Patent attributes
An optical coupler includes a first waveguide configured to supply a first optical signal having a wavelength and a second waveguide. The first optical signal having a first mode. The first waveguide has a tapered portion being spaced from the second waveguide by a distance sufficient to facilitate evanescent coupling of the first optical signal from the first waveguide to the second waveguide. A first effective refractive index of the first waveguide at a location in the tapered portion being equal to a second effective refractive index at a location in the second waveguide. The first effective refractive index being associated with the first mode and the second effective refractive index being associated with a second mode of a second optical signal having the wavelength. The second mode having a different order than the first mode, and the second waveguide being configured to supply the second optical signal.
