The Constructer Design And Characteristics Analysis Of The Doped-Core Photonic Crystal Fiber Filter

Wavelength Division MultiPlexing(WDM)/ Dense Wavelength Division MultiPlexing(DWDM) are the key technologies to achieve high-speed and large-capacity transmission of optical fiber communication system. As an important wavelength division multiplexing photonic device, fiber filter is widely used in optical fiber communication system, its performance is directly related to the quality of data transmission. Photonic crystal fiber filter is superior to conventional optical fiber filter, and it improves the efficiency of some original optical devices. It will in place of conventional optical fiber in many fields and become a center device for next generation of optical communication.In this paper ,by using the full vector beam propagation method (FV-BPM), two novel narrow-band filters with cores doped photonic crystal fiber (PCF) are proposed. In addition, RSoft is used to simulated the working characteristics of the Dual-Core and three-core photonic crystal fiber filters. These numical results lay a foundation for further research and practical application of PCF filter.The main contents are as follows:First, the computer simulations of optical wave-guide devices which are usually applied are introduced in detail, the priciple, formula and a numerical analysis of beam propagation method are introduced especially.Second, coupling theory of optical fiber and the application of optical fiber coupler in optical communication system are introduced. The principle, structure and characteritic of optical filter and wavelength division multiplexing device are introduced in detail.Third, Two kinds of photonic crystal fiber (PCF) filters which cores are doped are presented. After the structural parameter of the cladding of the dual core PCF and the doping degree in the dual core region are optimized. The index curves of the fundamental modes of the cores can cross at 1.55μm wavelength, As a result, wavelength-selective coupling is achieved. Full vector beam propagation method (FV-BPM) is used to simulated the working characteristics. Numerical investigations demonstrate that the values of the coupling length are 16.4 mm and 22.8 mm , and the filters with bandwidths of 9 nm and 8.9 nm at the loss of -3dB. The photonic crystal fiber filters achieve the small size, the low transmission loss and the narrow-band characteristic.