Method for manufacturing a fiber coupler and fiber coupler

Abstract

The application is suitable for the field of optical fiber communication technology, and provides a preparation method of an optical fiber coupler and the optical fiber coupler, wherein the preparation method of the optical fiber coupler comprises the following steps: pasting a plurality of optical fibers; simultaneously performing heating and tapering process operations on the plurality of optical fibers; and monitoring the power of the output end of the plurality of optical fibers to obtain the optical fiber coupler with a preset light splitting ratio during the heating and tapering process operations. The plurality of optical fibers are simultaneously heated and tapered to obtain a power-insensitive optical fiber coupler, and the light splitting ratio of the output end of the power-insensitive optical fiber coupler remains basically unchanged in the case of input light power variation, so that the communication system can ensure stable output of each output port signal when the input light source power changes, and is beneficial to subsequent upgrading of the communication system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical fiber communication, and more particularly to a preparation method of an optical fiber coupler and the optical fiber coupler. BACKGROUND

[0002] The optical fiber coupler plays a role in branching optical signals and is widely used in many fields such as optical fiber communication, CATV (Community Antenna Television), optical fiber gyroscope, optical fiber hydrophone, optical fiber sensing, and the like.

[0003] At present, with the development of society, the use power of products is getting higher and higher. During the use of the optical fiber coupler, the user finds that the output splitting ratio of the conventional optical fiber coupler will change obviously when the input power changes. For example, taking an optical fiber coupler with a splitting ratio of 2:98 as an example, when the input power changes from 100 uW to 1500 mW, the 2% port splitting ratio will change from about 2.0% to about 2.30%. This will have a great impact on the normal use of the customer. SUMMARY

[0004] The purpose of the embodiments of the application is to provide a preparation method of an optical fiber coupler and the optical fiber coupler, aiming to solve the technical problem that the output splitting ratio of the optical fiber coupler changes greatly when the input power changes.

[0005] To achieve the above-mentioned purpose, according to one aspect of the application, a preparation method of an optical fiber coupler is provided, comprising: abutting a plurality of optical fibers; simultaneously performing heating and tapering process operations on the plurality of optical fibers; and monitoring the power of the output end of the plurality of optical fibers to obtain an optical fiber coupler with a preset splitting ratio during the heating and tapering process operations.

[0006] Optionally, the preparation method of the optical fiber coupler further comprises: inputting input light with different power values to the optical fiber coupler to obtain actual splitting ratios of the optical fiber coupler corresponding to the input light; and determining whether the optical fiber coupler is sensitive to the power change of the input light according to the preset splitting ratio and the different actual splitting ratios.

[0007] Optionally, the simultaneously performing heating and tapering process operations on the plurality of optical fibers comprises: causing the heating zone of the plurality of optical fibers to melt to form one optical fiber.

[0008] Optionally, the determining whether the optical fiber coupler is sensitive to the power change of the input light according to the preset splitting ratio and the different actual splitting ratios comprises: calculating the difference between the preset splitting ratio and each different actual splitting ratio; comparing the difference with a preset range; if the difference is within the preset range, the optical fiber coupler is not sensitive to the power change of the input light; and if the difference is outside the preset range, the optical fiber coupler is sensitive to the power change of the input light.

[0009] Optionally, the inputting the input light with different power values to the fiber coupler to obtain actual splitting ratios of the fiber coupler corresponding to the input light comprises: inputting the input light with different power values to the splitting module by the light source module; splitting the input light into two paths by the splitting module, one path as monitoring light and the other path as test light; measuring and recording the first power value of the monitoring light and the second power value of the test light corresponding to each input light; connecting the test light to the input end of the fiber coupler to be tested, and measuring and recording the power value of the output end of the fiber coupler corresponding to each second power value.

[0010] Optionally, the inputting the input light with different power values to the splitting module by the light source module comprises: the light source module comprises a light source and an adjustable optical attenuator; connecting the output end of the light source to the input end of the adjustable optical attenuator, and connecting the output end of the adjustable optical attenuator to the input end of the splitting module; adjusting the adjustable optical attenuator to make the light source provide the input light with different power values.

[0011] Optionally, the splitting the input light into two paths by the splitting module comprises: the splitting module comprises a splitting coupler, and the splitting coupler comprises one input end and two output ends; connecting the input end of the splitting coupler to the output end of the adjustable optical attenuator; connecting one of the two output ends of the splitting coupler as a monitoring end for outputting monitoring light, and connecting the other output end as a test end for outputting test light.

[0012] Optionally, the measuring and recording the first power value of the monitoring light and the second power value of the test light corresponding to each input light comprises: connecting the monitoring end to a first optical power meter, and measuring and recording the first power value corresponding to the input light with different power values by the first optical power meter; connecting the test end to a second optical power meter, and measuring and recording the second power value corresponding to each first power value by the second optical power meter.

[0013] Optionally, the connecting the test light to the input end of the fiber coupler to be tested, and measuring and recording the power value of the output end of the fiber coupler corresponding to each second power value comprises: disconnecting the test end from the second optical power meter; connecting the output end of the fiber coupler to different third optical power meters respectively, wherein the number of the third optical power meters is the same as the number of the output ends of the fiber coupler; and measuring and recording the power value of each output end of the fiber coupler corresponding to each first power value by each third optical power meter.

[0014] According to another aspect of the present application, there is provided a fiber coupler prepared by the above preparation method.

[0015] The preparation method of the optical fiber coupler provided by the application has the beneficial effect that the multiple optical fibers are simultaneously heated and subjected to the tapering process, so that the power-insensitive optical fiber coupler is obtained, and the splitting ratio of the output end of the power-insensitive optical fiber coupler remains basically unchanged in the case of the change of input optical power, so that the communication system can ensure stable output of each output port signal when the input optical source power changes, which is beneficial to the upgrading of the communication system in the future. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 The contrast schematic diagram of the splitting ratio of the conventional optical fiber coupler under different input powers;

[0018] Figure 2 The flowchart of the preparation method of the optical fiber coupler provided by the embodiment of the application;

[0019] Figure 3 The contrast schematic diagram of the splitting ratio of the optical fiber coupler provided by the embodiment of the application under different input powers;

[0020] Figure 4 The schematic diagram of the coupling area of the optical fiber coupler provided by the embodiment of the application;

[0021] Figure 5 The schematic diagram of the power sensitivity test system of the optical fiber coupler provided by the embodiment of the application;

[0022] Figure 6 The schematic diagram of the establishment of the input optical power reference of the optical fiber coupler to be tested in the power sensitivity test system of the optical fiber coupler provided by the embodiment of the application;

[0023] Figure 7 The structural schematic diagram of the optical fiber coupler provided by the embodiment of the application.

[0024] The label details involved in the above drawings are as follows:

[0025] 01, U-shaped groove quartz substrate; 02, quartz round tube; 03, coupling area; 04, packaging glue; 05, packaging glue; 06, silica gel; 07, silica gel cap; 08, optical fiber; 09, steel pipe;

[0026] 10, light source; 11, adjustable optical attenuator; 12, optical coupler; 13, first optical power meter; 14, fiber coupler; 15, second optical power meter; 16, third optical power meter. DETAILED DESCRIPTION

[0027] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0028] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. The embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and embodiments.

[0029] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0030] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "plurality" is two or more, unless otherwise specifically limited.

[0031] As described in the background, at present, in the process of using the coupler, users find that the output splitting ratio of the conventional fiber coupler will change obviously when the input power changes. Taking a fiber coupler with a splitting ratio of 2%:98% as an example, when the input power changes from 100uW to 1500mW, the splitting ratio of the 2% port will change from about 2.0% to about 2.30%, and the specific data is shown in Table 1 and Figure 2 The output power change of the six conventional fiber couplers is shown in Table 1 and Table 2. Due to the large change in the splitting ratio, this will have a great impact on the normal use of the customer, so the conventional fiber coupler cannot meet the use occasions where the input power will change.

[0032]

[0033] Table 1 Comparison data of splitting ratio of conventional fiber coupler with splitting ratio of 2%:98% at different power

[0034] Referring to Figure 2 As shown in the drawings, to solve the above problems, according to one aspect of the present application, some embodiments of the present application provide a preparation method of a fiber coupler, comprising:

[0035] S1, abutting a plurality of optical fibers 08;

[0036] S2, simultaneously performing heating and tapering process operation on the plurality of optical fibers 08;

[0037] S3, monitoring the power of the output end of the plurality of optical fibers 08 during the heating and tapering process operation to obtain a fiber coupler 14 with a preset splitting ratio.

[0038] It should be noted that the fusion tapering process of the conventional fiber coupler includes: first, installing the main optical fiber (one) with the protective layer removed on the tapering jig, heating and appropriately stretching the main optical fiber with a flame, so that the diameter of the coupling region (including the core and cladding) of the main optical fiber is slightly different from the diameter of the other optical fibers; then, installing the other optical fibers on the tapering jig, and heating and stretching the main optical fiber and the other optical fibers with a flame until the splitting ratio meets the requirements, and then stopping heating and stretching, and packaging the finished product. The optical fiber 08 used in some embodiments of the present application is an optical fiber without pretreatment, wherein the pretreatment includes heating and stretching, and the optical fiber without pretreatment is an optical fiber that has not been subjected to heating and stretching operation. The abutting of the plurality of optical fibers 08 is that the circumferential sides of the optical fibers 08 are in close contact with each other. The heating and tapering process is to heat and stretch the plurality of optical fibers 08 in close contact by using a flame or a laser. That is, after the plurality of optical fibers 08 are abutted, heating and tapering are simultaneously performed, and the optical power meter is connected to the output end of each optical fiber 08 for monitoring to obtain a fiber coupler 14 with a preset splitting ratio. Through power sensitivity test of the fiber coupler 14, when the input power changes, the splitting ratio of the output end of the fiber coupler 14 remains basically unchanged, so that it is determined that the fiber coupler 14 is not sensitive to the change of the input power.

[0039] In some preferred embodiments of the present application, the plurality of optical fibers 08 in close contact are simultaneously heated and tapered, so that the coupling region 03 formed by the plurality of optical fibers 08 forms an axisymmetric structure.

[0040] The technical scheme provided in the application can simultaneously heat and taper a plurality of optical fibers 08 without pretreatment, thereby obtaining a power-insensitive fiber coupler 14, the splitting ratio of the output end of the power-insensitive fiber coupler 14 substantially remains unchanged in the case of input optical power variation, thereby being capable of ensuring stable output of each output port signal when the input optical source power of a communication system changes, and being beneficial to subsequent upgrading of the communication system.

[0041] Taking six 1x2 fiber couplers 14 with a splitting ratio of 2%:98% obtained by the technical scheme of the application as an example, the input power varies from 100uW to 1500mW, and the splitting ratio variation of the 2% port is shown in Table 2 and Figure 3 .

[0042]

[0043]

[0044] Table 2 Comparison data of the splitting ratio of the fiber coupler with a splitting ratio of 2%:98% prepared in the embodiment of the application at different powers

[0045] In some embodiments of the application, the preparation method of the fiber coupler 14 further includes: inputting input light with different power values to the fiber coupler 14 to obtain actual splitting ratios of the fiber coupler 14 corresponding to the input light; and determining whether the fiber coupler 14 is sensitive to the power variation of the input light according to the preset splitting ratio and the different actual splitting ratios, including: calculating the difference between the preset splitting ratio and each different actual splitting ratio, comparing the difference with a preset range, if the difference is within the preset range, the fiber coupler 14 is not sensitive to the power variation of the input light, and if the difference is outside the preset range, the fiber coupler 14 is sensitive to the power variation of the input light.

[0046] It should be noted that the preset range of the splitting ratio variation is -5%*CR to +5%*CR, including the end point values, such as ±0.5*CR, wherein CR is the preset splitting ratio. For example, for the fiber coupler with a preset splitting ratio of 2%:98%, the preset range of the splitting ratio variation of the 2% port is [-2%*5%~2%*5%] i.e. [-0.1%~0.1%], if the actual splitting ratio of the 2% port is 2.02%, the difference between the preset splitting ratio and the actual splitting is (2%-2.02%= -0.02%), and -0.02% is within the range of [-0.1%~0.1%], it is considered that the fiber coupler is not sensitive to the power variation of the input light.

[0047] Specifically, as shown in Table 2, the input light with the input power of 0.1 mW, 158 mW and 1500 mW is input to the fiber coupler 14 by different light sources respectively, the output ends of the fiber coupler 14 are connected to the optical power meters respectively, and the power values of the output ends corresponding to the input power of 0.1 mW, 158 mW and 1500 mW are recorded respectively. The preset splitting ratio of the six fiber couplers 14 is 2%:98%, and the preset range of the variation of the splitting ratio of the 2% port is [-2%*5%~2%*5%], that is, [-0.1%~0.1%]. Taking the actual splitting ratio of the 2% port corresponding to the input power of 0.1 mW, 158 mW and 1500 mW as an example, the actual splitting ratios of the 2% port are 2%, 2.02% and 2.06%, and the differences between the preset splitting ratio and each different actual splitting ratio are 0, -0.02% and -0.06% respectively. The above three differences are within the preset range, so the fiber coupler 14 is not sensitive to the power variation of the input light. Therefore, under the condition that the input power of the light increases, the splitting ratio of the fiber coupler 14 changes little and basically remains unchanged.

[0048] Referring to Figure 4 As shown in

[0049] For the convenience of description, two optical fibers 08 are taken as an example for description. As shown in Figure 4 The two optical fibers 08 are heated by flame or laser high temperature to completely fuse the heating zones of the two optical fibers 08 into one optical fiber, and the boundaries of the two optical fibers 08 disappear. The specific manufacturing parameters of the conventional fiber coupler and the optical coupler provided by the embodiment of the application are shown in Table 3 and Table 4.

[0050]

[0051] Table 3 Manufacturing parameters of a conventional fiber coupler

[0052]

[0053] Table 4 Manufacturing parameters of the fiber coupler of the embodiment of the application

[0054] Referring to Figure 5 and Figure 6 As shown in some embodiments, different power values of input light are input to the fiber coupler 14 to obtain the actual splitting ratio of the fiber coupler 14 corresponding to each input light, which includes:

[0055] (1) The light source module inputs input light with different power values to the splitting module, which specifically includes:

[0056] The light source module includes a light source 10 and an adjustable light attenuator 11; wherein, the light source 10 is a high-power light source;

[0057] Connect the output terminal of the light source 10 to the input terminal of the adjustable light attenuator 11, and connect the output terminal of the adjustable light attenuator 11 to the input terminal of the beam splitter module.

[0058] Adjusting the adjustable light attenuator 11 allows the light source 10 to provide input light with different power values.

[0059] like Figure 5 As shown, in some embodiments, a high-power light source with a maximum power of 2W is connected to the adjustable light attenuator 11.

[0060] (2) The input light is split into two paths by a beam splitter module, one path serving as the monitoring light and the other as the test light, specifically including:

[0061] The beam splitting module includes a beam splitting coupler 12, which includes one input terminal and two output terminals.

[0062] Connect the input end of the optical splitter 12 to the output end of the adjustable optical attenuator 11. In addition to using an optical fiber coupler, the optical splitting module can also use a beam splitter.

[0063] One of the two output terminals of the optical splitter 12 is used as the monitoring terminal, which is used to output monitoring light, and the other is used as the test terminal, which is used to output test light.

[0064] In some embodiments, such as Figure 5 As shown, a 1×2 splitter coupler 12 with a splitting ratio of 0.5% to 99.5% splits the input light of the light source 10 into two parts. The 0.5% port light is used as monitoring light to monitor the test light power entering the fiber coupler 14, and the 99.5% port light is used as the test light input to the fiber coupler 14.

[0065] (3) Measure and record the first power value of the monitoring light and the second power value of the test light corresponding to each input light, specifically including:

[0066] Connect the monitoring terminal to the first optical power meter 13, and measure and record the first power value corresponding to different input light power through the first optical power meter 13;

[0067] Connect the test terminal to the second optical power meter 15, and measure and record the second power value corresponding to each first power value through the second optical power meter 15.

[0068] Specifically, first, the high-power light source is turned on to its maximum power. Then, the attenuation of the adjustable optical attenuator 11 is adjusted. The optical power value reference for the fiber coupler 14 under test is established by reading the first optical power meter 13. The specific scheme is as follows:Figure 6 The actual input optical power of the fiber coupler to be tested is obtained, and a corresponding table of the actual input optical power of the fiber coupler to be tested is obtained, as shown in Table 5.

[0069] No. First optical power meter 13 reading (uW) Second optical power meter 15 reading (mW) 1 7700 1500 2 800 158 3 0.5 0.1

[0070] Table 5 Reference table of the input optical power of the fiber coupler to be tested

[0071] (4) The test light is connected to the input end of the fiber coupler to be tested, and the power value of the output end of the fiber coupler corresponding to each second power value is measured and recorded.

[0072] The test end is disconnected from the second optical power meter 15.

[0073] The output end of the fiber coupler 14 is connected to different third optical power meters 16, and the number of the third optical power meters 16 is the same as the number of the output ends of the fiber coupler 14.

[0074] The power value of each output end of the fiber coupler corresponding to each first power value is measured and recorded by each third optical power meter 16.

[0075] Specifically, after the readings of the first optical power meter 13 and the second optical power meter 15 are recorded, the second optical power meter 15 is disassembled, that is, the connection between the second optical power meter 15 and the optical splitter coupler 12 is disconnected; then, the fiber coupler to be tested is connected to the test system, that is, the input end of the fiber coupler to be tested is connected to the test end.

[0076] The output end of the fiber coupler 14 is connected to different third optical power meters 16, and the number of the third optical power meters 16 is the same as the number of the output ends of the fiber coupler 14. In some embodiments, the fiber coupler 14 has one input end and two output ends, and two third optical power meters 16 are provided at the same time, that is, the input end of the fiber coupler 14 is connected to the test end of the optical splitter coupler 12, and the two output ends of the fiber coupler 14 are connected to the two third optical power meters 16 one by one.

[0077] Then, the attenuation of the adjustable optical attenuator 11 is adjusted so that the first optical power meter 13 has the readings recorded in the above step (Table 5), and the corresponding input optical power of the fiber coupler to be tested is obtained according to the above recording. At this time, the power values of the output ends of the fiber coupler 14 can be obtained through the third optical power meters 16. The first optical power meter 13 is sequentially set to the readings recorded in the above step (Table 5), and the splitting ratios of the fiber coupler under different input optical powers can be calculated according to the output power values of the output ends of the fiber coupler under different input optical powers.

[0078] In some embodiments, as Figure 5The output end of the light source 10 is connected with the input end of the adjustable optical attenuator 11, the output end of the adjustable optical attenuator 11 is connected with the input end of the optical coupler 12, the optical coupler 12 has a monitoring end and a test end, the monitoring end is connected with the first optical power meter 13, the optical fiber coupler 14 to be tested is connected to the test end of the optical coupler 12, then the attenuation of the adjustable optical attenuator 11 is adjusted, the readings of the first optical power meter 13 are 0.5uW, 800uW and 7700uW respectively, according to Table 5, the input optical power of the optical fiber coupler 14 to be tested is 0.1mW, 158mW and 1500mW respectively, then the input power value of the optical fiber coupler 14 and the power value measured by the third optical power meter 16 corresponding to the third optical power meter 16 are recorded respectively, the specific test record table is shown in Table 6 and Table 2, according to the input power of the optical fiber coupler 14 and the output power value of each port, the splitting ratio and the loss value of the optical fiber coupler 14 under different optical powers can be calculated.

[0079]

[0080] Table 6: Output power record table of the optical fiber coupler under different input powers

[0081] In some optional embodiments, the output end of the optical fiber coupler 14 is connected with different third optical power meters 16, including: a fixed attenuator (not shown in the figure) is connected between the third optical power meter 16 and the output end of the optical fiber coupler 14, the number of the fixed attenuators is the same as the number of the third optical power meters 16. Since the measurement range of the power meter is usually small, in order to avoid exceeding the measurement range of the third optical power meter 16, the fixed attenuator is set, and according to the measurement value of the third optical power meter 16 and the attenuation of the fixed attenuator, the actual optical power value of the output end of the optical fiber coupler 14 can be calculated.

[0082] Referring to Figure 7 As shown, according to another aspect of the present application, an optical fiber coupler is provided, the optical fiber coupler 14 is prepared by the preparation method described above, so that the optical fiber coupler 14 is a power-insensitive optical fiber coupler, that is, under the condition that the input optical power changes, the splitting ratio change of the output end of the optical fiber coupler 14 is small and relatively stable, which can ensure that the communication system stably outputs the signals of each output port when the input optical source power changes, which is beneficial to the upgrading of the communication system in the future.

[0083] In some embodiments, the fiber coupler comprises a steel tube 09, a quartz round tube 02 placed in the steel tube 09, a U-shaped groove quartz substrate 01 placed in the quartz round tube 02, and an optical fiber 08 sequentially passing through the steel tube 09, the quartz round tube 02 and the U-shaped groove quartz substrate 01, part of the optical fiber 08 placed in the U-shaped groove quartz substrate 01 being a coupling area 03 of the optical fiber 08, wherein silica gel is filled between the steel tube 09 and the quartz round tube 02; the two ends of the U-shaped groove quartz substrate 01 and the optical fiber 08 are fixed by encapsulation glue 04, so that the coupling area 03 of the fiber coupler 14 is firmly fixed on the U-shaped groove quartz substrate 01; the two ends of the quartz round tube 02 and the optical fiber 08 are sealed by encapsulation glue 05; the two ends of the steel tube 09 are respectively provided with silica gel caps 07 for beautifying the appearance and protecting the optical fiber 08, and the two ends of the optical fiber 08 are respectively provided in the silica gel caps 07.

[0084] In summary, the preparation method of the fiber coupler and the fiber coupler provided by the embodiment have at least the following beneficial technical effects: by simultaneously heating and tapering a plurality of optical fibers 08, a power-insensitive fiber coupler 14 is obtained; by performing a power sensitivity test on the fiber coupler 14, it is further determined that the output end of the power-insensitive fiber coupler 14 has a substantially unchanged split ratio under the condition of a change in input optical power, so that the communication system can ensure stable output of each output port signal when the input optical source power changes, which is beneficial to the upgrading of the communication system in the future.

[0085] The above is only a preferred embodiment of the present application and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of making a fiber coupler, comprising: The application relates to a method for testing a fiber coupler, comprising the following steps: aligning a plurality of optical fibers; simultaneously performing heating and tapering process operations on the plurality of optical fibers; monitoring the output end power of the plurality of optical fibers during the heating and tapering process operations to obtain a fiber coupler with a preset splitting ratio; inputting input light with different power values into the fiber coupler to obtain actual splitting ratios of the fiber coupler corresponding to the input light; determining whether the fiber coupler is sensitive to power changes of the input light according to the preset splitting ratio and the actual splitting ratios; the step of inputting input light with different power values into the fiber coupler to obtain actual splitting ratios of the fiber coupler corresponding to the input light comprises the following steps: inputting input light with different power values into a splitting module through a light source module; the light source module comprises a light source and an adjustable optical attenuator, the output end of the light source is connected with the input end of the adjustable optical attenuator, and the output end of the adjustable optical attenuator is connected with the input end of the splitting module; the adjustable optical attenuator is adjusted to make the light source provide input light with different power values; dividing the input light into two paths through the splitting module, one path is used as monitoring light, and the other path is used as test light; the splitting module comprises a splitting coupler, the splitting coupler comprises one input end and two output ends; the input end of the splitting coupler is connected with the output end of the adjustable optical attenuator; one of the two output ends of the splitting coupler is used as a monitoring end, and the other is used as a test end; the monitoring end is used for outputting the monitoring light, and the test end is used for outputting the test light; measuring and recording the first power value of the monitoring light and the second power value of the test light corresponding to each input light; the monitoring end is connected with a first optical power meter, the first power value corresponding to the input light with different power is measured and recorded through the first optical power meter; the test end is connected with a second optical power meter, and the second power value corresponding to each first power value is measured and recorded through the second optical power meter; connecting the test light into the input end of the fiber coupler to be tested, and measuring and recording the power value of the output end of the fiber coupler corresponding to each second power value; the test end is disconnected from the second optical power meter; the output end of the fiber coupler is connected with different third optical power meters respectively, and a fixed attenuator is arranged between the third optical power meters and the output end of the fiber coupler, wherein the number of the third optical power meters and the number of the fixed attenuators are the same as the number of the output ends of the fiber coupler; the power value of each output end of the fiber coupler corresponding to each first power value is measured and recorded through each third optical power meter.

2. The method of claim 1, wherein the optical fiber coupler is prepared by a method comprising: the step of simultaneously performing heating and tapering process operations on the plurality of optical fibers comprises the following steps: melting the heating zone of the plurality of optical fibers to form one optical fiber.

3. The method for fabricating an optical fiber coupler according to claim 1, characterized in that, the step of determining whether the fiber coupler is sensitive to power changes of the input light according to the preset splitting ratio and the actual splitting ratios comprises the following steps: The difference between the preset splitting ratio and each different actual splitting ratio is calculated, and the difference is compared with a preset range. If the difference is within the preset range, the fiber coupler is not sensitive to the power variation of the input light. If the difference is outside the preset range, the fiber coupler is sensitive to the power variation of the input light.

4. An optical fiber coupler, characterized by, The fiber coupler is prepared by the preparation method in any one of claims 1 to 3.

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