In this paper, the proposed switch of T-type based on photonic crystal ring resonator has been studied. The proposed structure is composed of two waveguides, between them the photonic crystal ring resonator is placed. Our structure can switch two wavelengths together following an external effect. The proposed design has a simple geometric shape, therefore it is capable to realize optical switch applicable to photonic integrated circuits. The parameters that can characterized the performance of optical device are quality factor, crosswalk and foot print. The values of crosstalk, quality factor and footprint that have been obtained are – 41.5db, 330 and 89.38 μm<sup>2</sup>, respectively, which are superior to earlier reported values. The finite different time domain (FDTD) and plane wave extended (PWE) methods are used to calculate the outputs spectrum and band gap, respectively.
Spectrum properties of apodized fiber Bragg gratings (AFBGs) are well studied, in particular, when there is a need to reduce transmission side lobes. Otherwise, the polarization properties of these gratings are rarely reported when evaluating system performance. We analyze the reflected spectrum, the polarization-dependent loss (PDL), and the differential group delay (DGD) of an AFBG written in a single-mode fiber (SMF28). The evolution of these properties versus the grating parameters is studied based on the coupled mode theory. We mainly focus on the PDL and DGD maximum amplitudes and their wavelength separation. The simulation analysis is developed by means of the transfer matrix method. We demonstrate that the apodization function induces some asymmetry between the left and right parts of the PDL and DGD curves. The maximum amplitudes of the PDL and DGD converge to constant values versus birefringence but increase with grating length.