Dispersion Tailoring of the Quarter-Wave Bragg Reflection Waveguide

We present analytical formulae for the polarization dependent first- and second-order dispersion of a quarter-wave Bragg reflection waveguide (QtW-BRW). Using these formulae, we develop several qualitative properties of the QtW-BRW. In particular, we show that the birefringence of these waveguides changes sign at the QtW wavelength. Regimes of total dispersion corresponding to predominantly materialdominated and waveguide-dominated dispersion are identified. Using this concept, it is shown that the QtW-BRW can be designed so as to provide anomalous group velocity dispersion of large magnitude, or very small GVD of either sign, simply by an appropriate chose of layer thicknesses. Implications on nonlinear optical devices in compound semiconductors are discussed

Properties of the Quarter-Wave Bragg Reflection Waveguide: Theory

The Bragg reflection waveguide (BRW), or one-dimensional photonic crystal waveguide, has recently been proposed for a wide spectrum of applications ranging from particle acceleration to nonlinear frequency conversion. Here, we conduct a thorough analytical investigation of the quarter-wave BRW, in which the layers of the resonant cladding have a thickness corresponding to one quarter of the transverse wavelength of a desired guided mode. An analytical solution to the mode dispersion equation is derived, and it is shown that the quarter-wave BRW is polarization degenerate, although the TE and TM mode profiles differ significantly as the external Brewster’s angle condition in the cladding is approached. Analytical expressions for waveguide properties such as the modal normalization constants, propagation loss, and overlap factors between the mode and each waveguide layer are derived, as are dispersion and tuning curves

Novel, congenital iliac arterial anatomy: Absent common iliac arteries and left internal iliac artery.

Congenital anomalies of the iliac arterial system are rare and can be associated with ischemia. With an increase in vascular imaging and interventions, such anomalies are likely to be encountered with greater frequency. We present the case of a 25-year-old female who was incidentally found to have absence of the common iliac arteries bilaterally and the left internal iliac artery, a constellation not previously reported in the literature. We present relevant imaging findings, review embryonic vascular development, and discuss potential clinical implications