FBG and direct band gap semiconductor hybrid optical fiber temperature sensor
By combining a hybrid design of fiber Bragg gratings and direct bandgap semiconductor crystals, the temperature measurement problem of traditional sensors in fast response and electromagnetic interference environments is solved, achieving high-precision temperature measurement, which is suitable for in-situ monitoring of power electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional temperature sensors have shortcomings in terms of fast response and high-frequency temperature measurement. They cannot capture transient temperature changes of power electronic devices in real time, and their measurement accuracy decreases in environments with strong electromagnetic interference. Existing fiber Bragg grating sensors have low temperature measurement accuracy and poor interchangeability, making it difficult to achieve accurate temperature measurement in complex environments.
A hybrid fiber optic temperature sensor combining FBG and direct bandgap semiconductor is employed. The fiber Bragg grating structure provides coarse temperature localization, while the interference spectrum of the direct bandgap semiconductor crystal refines the measurement, achieving high resolution and high precision.
It achieves high-resolution and high-precision temperature measurement over a wide temperature range, has a compact structure, and is suitable for in-situ temperature monitoring of power electronic devices without requiring significant modifications to the device structure.
Smart Images
Figure CN223992647U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of temperature sensor technology, specifically to a hybrid fiber optic temperature sensor combining FBG and direct bandgap semiconductor. Background Technology
[0002] Modern power electronic devices, such as insulated-gate bipolar transistors (IGBTs) and integrated gate commutated thyristors (IGCTs), generate a significant amount of heat during operation. These devices typically operate under high voltage, high current, and high frequency conditions, and temperature variations directly impact their performance and reliability. Excessively high temperatures can lead to device failure or even system malfunctions. Therefore, real-time monitoring and precise control of the temperature of power electronic devices such as IGBTs and IGCTs are crucial for ensuring their safe and stable operation.
[0003] Traditional temperature sensing technologies, such as thermocouples and thermistors, while meeting temperature monitoring needs to some extent, have significant shortcomings in terms of rapid response and high-frequency temperature measurement. These sensors have slow response times and cannot capture transient temperature changes generated during high-speed switching of devices in real time. Furthermore, traditional sensors are susceptible to interference in environments with strong electromagnetic interference, leading to a decrease in measurement accuracy.
[0004] Fiber optic temperature sensors have gradually become an ideal choice for temperature monitoring of power electronic devices due to their advantages such as resistance to electromagnetic interference, high sensitivity, and fast response. Among them, temperature sensors based on fiber Bragg gratings (FBGs) have attracted widespread attention due to their simple structure and wide measurement range. However, they have significant limitations due to their low temperature measurement accuracy, poor interchangeability, and sensitivity to interference factors such as strain and pressure, making it difficult to achieve accurate temperature measurement in complex and variable environments. Interferometry can utilize the inherent properties of its interference cavity to reduce interference from non-temperature factors, resulting in high measurement accuracy and response speed. However, it suffers from the problem of overlapping interference spectra when measuring temperatures over a wide temperature range, leading to difficulties in accurate resolution, and it is also costly. Utility Model Content
[0005] (I) Purpose of the utility model
[0006] The purpose of this invention is to provide a hybrid fiber optic temperature sensor combining FBG and direct bandgap semiconductor that can achieve high-precision temperature measurement over a wide temperature range.
[0007] (II) Technical Solution
[0008] To address the aforementioned issues, this invention provides a hybrid fiber optic temperature sensor combining FBG and direct bandgap semiconductor, wherein the fiber optic temperature sensor comprises an optical fiber, a direct bandgap semiconductor crystal, and a reflective film.
[0009] The optical fiber, the direct bandgap semiconductor crystal, and the reflective film are connected in sequence;
[0010] The portion of the optical fiber closest to the direct bandgap semiconductor crystal is provided with a fiber Bragg grating structure.
[0011] In another aspect of this invention, preferably, the incident end of the direct bandgap semiconductor crystal is connected to one end of the optical fiber, and the reflecting end of the direct bandgap semiconductor crystal is away from the optical fiber and is provided with the reflective film.
[0012] The direct bandgap semiconductor crystal forms a Fabry-Perot cavity structure.
[0013] In another aspect of this utility model, preferably,
[0014] The incident and reflecting ends of the direct bandgap semiconductor crystal are parallel, and the incident and reflecting ends of the direct bandgap semiconductor crystal are parallel mirror surfaces of the Fabry-Perot cavity structure.
[0015] In another aspect of this invention, preferably, the fiber Bragg grating structure is arranged along the length direction of the fiber.
[0016] In another aspect of this invention, preferably, the fiber Bragg grating structure is a uniform grating structure.
[0017] In another aspect of this invention, preferably, the reflective film includes a reflective surface, a reflective mirror, and a reflective sheet. The reflective film is closely disposed on the reflective end of the direct bandgap semiconductor crystal, and the disposal method includes coating, chemical deposition, physical bonding, coupling, and adhesive bonding.
[0018] In another aspect of this invention, preferably, the direct bandgap semiconductor crystal is coupled to the end of the optical fiber, and / or the portion of the optical fiber connected to the direct bandgap semiconductor crystal is externally encapsulated.
[0019] In another aspect of this invention, preferably, the direct bandgap semiconductor crystal includes a cuboid structure, a cube structure, a cylindrical structure, and an irregular structure with parallel incident and reflecting ends.
[0020] In another aspect of this invention, preferably, the operating wavelength of the optical fiber covers the range of FBG reflection wavelength and direct bandgap semiconductor transmission wavelength.
[0021] In another aspect of this utility model, preferably,
[0022] The temperature sensor also includes a protective sleeve that encloses the optical fiber and the direct bandgap semiconductor crystal.
[0023] (III) Beneficial Effects
[0024] The above-mentioned technical solution of this utility model has the following beneficial technical effects:
[0025] This invention provides coarse temperature localization through a fiber Bragg grating structure, solving the problems of overlapping and resolution difficulties in interference spectra during wide-temperature measurements. Simultaneously, it utilizes interference spectral refinement compensation with a direct bandgap semiconductor crystal, achieving high-resolution and high-precision temperature measurement over a wide temperature range. This invention employs an integrated design of fiber optic and direct bandgap semiconductor crystals, resulting in a compact structure and small size. It can be easily embedded into the interior or surface of power electronic devices for in-situ temperature monitoring without significant modifications to the device structure. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present utility model;
[0027] Figure 2 This is a schematic diagram of the optical path of one embodiment of the present invention;
[0028] Figure 3 The temperature measurement principle is based on a fiber Bragg grating structure.
[0029] Figure 4 This is a schematic diagram of a direct bandgap semiconductor.
[0030] Figure label:
[0031] 1: Optical fiber; 2: Direct bandgap semiconductor crystal; 3: Reflective film; 4: Fiber Bragg grating structure; 201: Incident end; 202: Reflecting end. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of this utility model.
[0033] The accompanying drawings show structural schematic diagrams according to embodiments of the present invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.
[0034] Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.
[0035] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0036] The present invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by similar reference numerals. For clarity, the parts in the drawings are not drawn to scale.
[0037] Example 1
[0038] A hybrid fiber optic temperature sensor combining FBG and direct bandgap semiconductor. Figure 1 A schematic diagram of the overall structure of one embodiment of the present invention is shown, as follows: Figure 1 As shown, the fiber optic temperature sensor includes an optical fiber 1, a direct bandgap semiconductor crystal 2, and a reflective film 3; the optical fiber 1, the direct bandgap semiconductor crystal 2, and the reflective film 3 are connected in sequence to ensure that the optical signal can be efficiently transmitted to the direct bandgap semiconductor crystal 2 and reflected by the reflective film 3; a fiber Bragg grating structure 4 is provided on the portion of the optical fiber 1 near the direct bandgap semiconductor crystal 2. Figure 2 A schematic diagram of the optical path of one embodiment of the present invention is shown, as follows: Figure 2 As shown, the fiber Bragg grating structure 3 is a periodic refractive index modulation structure that can reflect light of a specific wavelength, the Bragg wavelength, while light of other wavelengths is transmitted into the direct bandgap semiconductor crystal 2. The fiber Bragg grating structure 3 is used to sense temperature changes. Figure 3 The temperature measurement principle of the fiber Bragg grating structure is shown, such as... Figure 3 As shown, when the temperature changes, the thermal expansion effect and thermo-optic effect of optical fiber will cause the Bragg wavelength to shift. Temperature measurement can be achieved by detecting the change in wavelength. The electromagnetic interference resistance of optical fiber makes it particularly suitable for working in strong electromagnetic environments, such as temperature measurement scenarios for power electronic devices such as IGBTs and IGCTs. Figure 4 A schematic diagram of a direct bandgap semiconductor structure is shown, such as... Figure 4As shown, in the structure of a direct bandgap semiconductor, the valence band top and conduction band bottom are located at the same position in momentum space. The energy gap between the conduction band and the valence band, i.e., the band gap, allows electrons to absorb photons (light of a specific wavelength) and directly transition from the valence band top (the highest energy position in the valence band) to the conduction band bottom (the lowest energy position in the conduction band), with the photon energy equal to or greater than its band gap width. This transition process does not involve the participation of other intermediate energy levels or states, and is therefore called a "direct" transition. Semiconductors with this band structure are called direct bandgap semiconductors. The material of the reflective film is not limited here. Those skilled in the art will understand that the reflective film 3 only needs to be able to reflect the light signal transmitted through the direct bandgap semiconductor crystal 2 back. The reflective film 3 is a mirror that can reflect light, including a reflective surface, a reflector, and a reflective sheet. The reflective film 3 is closely arranged at the reflective end 202 of the direct bandgap semiconductor crystal 2, and the arrangement methods include coating, chemical deposition, physical bonding, coupling, and adhesive bonding. The reflective film 3 is made of materials such as silver (Ag), aluminum (Al), gold (Au), silicon dioxide (SiO2), titanium dioxide (TiO2), and silicon nitride (Si3N4). The direct bandgap semiconductor crystal 2 is coupled to the end of the optical fiber 1, and / or the connection between the optical fiber 1 and the direct bandgap semiconductor crystal 2 is externally encapsulated. In this embodiment, the optical fiber 1 and the direct bandgap semiconductor crystal 2 can be initially fixed by bonding, and then a portion of the optical fiber 1 near the direct bandgap semiconductor crystal 2 can be externally encapsulated with the direct bandgap semiconductor crystal 2.
[0039] Furthermore, in this embodiment, the incident end 201 of the direct bandgap semiconductor crystal 2 is connected to one end of the optical fiber 1, and the reflecting end 202 of the direct bandgap semiconductor crystal 2 is away from the optical fiber 1 and is provided with the reflective film 3; the direct bandgap semiconductor crystal 2 forms a Fabry-Perot cavity structure; the incident end 201 and the reflecting end 202 of the direct bandgap semiconductor crystal 2 are parallel, and the incident end 201 and the reflecting end 202 of the direct bandgap semiconductor crystal 2 are parallel mirror surfaces of the Fabry-Perot cavity structure. Those skilled in the art will understand that the structure of the direct bandgap semiconductor crystal 2 only needs to satisfy the parallelism of the incident end 201 and the reflecting end 202. In this embodiment, the structure of the direct bandgap semiconductor crystal 2 can be a cuboid structure, a cube structure, a cylinder structure, or an irregular structure with parallel incident and reflecting ends. The operating wavelength of the optical fiber 1 covers the FBG reflection wavelength and the direct bandgap semiconductor transmission wavelength range. Light travels from the optical fiber to the direct bandgap semiconductor crystal 2. Upon reaching the interface between the optical fiber and the direct bandgap semiconductor crystal 2, part of the light is reflected back into the optical fiber, while the other part enters the direct bandgap semiconductor crystal 2 as incident light. The incident light undergoes reflection and transmission between the incident and reflecting ends of the direct bandgap semiconductor crystal 2, forming two sets of parallel beams with decreasing amplitudes on either side of the direct bandgap semiconductor crystal 2. The incident light from the direct bandgap semiconductor crystal 2 undergoes multiple reflections within the Fabry-Perot cavity structure, forming an interference spectrum. When the temperature changes, the thermal expansion effect of the direct bandgap semiconductor crystal 2 alters the optical path difference of the Fabry-Perot cavity, causing a shift in the interference spectrum. By detecting changes in the interference spectrum, high-precision temperature measurement can be achieved. This embodiment uses the FBG (Fast-Fast Gauge) to provide coarse temperature localization, solving the problems of overlap and resolution difficulties that may occur in interference spectra during wide-temperature measurements. Simultaneously, it uses the interference spectrum of the direct bandgap semiconductor crystal 2 for refinement compensation, achieving high-resolution and high-precision temperature measurement over a wide temperature range. In this embodiment, the material of the direct bandgap semiconductor crystal 2 can be gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), etc.; the temperature sensor in this embodiment achieves a temperature sensitivity of 0.12nm / ℃, a wavelength demodulation resolution of 0.1pm, and a temperature demodulation error of ±0.41℃ within a temperature measurement range of -20 to 150℃.
[0040] Furthermore, in this embodiment, the fiber Bragg grating structure 3 is arranged along the length direction of the optical fiber 1, and the shape of the fiber Bragg grating structure 3 is a uniform grating structure. The fiber Bragg grating structure 3 is distributed along the axial direction (length direction) of the optical fiber 1, which can fully utilize the transmission characteristics of the optical fiber and ensure efficient propagation of optical signals in the optical fiber. The Bragg grating arranged along the length direction can uniformly sense temperature changes along the optical fiber, making it suitable for scenarios requiring distributed temperature monitoring. The shape of the fiber Bragg grating structure 3 is a uniform grating structure, meaning that the refractive index modulation period of the grating remains consistent throughout the entire length direction. The characteristics of a uniform grating structure are a constant grating period, uniform refractive index modulation depth, and the ability to reflect light of the Bragg wavelength. The fiber Bragg grating of the uniform grating structure has narrowband reflection characteristics, capable of reflecting light of specific wavelengths while transmitting light of other wavelengths, providing optical signals for entering the direct bandgap semiconductor crystal 2. When the temperature changes, the thermal expansion effect and thermo-optic effect of the optical fiber cause a shift in the Bragg wavelength; temperature measurement can be achieved by detecting the change in wavelength.
[0041] Furthermore, the fiber optic temperature sensor also includes a protective sleeve that encloses the optical fiber 1 and the direct bandgap semiconductor crystal 2, protecting the fiber optic temperature sensor from damage.
[0042] This invention provides coarse temperature localization through a fiber Bragg grating structure, solving the problems of overlapping and resolution difficulties in interference spectra during wide-temperature measurements. Simultaneously, it utilizes interference spectral refinement compensation with a direct bandgap semiconductor crystal, achieving high-resolution and high-precision temperature measurement over a wide temperature range. This invention employs an integrated design of fiber optic and direct bandgap semiconductor crystals, resulting in a compact structure and small size. It can be easily embedded into the interior or surface of power electronic devices for in-situ temperature monitoring without significant modifications to the device structure.
[0043] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this utility model and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this utility model should be included within its protection scope. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.
[0044] The above description does not provide detailed explanations of the technical aspects of each layer's patterning and etching. However, those skilled in the art should understand that various methods existing in the prior art can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above.
[0045] The present invention has been described above with reference to embodiments thereof. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the present invention, and all such substitutions and modifications should fall within the scope of the present invention.
[0046] Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions and modifications can be made to the embodiments of the present invention without departing from the spirit and scope of the present invention.
[0047] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.
Claims
1. A FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor, characterized in that, The fiber temperature sensor comprises a fiber (1), a direct band gap semiconductor crystal (2) and a reflective film (3); The fiber (1), the direct band gap semiconductor crystal (2) and the reflective film (3) are sequentially connected; The part of the fiber (1) close to the direct band gap semiconductor crystal (2) is provided with a fiber Bragg grating structure (4).
2. The FBG and direct band gap semiconductor hybrid fiber temperature sensor according to claim 1, wherein, The incident end (201) of the direct band gap semiconductor crystal (2) is connected with one end of the fiber (1), and the reflective end (202) of the direct band gap semiconductor crystal (2) is away from the fiber (1) and provided with the reflective film (3); The direct band gap semiconductor crystal (2) forms a Fabry-Perot cavity structure.
3. The FBG and direct band gap semiconductor hybrid fiber temperature sensor according to claim 2, wherein, The incident end (201) and the reflective end (202) of the direct band gap semiconductor crystal (2) are parallel, and the incident end (201) and the reflective end (202) of the direct band gap semiconductor crystal (2) are parallel mirrors of the Fabry-Perot cavity structure.
4. The FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor of claim 1, wherein, The fiber Bragg grating structure (4) is arranged along the length direction of the fiber (1).
5. The FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor of claim 1, wherein, The shape of the fiber Bragg grating structure (4) is a uniform grating structure.
6. The FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor of claim 2, wherein, The reflective film (3) comprises a reflective surface, a mirror and a reflective sheet, and the reflective film (3) is closely arranged at the reflective end (202) of the direct band gap semiconductor crystal (2) in a manner including coating, chemical deposition, physical bonding, coupling and gluing.
7. The FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor of claim 1, wherein, The direct band gap semiconductor crystal (2) is coupled at the end of the fiber (1), and / or the fiber (1) and the connected part of the direct band gap semiconductor crystal (2) are encapsulated externally.
8. The FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor of claim 2, wherein, The direct band gap semiconductor crystal (2) comprises a cuboid structure, a square structure, a cylindrical structure and an irregular structure with parallel incident end and reflective end.
9. The FBG and direct bandgap semiconductor hybrid optical fiber temperature sensor of claim 1, wherein, The working wavelength of the fiber (1) covers the FBG reflection wavelength and the direct band gap semiconductor transmission wavelength range.
10. The FBG and direct band gap semiconductor hybrid fiber temperature sensor according to claim 1, wherein, The temperature sensor further comprises a protective sleeve, and the protective sleeve wraps the fiber (1) and the direct band gap semiconductor crystal (2).