Controllable optical device

A controllable optical device comprising

• a layer stack comprising at least two materials,
• at least two electrical contacts,
• wherein the said at least two materials in the said layer stack are substantially optically transparent in at least one operation wavelength of the device, at least one of the said at least two electrical contacts comprises material which is substantially optically transparent in at least one operation wavelength of the device and is electrically conductive, at least one of the said at least two materials in said layer stack is exhibiting Pockels effect which is used to introduce an optical function in the said controllable optical device by applying an electric field across the said at least one material in said layer stack exhibiting Pockels effect along at least one direction, and wherein the controllable optical device further comprises at least one periodically poled section comprising at least one domain inversion providing sum-frequency generation in at least one output wavelength, characterized in that the device further comprises an adiabatic and asymmetric y-branch coupler further comprising tilted grating for each channel for reflecting light, wherein the tilted grating further acts as a mode converter, and wherein all channels are coupled to the narrower port of the y-branch after reflection.