Study On Multi Core Optical Fiber Mode Converter Used In The Mode Division Multiplexing System

With the rapid development of modern information technology, the amount of data traffic is increasing, and the transmission bandwidth of optical fiber transmission network is higher. In order to meet the rapid growth of data traffic, time division multiplexing, wavelength division multiplexing technology, higher order modulation formats, polarization multiplexing and other new technologies appear one after another. To alleviate people as pressing danger of communication service bandwidth. However, due to the nonlinear effects of single mode fiber, transmission capacity is severely limited. Under this background, space division multiplexing emerged, which has the potential to expand the transmission capacity greatly. Space division multiplexing technology has become the focus of the current research direction and hot topics in the field of optical fiber. As an important way of space division multiplexing, the mode division multiplexing technology has attracted much attention. To achieve high efficiency, low complexity and high speed, high speed and high efficiency conversion of different modes is the prerequisite for the use of the mode division multiplexing technology. The specific work of this paper is as follows:Firstly, the research background and research status of space division multiplexing are introduced. Then starting from the Maxwell equations, the mode of small mode optical fiber is analyzed. Secondly, based on the waveguide coupling system, the principle of mode coupling is analyzed in detail, so as to provide theoretical basis for the mode conversion technology. At the same time, the specific application of mode conversion technology is introduced in detail. Then the theoretical analysis and summary of the method of beam propagation by using the numerical simulation method of the optical fiber used in this thesis is carried out. The birefringence of optical fiber to implement optical fiber is introduced. By using the theory and method mentioned above, this paper presents an equivalent dual core all fiber mode converter based on side polished fiber. At then, a variety of important parameters are simulated and optimized, and finally get the optimization results and achieve the purpose of high efficiency mode conversion.At last, the theory of the mode converter based on the side throw is used, and six core all fiber mode converter is analyzed and experimented, a variety of high order modes are excited by the converter. And the parameters are scanned, so as to obtain a more optimal results.