Optical control of semiconductor device using optical waveguide - has gate region and electrode of FET exposed to light from opening in sheath of superimposed optical fibre or adjacent pair of fibres

摘要

The field-effect transistor with its source (S), gate (G) and drain (D) electrodes is formed on a suitably doped substrate (T) of e.g. GaAs, and controlled by the illumination of its gate region. Its voltage and current may be modulated or its operating point adjusted by light radiated from the core (K) of a leaky optical fibre through a gap in its sheath (M). The device may be integrated monolithically with a strip light guide deposited over the gate and its surroundings, and protected by a coating of lower refractive index. Alternatively two fibres may be arranged side-by-side so as to radiate into the gate region on opposite sides of the electrode.