Various technologies for performing discrete-variable (DV) quantum key distribution (QKD) with integrated electro-optical circuits are described herein. An integrated DV-QKD system uses Mach-Zehnder modulators (MZMs) to modulate a polarization of photons at a transmitter and select a photon polarization measurement basis at a receiver. A transmitter of a DV-QKD system further uses phase shifters to correct for non-idealities of the MZM in output provided to a polarization beam splitter. A receiver of a DV-QKD system can use phase shifters between a polarization beam splitter and an MZM to correct for non-idealities of the polarization beam splitter and the MZM on the receiver side.