A bidirectional switch includes a plurality of unit cells 11 including a first ohmic electrode 15, a first gate electrode 17, a second gate electrode 18, and a second ohmic electrode 16. Each of the light emitting units includes a light source and a light converging element. Further, a connector is mounted on opposing faces of the frame. The two electrode rods penetrate the two through holes, respectively. The definitions combine to form a model element with the structural physical parameter using structural variables, and behaviors, that can be defined functionally. The smaller second sidewall spacers facilitate compliance with design rules by allowing source and drain contacts to be formed closer to the gate structure.