CN217878071U - Whispering gallery mode temperature sensor - Google Patents

Abstract

The utility model relates to a whispering gallery mode temperature sensor. A whispering gallery mode temperature sensor, comprising: the optical fiber comprises a multi-core optical fiber, an optical wave input structure, an optical wave output structure, an optical waveguide, a microsphere base and microspheres. The multi-core optical fiber is internally provided with a plurality of fiber cores for transmitting signal light; the optical waveguide is connected between the optical wave input structure and the optical wave output structure; the microsphere base is arranged on the end face; the microsphere is arranged on the microsphere base, a microsphere cavity is arranged in the microsphere, and the microsphere is mutually coupled with the optical waveguide. Above-mentioned whispering gallery mode temperature sensor has characteristics such as the space demand is little, the measurement accuracy is high, can adapt to the temperature detection under the narrow and small environment in space.

Description

Whispering gallery mode temperature sensor

Technical Field

The utility model relates to the field of optical technology, especially, relate to a whispering gallery mode temperature sensor.

Background

When detecting the ambient temperature, the existing temperature detection methods generally include a liquid thermometry method, a thermocouple thermometry method, a resistance thermometry method, an infrared thermometry method, and the like. With the continuous and gradual widening of the research on the optical devices, the optical devices are also gradually applied to temperature measuring equipment. The whispering gallery mode microcavity technology is a technology for realizing sensing by utilizing the characteristic that the whispering gallery mode resonant wavelength of a high-quality factor of a microcavity has high-sensitivity response to external stimuli, and particularly, when light waves propagate in a microspherical resonant cavity and the incident angle is larger than the critical angle of total reflection, the light is limited in the microspherical cavity to form a closed whispering gallery mode. The device for sensing temperature in the whispering gallery mode generally requires a larger coupling device to couple the spherical resonant cavity with the detection area, however, the larger coupling device is difficult to be applied to detection in a narrow space environment due to a larger volume when sensing detection is performed.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide a whispering gallery mode temperature sensor in order to solve the problem of the large size of the conventional whispering gallery mode sensing device.

A whispering gallery mode temperature sensor, comprising:

the optical fiber comprises a multi-core optical fiber, a plurality of optical fibers and a plurality of optical fiber cores, wherein the multi-core optical fiber is internally provided with the optical fibers for transmitting signal light;

one end face of the multi-core optical fiber is provided with a light wave input structure, a light wave output structure and an optical waveguide, wherein the light wave input structure and the light wave output structure respectively and correspondingly cover any two fiber cores of the multi-core optical fiber, and the optical waveguide is connected between the light wave input structure and the light wave output structure;

a microsphere base disposed on the end face;

the optical waveguide comprises a microsphere, wherein the microsphere is arranged on the microsphere base, a microsphere cavity is arranged in the microsphere, and the microsphere and the optical waveguide are mutually coupled.

According to the whispering gallery mode temperature sensor, the light wave input structure, the light wave output structure, the light waveguide, the microsphere base and the micro funnel are arranged on the end face of the multi-core optical fiber, so that the space required by the whispering gallery mode temperature sensor can be effectively reduced, the high-efficiency coupling of the light wave input structure, the light wave output structure and the multi-core optical fiber can be realized, and the utilization efficiency of signal light in the multi-core optical fiber and the measurement accuracy of the whispering gallery mode temperature sensor can be improved; the optical wave input structure and the optical wave output structure respectively correspond to any two fiber cores of the covered multi-core optical fiber, so that the high-efficiency coupling of the optical wave input structure, the optical wave output structure and the multi-core optical fiber can be realized, the information utilization rate in the multi-core optical fiber is improved, and the measurement stability of the whispering gallery mode temperature sensor is improved; through mutual coupling between the optical waveguide and the microsphere, evanescent waves formed by light rays outside the optical waveguide can be coupled into the microsphere cavity and form resonance in the microsphere cavity, and then a whispering gallery mode of the microsphere cavity is excited, so that temperature can be detected; set up in the micro-funnel through the microballon, the equipment of microballon and microstructure can be convenient for, and the micro-funnel also can play simultaneously and utilize surface tension to inhale the effect to the microballon outside with liquid, increases the area of contact of microballon and solution to promote echo wall mode sensor's detection efficiency and detection accuracy. Above-mentioned whispering gallery mode temperature sensor has characteristics such as the space demand is little, the measurement accuracy is high, can adapt to the temperature detection under the narrow and small environment in space.

In one embodiment, the whispering gallery mode temperature sensor further comprises a micro-funnel, wherein the micro-funnel is erected on one side of the microsphere base away from the end face; the microspheres are assembled to the microsphere seat through the micro-funnel.

In one embodiment, the whispering gallery mode temperature sensor further comprises a micro-funnel outer wall surrounding the micro-funnel.

In one embodiment, the optical wave input structure and the optical wave output structure each include a micro-cylinder, a total reflection prism, and a micro-pyramid connected in sequence, one end of the micro-cylinder is connected to the fiber core, and a small end of the micro-pyramid is connected to one end of the optical waveguide.

In one embodiment, the included angle between the reflecting surface of the total reflection prism and the end surface ranges from 30 degrees to 60 degrees.

In one embodiment, the reflecting surface of the total reflection prism is provided with a metal film.

In one embodiment, the thickness of the metal thin film is in the range of 100nm to 300nm; and/or the presence of a gas in the gas,

the metal film is made of gold.

In one embodiment, the whispering gallery mode temperature sensor further includes a micro-funnel outer wall surrounding the micro-funnel.

In one embodiment, the number of the cores in the multicore fiber is 6-8.

In one embodiment, the distance between the optical waveguide and the microsphere ranges from 0.8 μm to 1.2 μm; and/or the presence of a gas in the gas,

the distance between the microspheres and the end face ranges from 4 μm to 6 μm.

In one embodiment, the cross section of the optical waveguide perpendicular to the length direction is rectangular, and the distance between the optical waveguide and the end face is in a range of 18 μm to 20 μm.

In one embodiment, the light wave input structure, the light wave output structure, the light waveguide, the microsphere base and the micro funnel are made of photoresist materials.

Drawings

FIG. 1 is a schematic diagram of a partial structure of a whispering gallery mode temperature sensor in accordance with one embodiment;

FIG. 2 is a schematic diagram of a portion of a whispering gallery mode temperature sensor according to one embodiment;

FIG. 3 is a schematic perspective view of a whispering gallery mode temperature sensor according to one embodiment;

FIG. 4 is a spectrum of a whispering gallery mode temperature sensor of one embodiment at different temperatures;

FIG. 5 is a graph illustrating the sensitivity test results of an exemplary whispering gallery mode temperature sensor.

In the figure:

100. a whispering gallery mode temperature sensor; 110. a multi-core optical fiber; 120. a microcolumn; 121. a total reflection prism; 122. a micro vertebral body; 123. an optical waveguide; 130. a microsphere base; 131. a micro-funnel; 132. the outer wall of the micro funnel; 133. and (4) microspheres.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be interconnected within two elements or in a relationship where two elements interact with each other unless otherwise specifically limited. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The present application provides a whispering gallery mode temperature sensor 100. Referring to fig. 1 to 3 (the microspheres 133 are not shown in fig. 1 and 2), an exemplary whispering gallery mode temperature sensor 100 includes: a multi-core optical fiber 110, a lightwave input structure, a lightwave output structure, an optical waveguide 123, a microsphere mount 130, and microspheres 133.

Specifically, the multi-core optical fiber 110 has a plurality of cores for transmitting signal light. In some embodiments, the multi-core fiber 110 is a seven-core fiber, thereby enabling high-speed, high-capacity transmission of optical information. In other embodiments, the multicore fiber 110 may be a multicore fiber 110 having at least two cores, such as a two-core fiber, a four-core fiber, or a six-core fiber. Specifically, the seven-core optical fiber is a seven-core single-mode optical fiber, so that a larger bandwidth can be provided for the transmission of optical information, and the transmission speed of the optical information is increased. Since the length of the multi-core fiber 110 can be generally extended or shortened according to the transmission distance, the whispering gallery mode temperature sensor 100 can perform remote monitoring, and is suitable for more abundant application scenarios. Furthermore, the number of cores in the multi-core fiber 110 ranges from 6 to 8, and the multi-core fiber 110 can have the characteristics of large-capacity transmission and reasonable fiber diameter in this range.

Specifically, the light wave input structure and the light wave output structure respectively cover any two cores of the multi-core fiber 110, and the light waveguide 123 is connected between the light wave input structure and the light wave output structure. Therefore, information in the fiber cores correspondingly connected with the optical wave input structure can enter the optical wave input structure to the maximum extent, is transmitted to the optical wave output structure through the optical waveguide 123, and can enter the fiber cores correspondingly connected with the optical wave output structure to the maximum extent, namely, the high-efficiency coupling of the optical wave input structure, the optical wave output structure and the multi-core fiber 110 is realized, the information utilization rate in the multi-core fiber 110 is improved, and the measurement stability of the whispering gallery mode temperature sensor 100 is improved.

Specifically, the microsphere seat 130 is disposed on the end face. The microsphere mount 130 is disposed between the end faces of the micro-funnel 131 and the multi-core fiber 110 for fixing the position of the microsphere 133 and controlling the coupling distance between the microsphere cavity in the microsphere 133 and the optical waveguide 123.

Specifically, the microsphere 133 is disposed on the microsphere seat 130, and a microsphere cavity is disposed inside the microsphere 133. Specifically, the microspheres 133 are made of a polymer material, such as polybutadiene, polyisoprene, or polystyrene. In some embodiments, the microspheres 133 are polystyrene microspheres 133, and the polystyrene microspheres 133 have excellent physical properties such as small particle size, good relative stability, strong hydrophobicity, low adhesion, and the like, so that the prepared whispering gallery mode temperature sensor 100 has the characteristics of fast response speed, small size, high use stability, and convenience in assembly.

Specifically, microspheres 133 are coupled to optical waveguide 123. When the optical information propagates in the optical waveguide 123, the optical waveguide 123 is equivalent to an optically dense medium, and the gas environment or the liquid environment is equivalent to an optically sparse medium, so that an evanescent wave is formed outside the optical waveguide 123, and the evanescent wave refers to an electromagnetic wave generated by one side of the optically sparse medium due to total reflection when the optical information enters the optically sparse medium from the optically dense medium. The specific formation principle of the evanescent wave is as follows: in the optically dense medium, the reflected wave interferes with the incident wave to form a standing wave near the interface, and a very small part of energy permeates into the optically thinner medium and propagates for a certain distance along the interface, namely the evanescent wave. Specifically, the coupling of microsphere 133 and optical waveguide 123 means: evanescent waves formed outside the optical waveguide 123 can enter a microsphere cavity in the microsphere 133, echo wall mode resonance is generated in the microsphere cavity, and echo wall mode resonance can be transmitted back to the optical waveguide 123, that is, the distance between the microsphere 133 and the optical waveguide 123 is within the distance range in which evanescent waves formed by the optical waveguide 123 can be transmitted.

In some embodiments, the shortest distance between the optical waveguide 123 and the microsphere 133 is in a range of 0.9 μm to 1.1 μm, so that an evanescent wave formed outside the optical waveguide 123 can be more effectively coupled into the microsphere cavity, that is, critical coupling between the optical waveguide 123 and the microsphere 133 can be ensured, thereby preventing the optical information from being influenced by over-coupling or under-coupling between the two, reducing loss of the optical information, and improving the quality factor of the manufactured whispering gallery mode temperature sensor 100. Specifically, the shortest distance between optical waveguide 123 and microsphere 133 may be 0.932, 0.980, 1.000, 1.025, 1.060, or the like (in μm).

In some embodiments, the light wave input structure, the light wave output structure, the light waveguide 123, the micro funnel 131, and the micro ball seat 130 are made of a photoresist material, and can be formed by photolithography. The photoresist material can be positive photoresist or negative photoresist, when the photoresist material is the positive photoresist, the non-exposure area of the positive photoresist is in the shape of the required structure, and the exposure area is dissolved in the developing solution in the developing process; when the photoresist material is negative photoresist, the exposed area of the negative photoresist is in the shape of the required structure, and the unexposed area is dissolved in developing solution in the developing process. In some embodiments, the lightwave input structure, lightwave output structure, optical waveguide 123, microsphere mount 130, and micro-funnel 131 are negative resists, thereby facilitating the formation of a three-dimensional structure and reducing the loss of photoresist material and manufacturing costs.

The working principle of the whispering gallery mode temperature sensor 100 is as follows: the whispering gallery mode temperature sensor 100 is placed in a gas environment or a liquid environment which needs to measure temperature, optical information in the multi-core optical fiber 110 is transmitted to the optical wave input structure through one of the fiber cores, so that the optical information is transmitted through the optical waveguide 123 arranged between the optical wave input structure and the optical wave output structure, the optical waveguide 123 is coupled with the microsphere 133, evanescent waves formed outside the optical waveguide 123 are coupled into a microsphere cavity in the microsphere 133 to generate echo wall resonance, the resonated optical information is transmitted back to the optical waveguide 123 and then enters the optical wave output structure, so that the optical information returns to the other fiber core in the multi-core optical fiber 110, and temperature measurement can be achieved. Because the temperature of the changing environment changes the effective refractive index and the temperature of the microsphere 133, the resonant wavelength of the evanescent wave in the microsphere cavity shifts, so that the temperature change can be reflected by the optical information fed back by the microsphere 133, that is, the temperature measurement is realized. The resonant wavelength is usually in the order of nanometers, so the whispering gallery mode temperature sensor 100 has the characteristics of high measurement accuracy, high response speed and high sensitivity.

In the whispering gallery mode temperature sensor 100, the light wave input structure, the light wave output structure, the light waveguide 123, the microsphere base 130 and the micro-funnel 131 are arranged on the end surface of the multi-core fiber 110, so that the space required by the whispering gallery mode temperature sensor 100 can be effectively reduced, the high-efficiency coupling of the light wave input structure, the light wave output structure and the multi-core fiber 110 can be realized, and the utilization efficiency of signal light in the multi-core fiber 110 and the measurement accuracy of the whispering gallery mode temperature sensor 100 can be improved; the optical wave input structure and the optical wave output structure respectively correspond to any two fiber cores of the multi-core fiber 110, so that the high-efficiency coupling of the optical wave input structure and the optical wave output structure with the multi-core fiber 110 can be realized, the information utilization rate in the multi-core fiber 110 is improved, and the measurement stability of the whispering gallery mode temperature sensor 100 is improved; through mutual coupling between the optical waveguide 123 and the microsphere 133, evanescent waves formed by light rays outside the optical waveguide 123 can be coupled into the microsphere cavity and form resonance in the microsphere cavity, so that a whispering gallery mode of the microsphere cavity is excited, and temperature detection can be realized; the microspheres 133 are arranged in the micro-funnel 131, so that the assembly of the microspheres 133 and the microstructure can be facilitated, meanwhile, the micro-funnel 131 can also play a role in absorbing liquid to the outer side of the microspheres 133 by utilizing surface tension, and the contact area between the microspheres 133 and the liquid is increased, so that the detection efficiency and the detection accuracy of the whispering gallery mode sensor are improved; since the length of the multi-core fiber 110 can be generally extended or shortened according to the transmission distance, the whispering gallery mode temperature sensor 100 can perform remote monitoring, and is suitable for more abundant application scenarios. The whispering gallery mode temperature sensor 100 has the advantages of being small in space requirement, high in measurement accuracy, long in measurement distance and the like, and can be suitable for temperature detection in a narrow space environment.

In some embodiments, whispering gallery mode temperature sensor 100 further includes a micro-funnel 131. Specifically, the micro funnel 131 is erected on one side of the microsphere holder 130 far from the end face. Thus, the microspheres 133 can be assembled to the microsphere base 130 through the micro-funnel 131, and the microspheres 133 can enter the ordered state from the disordered state more quickly by using a template-assisted self-assembly method, i.e., the microspheres 133 can be combined with the microsphere base 130 more quickly, so that the assembly efficiency of the whispering gallery mode temperature sensor 100 can be improved. Specifically, the microsphere seat 130 is disposed between the micro-funnel 131 and the end surface of the multi-core fiber 110, and is used to fix the position of the microsphere 133 and control the coupling distance between the microsphere cavity in the microsphere 133 and the optical waveguide 123.

In some embodiments, the optical wave input structure and the optical wave output structure each include a micro-cylinder 120, a total reflection prism 121, and a micro-cone 122 connected in sequence, one end of the micro-cylinder 120 is connected to the fiber core, and a small end of the micro-cone 122 is connected to one end of the optical waveguide 123. The microcolumn 120 is used for collecting or feeding back optical information in the multi-core fiber 110, the total reflection prism 121 is used for performing total reflection on the optical information to adjust the transmission direction of the optical path, and the microcone 122 is used for changing the beam diameter of the optical information to realize convergence or divergence of the optical information. The transmission direction of the optical information is as follows: the optical information is transmitted to the micro-column 120 of the optical wave input structure by one of the fiber cores of the multi-core optical fiber 110, then the optical information enters the micro-cone 122 after changing the transmission direction through the total reflection prism 121, the micro-cone 122 converges the optical information and then couples the converged optical information into the optical waveguide 123, evanescent waves formed outside the optical waveguide 123 couple the evanescent waves into the micro-sphere cavity to form resonance and feed back the evanescent waves into the optical waveguide 123, the optical waveguide 123 couples the optical information into the micro-cone 122 of the optical wave output structure, and the micro-cone 122 disperses the optical information and then transmits the dispersed optical information to the other fiber core of the multi-core optical fiber 110 through the micro-column 120, thereby realizing the input and output of the optical information. Due to the reversibility of optical path transmission, the optical wave input structure and the optical wave output structure of the present embodiment can be interchanged according to the propagation requirement of optical information. In other embodiments, the light wave input structure and the light wave output structure may be other lenses or lens groups capable of changing the direction of the light path and focusing the light path.

In some embodiments, the angle between the reflecting surface and the end surface of the total reflection prism 121 is in the range of 30 ° to 60 °, and when the angle is in this range, the optical waveguide 123 connected to the total reflection prism 121 through the micro-cone 122 can be around the micro-sphere 133 and coupled to the micro-sphere 133. Specifically, the included angle between the reflection surface and the end surface of the total reflection prism 121 may be: 35 °, 40 °, 45 °, 50 °, 55 °, or the like.

In some embodiments, the reflective surface of the total reflection prism 121 is provided with a metal thin film. Specifically, when the difference between the refractive index of the reflection prism 121 in the light wave input structure and the refractive index of the reflection prism 121 in the light wave output structure is small, the reflection of the optical information at the reflection surface of the reflection prism 121 is affected, and a certain amount of energy and information loss is caused. The reflection surface of the total reflection prism 121 is evaporated with a metal film, so that the reflectivity of the optical information in the total reflection prism 121 can be fully ensured, and the integrity and accuracy of the optical information in the transmission process can be ensured.

Specifically, the metal thin film is formed by a thermal evaporation process in a vacuum atmosphere on the reflection surface of the total reflection prism 121. Further, if the optical waveguide 123 is covered with metal, the coupling efficiency between the optical waveguide 123 and the micro-sphere 133 is affected, thereby reducing the practicality and measurement efficiency of the whispering gallery mode temperature sensor 100. In some embodiments, the projection range of the outer edge of the micro funnel 131 on the end face of the multi-core fiber 110 is located between the reflection surface of the total reflection prism 121 and the projection of the optical waveguide 123 on the end face respectively. Therefore, the micro funnel 131 can protect the optical waveguide 123 from being covered by metal in the evaporation process during the preparation process, and the metal can cover the reflection surface of the total reflection prism 121, so as to ensure the functional integrity of the whispering gallery mode temperature sensor 100.

In some embodiments, the metal film is made of gold, and has the characteristics of convenience in evaporation, strong stability, difficulty in oxidation and the like. In some embodiments, the thickness of the metal film is in the range of 100nm-300nm, so that the compactness of the evaporated metal film can be ensured, and the cost of metal raw materials can be saved. Specifically, the thickness of the metal thin film may be: 125. 150, 175, 200, 225, 250, 275, etc. (units are nm).

In some embodiments, whispering gallery mode temperature sensor 100 further includes a micro-funnel outer wall 132 surrounding micro-funnel 131. Through enclosing the microleave fill outer wall 132 in the periphery, be convenient for microballon 133 is connected with microballon base 130 more accurately. The micro-funnel outer wall 132 serves to cover the light wave input structure, the light wave output structure, the light waveguide 123, the micro-funnel 131, and the micro-sphere base 130 on the end face of the multi-core fiber 110, so that the integration level and integrity of the whispering gallery mode temperature sensor 100 can be improved.

In some embodiments, the shortest distance between the optical waveguide 123 and the microsphere 133 is in a range of 0.8 μm to 1.2 μm, so that an evanescent wave formed outside the optical waveguide 123 can be more effectively coupled into the microsphere cavity, that is, critical coupling between the optical waveguide 123 and the microsphere 133 can be ensured, thereby preventing the optical information from being influenced by over-coupling or under-coupling between the two, and simultaneously reducing loss of the optical information and improving the quality factor of the manufactured whispering gallery mode temperature sensor 100. Specifically, the shortest distance between optical waveguide 123 and microsphere 133 may be 0.932, 0.980, 1.000, 1.025, 1.060, or the like (in μm).

In some embodiments, the distance between the microsphere 133 and the end surface is in a range from 4 μm to 6 μm, which can prevent the optical signal energy in the fiber core from affecting the resonance generated in the microsphere cavity, and can reduce the propagation path length of the optical information, and specifically, the distance between the microsphere 133 and the end surface can be 4.5, 5.0, or 5.5 (in μm).

In some embodiments, the cross section of the optical waveguide 123 perpendicular to the length direction is rectangular, which can ensure that the optical signal has higher optical density and uniformity in the transmission process, and can reduce the loss of the optical signal in the optical waveguide 123, thereby improving the transmission efficiency of the optical signal. Further, the distance between the optical waveguide 123 and the end face is in a range of 18 μm to 20 μm, so that the optical signal energy in the fiber core can be prevented from interfering with the optical signal in the optical waveguide 123, and the detection accuracy of the whispering gallery mode temperature sensor 100 can be improved. Specifically, the distance between the optical waveguide 123 and the end face may be: 18.6, 18.8, 19.0, 19.4 or 19.8, etc. (units are mum).

In some more specific embodiments: the diameter of the multicore fiber 110 is 124.5 μm, the diameter of the cores in the multicore fiber 110 is 6 μm, and the farthest distance between each pair of cores is 70 μm; the length, width and height of the microcolumn 120 are all 8 μm; the included angle between the total reflection prism 121 and the end face is 45 degrees, and the length, the width and the height are all 8 micrometers; the length of the microtome 122 is 20 μm; the outer radius of one side of the microsphere seat 130 close to the end face is 23 μm, the wall thickness is 3 μm, and the height along the length direction of the multi-core fiber 110 is 11 μm; the maximum radius of the outer edge of the micro funnel 131 is 44 μm, the wall thickness is 2.5 μm, and the height is 43 μm; the maximum radius of the outer wall 132 of the micro-funnel is 47 μm, the wall thickness is 2 μm, and the height is 50 μm; the length of the optical waveguide 123 is 22 μm, the width and the height are both 1 μm, and the distance between the end face and the optical waveguide 123 is 19 μm; the diameter of the microsphere cavity in the microsphere 133 is 30 μm, the refractive index is 1.59, the distance between the microsphere cavity and the optical waveguide 123 is 1.0 μm, and the shortest distance between the microsphere cavity and the end face is 5 μm; the thickness of the metal thin film was 200nm.

In some embodiments, when using whispering gallery mode temperature sensor 100 for temperature sensing, the wavelength band of the optical signal used is 1520nm-1570nm. Referring to fig. 4, fig. 4 is a spectrum diagram of the whispering gallery mode temperature sensor 100 at different temperatures according to an embodiment. To characterize the temperature sensing performance, the temperature of the liquid is gradually changed by placing the whispering gallery mode temperature sensor 100 in the liquid environment, and as can be seen from fig. 4, the formants of the optical signals in the microsphere cavity are red-shifted with increasing temperature. In the spectrum of the optical signal with the wavelength of 1520nm-1570nm, the sharp resonance peak can be seen as the whispering gallery mode. At a wavelength of 1535nm of the optical signal, a quality factor of 2880 can be obtained, the resonance peak is formed by interaction of the optical waveguide 123 and the microsphere cavity in the microsphere 133, the distance between the optical waveguide 123 and the microsphere cavity is 1 μm, and the diameter of the microsphere cavity is 30 μm. Therefore, it can be seen that the whispering gallery mode temperature sensor 100 of the present application can provide feedback of optical signals to changes in ambient temperature, and has high sensitivity to temperature changes and high measurement accuracy.

Referring to fig. 5, a graph of the sensitivity test result of the whispering gallery mode temperature sensor 100 according to an embodiment is shown. In fig. 5, the abscissa is different temperatures, and the ordinate is wavelength offset, and it can be seen from the experimental result and the fitting result that Δ λ = -0.03164t +0.81957 is linear between temperature and wavelength offset. The data in the graph is calculated, so that the detection sensitivity of the whispering gallery mode temperature sensor 100 to the temperature can reach 31.64 pm/DEG C, and the whispering gallery mode temperature sensor has a good temperature sensing effect.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. A whispering gallery mode temperature sensor, comprising:

the multi-core optical fiber is internally provided with a plurality of fiber cores for transmitting signal light;

one end face of the multi-core optical fiber is provided with a light wave input structure, a light wave output structure and an optical waveguide, wherein the light wave input structure and the light wave output structure respectively and correspondingly cover any two fiber cores of the multi-core optical fiber, and the optical waveguide is connected between the light wave input structure and the light wave output structure;

a microsphere base disposed on the end face;

the microsphere is arranged on the microsphere base, a microsphere cavity is arranged inside the microsphere, and the microsphere and the optical waveguide are mutually coupled.

2. The whispering gallery mode temperature sensor of claim 1, further comprising a micro-funnel mounted to a side of said microsphere mount distal from said end face; the microspheres are assembled to the microsphere seat through the micro-funnel.

3. The whispering gallery mode temperature sensor of claim 2, further comprising a micro-funnel outer wall surrounding said micro-funnel.

4. The whispering gallery mode temperature sensor of claim 1, wherein the light wave input structure and the light wave output structure each include a micro-cylinder, a total reflection prism, and a micro-cone connected in sequence, one end of the micro-cylinder is connected to the fiber core, and a small end of the micro-cone is connected to one end of the optical waveguide.

5. The whispering gallery mode temperature sensor of claim 4, wherein the angle between the reflecting surface of said total reflection prism and said end surface is in the range of 30 ° -60 °; and/or the presence of a gas in the gas,

and the reflecting surface of the total reflection is provided with a metal film.

6. The whispering gallery mode temperature sensor of claim 5, wherein said metal film has a thickness in the range of 100nm to 300nm; and/or the presence of a gas in the gas,

the metal film is made of gold.

7. The whispering gallery mode temperature sensor of claim 1, wherein the number of cores in said multicore fiber is 6-8.

8. The whispering gallery mode temperature sensor of claim 1, wherein the distance between said optical waveguide and said microsphere ranges from 0.8 μ ι η to 1.2 μ ι η; and/or the presence of a gas in the gas,

the distance between the microspheres and the end face ranges from 4 μm to 6 μm.

9. The whispering gallery mode temperature sensor of claim 1, wherein a cross-section of the optical waveguide perpendicular to the lengthwise direction is rectangular, and a distance between the optical waveguide and the end face is in a range of 18 μm to 20 μm.

10. The whispering gallery mode temperature sensor of any of claims 1-9, wherein the lightwave input structure, lightwave output structure, lightguide, microsphere mount, and microleaker are all photoresist materials.

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