Optically controlled rat-race coupler on silicon substrate

This paper presents an optically controlled microstrip rate race coupler fabricated on silicon substrate. Optically controlled can be realized by creating an optically induced load termination by a laser spot at the open end of controlling ports in rat-race coupler. To simulate the transmission behavior of proposed structure, the optically induced load at the open end of the port has been modeled as a resistive termination. The simulation and experimental results show that the phase and amplitude of the RF signal can be controlled by optical terminations at different intensities and can be used as an optically controlled reflection type RF phase shifter and attenuator.