribly immature, especially in our country. Further more, almost all existing fiber communications CAD production are developed by foreigners at present, so fiber CAD research in our country has been urged.We mainly use VC, MATLAB and MATCOM tools to develop a software named FIBERCAD. The FIBERCAD has not only been used as professional software in fiber field , but also accumulated some experience for advancing fiber communications CAD.The main functions of FIBERCAD include:It can introduce the basic structure of fiber, give geometry parameters by inputing indexes of core and cladding, core radius, and frequency.It can solve the eigenvalue equation of step-index fiber, propagation constant, give the relation diagram of normalized eigenvalue and normalized frequency by input fiber's parameters, and display fiber modes figure.It can give the diagram of fractional power flow in the cladding as a function of normalized frequency, and calculate the ratio of power flow in the eladding to total power under the given mode.The software has been tested and performs well, but its application field is limited. So we will perfect the software in the future.