Double-FP interference cavity sensing probe, detection method and manufacturing method

Abstract

The invention discloses a double-FP interference cavity sensing probe, a detection method and a manufacturing method, and belongs to the field of optical fiber sensors.The double-FP interference cavity sensing probe comprises a metal shell, a spring oscillator structure is arranged in the metal shell, an elastic thin film is arranged below the spring oscillator structure, an optical fiber is arranged below the elastic thin film, and the optical fiber is arranged below the elastic thin film. The top end of the optical fiber is inserted into the metal shell, the top end of the optical fiber is an optical fiber end face, an FP interference cavity is formed between the optical fiber end face and the bottom end of the elastic film, and an FP interference cavity is formed between the bottom end of the spring oscillator structure and the top end of the elastic film. According to the double-FP interference cavity sensing probe, the detection method and the manufacturing method, the detection advantages of scalar signals and vector signals are integrated, simultaneous detection of the scalar signals and the vector signals is achieved, higher environmental adaptability is achieved, and the double-FP interference cavity sensing probe can be used for various actual scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber sensors, and in particular to a double FP interference cavity sensing probe, a detection method and a manufacturing method. Background Art

[0002] The FP interferometer cavity, also known as the Fabry-Pérot resonant cavity, is an optical resonant cavity composed of two parallel mirrors. It has a wide range of applications in the fields of optics and lasers, and is used in optical interference, lasers, sensors, spectroscopy, etc.

[0003] Fiber optic scalar sensor probes are mainly used to detect physical quantities such as light intensity, temperature, pressure, and strain. Its working principle usually relies on the intensity change of the signal transmitted in the optical fiber, but the accuracy requirement is difficult to meet the current application scenarios and actual requirements. The fiber optic vector sensor probe can not only sense the amplitude of the signal, but also obtain information such as the directionality or polarization state of the signal. Its accuracy is greatly improved compared to the scalar sensor probe, but it is more susceptible to external environmental influences, such as temperature changes, mechanical vibrations, chemical corrosion, etc., which may cause signal interference or system instability.

[0004] Existing optical fiber scalar sensor probes and optical fiber vector sensor probes can only detect scalar signals and vector signals, but cannot detect scalar signals and vector signals at the same time, and have worse environmental adaptability. Summary of the invention

[0005] The purpose of the present invention is to provide a dual FP interferometer cavity sensor probe, a detection method and a manufacturing method, which integrate the detection advantages of scalar signals and vector signals, realize the simultaneous detection of scalar signals and vector signals, have stronger environmental adaptability, and can be used in a variety of practical scenarios.

[0006] To achieve the above-mentioned purpose, the present invention provides a dual FP interference cavity sensing probe, comprising a metal shell, a spring oscillator structure is arranged inside the metal shell, an elastic film is arranged below the spring oscillator structure, an optical fiber is arranged below the elastic film, the top end of the optical fiber is inserted into the metal shell, the top end of the optical fiber is the optical fiber end face, an FP interference cavity is formed between the optical fiber end face and the bottom end of the elastic film, and an FP interference cavity is formed between the bottom end of the spring oscillator structure and the top end of the elastic film.

[0007] Preferably, the metal shell comprises an upper metal cover and a lower metal cover, and the upper metal cover and the lower metal cover are locked and connected via a locking element.

[0008] Preferably, the spring oscillator comprises an upper mass block, a lower mass block, and an elastic diaphragm between the upper mass block and the lower mass block, and the upper mass block and the lower mass block are fixed by a fixing element.

[0009] Preferably, a groove is provided on the upper metal cover, and the elastic diaphragm is glued into the groove of the upper metal cover.

[0010] Preferably, the elastic film is installed inside the lower metal cover.

[0011] Preferably, the bottom end of the lower mass block and the end face of the optical fiber are both coated with a reflective film.

[0012] Preferably, the reflectivity of the reflective film at the bottom end of the lower mass block is 100%, the reflectivity of the reflective film on the end face of the optical fiber is 30%, and the reflectivity of the elastic film is 20%-70%.

[0013] Preferably, the ratio of the distance between the bottom end of the lower mass block and the elastic film to the distance between the elastic film and the end face of the optical fiber is greater than 2:1.

[0014] The present invention provides a method for manufacturing a dual FP interferometer cavity sensor probe, comprising the following steps: Step 1: fix the upper mass block and the lower mass block to the upper and lower surfaces of the elastic film respectively by fixing elements, and plate a reflectivity film on the lower end surface of the lower mass block to form a spring oscillator; Step 2: Fix the assembled spring vibrator to the groove of the upper metal cover with AB glue; Step 3, installing the elastic film on the lower part of the lower metal cover, inserting the optical fiber from the bottom end of the lower metal cover, and retaining the optical fiber interface; Step 4, assemble the upper metal cover and the lower metal cover, and lock them with a locking element; Step five, the stripped and cut optical fiber is fused with the jumper, and various parameters are subsequently collected and processed.

[0015] The present invention provides a detection method for a dual FP interferometer cavity sensor probe, comprising the following steps: When the sensing probe receives the vector signal in the axial direction of the upper mass block and the lower mass block, the length of the FP interference cavity formed by the bottom end of the lower mass block and the elastic film will become longer or shorter, resulting in a phase change, and the vector signal is detected; When the sensor probe receives a scalar signal, the elastic film is deformed, and the FP interference cavity formed between the elastic film and the optical fiber end face becomes longer or shorter, resulting in a phase change, thereby detecting the scalar signal.

[0016] Therefore, the present invention adopts the above-mentioned dual FP interferometer cavity sensor probe, detection method and manufacturing method, which has the following beneficial effects: (1) The present invention can detect vector signals and scalar signals simultaneously through a dual FP interferometer cavity, has stronger environmental adaptability, can detect more abundant parameters, and has a wide range of application scenarios; (2) The sensor probe of the present invention is light in weight and small in size, and has a wider range of application scenarios; (3) The sensor probe of the present invention can ensure both accuracy and stability by forming a double FP interference cavity.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the upper metal cover according to an embodiment of the present invention; Figure 3 Schematic diagram of the internal structure of the metal shell according to an embodiment of the present invention.

[0019] Reference numerals 1. Upper mass block; 2. Elastic diaphragm; 3. Upper metal cover; 4. Lower metal cover; 5. Elastic film; 6. Optical fiber; 7. Lower mass block. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0021] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0022] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0024] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Example like Figure 1 , Figure 2 As shown, a dual FP interferometric cavity sensing probe according to the present invention comprises a metal shell, and a spring oscillator structure is arranged inside the metal shell. The metal shell comprises an upper metal cover 3 and a lower metal cover 4, and the upper metal cover 3 and the lower metal cover 4 are locked and connected by a locking element. The locking element can be a screw, and the two metal shells are locked by reserved threaded holes corresponding to each other in the upper metal cover 3 and the lower metal cover 4.

[0026] like Figure 3 As shown, the spring vibrator includes an upper mass block 1, a lower mass block 7, and an elastic diaphragm 2 between the upper mass block 1 and the lower mass block 7. The upper mass block 1 and the lower mass block 7 are fixed by a fixing element. The fixing element can be a screw, and the two mass blocks are fixed tightly through the threaded holes reserved on the two mass blocks. A groove is provided on the upper metal cover 3, and the elastic diaphragm 2 is glued into the groove of the upper metal cover 3. The elastic diaphragm 2 is a metal sheet made of beryllium bronze with a thickness of 0.2 mm. The upper mass block 1 and the lower mass block 7 are two metal blocks made of brass, which are used to increase sensitivity.

[0027] An elastic film 5 is arranged below the spring oscillator structure, and an FP interference cavity is formed between the bottom end of the lower mass block 7 and the top end of the elastic film 5. The elastic film 5 is installed inside the lower metal cover 4, and the elastic film 5 is a PET film with a reflectivity of 20%-70%.

[0028] An optical fiber 6 is disposed below the elastic film 5, and the top end of the optical fiber 6 is inserted into the metal housing. The top end of the optical fiber 6 is the end face of the optical fiber 6, and an FP interference cavity is formed between the end face of the optical fiber 6 and the bottom end of the elastic film 5. The optical fiber 6 is a single-mode optical fiber 6, and the type is not limited. The loss of the single-mode optical fiber 6 can be ignored.

[0029] The bottom end of the lower mass block 7 and the end face of the optical fiber 6 are both coated with a reflective film. The reflectivity of the reflective film at the bottom end of the lower mass block 7 is close to 100%, and the reflectivity of the reflective film on the end face of the optical fiber 6 is 30%. The ratio of the distance between the bottom end of the lower mass block 7 and the elastic film 5 to the distance between the elastic film 5 and the end face of the optical fiber 6 is greater than 2:1.

[0030] The manufacturing method of a dual FP interferometer cavity sensor probe described in the present invention comprises the following steps: Step 1: fix the upper mass block 1 and the lower mass block 7 to the upper and lower surfaces of the elastic film 5 with screws respectively, and plate a reflectivity film on the lower end surface of the lower mass block 7 to form a spring oscillator; Step 2: fix the assembled spring vibrator to the groove of the upper metal cover 3 with AB glue; Step 3, install the elastic film 5 on the lower part of the lower metal cover 4, insert the optical fiber 6 from the bottom end of the lower metal cover 4, and retain the interface of the optical fiber 6; Step 4: Assemble the upper metal cover 3 and the lower metal end cover and tighten them with screws; Step five, the stripped and cut optical fiber 6 is fused with the jumper, and various parameters are subsequently collected and processed.

[0031] The detection method of a dual FP interferometric cavity sensing probe of the present invention comprises the following steps: When the sensing probe receives the vector signal in the axial direction of the upper mass block 1 and the lower mass block 7, the length of the FP interference cavity formed by the bottom end of the lower mass block 7 and the elastic film 5 will become longer or shorter, resulting in a phase change, and the vector signal is detected; When the sensor probe receives a scalar signal, the elastic film 5 is deformed, and the FP interference cavity formed between the elastic film 5 and the end face of the optical fiber 6 becomes longer or shorter, resulting in a phase change, and the scalar signal is detected.

[0032] Therefore, the present invention adopts the above-mentioned dual FP interferometer cavity sensor probe, detection method and manufacturing method, combines the detection advantages of scalar signals and vector signals, realizes simultaneous detection of scalar signals and vector signals, has stronger environmental adaptability, and can be used in a variety of practical scenarios.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A dual FP interferometric cavity sensing probe, characterized in that: It includes a metal shell, a spring oscillator structure is arranged inside the metal shell, an elastic film is arranged below the spring oscillator structure, an optical fiber is arranged below the elastic film, the top end of the optical fiber is inserted into the metal shell, the top end of the optical fiber is the optical fiber end face, an FP interference cavity is formed between the optical fiber end face and the bottom end of the elastic film, and an FP interference cavity is formed between the bottom end of the spring oscillator structure and the top end of the elastic film.

2. The dual FP interferometric cavity sensing probe according to claim 1, characterized in that: The metal shell comprises an upper metal cover and a lower metal cover, and the upper metal cover and the lower metal cover are locked and connected via a locking element.

3. The dual FP interferometric cavity sensing probe according to claim 2, characterized in that: The spring oscillator comprises an upper mass block, a lower mass block, and an elastic diaphragm between the upper mass block and the lower mass block. The upper mass block and the lower mass block are fixed by a fixing element.

4. The dual FP interferometric cavity sensing probe according to claim 3, characterized in that: The upper metal cover is provided with a groove, and the elastic diaphragm is glued in the groove of the upper metal cover.

5. The dual FP interferometric cavity sensing probe according to claim 4, characterized in that: The elastic film is installed inside the lower metal cover.

6. The dual FP interferometric cavity sensing probe according to claim 5, characterized in that: The bottom end of the lower mass block and the end face of the optical fiber are both plated with a reflective film.

7. The dual FP interferometric cavity sensing probe according to claim 6, characterized in that: The reflectivity of the reflective film at the bottom of the lower mass block is 100%, the reflectivity of the reflective film on the end face of the optical fiber is 30%, and the reflectivity of the elastic film is 20%-70%.

8. The dual FP interferometric cavity sensing probe according to claim 1, characterized in that: The ratio of the distance between the bottom end of the lower mass block and the elastic film to the distance between the elastic film and the end face of the optical fiber is greater than 2:

1.

9. A method for manufacturing a dual FP interferometric cavity sensing probe according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: fix the upper mass block and the lower mass block to the upper and lower surfaces of the elastic film respectively by fixing elements, and plate a reflectivity film on the lower end surface of the lower mass block to form a spring oscillator; Step 2: Fix the assembled spring vibrator to the groove of the upper metal cover with AB glue; Step 3, installing the elastic film on the lower part of the lower metal cover, inserting the optical fiber from the bottom end of the lower metal cover, and retaining the optical fiber interface; Step 4, assemble the upper metal cover and the lower metal cover, and lock them with a locking element; Step five, the stripped and cut optical fiber is fused with the jumper, and various parameters are subsequently collected and processed.

10. A detection method for a dual FP interferometric cavity sensing probe according to any one of claims 1 to 8, characterized in that: The following steps are involved: When the sensing probe receives the vector signal in the axial direction of the upper mass block and the lower mass block, the length of the FP interference cavity formed by the bottom end of the lower mass block and the elastic film will become longer or shorter, resulting in a phase change, and the vector signal is detected; When the sensor probe receives a scalar signal, the elastic film is deformed, and the FP interference cavity formed between the elastic film and the optical fiber end face becomes longer or shorter, resulting in a phase change, thereby detecting the scalar signal.

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