Temperature sensor based on series double micro-ring resonant cavities

Abstract

The invention relates to a temperature sensor based on a series double micro-ring resonant cavity, which is connected with an input light source, and comprises a series double micro-ring resonator which is connected with the input light source through an input grating coupler and is connected with a photoelectric detector through an output grating coupler; the series double-micro-ring resonator is provided with a first micro-ring resonant cavity and a second micro-ring resonant cavity which are different in perimeter. By introducing the design of the series double micro-ring resonant cavities with different waveguide widths and radiuses, the sensitivity of temperature sensing is improved.

Description

Technical Field

[0001] The invention relates to the technical field of temperature sensors, and in particular to a temperature sensor based on a series double micro-ring resonant cavity. Background Art

[0002] Temperature sensors play an important role in a variety of applications due to their high accuracy, stability and convenience. However, their high cost and slow response time limit their wider application. As an emerging technology, optical waveguide temperature sensors stand out for their high sensitivity, low cost and ease of manufacturing. This sensor uses an optical waveguide structure to detect temperature by monitoring changes in the spectrum, showing excellent linear response and high resolution. Optical waveguide temperature sensors have great application potential in fields such as precision sensing, indicating their important position in future temperature monitoring technology. The anti-electromagnetic interference ability of optical waveguide technology enables it to show better stability and reliability in harsh environments, providing a new direction for the development of temperature sensors.

[0003] Optical waveguide sensors based on SOI (Silicon-On-Insulator) technology include the design of micro-ring resonant cavities. Since the silicon waveguide core has a large positive thermo-optic coefficient, this feature ensures that silicon-based optical waveguide sensors have significant advantages and broad application prospects in temperature sensing applications. At present, the demand for high-sensitivity temperature sensors is still very urgent because they play a key role in improving measurement accuracy and response speed.

[0004] In view of the above technical problems, an improved technical solution is proposed. Summary of the invention

[0005] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is: a temperature sensor based on a series double microring resonant cavity, connected to an input light source, comprising:

[0006] A series double micro-ring resonator, wherein the series double micro-ring resonator is connected to an input light source via an input grating coupler and is connected to a photodetector via an output grating coupler;

[0007] The series double microring resonator is provided with a first microring resonant cavity and a second microring resonant cavity with different circumferences.

[0008] Preferably, the series dual microring resonator is further provided with a coupled input waveguide and a coupled output waveguide; the coupled input waveguide is connected to an input grating coupler, and the coupled output waveguide is connected to an output grating coupler.

[0009] Preferably, the transmission mode of the waveguide adopts TE polarization mode.

[0010] Preferably, the upper cladding of the series double microring resonant cavity is made of silicon dioxide.

[0011] Preferably, the input light source is a tunable laser.

[0012] Preferably, the sensitivity of the series dual microring resonator to temperature changes is:

[0013] S=F1S1+F2S2

[0014] Among them, F1 and F2 represent the vernier magnification factors of the two microrings, F1 = FSR2 / (FSR2-FSR1),

[0015] F2 = FSR1 / (FSR1-FSR2), FSR1 and FSR2 are the free spectral ranges of the two microrings, and S1 and S2 are the sensitivity of the two microrings to temperature respectively.

[0016] Preferably, the tunable laser detects the transmission spectrum in the wavelength range of the CL band.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The sensitivity of temperature sensing is improved by introducing a series double microring resonant cavity design with different waveguide widths and radii. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the temperature sensor in the present invention;

[0020] Figure 2 A schematic diagram of the change in the temperature waveguide sensitivity corresponding to different waveguide widths in the present invention;

[0021] Figure 3 A graph showing changes in the output transmission spectrum of the sensor of the present invention as the temperature changes;

[0022] In the figure: 1. tunable laser; 2. series dual microring resonator; 21. input grating coupler; 22. coupled input waveguide; 23. first microring resonator; 24. second microring resonator; 25. coupled output waveguide; 26. output grating coupler; 3. photodetector. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example:

[0025] like Figures 1 to 3 As shown, the present invention provides a technical solution: a temperature sensor based on a series double micro-ring resonator, connected to an input light source, the input light source adopts a tunable laser 1, and the tunable laser 1 detects a transmission spectrum in the wavelength range of the CL band. The tunable laser 1 provides input light for the temperature sensor.

[0026] include:

[0027] The series double microring resonator and the series double microring resonator cavity 2 are key devices for converting temperature sensing signals into optical signals.

[0028] The series double micro-ring resonator 2 is connected to the tunable laser 1 via an input grating coupler 21 , and the series double micro-ring resonator 2 is connected to a photodetector 3 via an output grating coupler 26 , and the photodetector 3 collects and extracts spectral information.

[0029] The series double microring resonant cavity 2 is provided with a first microring resonant cavity 23 of a silicon dioxide upper cladding and a second microring resonant cavity 24. The first microring resonant cavity 23 and the second microring resonant cavity 24 are key components for generating a vernier effect for temperature sensing.

[0030] The series double microring resonator 2 is further provided with a coupled input waveguide 22 and a coupled output waveguide 25 ; the coupled input waveguide 22 is connected to the input grating coupler 21 , and the coupled output waveguide 25 is connected to the output grating coupler 26 .

[0031] The working method of the temperature sensor based on the series double microring resonator includes: the light of the tunable laser 1 enters the coupled input waveguide 22 through the input grating coupler 21, the light passes through the three coupling regions in the first microring resonator 23 and the second microring resonator 24 in turn, and enters the coupled output waveguide 25; the light is output to the photodetector 3 through the output grating coupler 26, and finally the experimental data is collected and processed by a computer.

[0032] The transmission mode of the optical waveguide adopts the TE polarization mode. The silicon waveguide in the TE polarization mode has a larger thermo-optic coefficient, which helps to improve the sensitivity of temperature sensing. The optical waveguide structure of this embodiment adopts a rectangular waveguide made on an SOI platform, and the waveguide height is 220nm.

[0033] When the first microring resonant cavity 23 and the second microring resonant cavity 24 correspond to different waveguide widths, the temperature influence on the sensor is different.

[0034] When the external temperature changes, the effective refractive index of the waveguide will also change. The rate of change is the temperature waveguide sensitivity. The temperature waveguide sensitivities of the two microrings are expressed as St1 and St2 respectively.

[0035] like Figure 2 As shown, the temperature waveguide sensitivity corresponding to different waveguide widths is demonstrated. The widths of the two micro-ring waveguides in the present invention are selected to be 500 and 650 nm. When the waveguide width increases, the waveguide sensitivity of temperature sensing decreases.

[0036] In the sensing process, the two microrings can obtain a greater temperature sensing sensitivity due to the vernier effect. The waveguide width and radius of the first microring resonant cavity 23 and the second microring resonant cavity 24 are designed differently. The sensitivity of the series dual microring resonant cavity 2 to temperature changes is:

[0037] S=F1S1+F2S2

[0038] Among them, F1 and F2 represent the vernier magnification factors of the two microrings, F1 = FSR2 / (FSR2-FSR1),

[0039] F2 = FSR1 / (FSR1-FSR2), FSR1 and FSR2 are the free spectral ranges of the two microrings, and FSR itself stands for free spectral range, a commonly used abbreviation.

[0040] S1 and S2 are the temperature sensitivities of the two microrings, respectively.

[0041] Where FSR1 = λ 2 / (L1×ng); S1=St1×λ / ng, L1 represents the circumference of the first microring resonator 23, λ and ng represent the wavelength and the group refractive index respectively, the size of St1 is mainly related to the waveguide structure, and the subscript 1 represents the first microring resonator 23. The calculation formulas of FSR2 and S2 are the same as FSR1 and S1 of the first microring resonator 23.

[0042] Assuming that the radii of the two microrings are 150 μm and 157.5 μm, respectively, and the waveguide widths are 500 nm and 650 nm, respectively, the temperature waveguide sensitivities are 1.99×10 -4 and 1.945×10 -4 , the group refractive indices corresponding to the temperature of 300K at a wavelength of 1550nm are 4.239 and 4.048, and the effective refractive indices are 2.448 and 2.607 respectively.

[0043] like Figure 3 As shown, when the temperature increases by ΔT=10K, the resonance peak envelope of the transmission spectrum red-shifts. By collecting the change in the envelope peak wavelength Δλ, the sensitivity can be calculated to be Δλ / ΔT, generally in units of nm / K.

[0044] In order to increase the overall sharpness of the transmission spectrum envelope, the coupling coefficients of the three coupling regions of the series double microring resonator 2 are set to 0.65, 0.24 and 0.65 respectively.

[0045] The temperature sensing sensitivity shown in the figure is 682nm / K. In addition, higher sensitivity can be achieved by designing different waveguide widths and micro-ring radii.

[0046] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A temperature sensor based on a series double micro-ring resonant cavity, connected to an input light source, characterized in that: include: A series double micro-ring resonator, wherein the series double micro-ring resonator is connected to an input light source via an input grating coupler and is connected to a photodetector via an output grating coupler; The series double microring resonator is provided with a first microring resonant cavity and a second microring resonant cavity with different circumferences.

2. The temperature sensor based on the series double microring resonant cavity according to claim 1 is characterized in that: The series double microring resonator is also provided with a coupled input waveguide and a coupled output waveguide; the coupled input waveguide is connected to the input grating coupler, and the coupled output waveguide is connected to the output grating coupler.

3. The temperature sensor based on the series double microring resonant cavity according to claim 2 is characterized in that: The transmission mode of the waveguide adopts TE polarization mode.

4. The temperature sensor based on the series double microring resonant cavity according to claim 1 is characterized in that: The upper cladding of the series double microring resonator is made of silicon dioxide.

5. The temperature sensor based on the series double microring resonant cavity according to claim 1 is characterized in that: The input light source is a tunable laser.

6. The temperature sensor based on the series double microring resonant cavity according to claim 5 is characterized in that: The sensitivity of the series dual microring resonator to temperature changes is: S=F1S1+F2S2 Among them, F1 and F2 represent the vernier magnification factors of the two microrings, F1 = FSR2 / (FSR2-FSR1), F2 = FSR1 / (FSR1-FSR2), FSR1 and FSR2 are the free spectral ranges of the two microrings, and S1 and S2 are the sensitivity of the two microrings to temperature respectively.

7. The temperature sensor based on the series double microring resonant cavity according to claim 5 is characterized in that: The tunable laser detects the transmission spectrum in the wavelength range of the CL band.

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