Study On Bandgap Property Of Photonic Crystal Fibers

Guiding Light through photonic bandgap (PBG) mechanism is a significant property of photonic crystal fiber (PCF). This paper mainly focuses on the PBG property of PCF by theory analysis and experimental research. Especially, emphasizing on studying the PBG property of hollow-core photonic crystal fiber (HC-PCF), the advantages of HC-PCF in contrast with the conventional optical fiber are analyzed. By theory analysis and numerical simulation, the relation between the PBG property and the structure parameters of PCF has been found. The experimental method for testing the PBG property of PCF is put forward. Further more, the experimental measuring system has been set up.Using the full-vector plane-wave method (FVPWM), we can numerically simulate the photonic energy band structure and the PBG structure. Based on the energy band theory, the origin of bandgap in PCF is analyzed. Especially, we focus on studying the property of two-dimensional (2D) photonic crystal energy band and analyzing the medium effect to the PBG of PCF. Moreover, we research on the PBGs with varied crystal lattice structures. Finally, according to the analytic result, PCF with more optimized PBG is designed.Using the method of transmission spectrum to measure the PBG of PCF, the experimental measurement system of the visible light waveband region is set up. During the measurement, we mainly test the transmission spectrum of light wave that propagates in HC-PCF. Dealing with the experimental datum, the PBG spectrum figure of HC-PCF can be obtained. Using the FVPWM, we calculate the PBG of HC-PCF with the similar structure, then compares it with the experimental result. Though this process, we can validate whether the experiment is feasible.Finally, we illustrate the developments and transmission properties of PCF with the photonic bandgap centred at the wavelength of 1 550nm. Theoretically, calculating the HC-PCF that we have fabricated, we can find that the PBG is located in the wavelength of 1550 nm. The achieved result requires further research on PBG of near-infrared light region.