A chirped fiber grating with cladding made of uniaxial crystal material whose optical axis is parallel to the axis of grating, i.e., z-axis is proposed. Electro-optic effect and elasto-optic effect in this kind of fiber gratings are theoretically analyzed for the first time. The influences of the electric field and the strain applied to the fiber grating cladding along z-axis on Bragg wavelength kB and the reflectivity spectra of this kind of chirped grating are theoretically examined using coupled-mode theory and transfer matrix method. The curves of Bragg wavelength kB as a function of an external electric field or the strain are theoretically obtained respectively for three kinds of uniaxial crystal materials as the grating claddings. The calculated results indicate that when the axial electric field applied to the grating cladding varies from 1

In this paper, the chromatic dispersion and chromatic dispersion slope of two kinds of triple-clad single-mode fibers with a depressed index inner cladding named WI-and WII-type were examined. A feasible approach to calculate chromatic dispersion and higher-order dispersion was established successfully, and the influences made by the optical parameters and geometric parameters on the chromatic dispersion coefficient and its slope were analyzed in detail. The calculated results show that the optical parameter R2; which symbolizes the third cladding effect, has a strong impact on the chromatic dispersion coefficient and the chromatic dispersion slope, and the degrees of such impact are closely related to the other parameters.

fiber Bragg grating with cladding made of uniaxial crystal material whose optical axis is parallel to the axis of fiber Bragg grating was proposed. The ratio (Kcl) of the extraordinary to the ordinary ray refractive index was introduced and the influence of parameter Kcl upon the reflectivity γ, Bragg wavelength λB, the bandwidth of reflected wave △λ and the dispersion dq of this kind of fiber Bragg grating was examined using coupled-mode theory. The calculated results indicate that parameter Kcl has a strong impact on the characteristics of this kind of fiber Bragg grating, and the degrees of such impact are closely related to the values of parameter Kcl. This means Kcl can lead to the variation of Bragg wavelength while keeping its length, periodicity and the other parameters as constants. The fiber Bragg gratings using two kinds of uniaxial crystal material as cladding were discussed, respectively.

Two kinds of the large effective-area fibers with the ring index profiles named RI and RII type were proposed. In view of the impossibility to deduce the expression of waveguide dispersion directly due to the complexity of the characteristic equations, a feasible approach to calculate waveguide dispersion was established successfully. The influences made by the geometric parameters and optical parameters on the waveguide dispersion and cutoff characteristics of low order modes were analyzed. The calculated results indicate that the dispersion-flattened and large effective-area performances can be achieved simultaneously by adjusting the geometric and optical parameters in a region of wavelengths. A dispersion-flattened fiber design with the total dispersion of about 4.5 ps/nm/km, dispersion slope of below 0.006 ps/nm2/km and the effective areas from 95 to 118 lm2 in the spectral range of 1540–1620 nm was presented and its tolerance analysis and bending loss characteristics at 1550 nm were also examined.

The chirped Gaussian pulse broadening induced by chromatic dispersion in two kinds of tripleclad single-mode fibers with a depressed index inner cladding was examined in this paper. In view of the impossibility to deduce the expression of chromatic dispersion directly due to the complexity of the characteristic equations, a feasible approach to calculate chromatic dispersion was established, and the influences made by the optical parameters and geometric parameters on the chromatic dispersion and chirped Gaussian pulse broadening were analyzed. The calculated results indicated that the optical parameter, that symbolizes the third clad effect, has a strong impact on chromatic dispersion and pulse broadening, and the degrees of such impact were closely related to the other parameters and operating wavelength. The evolvement processes of a traveling chirped Gaussian pulse in the kinds of triple-clad single-mode fibers with different parameters were also analyzed