A processing method for preparing a smooth end face of a microstructured optical fiber

Abstract

The present invention relates to a processing method for preparing a smooth end face of a microstructure optical fiber, and the steps are as follows: 1. inserting the end of the optical fiber to be processed vertically into a concentrated sulfuric acid corrosive solution, and removing the coating layer of the optical fiber when an inert gas is introduced into the optical fiber air hole at the other end of the optical fiber, so as to obtain a bare optical fiber of a required length; 2. preliminarily rinsing the corroded optical fiber end with distilled water; 3. placing the optical fiber end in an ultrasonic cleaning machine for deep cleaning; 4. vertically inserting the bare optical fiber end to be processed into the corrosive solution, and removing the end face of the bare optical fiber when an inert gas is introduced into the optical fiber air hole at the other end of the optical fiber; 5. preliminarily rinsing the corroded bare optical fiber end with distilled water; 6. placing the bare optical fiber end in an ultrasonic cleaning machine for deep cleaning; 7. drying the optical fiber end after deep cleaning to complete the end face smoothing of the optical fiber. The present invention can obtain a smooth microstructure optical fiber end face on the one hand, and will not cause damage to the optical fiber on the other hand.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber processing, relates to an end face processing technology of a microstructure optical fiber, and specifically relates to a processing method for preparing a smooth end face of a microstructure optical fiber. Background Art

[0002] The core or cladding of microstructured optical fiber is no longer a single structure of traditional optical fiber, but introduces some tiny structures, such as defective structure in the core and periodic structure in the cladding, so as to obtain the required light transmission characteristics. Microstructured optical fiber has the characteristics of single material, good temperature characteristics, small bending loss, flexible dispersion characteristics, etc., and is an ideal new material for optical fiber sensing and optical communication. Microstructured optical fiber, especially hollow core bandgap photonic crystal fiber, is more fragile than ordinary optical fiber due to the thin wall structure inside the optical fiber. The introduction of mechanical stress during use is more likely to produce microcracks. When the optical fiber is used, the stripping of the optical fiber coating and the smoothing of the end face of the fusion spliced ​​optical fiber are more difficult than those of ordinary optical fiber. Usually, optical fiber adopts mechanical coating stripping and mechanical fiber cutting, and the application is relatively mature. However, mechanical stripping can easily cause the stripping position to be damaged due to excessive mechanical stress of stripping, causing the microporous structure inside the microstructured optical fiber to change and affect the light transmission characteristics, and even break with the damaged microcracks; mechanical cutters can easily leave knife marks on the end face of the optical fiber, and even cause problems such as collapse of the microstructured optical fiber hole wall, uneven end face of the optical fiber, and unsatisfactory cutting angle. At the same time, there are many types of existing microstructured optical fibers, and existing tools often cannot directly meet usage requirements. A lot of time is required for adjustment and the above problems cannot be avoided, which increases the difficulty of the application of microstructured optical fibers. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a processing method for preparing a smooth end face of a microstructured optical fiber, which can obtain a smooth end face of a microstructured optical fiber and will not cause damage to the optical fiber.

[0004] One of the purposes of the present invention is achieved through the following technical solution:

[0005] A method for preparing a smooth end face of a microstructured optical fiber, characterized in that it comprises the following steps:

[0006] Step 1, vertically insert the end of the optical fiber to be treated into a concentrated sulfuric acid corrosive solution, and remove the coating layer of the optical fiber by etching while passing an inert gas into the optical fiber air hole at the other end of the optical fiber to obtain a bare optical fiber of the required length;

[0007] Step 2, preliminarily rinse the corroded optical fiber end with distilled water;

[0008] Step 3: Place the fiber end after preliminary rinsing in an ultrasonic cleaning machine for deep cleaning and wipe it clean;

[0009] Step 4, vertically insert the bare optical fiber end to be processed into the etching solution, and when an inert gas is introduced into the optical fiber air hole at the other end of the optical fiber, the end face of the bare optical fiber is corroded and removed by etching;

[0010] Step 5, preliminarily rinse the bare optical fiber end that has been corroded with distilled water;

[0011] Step 6: Place the bare optical fiber end after preliminary washing in an ultrasonic cleaning machine for deep cleaning;

[0012] Step 7: Dry the optical fiber end after deep cleaning to complete the end face smoothing of the optical fiber.

[0013] Further: in step 1 and step 4, an inflation air pump is connected to the non-immersed end of the optical fiber, and an inert gas is introduced through the inflation air pump.

[0014] Further: in step 4, the etching liquid is a hydrofluoric acid etching liquid, the concentration of the hydrofluoric acid etching liquid is less than 1 mol / L, and the temperature of the hydrofluoric acid etching liquid is 40-50°C.

[0015] Further: the hydrofluoric acid etching solution is contained in a corrosion reaction container, and the corrosion reaction container is placed on a heating and heat preservation plate.

[0016] Further: in step 1 and step 4, an optical fiber clamp adjustment frame is used to vertically fix the optical fiber; the optical fiber clamp adjustment frame includes a bottom support plate, a column, a crossbeam, an optical fiber end fixing seat, and an optical fiber clamping head; the bottom support plate is used to support the corrosion reaction container, the bottom support plate is connected to a plurality of leveling screws, and a spirit level is provided at the upper end of the bottom support plate; the column is vertically fixed to the upper end of the bottom support plate, the crossbeam is connected to the column in an adjustable manner up and down, a locking screw is connected to one end of the crossbeam to fix the crossbeam to the column, the optical fiber clamping head is fixed to the other end of the crossbeam, and a clamping hole is provided on the optical fiber clamping head for vertically passing the end of the optical fiber to be processed; the optical fiber end fixing seat is fixedly installed on the top of the column, and is used to fix the end of the optical fiber that does not need to be processed.

[0017] The advantages and positive effects of the present invention are:

[0018] 1. The present invention adopts chemical corrosion to avoid mechanical stress damage caused by mechanical stripping and cutting.

[0019] 2. The present invention uses concentrated sulfuric acid to remove the optical fiber coating, and the removal length is adjustable, thereby avoiding damage to the microstructure optical fiber caused by mechanical stripping stress.

[0020] 3. The existing common corrosion method is prone to excessive corrosion of the air hole edge by the corrosive liquid due to the surface tension of the liquid, causing the thin-walled structure of the microstructure optical fiber to be corroded and damaged. The end face of the optical fiber after corrosion is uneven, which is easy to destroy the light-guiding characteristics of the microstructure optical fiber, affecting the subsequent processing and application of the microstructure optical fiber. The present invention uses a hydrofluoric acid solution to corrode the end face of the optical fiber, and at the same time uses an air pump to fill the optical fiber air hole with an inert gas. On the one hand, the inert gas fills the air hole of the optical fiber, avoiding the excessive corrosion of the edge of the optical fiber air hole by the corrosive liquid due to the surface tension of the liquid. On the other hand, the inert gas is used, and the inert gas will not react chemically with the corrosive liquid, and has good stability, so it will not have an adverse effect on the end face corrosion treatment of the optical fiber.

[0021] 4. The optical fiber end face processed by the present invention is flat, which is conducive to subsequent welding, sensor device manufacturing and other operations. It is compatible with the processing of optical fibers of various fiber diameters, has no special length requirement for stripping the optical fiber coating layer, can effectively shorten the secondary coating length after optical fiber welding, and can effectively improve the tensile strength of the melting point after welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of a microstructured optical fiber;

[0023] Figure 2 It is a structural schematic diagram of the present invention for performing corrosion operation. DETAILED DESCRIPTION

[0024] The structure of the present invention is further described below with reference to the accompanying drawings and by way of examples. It should be noted that the present examples are descriptive rather than restrictive.

[0025] A processing method for preparing a smooth end face of a microstructured optical fiber mainly includes seven steps;

[0026] Step 1, vertically insert the end of the optical fiber to be treated into a concentrated sulfuric acid corrosive solution, and remove the coating layer of the optical fiber by etching while passing an inert gas into the optical fiber air hole at the other end of the optical fiber to obtain a bare optical fiber of the required length;

[0027] Step 2, preliminarily rinse the corroded optical fiber end with distilled water;

[0028] Step 3: Place the fiber end after preliminary rinsing in an ultrasonic cleaning machine for deep cleaning and wipe it clean;

[0029] Step 4, vertically insert the bare optical fiber end to be processed into the etching solution, and when an inert gas is introduced into the optical fiber air hole at the other end of the optical fiber, the end face of the bare optical fiber is corroded and removed by etching;

[0030] Step 5, preliminarily rinse the bare optical fiber end that has been corroded with distilled water;

[0031] Step 6: Place the bare optical fiber end after preliminary washing in an ultrasonic cleaning machine for deep cleaning;

[0032] Step 7: Dry the fiber end after deep cleaning to complete the end surface smoothing of the fiber

[0033] The device used in the treatment method mainly includes a corrosive liquid container, an ultrasonic cleaning machine, a heating and heat preservation plate, an optical fiber clamp adjustment frame and an air pump.

[0034] The present invention uses the corrosive dissolving effect of acid, alkali or salt to perform chemical corrosion to obtain a special processing method of the desired state. First, the coating layer of the optical fiber to be processed is corroded and removed using concentrated sulfuric acid corrosive solution without damaging the optical fiber cladding. Then, the bare optical fiber end is corroded using hydrofluoric acid solution. Hydrofluoric acid is a weak acid with hydrogen bonds and HF covalent bonds between molecules. It has high stability and low ionization degree and partially dissociates in a dilute solution. The material of the optical fiber is quartz material. The chemical reaction between quartz material and hydrofluoric acid can be expressed as

[0035] SiO2+4HF→SiF4+2H2O

[0036] In order to ensure the corrosion rate of the corrosion solution, the corrosion solution is heated and kept warm by a heating and heat preservation plate 7 arranged at the bottom of the corrosion solution container 8, and the temperature is 40-50°C.

[0037] The optical fiber clamp adjustment frame includes a bottom support plate 6, a column 2, a crossbeam 3, an optical fiber end fixing seat 1, and an optical fiber clamping head 9; a corrosion reaction container is placed on the upper end of the bottom support plate. The bottom support plate is connected with a plurality of leveling screws 5 for leveling, and is judged by a level meter installed on the top of the bottom support plate to ensure that the level of the etching liquid and the optical fiber end surface is guaranteed. The column is vertically fixed to the upper end of the bottom support plate, the crossbeam is connected to the column in an adjustable manner, a locking screw 4 is connected to one end of the crossbeam to fix the crossbeam on the column, and the optical fiber clamping head is fixed to the other end of the crossbeam, and a clamping hole is provided on the optical fiber clamping head for vertically passing the end of the optical fiber to be processed. The optical fiber clamping head is a low-stress clamp used to realize vertical clamping of the optical fiber to keep the optical fiber stable, and can be composed of a clamping block with a V-groove and a low-stress clamping plate, and the clamping block and the clamping plate are attracted by magnetic force. The optical fiber end fixing seat is fixedly installed on the top of the column and is used to fix the end of the optical fiber that does not need to be processed. The columns can be provided with scales, and the upper and lower positions of the beams can be adjusted as needed according to the scales, thereby adjusting the upper and lower positions of the optical fiber clamping heads and adjusting the corrosion length of the optical fiber ends.

[0038] The above-mentioned optical fiber clamp adjustment frame is used to clamp the optical fiber vertically and ensure that the surface to be etched faces downward. The distance between the optical fiber clamping head and the etching liquid surface is adjustable, and the stripping length and the bare fiber end etching length can be adjusted according to the needs of the fusion splicer. The shorter exposed length can effectively improve the tensile strength of the melting point after fusion.

[0039] The optical fiber 100 is inserted into the hydrofluoric acid etching solution. To prevent the liquid tension from causing the etching solution to erode the edge 101 of the optical fiber air hole, the non-immersed end of the optical fiber is connected to an air pump, and a small amount of inert gas, such as nitrogen, is filled from the other end of the optical fiber to ensure the flatness of the etching end surface. The pressure of the inert gas should be stable and adjustable.

[0040] After the corrosion is completed, soak it in distilled water for preliminary cleaning; then place it in an ultrasonic cleaner for deep cleaning, and finally blow dry it. Remove the optical fiber for standby use, and the optical fiber surface treatment is completed.

[0041] During the entire operation, do not touch the optical fiber end face being processed, and handle it with care to avoid damaging the optical fiber and its end face.

[0042] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A method for preparing a smooth end face of a microstructured optical fiber, It is characterized by: The steps include: Step 1, vertically insert the end of the optical fiber to be treated into a concentrated sulfuric acid corrosive solution, and remove the coating layer of the optical fiber by etching while passing an inert gas into the optical fiber air hole at the other end of the optical fiber to obtain a bare optical fiber of the required length; Step 2, preliminarily rinse the corroded optical fiber end with distilled water; Step 3: Place the fiber end after preliminary rinsing in an ultrasonic cleaning machine for deep cleaning and wipe it clean; Step 4, vertically insert the bare optical fiber end to be processed into the etching solution, and when an inert gas is introduced into the optical fiber air hole at the other end of the optical fiber, the end face of the bare optical fiber is corroded and removed by etching; Step 5, preliminarily rinse the bare optical fiber end that has been corroded with distilled water; Step 6: Place the bare optical fiber end after preliminary washing in an ultrasonic cleaning machine for deep cleaning; Step 7: Dry the optical fiber end after deep cleaning to complete the end surface smoothing of the optical fiber; In step 1 and step 4, an air pump is connected to the non-immersed end of the optical fiber, and an inert gas is introduced through the air pump; in step 4, the etching liquid is a hydrofluoric acid etching liquid, the concentration of the hydrofluoric acid etching liquid is less than 1 mol / L, and the temperature of the hydrofluoric acid etching liquid is 40-50°C; The hydrofluoric acid etching solution is contained in a corrosion reaction container, and the corrosion reaction container is placed on a heating and heat preservation plate; In step 1 and step 4, an optical fiber clamp adjustment frame is used to vertically fix the optical fiber; the optical fiber clamp adjustment frame includes a bottom support plate, a column, a crossbeam, an optical fiber end fixing seat, and an optical fiber clamping head; the bottom support plate is used to support the corrosion reaction container, the bottom support plate is connected to a plurality of leveling screws, and a spirit level is provided at the upper end of the bottom support plate; the column is vertically fixed to the upper end of the bottom support plate, the crossbeam is connected to the column in an adjustable manner up and down, a locking screw is connected to one end of the crossbeam to fix the crossbeam to the column, the optical fiber clamping head is fixed to the other end of the crossbeam, and a clamping hole is provided on the optical fiber clamping head for vertically passing the end of the optical fiber to be processed; the optical fiber end fixing seat is fixedly installed on the top of the column, and is used to fix the end of the optical fiber that does not need to be processed.

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