Radio-Frequency Intensity Interrogation for Temperature Measurement

In this letter, an optical-carrier microwave interferometer based on radio frequency Mach-Zehnder (RF-MZI) structure for temperature measurement is numerically investigated and experimentally demonstrated. The input RF signal travels along with the optical carrier to experience different phase differences caused by the applied temperature, leading to the intensity change of the RF signal. Thus, by tracking the RF intensity variation, the temperature can be recovered. Furthermore, the sensitivity affected by the power ratio between two arms of the RF-MZI is investigated for the first time. Results show that the sensing character is associated tightly with the selected initial phase difference. In the approximately linear region, the sensitivity can be enhanced ~2.79 times when the power ratio improved from 0.25 to 0.84.