An optoelectronic attenuator for the control of microwave circuits

An optoelectronic technique suitable for the control of microwave circuits has been demonstrated. using a coplanar waveguide-photoconductive switch (CPW-PCS), the RF impedance is varied by using a laser diode to create a conductive plasma in the switch gap. With a fiber pigtailed AlGaAs laser diode and a silicon CPW-PCS, 30 dB of RF attenuation was achieved with a laser peak power of 375 mW. Intensity saturation of the Si:CPW-PCS was also observed and characterized to improve the attenuator performance.<
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