CN-114755535-B - Optical fiber Fabry-Perot ultrasonic sensor and manufacturing method thereof

CN114755535BCN 114755535 BCN114755535 BCN 114755535BCN-114755535-B

Abstract

The invention relates to an optical fiber Fabry-Perot ultrasonic sensor and a manufacturing method thereof, wherein the double-sided groove type quartz diaphragm is prepared by utilizing photoetching and hydrofluoric acid corrosion technology on the basis of a traditional quartz diaphragm, the central thickness of the quartz diaphragm is reduced, the quartz diaphragm can generate larger deformation when being subjected to ultrasonic action, the sensor is more sensitive and accurate to capture a local discharge signal, the sensor sensitivity is improved, the natural frequency of the diaphragm is improved, the frequency detection range of the sensor is increased, a plurality of rectangular grooves arranged on the quartz diaphragm are communicated with air inside and outside a Fabry-Perot cavity, the sensor measurement error caused by gas expansion in the cavity after the temperature is increased is avoided, the external environment gas can conveniently enter the Fabry-Perot cavity, the change of the environment gas can be judged by utilizing the change of different gas refractive indexes, the double-parameter sensor is realized, the whole device has the advantages of simple structure, the whole stability is good, the service period is long, the manufacturing cost is low, and the optical fiber Fabry-Perot ultrasonic sensor is suitable for practical use.

Inventors

WANG TINGYUN
Niu xiling
HUANG YI
DENG CHUANLU
HU CHENGYONG
ZHANG XIAOBEI

Assignees

上海大学
上海大学

Dates

Publication Date: 20260421
Application Date: 20220302
Priority Date: 20220302

Claims (3)

1. The optical fiber Fabry-Perot ultrasonic sensor is characterized by comprising a quartz diaphragm, wherein one end of the quartz diaphragm is provided with a first groove, and the other end of the quartz diaphragm is provided with a plurality of second grooves; the quartz tube is provided with a third groove and a fourth groove along the length direction of the quartz tube, the third groove and the fourth groove are communicated with each other, and after the quartz diaphragm is connected with the quartz tube, a cavity formed by the quartz diaphragm and the third groove is communicated with the outside through the second groove, so that the outside gas enters the cavity; The quartz tube comprises a first quartz tube, a second quartz tube and a third quartz tube which are all in a circular tube shape, the first quartz tube is sleeved on a single-mode optical fiber, the second quartz tube is sleeved on the first quartz tube, and the third quartz tube is sleeved on the second quartz tube, wherein one ends of the single-mode optical fiber, the first quartz tube and the second quartz tube which are positioned on the same side are positioned in the same plane, and the third quartz tube form the third groove; A first reflection enhancing film is arranged on the end face of the single-mode fiber adjacent to the third groove, and a second reflection enhancing film is arranged on the end face of the quartz diaphragm connected with the quartz tube; the quartz diaphragm is cylindrical, and the quartz diaphragm and the quartz tube are coaxially arranged; the first groove is coaxially arranged on the quartz diaphragm; the second grooves are symmetrically arranged by taking the center of the end face as the center.
2. A method for manufacturing an optical fiber Fabry-Perot ultrasonic sensor according to claim 1 is characterized by comprising the steps of inserting a single-mode fiber into a first quartz tube, enabling a plane where one end of the single-mode fiber is located to be flush with a plane where one end of the first quartz tube is located, fixing the single-mode fiber on the first quartz tube, sleeving a second quartz tube on the first quartz tube, enabling one end of the first quartz tube flush with the single-mode fiber to be flush with one end of the second quartz tube, fixing the second quartz tube on the first quartz tube, inserting a combination of the fixed first quartz tube, the second quartz tube and the single-mode fiber into the third quartz tube, enabling one end of the third quartz tube and one end of the combination to be far away from each other to form a third groove, adjusting the depth of the third groove formed by the third quartz tube and the combination through a microscope, then fixing the third quartz tube on the second quartz tube, tightly fitting one end of the quartz diaphragm provided with the second groove with the third quartz tube, enabling the fixed quartz diaphragm to form a cavity with the third groove with the quartz tube, and fixing the third quartz diaphragm together.
3. A method for manufacturing a quartz diaphragm of an optical fiber Fabry-Perot ultrasonic sensor according to claim 2 is characterized by comprising the steps of uniformly coating a layer of photoresist on the quartz diaphragm, baking the photoresist until the photoresist is solidified, photoetching a photoresist area except for a pattern corresponding to a first groove on one end face of the quartz diaphragm according to the shape and the position of the first groove and a second groove, photoetching a photoresist area except for a pattern corresponding to the second groove on the other end face of the quartz diaphragm, flushing the quartz diaphragm after photoetching by adopting a developing solution, flushing photoresist of the non-photoetching area, exposing quartz, keeping the photoresist of the photoetching area on the quartz diaphragm, pickling the flushed quartz diaphragm, etching the areas without photoresist covering on the two end faces of the quartz diaphragm to obtain the first groove and the second groove, controlling the pickling time until the depths of the first groove and the second groove reach a preset depth, taking out the quartz diaphragm, and cleaning the cleaned quartz diaphragm.

Description

Optical fiber Fabry-Perot ultrasonic sensor and manufacturing method thereof Technical Field The invention relates to the technical field of ultrasonic sensing, in particular to an optical fiber Fabry-Perot ultrasonic sensor and a manufacturing method thereof. Background The optical fiber Fabry-Perot ultrasonic sensor is an important component of a partial discharge on-line monitoring system, judges whether partial discharge phenomenon exists by detecting ultrasonic signals synchronously generated during partial discharge, and is widely applied to fault monitoring of electrical cable equipment. The existing optical fiber Fabry-Perot sensor has contradiction between detection sensitivity and frequency detection range, is difficult to realize high sensitivity and wide detection range at the same time, has a single structure, cannot be structurally adjusted according to application scenes, and accordingly obtains more accurate sensing results, and is mainly characterized in that a sealed cavity is adopted as the Fabry-Perot cavity, when the temperature rises, air in the Fabry-Perot cavity expands, expanded gas extrudes the cavity, the length of the cavity is possibly changed, the final detection result is influenced, false alarm is caused, and the existing optical fiber Fabry-Perot sensor can only detect single parameters, and the utilization rate of detection equipment is low. Disclosure of Invention The optical fiber Fabry-Perot sensor has the advantages that the contradiction between detection sensitivity and frequency detection range in the optical fiber Fabry-Perot sensor in the prior art is overcome, high sensitivity and wide detection range are difficult to realize at the same time, the sensor is single in structure, structure adjustment cannot be conducted on an application scene, so that a more accurate sensing result is obtained, the existing optical fiber Fabry-Perot sensor mainly adopts a sealed cavity as a Fabry-Perot cavity, when the temperature rises, air in the Fabry-Perot cavity expands, expanded gas extrudes the cavity, the change of the cavity length possibly occurs, the final detection result is influenced, false alarm is caused, the existing optical fiber Fabry-Perot sensor only can detect a single parameter, and the utilization rate of detection equipment is low. In order to solve the technical problems, the present invention provides an optical fiber fabry perot ultrasonic sensor, comprising: the quartz membrane is provided with a first groove at one end and a plurality of second grooves at the other end; The quartz tube is provided with a third groove and a fourth groove along the length direction of the quartz tube, the third groove and the fourth groove are communicated with each other, and after the quartz diaphragm is connected with the quartz tube, a cavity formed by the quartz diaphragm and the third groove is communicated with the outside through the second groove, so that the outside air enters the cavity; And the single mode fiber is arranged in the fourth groove, and the end surfaces of the single mode fiber adjacent to the quartz diaphragm form two reflecting surfaces of the Fabry-Perot cavity. In one embodiment of the present invention, the quartz tube includes a first quartz tube, a second quartz tube and a third quartz tube, which are all in a circular tube shape, the first quartz tube is sleeved on a single-mode fiber, the second quartz tube is sleeved on the first quartz tube, and the third quartz tube is sleeved on the second quartz tube, where one ends of the single-mode fiber, the first quartz tube and the second quartz tube on the same side are located in the same plane, and the third groove is formed by the third quartz tube and the first quartz tube. In one embodiment of the invention, a first reflection enhancing film is arranged on the end face of the single-mode fiber adjacent to the third groove, and a second reflection enhancing film is arranged on the end face of the quartz diaphragm connected with the quartz tube. In one embodiment of the invention, the quartz diaphragm is cylindrical and is arranged coaxially with the quartz tube. In one embodiment of the present invention, the first groove is coaxially disposed on the quartz diaphragm. In one embodiment of the present invention, the plurality of second grooves are symmetrically arranged with the center of the end face as the center. A method for manufacturing an optical fiber Fabry-Perot ultrasonic sensor according to any one of the above steps, Inserting a single-mode fiber into the first quartz tube, enabling the plane of one end of the single-mode fiber to be flush with the plane of one end of the first quartz tube, and fixing the single-mode fiber on the first quartz tube; The second quartz tube is sleeved on the first quartz tube, so that one flush end of the first quartz tube and the single-mode fiber is flush with one end of the second quartz tube, and the second quartz tube is fixed on the first qu