In this paper

a micro-ring-assisted Mach-Zehnder（M-Z） temperature sensor within micron size is proposed. A liquid micro-ring cavity is coupled to one arm of the M-Z interferometer

and the temperature-sensitive liquid is injected into the cavity based on the microfluidic technique. The temperature change can be detected by analyzing the output spectrum of the sensor. In order to obtain good filtering performances

the arm-length difference of ordinary M-Z filter is usually in the order of millimeters. The arm-length difference of the temperature sensor presented in this paper is only μm micron order. The results show that the proposed sensor has good filtering performances and a temperature resolution. The extinction ratio is more than 10 dB

with 3 dB bandwidth less than 1 nm. The resolution of temperature detection is 0.1 ℃. In addition

the temperature detection range of the sensor can be adjusted by changing the type of liquid in the micro-ring.