US Patent 6987908 Grating dispersion compensator and method of manufacture

A grating dispersion compensator (GDC), including: a substrate; a dielectric grating layer; a planar waveguide; and a passivation layer. The dielectric grating layer may be formed on the substrate and includes a variation in refractive index. This variation in refractive index defines a grating period. The grating period may vary along the longitudinal axis of the GDC according to a predetermined function. A selected center wavelength and dispersion curve may be created. The chirp of the grating period may be controlled by current, voltage, temperature, or pressure. The planar waveguide is formed on the dielectric grating layer and includes an input/output (I/O) surface normal to the longitudinal axis of the planar waveguide. The passivation layer is formed on the planar waveguide. Alternatively, a GDC may be formed with the dielectric grating layer on top of the planar waveguide rather then beneath it.