Abstract: A method of mode selective coupling or mode multiplexing between integrated multimode (600) and single mode (602) waveguides. Evanescent coupling and tapering is used so that the signal may be transferred adiabatically from a first region of a first waveguide to a second, proximal, region of a second waveguide.

Abstract: An optical switching device for switching M input signals into N output signals, wherein M and N are each equal to or greater than one, including a mode division multiplexer to join the M input signals into a first multi-mode signal having M initial modes, a mode converter to convert the first multi-mode signal into a second multi-mode signal having N converted modes, and a mode division demultiplexer to separate the second multi-mode signal into the N output signals, wherein the converter is able to be controllably activated such that the N converted modes are separated by the demultiplexer to the N output signals according to a desired scheme.

Abstract: A mode conversion apparatus including a dynamic waveguide section associated with a plurality of control elements that, when activated, are able to produce a periodic refractive-index perturbation pattern in the dynamic waveguide section, wherein the periodic refractive-index perturbation pattern is able to convert at least a fraction of an input signal from a first guided mode of the dynamic waveguide section into a second guided mode of the dynamic waveguide section.

Abstract: A method of mode selective coupling or mode multiplexing between integrated multimode (600) and single mode (602) waveguides. Evanescent coupling and tapering is used so that the signal may be transferred adiabatically from a first region of a first waveguide to a second, proximal, region of a second waveguide.

Abstract: An optical switching device for switching M input signals into N output signals, wherein M and N are each equal to or greater than one, including a mode division multiplexer to join the M input signals into a first multi-mode signal having M initial modes, a mode converter to convert the first multi-mode signal into a second multi-mode signal having N converted modes, and a mode division demultiplexer to separate the second multi-mode signal into the N output signals, wherein the convener is able to be controllably activated such that the N converted modes are separated by the demultiplexer to the N output signals according to a desired scheme.

Abstract: A mode conversion apparatus including a dynamic waveguide section associated with a plurality of control elements that, when activated, are able to produce a periodic refractive-index perturbation pattern in the dynamic waveguide section, wherein the periodic refractive-index perturbation pattern is able to convert at least a fraction of an input signal from a first guided mode of the dynamic waveguide section into a second guided mode of the dynamic waveguide section.

Abstract: The invention is a waveguide structure (10) that includes two waveguides (90, 94) flanking a coupling region (92) whose effective refractive index is less than those of the waveguides. Outboard of the waveguides are bounding regions (88, 96) whose effective refractive indices decrease inwards adiabatically at the proximal and distal ends of the bounding regions. The waveguides are coupled optically by periodic perturbations of the waveguide geometry, or by reversible uniform or periodic perturbations of the effective refractive indices. In an optical switch matrix based on the waveguide structure, all the waveguides are straight and parallel. A second aspect of the invention is a directional coupler comprising mechanisms for reversibly and quasiperiodically perturbing the effective refractive indices of the waveguides. The respective envelope functions vary monotonically in opposite senses.