Passive optical fiber overload fuse and manufacturing method thereof

Abstract

The invention provides a passive optical fiber overload fuse and a manufacturing method thereof, and the fuse comprises an input single-mode optical fiber which is used for inputting an optical signal; the output single-mode optical fiber is used for outputting an optical signal; two ends of the fused biconical taper optical fiber section are respectively welded with fiber cores of the input single-mode optical fiber and the output single-mode optical fiber to form a continuous optical path, and an optical signal input by the input single-mode optical fiber is transmitted to the output single-mode optical fiber so as to output the optical signal; the sealed protection tube shell is used for packaging the fused biconical taper optical fiber section, the fused biconical taper optical fiber section is arranged in the sealed protection tube shell, and the input single-mode optical fiber and the output single-mode optical fiber penetrate into the fused biconical taper optical fiber section from the two ends of the sealed protection tube shell respectively to be connected with the fused biconical taper optical fiber section; the fused biconical taper optical fiber section is of a conical structure with the thin middle and the two thick ends and comprises a conical waist area located in the middle and thick conical areas located at the two ends, the conical waist area allows optical signals with the power smaller than or equal to a set threshold value to pass through, and when the power of the input optical signals is larger than the set threshold value, the conical waist area is fused.

Description

Technical Field

[0001] This invention relates to the field of optical fiber technology, and in particular to a passive optical fiber overload fuse and its manufacturing method. Background Technology

[0002] In fields such as fiber optic communication, high-power laser processing, and optical sensing, optical components (such as laser diodes, optical amplifiers, and precision detectors) are extremely sensitive to input optical power. Instantaneous power overload (such as that caused by accidental reflection, pump source failure, lightning-induced current, etc.) can easily lead to permanent damage and cause huge economic losses.

[0003] Currently, common protection schemes are mainly based on the following two principles: Optical switch type: This type of solution utilizes thermo-optic, electro-optic, or acousto-optic effects to control an optical switch to switch or shut down the optical path when an overload is detected. While this method offers fast response times, it is structurally complex, expensive, requires external power supply and control circuitry, and its reliability is affected by the electronic components.

[0004] Recoverable: This type utilizes the nonlinear optical effects of certain materials (such as nonlinear scattering and saturable absorption) to attenuate the optical signal when the power is too high. Once the power returns to normal, the device function is restored. However, its dynamic range is limited, its protection against extreme overloads (such as pulse shocks) is insufficient, and it may introduce nonlinear distortion.

[0005] Therefore, it is necessary to provide a passive fiber optic overload fuse and its manufacturing method to effectively solve the above problems. Summary of the Invention

[0006] This invention provides a passive optical fiber overload fuse and its manufacturing method. It uses a single-mode optical fiber with a fused taper fiber section to achieve irreversible fusion physical fracture due to thermal imbalance under a specific overload power, thus realizing passive overload protection.

[0007] This invention provides a passive fiber optic overload fuse, comprising: Input single-mode fiber for inputting optical signals; Output single-mode fiber for outputting optical signals; The fused taper fiber segment has its two ends fused to the cores of the input single-mode fiber and the output single-mode fiber, respectively, to form a continuous optical path, transmitting the optical signal input from the input single-mode fiber to the output single-mode fiber to output the optical signal; A sealed protective housing is used to encapsulate the fused tapered fiber segment, which is disposed in the sealed protective housing. The input single-mode fiber and the output single-mode fiber pass through the sealed protective housing from both ends and connect to the two ends of the fused tapered fiber segment. The fused tapered fiber segment has a tapered structure that is thinner in the middle and thicker at both ends, including a tapered waist region in the middle and thicker tapered regions at both ends. The tapered waist region allows optical signals with power less than or equal to a set threshold to pass through. When the power of the input optical signal is greater than the set threshold, the tapered waist region melts and blocks the optical signal from passing through.

[0008] Preferably, the threshold of the maximum power of the optical signal allowed to pass through the tapered waist region of the fused biconical fiber segment is determined by the effective length and minimum diameter of the tapered waist region, as well as the absorption coefficient of the material in the tapered waist region at the operating wavelength and the heat dissipation constant of the material.

[0009] Preferably, the threshold value of the maximum power of the optical signal allowed to pass through the waist region of the fused biconical fiber segment is calculated by the following formula:

[0010] P: is the threshold value of the maximum power of the optical signal allowed to pass through the waist region of the fused biconical fiber segment; K: A comprehensive constant related to the thermal conductivity, specific heat capacity, and heat dissipation conditions of the material in the conical waist region, obtained through experimental calibration; : The material of the cone waist region at the operating wavelength The absorption coefficient at the specified depth; d: the minimum diameter of the conical waist region (unit: μm); L: The effective length of the conical waist region (unit: mm).

[0011] Preferably, the minimum diameter of the waist region of the fused taper fiber segment ranges from 1 μm to 5 μm.

[0012] Preferably, the fiber material of the fused taper fiber segment is doped and modified, and the doping elements include iron (Fe) ions, copper (Cu) ions or hydroxyl (OH-) ions, in order to increase the absorption coefficient at a set wavelength.

[0013] Preferably, the system further includes a substrate disposed within the sealed protective housing. The input single-mode optical fiber passes through the sealed protective housing and is fixed to one end of the substrate by UV adhesive. The output single-mode optical fiber passes through the sealed protective housing and is fixed to the other end of the substrate by UV adhesive.

[0014] Preferably, the sealed protective casing is made of glass, ceramic, or metal.

[0015] Preferably, both ends of the sealed protective tube shell are sealed with a sealing material, which is a UV-curable adhesive, epoxy resin, or metal solder.

[0016] Based on the same concept, the present invention also provides a method for manufacturing the above-mentioned passive fiber optic overload fuse, comprising the following steps: Select the single-mode fiber to be processed based on the threshold of the maximum power of the optical signal allowed by the passive fiber overload fuse, and set the length L and minimum diameter d of the tapered waist region of the fused biconical fiber segment. The middle part of the single-mode fiber to be processed is stripped and cleaned. In the tapering equipment, the middle region of the single-mode fiber to be processed is heated and stretched to form a fused tapered fiber segment with a predetermined minimum diameter d and length L. The portions of the single-mode fiber to be processed connected to the two ends of the fused tapered fiber segment are used as the input single-mode fiber and the output single-mode fiber. A substrate is provided to fix the input single-mode fiber and the output single-mode fiber to both ends of the substrate using UV adhesive, such that the fused taper fiber segment is located in the middle of the substrate; A sealed protective housing is provided, the substrate is placed in the sealed protective housing, and the input single-mode fiber and the output single-mode fiber respectively pass through the two ends of the sealed protective housing; Provide sealing material to seal both ends of the sealed protective tube shell.

[0017] Based on the same concept, the present invention also provides an optical device, including a laser source, optical functional devices and optical fibers connecting them, wherein the aforementioned passive optical fiber overload fuse is connected in series in the optical path between the laser source and the optical functional devices.

[0018] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects: This invention provides a passive fiber optic overload fuse and its manufacturing method. A fused abducted fiber segment is incorporated into a single-mode fiber. When the power of the input optical signal exceeds a set threshold, the fuse melts at the waist of the fused abducted fiber segment, preventing the optical signal from passing through and achieving overload protection. It operates completely passively, requiring no external power supply, sensor, or control circuit, resulting in extremely high reliability. The response speed is extremely fast, with heat accumulation and melting processes completed within microseconds to milliseconds, effectively handling destructive optical pulses. The structure is simple and low-cost, based on mature fiber abducting technology, making mass production easy. The protection is reliable; once activated, the fiber is physically disconnected with no possibility of recovery, completely eliminating subsequent risks. It is also highly customizable; by changing the diameter, length, and material of the waist, the melting threshold for different wavelengths and powers can be precisely designed. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention, but not all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of a passive fiber optic overload fuse structure provided in one embodiment of the present invention; Figure 2 A schematic diagram of a fused biconical taper fiber segment structure provided in one embodiment of the present invention; Figure 3 A flowchart illustrating a method for manufacturing a passive optical fiber overload fuse according to an embodiment of the present invention.

[0021] In the picture: 1-Sealed protective casing; 2-Substrate; 3-Input single-mode fiber; 4-UV adhesive; 5-Fused tapered fiber segment; 51-Rough tapered region; 52-Tapered waist region; 6-Sealing material; 7-Output single-mode fiber. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0024] Based on the problems existing in the prior art, this invention provides a passive optical fiber overload fuse and its manufacturing method. It uses a single-mode optical fiber with a fused taper fiber section to achieve irreversible fusion physical fracture due to thermal imbalance under a specific overload power, thus realizing passive overload protection.

[0025] Figure 1 A schematic diagram of a passive fiber optic overload fuse structure provided in one embodiment of the present invention; Figure 2 A schematic diagram of a fused biconical taper fiber segment structure provided in one embodiment of the present invention; Figure 3 A flowchart illustrating a method for manufacturing a passive optical fiber overload fuse according to an embodiment of the present invention.

[0026] Now see Figure 1 and Figure 2 This invention provides a passive fiber optic overload fuse, comprising: Input single-mode fiber 3 is used to input optical signals; Output single-mode fiber 7, used to output optical signals; The fused tapered fiber segment 5 has its two ends fused to the cores of the input single-mode fiber 3 and the output single-mode fiber 7 respectively to form a continuous optical path, transmitting the optical signal input from the input single-mode fiber 3 to the output single-mode fiber 7 to output the optical signal; A sealed protective tube shell 1 is used to encapsulate the fused tapered fiber segment 5. The fused tapered fiber segment 5 is disposed in the sealed protective tube shell 1. The input single-mode fiber 3 and the output single-mode fiber 7 pass through the sealed protective tube shell 1 from both ends and connect to the two ends of the fused tapered fiber segment 5. The fused tapered fiber segment 5 has a tapered structure that is thinner in the middle and thicker at both ends, including a tapered waist region 52 in the middle and thick tapered regions 51 at both ends. The tapered waist region 52 allows optical signals with power less than or equal to a set threshold to pass through. When the power of the input optical signal is greater than the set threshold, the tapered waist region 52 melts and blocks the optical signal from passing through.

[0027] Specifically, according to electromagnetic field theory, when an optical signal propagates in the cone waist region 52, some of the light propagates outside the fiber cladding in the form of an evanescent field. At the minimum diameter of the cone waist region 52, the optical field is greatly compressed, resulting in a significantly higher optical power density in this region compared to other regions. The fiber material (quartz) has extremely weak absorption of light (especially at specific wavelengths, which can be enhanced by doping), and this absorbed energy is converted into heat. Under normal operating power, the generated heat can be dissipated in a timely manner through thermal conduction and convection, keeping the temperature stable. Once the input power exceeds a set threshold, the heat absorbed by the cone waist region 52 will exceed its heat dissipation capacity, causing the temperature in this region to rise sharply. When the temperature reaches the softening point of the quartz glass (approximately 1600°C), the region will rapidly melt, shrink, and eventually burn out, forming a physical break in the circuit, permanently severing the optical path.

[0028] In some embodiments, the threshold of the maximum power of the optical signal allowed to pass through the tapered waist region 52 of the fused tapered fiber segment 5 is determined by the effective length and minimum diameter of the tapered waist region 52, as well as the absorption coefficient of the material of the tapered waist region 52 at the operating wavelength and the heat dissipation constant of the material.

[0029] In some embodiments, the threshold value of the maximum power of the optical signal allowed to pass through the waist region 52 of the fused biconical fiber segment 5 is calculated by the following formula:

[0030] P: is the threshold value of the maximum power of the optical signal allowed to pass through the waist region of the fused biconical fiber segment; K: A comprehensive constant related to the thermal conductivity, specific heat capacity, and heat dissipation conditions of the material in the conical waist region, obtained through experimental calibration; : The material of the cone waist region at the operating wavelength The absorption coefficient at the specified depth; d: the minimum diameter of the conical waist region (unit: μm); L: The effective length of the conical waist region (unit: mm).

[0031] In some embodiments, the minimum diameter of the waist region 52 of the fused tapered fiber segment 5 ranges from 1 μm to 5 μm.

[0032] In some embodiments, the fiber material of the fused taper fiber segment 5 is doped and modified, and the doping elements include iron (Fe) ions, copper (Cu) ions or hydroxyl (OH-) ions, in order to increase the absorption coefficient at a set wavelength.

[0033] In some embodiments, the substrate 2 is further included. The substrate 2 is disposed inside the sealed protective tube shell 1. The input single-mode optical fiber 3 is inserted into the sealed protective tube shell 1 and fixed to one end of the substrate 2 by UV adhesive 4. The output single-mode optical fiber 7 is inserted into the sealed protective tube shell 1 and fixed to the other end of the substrate 2 by UV adhesive 4.

[0034] Specifically, the input single-mode fiber 3 and the output single-mode fiber 7 are bonded to the substrate 2 with UV adhesive (ultraviolet curing adhesive) 4 to reduce the impact of the input single-mode fiber 3 and the output single-mode fiber 7 on the fused tapered fiber segment 5. This prevents the input single-mode fiber 3 or the output single-mode fiber 7 from applying tension to the fused tapered fiber segment 5 during installation or use, which could cause the tapered waist region 52 of the fused tapered fiber segment 5 to break and result in damage.

[0035] In some embodiments, the sealed protective shell 1 is made of glass, ceramic or metal, and its internal cavity is a closed environment, which is air, inert gas or vacuum.

[0036] In some embodiments, both ends of the sealed protective tube shell 1 are sealed by sealing material 6, which is UV-curable adhesive, epoxy resin or metal solder.

[0037] Specifically, when the sealing and protective casing 1 is made of glass, the sealing material 6 is made of UV-curing adhesive; when the sealing and protective casing 1 is made of ceramic, the sealing material 6 is made of epoxy resin; when the sealing and protective casing 1 is made of metal, the sealing material 6 is made of metal solder.

[0038] Please see Figure 3The present invention also provides a method for manufacturing a passive fiber optic overload fuse, comprising the following steps: S1: Select the single-mode fiber to be processed based on the threshold of the maximum power of the optical signal allowed by the passive fiber overload fuse, and set the length L and minimum diameter d of the tapered waist region 52 of the fused taper fiber segment 5. S2: Stripping and cleaning the middle part of the single-mode fiber to be processed; S3: In the tapering equipment, the region of the middle part of the single-mode fiber to be processed is heated and stretched to form a fused tapered fiber segment 5 with a tapered waist region 52 having a predetermined minimum diameter d and length L. The parts of the single-mode fiber to be processed connected to the two ends of the fused tapered fiber segment 5 are used as the input single-mode fiber 3 and the output single-mode fiber 7. S4: The substrate 2 is provided to fix the input single-mode fiber 3 and the output single-mode fiber 7 to both ends of the substrate 2 with UV glue 4, so that the fused tapered fiber segment 5 is located in the middle of the substrate 2. S5: Provide a sealed protective housing 1, place the substrate 2 in the sealed protective housing 1, and allow the input single-mode fiber 3 and the output single-mode fiber 7 to pass through the two ends of the sealed protective housing 1 respectively. S6: Provide sealing material 6 to seal and protect both ends of the casing 1.

[0039] Specifically, the single-mode fiber to be processed can be selected based on the application of the passive fiber overload fuse, such as the wavelength of the optical signal to be transmitted. That is, the single-mode fiber to be processed can be selected based on the wavelength and power of the transmitted optical signal and modified with characteristic doping elements.

[0040] The present invention also provides an optical device, including a laser source, optical functional devices and optical fibers connecting them, wherein a passive optical fiber overload fuse is connected in series in the optical path between the laser source and the optical functional devices.

[0041] In summary, the passive fiber optic overload fuse and its manufacturing method provided by this invention involve setting a fused biconical taper fiber segment 5 in a single-mode fiber. When the power of the input optical signal exceeds a set threshold, the tapered waist region 52 of the fused biconical taper fiber segment 5 melts, preventing the optical signal from passing through and achieving overload protection. It operates completely passively, requiring no external power supply, sensor, or control circuit, resulting in extremely high reliability. Its response speed is extremely fast, with heat accumulation and melting processes completed within microseconds to milliseconds, effectively handling destructive optical pulses. It has a simple structure, low cost, and is based on mature fiber taper technology, making mass production easy. The protection is reliable; once activated, it physically disconnects without any possibility of recovery, completely eliminating subsequent risks. It is also highly customizable; by changing the diameter, length, and material of the tapered waist region 52, the melting threshold for different wavelengths and powers can be precisely designed.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A passive fiber optic overload fuse, characterized in that, include: Input single-mode fiber for inputting optical signals; Output single-mode fiber for outputting optical signals; The fused taper fiber segment has its two ends fused to the cores of the input single-mode fiber and the output single-mode fiber, respectively, to form a continuous optical path, transmitting the optical signal input from the input single-mode fiber to the output single-mode fiber to output the optical signal; A sealed protective housing is used to encapsulate the fused tapered fiber segment, which is disposed in the sealed protective housing. The input single-mode fiber and the output single-mode fiber pass through the sealed protective housing from both ends and connect to the two ends of the fused tapered fiber segment. The fused tapered fiber segment has a tapered structure that is thinner in the middle and thicker at both ends, including a tapered waist region in the middle and thicker tapered regions at both ends. The tapered waist region allows optical signals with power less than or equal to a set threshold to pass through. When the power of the input optical signal is greater than the set threshold, the tapered waist region melts and blocks the optical signal from passing through.

2. The passive fiber optic overload fuse according to claim 1, characterized in that, The threshold of the maximum power of the optical signal allowed to pass through the waist region of the fused biconical taper fiber segment is determined by the effective length and minimum diameter of the waist region, as well as the absorption coefficient of the material in the waist region at the operating wavelength and the heat dissipation constant of the material.

3. The passive fiber optic overload fuse according to claim 1, characterized in that, The threshold value for the maximum power of the optical signal allowed to pass through the waist region of the fused biconical taper fiber segment is calculated by the following formula: P: is the threshold value of the maximum power of the optical signal allowed to pass through the waist region of the fused biconical fiber segment; K: A comprehensive constant related to the thermal conductivity, specific heat capacity, and heat dissipation conditions of the material in the conical waist region, obtained through experimental calibration; : The material of the cone waist region at the operating wavelength The absorption coefficient at the specified depth; d: the minimum diameter of the conical waist region; L: is the effective length of the conical waist region.

4. The passive fiber optic overload fuse according to claim 1, characterized in that, The minimum diameter range of the waist region of the fused taper fiber segment is 1 μm - 5 μm.

5. The passive fiber optic overload fuse according to claim 1, characterized in that, The fiber material of the fused biconical taper fiber segment is doped and modified. The doping elements include iron ions, copper ions, or hydroxyl groups to increase the absorption coefficient at a set wavelength.

6. The passive fiber optic overload fuse according to claim 1, characterized in that, It also includes a substrate, which is disposed inside the sealed protective tube shell. The input single-mode optical fiber passes through the sealed protective tube shell and is fixed to one end of the substrate by UV adhesive; the output single-mode optical fiber passes through the sealed protective tube shell and is fixed to the other end of the substrate by UV adhesive.

7. The passive fiber optic overload fuse according to claim 1, characterized in that, The sealed protective casing is made of glass, ceramic, or metal.

8. The passive fiber optic overload fuse according to claim 1, characterized in that, Both ends of the sealed protective tube shell are sealed with sealing material, which may be UV-curable adhesive, epoxy resin, or metal solder.

9. A method for manufacturing a passive optical fiber overload fuse as described in any one of claims 1-8, characterized in that, Includes the following steps: Select the single-mode fiber to be processed based on the threshold of the maximum power of the optical signal allowed by the passive fiber overload fuse, and set the length L and minimum diameter d of the tapered waist region of the fused biconical fiber segment. The middle part of the single-mode fiber to be processed is stripped and cleaned. In the tapering equipment, the middle region of the single-mode fiber to be processed is heated and stretched to form a fused tapered fiber segment with a predetermined minimum diameter d and length L. The portions of the single-mode fiber to be processed connected to the two ends of the fused tapered fiber segment are used as the input single-mode fiber and the output single-mode fiber. A substrate is provided to fix the input single-mode fiber and the output single-mode fiber to both ends of the substrate using UV adhesive, such that the fused taper fiber segment is located in the middle of the substrate; A sealed protective housing is provided, the substrate is placed in the sealed protective housing, and the input single-mode fiber and the output single-mode fiber respectively pass through the two ends of the sealed protective housing; Provide sealing material to seal both ends of the sealed protective tube shell.

10. An optical device comprising a laser source, optical functional components, and an optical fiber connecting them, characterized in that, A passive fiber optic overload fuse as described in any one of claims 1 to 8 is connected in series in the optical path between the laser source and the optical functional device.

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