High-sensitivity on-chip temperature sensor based on cascaded microring resonators

This article proposes an on-chip optical temperature sensor based on a cascaded microring resonator, which is composed of a reference ring and a sensing ring cascaded with different temperature sensitivities and free spectral ranges. By changing the temperature of the sensing window environment, the thermal optical effect of the waveguide causes a change in the refractive index of the waveguide, which affects the temperature sensitivity and free spectrum changes of the sensor. The output spectral response of the sensor shifts, achieving temperature sensing detection. The experimental results show that the temperature sensitivity of this microring cascaded temperature sensor is 303.6 pm/degrees C, which is 3.65 times the limit of a single microring temperature sensitivity of 83 pm/degrees C. The temperature-sensing range of the sensor is 100 degrees C, which can well meet the temperature-monitoring requirements of ultra-large-scale integrated circuits.