We report on the properties of light transmission in one-dimension photonic crystals with defects of nonlinear dielectric material, photonic crystals have simple and complex period dielectric structure with multi-unit layer. In particular, we are interested in the transmittance of defect mode and the intensity enhancement factor of localized light. By the transfer-matrix method, we can calculate the electromagnetic waves transmission through a photonic crystal, the intensity enhancement factor of localized light can be obtained. The method calculated the transmission properties normal incident on a finite thickness slab of material. The numerical calculation shows that the transmission with defect layer of nonlinear dielectric material can induced to bring about change by the input intensity of light, and the change of the transmission shows the bistability. For simple and complex period dielectric in PC, if the threshold of input intensity be satisfied, the properties should be emerged easier. For complex period dielectric in PC, the transmission can show the property of complex results. When the total transmission is big, the bistability is also displayed. In addition, the character is seen to determine by the saturation absorption coefficient of the defect medium, the refractive index ratio and the number of layers.
Erbium doped fiber amplifier have been demonstrated at several wavelengths. The exceptionally broad and intense absorption spectrum of erbium with other rare-earth co-doped fiber is advantage in high power amplifiers and fiber lasers. In order to broaden amplifying band, it is important to modify spectrum properties of erbium doped optical fiber. In this dissertation, erbium with ytterbium, thulium and Lanthanum co-doped fibers were fabricated by MCVD. This paper focus on the influence of concentration and ratio of rare-earth on spectrum properties of fiber. It was found that absorption of the EDFs was affected by erbium concentration and ratio of erbium and other rare-earth. Absorption band were broadened by adding dopant of other rare-earth.
The dispersion and self phase modulation is two important factors of the limit transmission distance in optical fiber communication. A novel method for measuring the dispersion slope of a long single-mode fiber was reported. By asymmetric modulation and Mach-Zehnder interferometer, the interferometer causes counter propagating wave to travel in test fiber with different propagation constants. We introduced the fast Fourier transform technique, the autocorrelation function is brought forward, and the information of the interference fringe is analysis with high speed so that the accuracy of signal is estimated. Successively, the experiment was performed on the test fiber to determine the nonlinear refractive index and self phase modulation, exact pulse bandwidth solution is presented. We found that
quantity was depends on the intensity of incidence light and the peak power, and the frequency spectrum is broadening clearly. The result shows that the intensity input and the peak power can affect the phase shift value.