A coherent optical data receiver having a digital signal processor (DSP) capable of mitigating equalization-enhanced phase noise (EEPN). In an example embodiment, the DSP mitigates EEPN by applying individual phase adjustments to different spectral slices of a digital stream carrying CD-compensated digital samples of the received optical data signal. In different embodiments, the individual phase adjustments can be dynamically selected based on symbol decisions taken prior to EEPN mitigation, based on transmitted pilot symbols, and/or using moving averages computed for different spectral slices. Some embodiments are suitable for handling polarization-division-multiplexed optical data signals. Some embodiments are advantageously capable of producing an effective SNR gain of approximately 1 dB.