Optical device having optical waveguide including organic Bragg grating sheet

An optical device used as a tunable wavelength filter or a tunable dispersion compensator, the optical device comprising:

• a cladding layer formed on a substrate;
• an optical waveguide formed within the cladding layer;
• and
• a thermal electrode formed on the optical waveguide,
• wherein the optical waveguide comprises a lower core layer, an upper core layer, and an organic Bragg grating sheet including a residue layer and bars on the residue layer located between the upper core layer and the lower core layer,
• the organic Bragg grating sheet comprises a residue layer and bars on the residue layer in which the residue layer has a thickness greater than zero and less than a thickness of the bars such that the thickness of the residue layer is adjusted to effectively control the effective refractive index of the entire organic Bragg grating sheet,
• the refractive index of the entire organic Bragg grating sheet is higher than the refractive index of the core layer,
• the organic Bragg grating sheet has a thickness not exceeding one half of the entire thickness of the core layer, and
• the organic Bragg grating sheet has a refractive index higher than the refractive indices of the upper and lower core layers to reflect or transmit light having a predetermined wavelength.