Research On On-chip Temperature Sensor Based On Microring Resonator

The temperature monitoring of integrated circuits plays an important role in the efficient operation of the circuit system.At present,the applied temperature sensor has large size and low sensitivity,which can not meet the development needs of micro size and high performance of integrated circuit.Microring Resonator MRR is a widely used multifunctional device in the field of integrated optics.Because of its small size,high integration,low energy consumption and other advantages,it has been widely used and developed in optical communication,optical information processing and other photoelectric fields.In this paper,based on the traditional microring resonator,an on-chip temperature sensor is researched and designed.By constructing a special waveguide structure to increase the coincidence of the optical field and the environment to be measured,and coating the surface of the waveguide with a temperature-sensitive material as a cladding to improve the sensor sensitivity,reducing device size and power consumption.The main contents of the paper are as follows:1.On-chip temperature sensor on long waveguide based on microring resonatorStarting from increasing the coincidence between the environment to be measured and the optical field,a micro-ring waveguide and a racetrack-type waveguide with the same bending radius are cascaded to form an optical waveguide sensor.At different temperatures,the effective refractive index of the sensor waveguide changes under the action of thermaloptic effect,and the length of the waveguide is also affected by thermal expansion effect,resulting in a shift of the spectral resonance peak.When the microring waveguide radius of the sensor is 3.1μm and the straight waveguide of the racetrack waveguide is 9.7μm,the sensitivity of the sensor is 100/℃ through experimental simulation,breaking the limit of single microring sensitivity 83/℃.The free spectral range(FSR)is 39.25 nm and the resolution is 0.47℃,which improves the temperature measurement range and obtains better resolution.2.On chip temperature sensor of cascaded microring resonator based on vernier effectStarting from the complex sensor structure,two microrings with different temperature sensitivity and free spectral range were vertically cascaded as the reference ring and the sensor ring.The reference ring and the cascaded waveguide are covered with Ti O2 with negative thermo-optic coefficient as the upper covering layer,leaving the sensing ring as the sensing window.When the temperature changes,the output spectrum of the sensing ring is shifted due to the influence of thermo-optic effect and thermal expansion effect,and a vernier effect occurs under the action of the two rings to amplify the sensing spectrum shift.When the radius of the cascaded double ring in the sensor structure is 39.52μm and 38.17μm,the experimental sensitivity of the sensor reaches 303.6/℃,which is 3.65 times that of the single microring temperature sensitivity,and the measurement range of the sensor is 100°C.3.Micro ring on-chip temperature sensor based on temperature sensitive claddingStarting from coating the cladding of temperature-sensitive materials,coating temperature-sensitive materials on the sensor waveguide structure to increase the sensitivity of the waveguide to temperature changes.An all-pass micro-ring resonator is used as the basic structure of the sensor,and a layer of ethanol,which is more sensitive to temperature,is coated on the surface of the waveguide as the cladding of the waveguide.The temperature sensitivity of the waveguide structure is increased,and the sensitivity of the sensor is improved.When the designed radius of the sensor is 3.34μm and the coating thickness of the temperature-sensitive material cladding is 0.12μm,the sensitivity of the sensor reaches 105 /℃ through experimental.It has good linearity,and has greatly improved and improved in terms of sensitivity and sensor size.