Dual-channel fiber optic current sensor based on carrier-transposed demodulation technique

Abstract

A dual-channel fiber optic current sensor based on carrier-transposed demodulation technique is proposed and experimentally demonstrated. The system is implemented by adding another sensing channel to a standard reflective fiber optic current sensor, which shares numerous key optical devices without much additional expense. The output properties of the system are theoretically analyzed and numerically investigated to demonstrate the feasibility of independent current measurement at different operating frequencies. And the current sensitivity can be flexibly adjusted by changing the modulation amplitude. Based on the carrier-transposed demodulation technique, the current sensing information of both channels can be obtained independently and the cross-talk between them can be eliminated tactfully. The experimental results demonstrate that the current measurements for both channels are well independent and the channel-to-channel influences is relatively low with the standard deviation of 0.0197 mV and 0.0141 mV, respectively. The proposed scheme provides a promising approach for dual-channel current measurement with the advantages of compactness and simplicity and can be applied in practical applications without much additional cost.