Analysis of a high-speed laser-controlled microstrip directional coupler

Abstract

A new type of high-speed optoelectronic microwave device is proposed and analyzed. The device is a laser-controlled microstrip directional coupler that utilizes the photoconductivity produced by laser illumination. The analysis, which is based on the even and odd mode approach, shows that several important advantages over conventional microstrip directional couplers are obtained. The device is capable of controlling the coupling parameters with a controlling range which varies at different ports but is at least 3 dB. Moreover, a comparison with conventional microstrip directional couplers shows that when illuminated, an improved bandwidth of more than 50% is achieved.