Direct refractive index measurement technique to observe waveguide dispersion characteristics of short waveguides utilising the higher order modes of integrated Bragg grating structures

A dispersion measurement technique has been developed for short planar waveguides utilising integrated Bragg grating structures within the waveguide itself. By fabricating numerous Bragg gratings over a wide range of central wavelengths within a short planar waveguide, a direct refractive index measurement of the waveguide at these wavelengths can be carried out, and the chromatic dispersion characteristics of the waveguide obtained.