Analysis Of The Band Gap Of Photonic Crystal Fiber

With the continuous development of communication technology, in practical applications, the requirements of the fiber become strict more and more, how to design a series of optical fiber with excellent properties such as fast transmission speed and small loss, which has become one of the major key issues in the optical fiber manufacturing. Since there are some limitations in the traditional optical fiber itself, so it can not play the transmission characteristics of optical fiber in exceptional circumstances, which also birth the research and production of photonic crystal fiber. Photonic crystal fiber has a unique mechanism of guided optical and the guide properties of photonic crystal fiber is more superior than the ordinary optical fiber, which give it a broader development prospects, after declined the cost of production generally, the photonic crystal fibers will certainly be widely used in practical engineering.The concept, characteristics, mechanism of guided optical and theoretical research methods of photonic crystal fiber are lucubrated in this paper, particularly using the finite difference time domain method simulate and analysis the band-gap of photonic crystal fiber, and obtain a series of conclusions.First, the band gap photonic crystal fiber with the cladding air holes of hexagonal structure is studied, discuss in the circumstances of the sane free space wavelength, to change the aperture size of the hole and the ratio between the hole spacing, and set the size of each layer of air holes for showing the law of ascending or descending features, in this structure, the band gap properties conclusions of band gap photonic crystal fiber are obtained; Secondly, the band gap photonic crystal fiber with the cladding air holes of rectangular structure is studied, still set the seven layer hole structure, scientific research has shown that the band gap type photonic crystal fiber properties relevant the relative size of the photonic crystal fiber, namely, the ratio of hole size and hole spacing d/A is the important factor affecting the properties of photonic crystal fibers. In this paper, Using the following three ways to achieve simulation of the band gap photonic crystal fiber with the cladding air holes of rectangular structure, the first by changing the hole size to achieve the purpose of changing d/A, and the second by changing the hole spacing to achieve the purpose of changing d/A, and reach the same conclusion, the third increase the size of the hole size and hole spacing in proportion, but make the value of d/A not change; Finally, the different materials band gap photonic crystal fiber are simulated, and make comparison with injection wave types, can be concluded that the material of GaAs is very suitable for the production of band gap photonic crystal fiber, whether the width of band gap, or if the band gap near the center of the light source lines, the effect of GaAs material band gap photonic crystal fiber is far superior to quartz or other materials band gap photonic crystal fiber; By comparison of injection wave type, it can be concluded that TE type wave is easier to be limited to transmit in the structure of the band gap photonic crystal fiber which designed in this article.In this paper, through researching the band gap photonic crystal fibers, provides a theoretical basis of how to find f the band gap of photonic crystal fiber, and better using the band gap in the actual production. At last, a modified rectangular photonic crystal fiber is designed in this article, this structure can get a wider band gap, and the band of transmitted light is stretched.