Investigation of Co-Cable Identification Based on Ultrasonic Sensing in Coherent Systems

A novel fiber co-cable recognition method based on fiber-optic acoustic sensing and digital coherent receivers is proposed for fiber-optic cable management in telecom networks. By utilizing ultrasound to stimulate the fiber-optic cable and distinguishing the distinct vibration features in coherent receivers, fibers within the same cable are recognized. The vibration features are tracked and extracted using the carrier phase estimation (CPE) algorithm in the digital receiver, and a multi-segment fitting-based frequency offset estimation (FOE) algorithm is introduced for continuous phase compensation. Both theoretical analysis and experiments have validated the feasibility of recognizing the features. Experimental results demonstrate a phase sensitivity of 0.09 rad using 100-kHz lasers and 30-kHz ultrasound. It is promising that the method is suitable for integration into optical pluggable modules to extend functionality.