CN201072455Y - Optical fibre coupler - Google Patents

Abstract

The utility model relates to an optical fiber coupler used in the field of optical communication, which comprises a coupling junction composed of bare cores of at least two optical fibers. The optical fiber coupler is fixed in the protective tube with a through hole along its longitudinal direction. The parts of the coupling junction corresponding to the edge of the flame during tapering along the longitudinal direction of the optical fiber are respectively fixed in the protective tube through support blocks. The supporting block is kept in close contact with the part of the coupling junction corresponding to the edge of the flame in the longitudinal direction of the optical fiber. The fiber coupler has good shockproof and shockproof ability.

Description

fiber optic coupler

technical field

The utility model relates to an optical component used in the field of optical communication, in particular to an optical fiber coupler for distributing optical signals from one optical fiber to multiple optical fibers. It is widely used in the field of communication.

Background technique

Optical fiber is the basic transmission channel for transmitting optical signals in the field of long-distance communication. The material of choice for making optical fibers is quartz glass fibers. The cross-sectional structure of the optical fiber usually includes a core, a cladding for increasing the intensity of total reflection, and an outer layer for protection.

Fused-cone optical fiber devices are the most representative of all-optical devices, and they are also a basic device that constitutes other devices. Due to its characteristics of low additional loss, good directivity, excellent environmental stability, simple control method, and low manufacturing cost, it has been widely used in optical fiber communication.

A fiber optic coupler is a fused tapered optical fiber device that distributes optical signals from one optical fiber to multiple optical fibers. When working, the optical signal is automatically propagated and divided into beams of different wavelengths in the fiber coupler according to the propagation law of light, without any external light energy or electrical energy. The structure of the fiber coupler is to bring two or more optical fibers with the coating removed in a parallel and side-by-side manner, heat and melt under the action of a high temperature above 1000°C generated by the H ₂ -O ₂ flame, and at the same time move toward the optical fiber longitudinally. The axes are stretched in opposite directions, and finally a biconical special waveguide structure is formed in the heating area.

Fig. 1 shows a core element 1 of an optical fiber coupler prepared by the existing fused tapered technology. When preparing the fiber coupler core element 1, first put the two optical fibers 101, 102 together in a parallel and side-by-side manner, and strip off a section of outer layer in the middle of the longitudinal axis of the two optical fibers 101, 102 at the same time, so that their The core layer composed of the core and the cladding is in a bare state, and the bare core layers 103 and 104 are obtained. Then twist the bare core layers 103, 104 clockwise or counterclockwise and maintain a section of parallel arrangement area, so that the bare core layers 103, 104 of the two optical fibers 101, 102 form a parallel portion 105 ( See Fig. 1 a); Or make knot 106 after twisting them respectively at the longitudinal two ends of bare fiber core layer 103,104, so that the bare fiber core layer 103,104 of two optical fibers 101,102 is positioned in knot 106 The side-by-side portions 107 are next to each other and close together (see FIG. 1b). Immediately use H ₂ -O ₂ flame to heat the parallel portion 105 of the bare core layers 103, 104 of the two optical fibers 101, 102 or the side-by-side portion 107 in the knot 106 to a high temperature above 1000°C, and while heating The longitudinal axes of the two optical fibers 101, 102 apply pulling forces f1, f2 equal in size but opposite in direction to thin the parallel portion 105 or the side-by-side portion 107 inside the knot 106, so that a waist-drum shape with a thin center and thick ends at both ends can be obtained. A core element 1 of a double-cone optical fiber coupler whose cone tops are buckled together upside down.

The packaging method of the above-mentioned fiber optic coupler is generally to use colloid to fix the two ends of the two optical fibers placed in the semicircular tube outside the double cone, and then cover the outside with a heat-shrinkable sleeve, silicone tube or steel tube for protection and packaging. That is to say, the core component 1 of the optical fiber coupler needs to be provided with a protective cover before it can be applied in an actual working environment. This packaging method has high production efficiency and can pass the vibration and shock test required by the industry standard G1201. However, during the use and transportation of the product, there will inevitably be a large external force impact, which will cause the optical fiber inside the coupler to break and cause functional failure. This is because the fusion tapered technology will cause the optical fiber in the coupling area, especially the residual internal stress at both ends of the coupling junction. Under the impact of external force, the residual internal stress area is extremely prone to cracking and fracture. For fused tapered products, whether it is a twisted tapered tape or a knotted tapered tapered part, the optical fiber in the tapered part will produce residual internal stress due to high temperature treatment and diameter reduction, and since the tapered tapering step is implemented Appears and has been accompanied by the product, so external shocks are often prone to fatal damage to the fiber coupler, such as fiber breakage. According to preliminary statistics, about 95% of the functional failure obstacles without light are caused by the breakage of the optical fibers at both ends of the coupling junction.

Utility model content

The utility model aims at the above technical problem of fiber breakage, and aims to provide a fiber coupler, which can weaken the internal stress remaining in the optical fiber of the tapered part or shorten the vibration force arm that works together with the internal stress, thereby reducing the impact on the fiber connection. The characteristic torque can improve the connection strength and shock resistance of the optical fiber, and avoid the optical fiber breakage caused by the shock and impact of the external environment on the internal stress residual area.

According to the above purpose, the optical fiber coupler designed by the utility model includes a coupling junction composed of bare cores of at least two optical fibers. The optical fiber coupler is fixed in the protective tube with a through hole along its longitudinal direction. The coupling junction corresponds to the position of the flame edge during tapering along the longitudinal direction of the fiber, and is respectively fixed in the protective tube through the supporting blocks. The supporting block is kept in close contact with the part of the coupling junction corresponding to the edge of the flame during tapering along the longitudinal direction of the optical fiber.

Generally, in the aforementioned optical fiber coupler, the coupling junction along the longitudinal direction of the fiber corresponds to the edge of the flame during tapering, which is a knot formed by twisting the longitudinal ends of the bare fiber core respectively.

Preferably, in the aforementioned optical fiber coupler, the supporting block is a cured colloid with knots wrapped inside it.

In view of the problem of residual internal stress at both ends of the coupling junction in the optical fiber coupler made by the fusion tapered technology, the optical fiber coupler of the present invention uses the support blocks in the form of colloid provided at both ends of the coupling junction to separate the two ends of the coupling junction Covered and supported in the colloidal support block, on the one hand, the two ends of the coupling junction are covered and supported extremely tightly in all directions, so that the impact and vibration of the external environment are borne by the support block, and the remaining internal stress The two ends of the coupling junction are no longer affected by the external shock vibration; on the other hand, when the external shock vibration deviates from the two ends of the coupling junction, the support block helps to shorten the force arm of the external shock vibration to the two ends of the coupling junction, thereby reducing the effect The impact moment on the fiber coupling junction. In this way, the ability of the optical coupler of the utility model to resist external shocks is greatly improved, and the optical coupler has a simple structure, high production efficiency and yield rate, and is suitable for the production needs of modern couplers. Experiments show that the optical coupler of the utility model can withstand the impact of 2000 gravitational accelerations, which is greatly improved compared with the impact resistance of 1000 gravitational accelerations required by ordinary products.

Illustration

Figure 1a is a schematic diagram of the planar structure of an existing optical fiber coupler.

Fig. 1b is the second schematic diagram of the planar structure of the existing fiber coupler.

Fig. 2 is a schematic cross-sectional structure diagram of the first embodiment of the fiber coupler of the present invention.

Fig. 3 is a schematic cross-sectional structure diagram of the second embodiment of the optical fiber coupler of the present invention.

Fig. 4 is a schematic diagram of the preparation process of the optical fiber coupler of the present invention.

Detailed ways

See 2, the cross-sectional structure diagram of the optical fiber coupler of the present invention.

The optical fiber coupler 2 of the present invention includes a coupling junction 201 and a protection tube 202 .

The coupling junction 201 is the core component of the fiber coupler 2, which can distribute the optical signal from one optical fiber to multiple optical fibers, for example, from the optical fiber a1 at the left end to the two optical fibers a1` and a2` at the right end through the coupling junction 201 . Optical fibers a1 and a1' refer to the end lines of the same optical fiber located at the longitudinal sides of the coupling junction 201 after forming the coupling junction 201; similarly, optical fibers a2 and a2' refer to another same optical fiber located at the coupling junction 201 after forming the coupling junction 201 Longitudinal end lines on both sides. At both ends of the coupling junction 201 in the longitudinal direction, there are knots 205 formed by twisting the fiber core 204 formed by the remaining core and cladding after the optical fibers a1 and a1 ′ are stripped of the protective layer 203 . In this way, from left to right along the longitudinal axis of the optical fiber a1, such a structural relationship is obtained. The optical fiber a1 composed of the protective layer 203 and the fiber core 204, wherein the fiber core 204 is composed of the core and the cladding, passes through a section of the fiber core 204 Then connect to the knot 205, and then connect to the coupling junction 201 after passing through a section of fiber core 204, continue to look towards the original direction along the coupling junction 201, after passing through a section of fiber core 204, there are knot 205, fiber core 204 and optical fiber a1` in sequence . Similarly, from left to right along the longitudinal axis of the optical fiber a2, such a structural relationship is obtained, the optical fiber a2 consisting of the protective layer 203 and the fiber core 204, wherein the fiber core 204 is formed by the core and the cladding, passes through a section of the fiber core After 204, it is connected to the knot 205, and after passing through a section of fiber core 204, it is connected to the coupling junction 201. Continue to look at the original direction along the coupling junction 201, and after passing through a section of fiber core 204, it is followed by knot 205, fiber core 204 and optical fiber a2 `.

The protective tube 202 is a quartz glass tube whose cross section is semicircular or notched. The above-mentioned device with the coupling junction 201 is placed in the quartz glass tube in such a way that its longitudinal direction is parallel to the central axis of the protection tube 202 . Wherein, the coupling junction 201, the fiber core 204 and the knot 205 are placed in the middle of the quartz glass tube, and the optical fibers a1 and a1' composed of the protective layer 203 and the fiber core 204 are respectively placed at the port of the protective tube 202 and penetrated into the one of them. Then, use the adhesive 206 to solidify and bond the optical fibers a1, a1', a2, a2' that go deep into the port of the protection tube 202 to the inner wall of the port of the quartz glass tube, so that the four optical fiber terminals a1, a1, a2' of the device with the coupling junction 201 a1`, a2, a2` are positioned. Afterwards, the knots 205 on both axial sides of the coupling knot 201 are cured and bonded to the inner wall of the middle part of the quartz glass tube by using an adhesive 207 . Because the diameter of the fiber core 204 in the area where the coupling junction 201 is located is very thin, 125 μm, and lacks effective outer layer protection, it is easy to break, so when applying the adhesive 207, a dispensing stick with a smaller diameter should be used to complete the rope. Knot 205 is fixed. In this way, the fiber coupler 2 composed of the coupling junction 201 and the protection tube 202 can be obtained.

Referring to Fig. 3, it is the cross-sectional structure of the second embodiment of the optical fiber coupler of the present invention, that is, for the parallel arrangement coupling junction 201' obtained directly through the twisted fiber core 204, that is, there are no ropes at both ends. In the case of the junction 205, on the basis of _the aforementioned _embodiment shown in FIG. The region 205 ′ is solidified and bonded to the inner wall of the middle part of the quartz glass tube to obtain the optical fiber coupler 2 composed of the coupling junction 201 ′ and the protective tube 202 .

Referring to Fig. 4, the preparation process of the core component of the optical fiber coupler of the present invention. A coupler preform 305 is formed by inserting the first optical fiber 301 and the second optical fiber 302 from which the polymer-coated protective layer has been removed, into the through hole 304 of the cladding glass tube 303. The preform 305 passes through the annular burner 306 and is clamped on two stretch chucks 307 , 308 . Two stretch chucks 307, 308 are mounted on motor consoles 309, 310, respectively. After the first optical fiber 301 and the second optical fiber 302 pass through the vacuum generating chambers 311 , 312 at the same time, the ends of the coupler preform 305 are sealed in the vacuum generating chambers 311 , 312 . The conduits 313 and 314 communicate with the external vacuum pump and the vacuum generating chambers 311 and 312 respectively. A rubber sleeve 315 is installed at the end of the vacuum generating chambers 311 , 312 opposite to the preform 305 . After the coupler preform 305 is fixed on the two stretching chucks 307, 308, the vacuum generating chambers 311, 312 are respectively evacuated through the conduits 313, 314. After reaching a predetermined vacuum degree, the coupler is heated by the annular burner 306. At the same time, the motor consoles 309, 310 respectively drive two stretching chucks 307, 308 to stretch the heating area in opposite directions, and the core component corresponding to the fiber coupler shown in Fig. 1 can be obtained 1 or the coupling junction 201 of the fiber coupler 2 shown in FIG. 2 .

After the corresponding core components or coupling junctions are obtained through the preparation process shown in FIG. 4 , they are packaged in the quartz glass protective tube described above to obtain the fiber coupler.

Claims (3)

1. A fiber optic coupler, comprising a coupling junction made of bare cores of at least two optical fibers, said fiber optic coupler being fixed in a protective tube with a through-hole along its longitudinal direction, characterized in that said coupling junction is along said The longitudinal position of the optical fiber corresponding to the edge of the flame during tapering is respectively fixed in the protective tube through support blocks, and the support block is kept between the coupling junction and the position corresponding to the edge of the flame during the longitudinal direction of the optical fiber. Close contact. 2. The optical fiber coupler according to claim 1, characterized in that the position of the coupling junction along the longitudinal direction of the optical fiber corresponding to the edge of the flame during tapering is formed by twisting the two longitudinal ends of the bare fiber core respectively knot. 3 . The optical fiber coupler according to claim 2 , wherein the supporting block is a cured colloid that wraps the knot inside. 4 .

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