Demonstration of High Sensitivity Detection and High Precision Localization of Vibrations in Bidirectional Coherent Transmission Systems Enabled by Carrier Laser Phase Noise Retrieval

We demonstrate a method for mitigating the effects of laser phase noise on the detection and localization of vibrations in a bidirectional coherent optical fiber transmission system. By introducing a relative delay between the two frequency tones generated at the transmitter, we retrieve an estimate of the transmitter laser phase noise at the coherent receiver. We demonstrate 200 Gbps, 16 QAM error-free transmission over 80 km while simultaneously detecting and localizing a 3 kHz vibration with 24 rad peak-to-peak phase swing. Compared to conventional methods, our method results in a reduction of localization error by 58%, from 102 m to 43 m, and a reduction in standard deviation of estimated locations by 81%, from 355 m to 67 m.