Sensor, manufacturing method therefor, and interferometric measurement system including same

Abstract

A sensor, comprising: a base (1), wherein a pressure-sensitive diaphragm (2) is arranged on a first end (11) of the base (1), and the end face of a second end (12) of the base (1) opposite the first end (11) is fixedly connected to a hollow tube (6); a pressure sensing cavity (3), which is formed between the first end (11) of the base (1) and the pressure-sensitive diaphragm (2) and is sealed by the first end (11) of the base (1) and the pressure-sensitive diaphragm (2), the cavity length of the pressure sensing cavity (3) varying as a pressure to be measured changes; and a temperature sensing cavity (4), which is formed between an incident optical fiber (5) in the hollow tube (6) and a reflective end face of the temperature sensing cavity (4), the cavity length of the temperature sensing cavity (4) varying as a temperature to be measured changes, wherein the temperature sensing cavity (4) and the pressure sensing cavity (3) are arranged opposite each other in the direction in which light exits from the incident optical fiber (5). The manufacturing process is simple, and the pressure and temperature can be demodulated by means of the same demodulation device. Further provided are a sensor manufacturing method and an interferometric measurement system.

Description

Sensor, method for manufacturing the same, and interferometric measurement system including the same

[0001] This application claims priority to Chinese Patent Application No. 202411087533.8, filed on August 8, 2024, and Chinese Patent Application No. 202421921190.6, filed on August 8, 2024, the contents of which are incorporated herein in their entirety as part of this application. TECHNICAL FIELD

[0002] The present disclosure relates to a sensor, a method for manufacturing the same, and an interferometric measurement system including the same. BACKGROUND

[0003] Optical fiber sensors have been widely used in various industries, such as oil, aviation, aerospace, medical, marine, etc., and have shown excellent performance. At present, the application requirements of simultaneous measurement of temperature and pressure parameters have been proposed in various fields.

[0004] An existing optical fiber F-P cavity pressure sensor with temperature self-compensation uses a fiber grating as a conducting fiber, and an optical F-P cavity as a pressure sensitive element. The fiber grating and the optical F-P cavity are connected by adhesive bonding or carbon dioxide laser welding. This kind of sensor has the following problems: the composite sensor needs to be equipped with a fiber grating demodulation system and an F-P cavity length demodulation system at the same time, which increases the time and space cost. SUMMARY

[0005] Therefore, the purpose of the present disclosure is to provide a sensor which can realize the demodulation of the pressure sensing cavity and the temperature sensing cavity by the same demodulation device.

[0006] The above-mentioned purpose is achieved by the sensor according to the following description.

[0007] The present disclosure provides a sensor, comprising: a base, a first end of the base is provided with a pressure sensitive diaphragm, an end surface of a second end of the base opposite to the first end is fixedly connected with a hollow tube; a pressure sensing cavity is formed between the first end of the base and the pressure sensitive diaphragm, and is closed by the first end of the base and the pressure sensitive diaphragm, a cavity length of the pressure sensing cavity changes according to the change of a pressure to be measured; a temperature sensing cavity is formed between an incident optical fiber in the hollow tube and a reflection end surface of the temperature sensing cavity, a cavity length of the temperature sensing cavity changes according to the change of a temperature to be measured; the temperature sensing cavity and the pressure sensing cavity are oppositely arranged along the direction of light emitted from the incident optical fiber.

[0008] In one embodiment, the reflective end face of the temperature sensing cavity is an end face of the second end portion of the base, and the temperature sensing cavity is formed between the end face of the second end portion of the base and an end face of the incident optical fiber.

[0009] In one embodiment, further comprising a reflective optical fiber disposed in the hollow tube, the reflective optical fiber is fixed to the end face of the second end portion of the base, and the temperature sensing cavity is formed between the end face of the incident optical fiber and an end face of the reflective optical fiber.

[0010] In one embodiment, the coefficient of thermal expansion of the hollow tube is 2*10 -6 / k-30*10 -6 / k.

[0011] In one embodiment, the length of the hollow tube is not less than 0.5mm.

[0012] In one embodiment, at least one local region of the pressure sensitive diaphragm has a dopant material doped into a base material of the pressure sensitive diaphragm to create stress.

[0013] In one embodiment, the difference between the cavity length of the temperature sensing cavity and the cavity length of the pressure sensing cavity is not less than 1μm.

[0014] In one embodiment, the difference between the cavity length of the temperature sensing cavity and the cavity length of the pressure sensing cavity is less than 100μm.

[0015] The present disclosure also provides a manufacturing method of a sensor, comprising: manufacturing a base having a cavity at a first end portion or a pressure sensitive diaphragm having a cavity; combining the pressure sensitive diaphragm and the first end portion of the base together so that the cavity is enclosed by the pressure sensitive diaphragm and the base to form a pressure sensing cavity; fixing a hollow tube to a second end portion of the base and inserting an incident optical fiber into the hollow tube to form a temperature sensing cavity so that the temperature sensing cavity and the pressure sensing cavity are oppositely arranged along a direction in which light is emitted from the incident optical fiber.

[0016] The present disclosure also provides an interferometric measurement system, comprising: a light source emitting coherent light; a sensor as described in any of the above, configured to receive the coherent light and form and output modulated light modulated by a to-be-measured pressure and a to-be-measured temperature; and an interference demodulation device configured to receive the modulated light and demodulate the modulated light to obtain an interference spectrum of the pressure sensing cavity and an interference spectrum of the temperature sensing cavity.

[0017] In one embodiment, the interference demodulation device comprises a condenser configured to receive the modulated light; a first polarizer disposed downstream of the condenser and having a first polarization direction; a second polarizer disposed downstream of the first polarizer and having a second polarization direction perpendicular or parallel to the first polarization direction; and a birefringent element located between the first polarizer and the second polarizer and having an optical axis at 45° or -45° to the first polarization direction.

[0018] The present disclosure has the following advantages: the first end and the second end of the base form a pressure sensing cavity and a temperature sensing cavity respectively, the temperature sensing cavity is arranged opposite to the pressure sensing cavity along the incident optical fiber, light of the incident optical fiber is incident to the temperature sensing cavity and the pressure sensing cavity in sequence, the modulated light modulated by the pressure sensing cavity and the temperature sensing cavity is formed and output, the modulated light can carry optical path information corresponding to the cavity length of the pressure sensing cavity and the cavity length of the temperature sensing cavity, and the demodulation of the pressure sensing cavity and the temperature sensing cavity can be realized by the same demodulation device; and the sensor structure and manufacturing process are simple and the cost is low.

[0019] 1-base 11-first end of the base 12-second end of the base 2-pressure sensitive diaphragm 3-pressure sensing cavity 4-temperature sensing cavity 5-incident optical fiber 51-reflective optical fiber 6-hollow tube 61-tail end of the hollow tube BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a structural schematic diagram of a sensor of one embodiment of the present disclosure;

[0021] Fig. 2 is a structural schematic diagram of a sensor of one embodiment of the present disclosure;

[0022] Fig. 3 is an interference spectrum schematic diagram of a sensor of one embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the technical scheme of the present disclosure clearer, the technical scheme of the embodiments of the present disclosure will be described clearly and completely in the following with reference to the drawings of the embodiments of the present disclosure. The same reference signs in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present disclosure.

[0024] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not necessarily indicate a quantity limitation. The terms “comprising,” “including,” or “having,” and similar terms mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. The terms “connected” or “connected,” and similar terms are not limited to the physical or mechanical connection or connection shown in the drawings, but may include equivalent connections or connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, which may change accordingly when the absolute position of the described object changes.

[0025] The implementation of the sensor according to this disclosure is described in detail below with reference to Figures 1 and 2.

[0026] This disclosure provides a sensor, comprising: a base 1, a pressure-sensitive diaphragm 2 disposed at a first end 11 of the base, and an end face of a second end 12 of the base opposite to the first end 11 fixedly connected to a hollow tube 6; a pressure sensing cavity 3 formed between the first end 11 of the base and the pressure-sensitive diaphragm 2, and closed by the first end 11 of the base and the pressure-sensitive diaphragm 2, the cavity length of the pressure sensing cavity changing according to the change of the pressure to be measured; and a temperature sensing cavity 4 formed between an incident optical fiber 5 in the hollow tube 6 and a reflecting end face of the temperature sensing cavity 4, the cavity length of the temperature sensing cavity changing according to the change of the temperature to be measured; the temperature sensing cavity 4 and the pressure sensing cavity 3 are arranged opposite to each other along the direction in which light exits from the incident optical fiber 5.

[0027] The principle by which the sensor disclosed herein can achieve demodulation in the same demodulation device is as follows: the temperature sensing cavity 4 and the pressure sensing cavity 3 are arranged opposite each other along the direction in which light exits from the incident optical fiber 5, so that the light exiting from the incident optical fiber 5 is sequentially incident into the temperature sensing cavity and the pressure sensing cavity. Part of the light generates a partial reflection signal through the reflective end face of the temperature sensing cavity, which is superimposed with part of the incident light at the end of the incident optical fiber; part of the light generates a reflection signal through the end face forming the base of the pressure sensing cavity 3, and part of the light is reflected back to the end face forming the base of the pressure sensing cavity through the pressure-sensitive diaphragm 2 and superimposed, forming and outputting modulated light modulated by the pressure sensing cavity and the temperature sensing cavity. The modulated light carries optical path information corresponding to the cavity length of the pressure sensing cavity and the cavity length of the temperature sensing cavity. Therefore, demodulation of the temperature sensing cavity and the pressure sensing cavity can be realized in the same optical path.

[0028] The temperature sensing cavity 4 is arranged opposite to the pressure sensing cavity 3 along the direction of light emitted by the incident optical fiber 5, preferably the incident optical fiber 5 is directly opposite to the pressure sensing cavity 3, and the projection of the incident optical fiber 5 on the pressure sensitive diaphragm 2 is within the cross-sectional range of the pressure sensing cavity, so that the light emitted by the incident optical fiber 5 is entirely incident into the pressure sensing cavity. Preferably, when the pressure sensing cavity 3 is a circular cavity, the diameter of the pressure sensing cavity 3 is not less than the diameter of the incident optical fiber 5.

[0029] The reflective end face of the temperature sensing cavity can be the end face of the second end portion 12 of the base or the end face of the reflective optical fiber 51 arranged in the hollow tube. In one embodiment, as shown in FIG. 1, the reflective end face of the temperature sensing cavity is the end face of the second end portion 12 of the base, and the temperature sensing cavity 4 is formed between the end face of the second end portion 12 of the base and the end face of the incident optical fiber 5. The sensor structure and manufacturing process of the present embodiment are simple and low in cost. In one embodiment, as shown in FIG. 2, the reflective end face of the temperature sensing cavity is the end face of the reflective optical fiber 51 arranged in the hollow tube. In the present embodiment, the sensor further comprises a reflective optical fiber 51, which is arranged in the hollow tube 6 and fixed to the end face of the second end portion 12 of the base, and the temperature sensing cavity 4 is formed between the end face of the incident optical fiber 5 and the end face of the reflective optical fiber 51.

[0030] The difference between the cavity lengths of the pressure sensing cavity and the temperature sensing cavity is not limited, preferably the difference between the cavity lengths of the pressure sensing cavity and the temperature sensing cavity is not less than 1 μm, so as to ensure that the demodulation signals of the pressure sensing cavity and the temperature sensing cavity are not overlapped. Preferably, the difference between the cavity lengths of the pressure sensing cavity and the temperature sensing cavity is less than 100 μm, so as to realize the demodulation of the temperature sensing cavity and the pressure sensing cavity in the same channel of a demodulation device, and to reduce the range of the demodulation device and thus reduce the cost. The demodulation of the temperature sensing cavity and the pressure sensing cavity is realized in the same channel of the demodulation device, i.e. the demodulation of the temperature sensing cavity and the pressure sensing cavity is realized in the same optical path of the demodulation device.

[0031] The material of the base 1 is preferably glass, but other materials such as but not limited to single crystal silicon, silicon carbide, sapphire, etc. can also be selected, so as to achieve good light guiding performance. The thickness of the base can be selected to be 200 μm to 500 μm. The shape of the base is not limited.

[0032] The sensitivity of the temperature sensing cavity 4 is proportional to the length of the hollow tube and the thermal expansion coefficient of the hollow tube. The sensitivity of the temperature sensing cavity 4 can be adjusted by adjusting the material and length of the hollow tube 6. The thermal expansion coefficient of the hollow tube 6 covering the incident optical fiber 5 is preferably 2*10 -6 -30*10 -6The material of the hollow tube 6 can be glass, ceramic, stainless steel, etc. The longer the length of the hollow tube 6, the higher the sensitivity of the temperature sensing cavity. The sensor of the present disclosure forms a pressure sensing cavity and a temperature sensing cavity at two ends of the base respectively, and forms the temperature sensing cavity by the hollow tube and the incident optical fiber arranged in the hollow tube, which not only can demodulate the double-cavity length in the same demodulation device, but also realizes the improvement of the sensitivity of the temperature sensing cavity at the same time. Preferably, the length of the hollow tube 6 is not less than 0.5 mm. Taking the cavity length of 50-100 μm of a common temperature Fabry-Perot sensor as an example, the sensitivity can be improved by 5-10 times.

[0033] The hollow tube 6 can be fixed to the second end 12 of the base by, for example, bonding or laser welding. The inner diameter of the hollow tube 6 is smaller than the size of the base, so as to facilitate the fixation of the hollow tube 6 to the second end 12 of the base. The inner diameter of the hollow tube 6 is slightly larger than the outer diameter of the incident optical fiber 5. In an embodiment, the incident optical fiber is a multi-mode optical fiber, and the outer diameter of the incident optical fiber is 0.125 mm, and the inner diameter of the hollow tube 6 is 0.126-0.13 mm. The incident optical fiber 5 can be fixed to the tail end 61 of the hollow tube 6 by bonding or laser welding.

[0034] The pressure sensing cavity 3 is arranged in the base 1, and the pressure sensing cavity 3 can also be processed in the pressure sensitive diaphragm 2. The material of the pressure sensitive diaphragm 2 includes but is not limited to single crystal silicon. The thickness of the pressure sensitive diaphragm 2 can be selected to be 1-5 μm. Generally, the pressure sensing cavity 3 is formed in a vacuum state, which can improve the stability of the pressure sensing cavity. The cavity of the pressure sensing cavity 3 can be a cavity with a circular cross section, but is not limited thereto. For the circular cavity, the diameter thereof can be selected to be 80-300 μm.

[0035] With the change of pressure, the pressure sensitive diaphragm 2 can be deformed towards or away from the base 1, so as to change the cavity length of the pressure sensing cavity, and then be used for sensing pressure. The cavity length of the temperature sensing cavity changes with temperature. When the temperature rises, the hollow tube 6 drives the incident optical fiber 5 to expand, the cavity length of the temperature sensing cavity increases, and the interference signal of the temperature sensing cavity moves to the right in the spectral position; when the temperature decreases, the hollow tube 6 drives the incident optical fiber 5 to contract, the cavity length of the temperature sensing cavity decreases, and the interference signal of the temperature sensing cavity moves to the left in the spectral position.

[0036] Specifically, when measuring, the measuring light is introduced by the incident optical fiber 5. A part of the measuring light produces a partial reflection signal through the end face of the second end portion 12 of the base or the end face of the reflection optical fiber, and is superimposed with a part of the outgoing light at the incident optical fiber end portion; a part of the light produces a reflection signal through the end face of the base forming the pressure sensing cavity 3, and a part of the light is reflected back to the end face of the base forming the pressure sensing cavity 2 and is superimposed. The pressure change in the external environment causes the pressure sensitive diaphragm 2 to deform, changes the cavity length of the pressure sensing cavity 3, and thus changes the optical path difference. The temperature change in the external environment causes the temperature sensing cavity to deform, changes the cavity length of the temperature sensing cavity, and thus changes the optical path difference. By detecting the light signal transmitted back through the incident optical fiber 5, the cavity length of the pressure sensing cavity and the cavity length of the temperature sensing cavity can be obtained by demodulation.

[0037] In one embodiment, at least one local area of the pressure sensitive diaphragm 2 has a doping substance doped into the base material of the pressure sensitive diaphragm to produce stress, which can reduce the temperature coefficient of the pressure sensing cavity, so that the cavity length of the pressure sensing cavity does not change due to the change of temperature. The temperature coefficient of the pressure sensing cavity is low, so that temperature correction is not required. The doping substance can be one or more of the following materials: P, B, As, Al, Ga, Sb, Ge, O, Au, Fe, Cu, Ni, Zn, Mg.

[0038] In one embodiment, the sensor further comprises a reflective film arranged at the end face of the incident optical fiber and / or the reflective end face of the temperature sensing cavity. The material of the reflective film can be one of the following: Cr, Ti, Au, Ag, TaN, Al2O3, Ta2O5.

[0039] The sensor of the present disclosure includes a pressure sensing cavity formed between the first end portion of the base and the pressure sensitive diaphragm, and a temperature sensing cavity formed between the incident optical fiber in the hollow tube and the reflective end face of the temperature sensing cavity, which is oppositely arranged with the pressure sensing cavity along the direction in which light is emitted from the incident optical fiber. The light of the incident optical fiber is sequentially incident to the temperature sensing cavity and the pressure sensing cavity, forms and outputs modulated light modulated by the pressure sensing cavity and the temperature sensing cavity. The modulated light carries optical path information corresponding to the cavity length of the pressure sensing cavity and the cavity length of the temperature sensing cavity. The demodulation of the pressure sensing cavity and the temperature sensing cavity can be realized by the same demodulation device. Moreover, the sensor structure and manufacturing process of the present disclosure are simple and low in cost.

[0040] The present disclosure also provides a manufacturing method of a sensor, comprising: manufacturing a base having a cavity at a first end or a pressure sensitive diaphragm 2 having a cavity; combining the pressure sensitive diaphragm 2 and the first end 11 of the base together so that the cavity is enclosed by the pressure sensitive diaphragm 2 and the base 1 to form a pressure sensing cavity 3; fixing a hollow tube 6 to a second end 12 of the base and inserting an incident optical fiber 5 into the hollow tube 6 to form a temperature sensing cavity 4 so that the temperature sensing cavity 4 is oppositely arranged with the pressure sensing cavity 3 along a direction in which light is emitted from the incident optical fiber. The manufacturing method of the present disclosure is simple and low in cost. In one embodiment, the manufacturing method of a sensor further comprises the following steps: fixing a tail end 61 of the hollow tube to the incident optical fiber 5.

[0041] In one embodiment, the manufacturing method of a sensor further comprises the following steps: fixing a reflecting optical fiber in the hollow tube to the second end 12 of the base.

[0042] It should be noted that the steps listed above are preferred steps for manufacturing the sensor of the present disclosure, and the order of the operation steps is not limited. Based on the above description, a person skilled in the art can also change or omit a specific operation, add a specific operation, or adjust the order of one or more operation steps according to specific circumstances.

[0043] The present disclosure also provides an interferometric measurement system, comprising: a light source emitting coherent light; the above-mentioned sensor configured to receive the coherent light and form and output modulated light modulated by a to-be-measured pressure and a to-be-measured temperature; and an interference demodulation device configured to receive the modulated light and demodulate the modulated light to obtain an interference spectrum of the pressure sensing cavity and an interference spectrum of the temperature sensing cavity.

[0044] In one embodiment, the interference demodulation device comprises: a condenser configured to receive the modulated light; a first polarizer disposed downstream of the condenser and having a first polarization direction; a second polarizer disposed downstream of the first polarizer and having a second polarization direction perpendicular or parallel to the first polarization direction; and a birefringent element between the first polarizer and the second polarizer and having an optical axis at 45° or -45° to the first polarization direction.

[0045] The process of cavity length demodulation is as follows: light emitted by a light source (the light source is for example a white light LED, a xenon lamp or a halogen lamp) is coupled into an optical fiber and enters a coupler or optical circulator, and is transmitted to a sensor through an optical fiber from the other end, and the light signal reflected by the sensor enters the interference demodulation device again after passing through the coupler. The light beam entering the demodulation device forms a linear light beam after passing through a first polarizer, and is incident on a birefringent wedge. The linear light beam undergoes equal-thickness interference on the upper and lower surfaces of the birefringent wedge, and the interference spectrum of the pressure sensing cavity is obtained at a position where the thickness of the birefringent wedge is equal to the cavity length of the pressure sensing cavity, and the interference spectrum of the temperature sensing cavity is obtained at a position where the thickness of the birefringent wedge is equal to the cavity length of the temperature sensing cavity. The above describes that the demodulation of the temperature sensing cavity and the pressure sensing cavity is realized in the same channel of the demodulation device, that is, the demodulation of the temperature sensing cavity and the pressure sensing cavity is realized in the same optical path of the demodulation device, for example, the light signal reflected by the sensor and modulated by the to-be-measured pressure and the to-be-measured temperature passes through the same polarizer and birefringent element in sequence in the same optical fiber to obtain the interference spectrum of the pressure sensing cavity and the interference spectrum of the temperature sensing cavity.

[0046] When the pressure acting on the pressure-sensitive diaphragm and / or the temperature changes, the cavity length of the pressure sensing cavity and / or the cavity length of the temperature sensing cavity changes, and the position of the interference spectrum of the pressure sensing cavity and / or the temperature sensing cavity changes, so that the size of the pressure and the temperature is calculated. As shown in FIG. 3, the simulation result of the demodulation signal of the sensor based on the white light interference coherent demodulation method is shown, and from the figure it can be seen that the interference spectrum of the temperature sensing cavity and the interference spectrum of the pressure sensing cavity appear on the same interference spectrum diagram.

[0047] The interference measurement system of the present disclosure can realize the demodulation of the pressure sensing cavity and the temperature sensing cavity through the same demodulation device, and has simple structure and manufacturing process and low cost.

Claims

1. A sensor, characterized by The sensor comprises: a base, a first end of the base being provided with a pressure sensitive diaphragm, an end surface of a second end of the base opposite to the first end being fixedly connected with a hollow tube; a pressure sensing cavity formed between the first end of the base and the pressure sensitive diaphragm and enclosed by the first end of the base and the pressure sensitive diaphragm, a cavity length of the pressure sensing cavity changing according to a change of a pressure to be measured; a temperature sensing cavity formed between an incident optical fiber in the hollow tube and a reflecting end surface of the temperature sensing cavity, a cavity length of the temperature sensing cavity changing according to a change of a temperature to be measured; the temperature sensing cavity and the pressure sensing cavity are oppositely arranged along a direction in which light is emitted from the incident optical fiber.

2. The sensor of claim 1, wherein, The reflecting end surface of the temperature sensing cavity is the end surface of the second end of the base, and the temperature sensing cavity is formed between the end surface of the second end of the base and an end surface of the incident optical fiber.

3. The sensor of claim 1, wherein, Further comprising a reflecting optical fiber arranged in the hollow tube, the reflecting optical fiber being fixed to the end surface of the second end of the base, and the temperature sensing cavity being formed between the end surface of the incident optical fiber and an end surface of the reflecting optical fiber.

4. The sensor of claim 1, wherein, The coefficient of thermal expansion of the hollow tube is 2*10 -6 / k-30*10 -6 / k.

5. The sensor of claim 1, wherein, The length of the hollow tube is not less than 0.5 mm.

6. The sensor of claim 1, wherein, At least one local area of the pressure sensitive diaphragm has a doping substance doped into a base material of the pressure sensitive diaphragm to generate stress.

7. The sensor of claim 1, wherein, The difference between the cavity length of the temperature sensing cavity and the cavity length of the pressure sensing cavity is not less than 1 μm.

8. The sensor of claim 1, wherein, The difference between the cavity length of the temperature sensing cavity and the cavity length of the pressure sensing cavity is less than 100 μm.

9. A method of manufacturing a sensor, characterized by, The sensor comprises: manufacturing a base having a cavity at a first end or a pressure sensitive diaphragm having a cavity; bonding the pressure sensitive diaphragm and the first end of the base together so that the cavity is enclosed by the pressure sensitive diaphragm and the base to form a pressure sensing cavity; fixing a hollow tube to a second end of the base and inserting an incident optical fiber into the hollow tube to form a temperature sensing cavity so that the temperature sensing cavity and the pressure sensing cavity are oppositely arranged along a direction in which light is emitted from the incident optical fiber.

10. An interferometry system, comprising: The interference measurement system comprises: a light source emitting coherent light; a sensor according to any one of claims 1-8 configured to receive the coherent light and form and output modulated light modulated by the pressure to be measured and the temperature to be measured; an interference demodulation device configured to receive the modulated light and demodulate the modulated light to obtain an interference spectrum of the pressure sensing cavity and an interference spectrum of the temperature sensing cavity.

11. The interferometry system of claim 10, wherein, The interference demodulation device comprises: a condenser configured to receive modulated light; a first polarizer arranged downstream of the condenser and having a first polarization direction; a second polarizer arranged downstream of the first polarizer and having a second polarization direction perpendicular or parallel to the first polarization direction; and a birefringent element located between the first polarizer and the second polarizer and having an optical axis at 45° or -45° to the first polarization direction.

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