EFFECT OF CAPACITATIVE IMBALANCE ON COMMON-MODE REJECTION OF BALANCEDPHOTODETECTOR PAIRS

The Letter shows that the common-mode rejection ratio of balanced phot odetector pairs, as used for coherent lightwave reception, is insensit ive to capacitance differences between the detectors in the absence of parasitic series impedance. These results indicate that balanced perf ormance can be achieved in high-speed detector pairs, even when a capa citance imbalance occurs. The effect of detector series resistance or inductance on common mode rejection is quantitatively analysed.