  We demonstrate a silicon photonic dual-polarization phase retrieval receiver.
The receiver recovers phase from intensity-only measurements without a local
oscillator or transmitted carrier. We design silicon waveguides providing long
delays and microring resonators with large dispersion to enable
symbol-to-symbol interference and dispersive projection in the phase retrieval
algorithm. We retrieve the full field of a polarization-division multiplexed
30-GBd QPSK and 20-GBd 8QAM signals over 80 km of SSMF.
