A new fiber self-mixing temperature sensor with phase compensation for harmonic vibrations

Abstract A new fiber temperature sensor is proposed based on dual-longitudinal mode laser self-mixing interference effect in a distributed Bragg reflector fiber laser. The temperature analytical model is established by use of the three-mirror cavity model and the interference superposition theory of the multi-longitudinal mode laser. It is indicated that this preferable model is sufficient to real-time track the change of the self-mixing signal waveform resulting from the ambient temperature variation by means of the phase compensation method and the waveform separation phenomena. Furthermore, the experimental measurements show that the relative error can be lower to 1.43% corresponding to 4.95 × 10-4 m/°C of the temperature sensitivity ranging from 20.14 to 46.02 °C. It has demonstrated that the measured results are in good consistent with the reference values, thereby which this sensor proves capable of measuring ambient temperature with high sensitivity and accuracy.