Integrated communication and polarization sensing in self-homodyne coherent systems

We propose and demonstrate an integrated polarization sensing technique by fully exploiting the adaptive polarization controller (APC) in a self-homodyne coherent (SHC) communication system. By analyzing the APC control signal, the input state of polarization (SOP) can be fully restored. The effect of the polarization tracking results on sensing accuracy is carefully studied in simulation to determine the acceptable SOP rotation speed. We experimentally restore the SOP rotation trajectory using an APC, conduct a comparison with a polarization analysis instrument, and verify its potential as a polarization measurement. Finally, without additional components or burdening digital signal processing (DSP), in-service detections of up to 400-Hz vibration and 2.4-nε micro-strain are achieved in the operated SHC system with 400-Gb/s DP-16QAM transmission.