Patent ID: 6865319

Claim:
An optical structure for the compensation of chromatic dispersion in a light signal having a plurality of wavelength channels, each wavelength channel having accumulated a different chromatic dispersion, said optical structure comprising: an optical waveguide having a light propagation axis; and a Bragg grating provided in said waveguide across the light propagation axis, said Bragg grating having a plurality of grating components each of said components being associated with a limited number of said wavelength channels and having a spatially variable period chosen to compensate for the chromatic dispersion of said limited number of wavelength channels, said Bragg grating defining a longitudinal refractive index profile in said waveguide as defined by the equation: n ⁢ ( z ) = n eff ⁢ ( z ) + ∑ i = 1 m ⁢ Δ ⁢ ⁢ n i ⁢ ( z ) ⁢ sin ⁡ ( ∫ 0 z ⁢ 2 ⁢ π p i ⁡ ( z ′ ) ⁢ ⁢ ⅆ z ′ + ϕ i ) where z is the propagation axis of the waveguide, n eff (z) is the average effective index in the waveguide considered slowly varying along the propagation axis, m is the number of grating components in the Bragg grating, Δn i (z) is the spatially dependent index modulation amplitude of a i th grating component, p i (z) is the spatially variable period of the i th grating component and φ i is a relative phase associated with the i th grating component.