Switched optoelectronic microwave load

The paper presents the analysis of a switched optoelectronic microwave load which can work either as a laser-controlled, matched or adjustable, resistive load or as a high-speed optoelectronic microwave switch. The device consists of a GaAs microstrip section controlled by a pulse-operated laser diode via substrate-edge-excitation. The exponential decay of photoconductivity across a longitudinal section of the microstrip forms a laser-induced electron-hole plasma wedge that works as a lossy tapered transmission-line section. The specific microwave power distribution within the excited region is derived in detail, as is the total input reflection coefficient under two special operating conditions (open-ended section and matched section). Numerical results are presented for a 906 nm excitation.