The Research On Dispersion Compensation Of Photonic Crystal Fibers

The photonic crystal fiber can be widely used in optical communication, sensingand nonlinear applications due to its flexible structure. Dispersion can cause pulsediffusion problem so seriously that it must be compensated. In this dissertation, thetheory of dispersion and the means of dispersion compensation are explored. Anoctagonal dispersion compensation fiber is designed and the properties of the octagonaldispersion compensation are analyzed. Besides, the coupling of leaky modes indual-concentric-core dispersion compensation fiber and in photonic crystal fibers withfinite layers is analyzed based on Finite Element Method. We find such kind of photoniccrystal fibers’ possibility of sensing applications. The primary work could be describedas follows:The transmission properties of the octagonal photonic crystal fiber and hexagonalphotonic crystal fiber are investigated based on the same air filling rate. The resultsshow the octagonal photonic crystal fiber has better transmission properties such aswide single mode region, low confinement loss and high dispersion, which is moresuitable for optical communication. An octagonal dispersion compensation photoniccrystal fiber for high speed transmission systems is proposed. The negative dispersioncan be gained in entire S+C+L waveband without doping. Meanwhile, the fiber exhibitslow nonlinear coefficient less than3.3(w.km)-1and the nonlinear affect can beeliminated effectively. The coupling of the leaky modes in the designed octagonaldispersion compensation fiber is analyzed. It’s shown that both the confinement loss andthe phase can match at1.55μm without doping. So the designed dispersioncompensation can be used in WDM. Besides, the relationship between the leaky modecoupling and the structure parameters is discussed.The coupling of the leaky mode between the core and outer cladding in octagonalindex-guiding PCF with finite outer cladding is analyzed. The results show that thecoupling can contribute to the confinement loss peak of the fundamental mode. The losspeak is related with the numbers of the cladding, the external material and the diametersof the outer cladding. Our results should provide theoretical support for the applicationsof PCFs with finite cladding layer in optical communication system.We find the possibility of sensing applications for the octagonal photonic crystalfiber with finite outer cladding. Compared with the grating used in sensing, the designed fiber can greatly reduce the difficulty of the production.