An electro-optically coupled switch includes first and second waveguides which are aligned in parallel to each other, with a thin, flat layer of cross-coupling material sandwiched therebetween. A voltage source is provided to establish a strong uniform electric field that is oriented perpendicular across the entire layer of cross-coupling material between the waveguides. Incorporated with the voltage source is a switch for changing the electric field, to thereby alter the refractive index of the cross-coupling material for transferring the transmission of an optical signal from one waveguide to the other.

The present invention relates to a method of forming a graphene-containing laminate, the method comprising: providing a first graphene layer structure on a substrate; forming a first metal oxide layer on the graphene layer structure by depositing and then oxidising a layer of metal; forming a second metal oxide layer on the first metal oxide layer; and forming a second graphene layer structure on the second metal oxide layer by CVD.

An acousto-optic modulator that includes a waveguide on an acoustic actuator is disclosed. The waveguide carries an optical signal having a UV or visible wavelength. When the acoustic actuator is activated, the optical signal in the waveguide is bathed in intense acoustic waves. By using a waveguide having the appropriate dimensions to strongly confine both the optical signal and the acoustic waves, strong optomechanical coupling may be achieved between the optical and acoustic modes, resulting in an efficient modulator. By employing either intra-modal or inter-modal conversion, the modulator may be used to implement a variety of dual- or single-sideband functions, including an isolator, a phase modulator, a single-sideband frequency shifter, or a high-extinction shutter.