Abstract: In an optically controlled thyristor having a four layer thyristor structure with respective first, second, third and fourth layers, the first and third layers have a first doping type, and the second and fourth layers have a second doping type different from the first doping type. A first shorting structure, formed from a semiconductor material of opposite doping from the first layer, is electrically coupled to the second layer by an electrically conducting, optically opaque layer. A first conductive layer connects between the first layer and the shorting structure and is adapted to transmit light into the first shorting structure. The first semiconductor layer of an optically controlled thyristor may have an aperture therethrough to permit light to enter the second layer from a first conductive layer side without propagating within the first layer.