New design and analysis of Bragg grating waveguides.

New design of optical waveguides is presented to synthesize Bragg grating waveguides without inducing birefringence. In the design, waveguide core has a thin trench on the top surface of the core and width of the trench is modulated concurrently with width modulation of the waveguide core. Effective refractive index profiles in Bragg grating waveguides are obtained by a differential inverse scattering algorithm and converted to waveguide width profiles by using the new core design.

Warm-white light-emitting diode with yellowish orange SiALON ceramic phosphor.

A warm-white light-emitting diode (LED) without blending of different kinds of phosphors is demonstrated. An approach that consists of a blue LED chip and a wavelength-conversion phosphor is carried out. The phosphor is a newly developed yellowish orange CaEuSiAlON ceramic phosphor with high efficiency.