Resonance in Link RF Gain by Negative Photocurrent Resistance of Electroabsorption Modulator Under Very High Optical Power

We examine the photocurrent effect in the electroabsorption modulator (EAM) under very high optical power and investigate its implication in the link radio-frequency (RF) gain. After reviewing the effect of the photocurrent in the EAM, using the voltage-source model with the device capacitance included, we demonstrate a possibility that the RF gain can be enhanced by resonance due to the photocurrent if the photocurrent decreases with device bias, exhibiting negative differential resistance. We explore an EAM with intrastep quantum wells showing blueshift to achieve the negative photocurrent resistance and demonstrate a case where an enhancement in the link RF gain is possible.