Use of depressed index cladding layers to tailor the chromatic dispersion and birefringence of planar geometry waveguides

We numerically compute the chromatic dispersion and birefringence of a rectangular channel waveguide having a depressed index inner cladding. We assume the materials in the core and outer cladding of the waveguide to be doped silica glasses, whereas we take the inner cladding material to be either a doped silica glass or a polycrystalline fluoride, e.g., CaF/sub 2/ or MgF/sub 2/. Planar lightguide circuits (PLC's) based on such waveguides have application for wavelength or dense wavelength division multiplexing (WDM/ DWDM) in optical fiber transmission systems. Some of the described structures have application in polarization maintaining waveguide devices.