abstract |
The present invention relates to an optical waveguide coupler device. As shown in FIG. 1 , the optical waveguide coupler device 8 comprises two optical waveguide cores 2, 3 formed on the surface of a substrate 1 . The optical waveguide cores 2, 3 are covered by lower and upper cladding layers 6, 7 both formed on the substrate 1 ; and the two optical waveguide cores 2, 3 are brought close to and in parallel with each other at two sites to form two directional couplers 4, 5 there. The cross-section and refractive index of each of the optical waveguide cores 2, 3 and the parameters of other elements of the circuit are optimized such that an optical signal is reliably routed by the circuit without undergoing a wavelength shift even when the circuit is exposed to the changes of polarization and ambient temperature. |