Optical fiber cable and production method for optical fiber cable

Abstract

This optical fiber cable comprises: a core wire group that is formed by bundling a plurality of optical fiber core wires; at least one bundling member that is wound around the core wire group; and an inclusion that is formed using a material different from the bundling member, and is provided further inward than the at least one bundling member in a cross-section perpendicular to the longitudinal direction.

Description

Optical fiber cable and method for manufacturing optical fiber cable

[0001] The present disclosure relates to an optical fiber cable and a method for manufacturing an optical fiber cable.

[0002] Patent Document 1 discloses an optical fiber cable formed by wrapping an optical fiber unit, which is formed by bundling a plurality of optical fiber cores, with two bundling members. Since the two bundling members are wound around the optical fiber cores, the bundled optical fiber cores are less likely to come loose.

[0003] Japanese Unexamined Patent Publication No. 2011-169939

[0004] An optical fiber cable according to an aspect of the present disclosure includes: a core wire group formed by bundling a plurality of optical fiber cores; at least one bundling member wound around the core wire group; and an inclusion formed of a material different from that of the bundling member and provided inward of at least one of the bundling members in a cross section perpendicular to the longitudinal direction.

[0005] A method for manufacturing an optical fiber cable according to an aspect of the present disclosure is a method for manufacturing an optical fiber cable including: a core wire group formed by bundling a plurality of optical fiber cores; at least one bundling member wound around the core wire group; and an inclusion formed of a material different from that of the bundling member and provided inward of at least one of the bundling members, the method comprising: a first step of wrapping the inclusion around the plurality of bundled optical fiber cores; a second step of wrapping at least one bundling member such that at least a part of the bundling member overlaps the inclusion after the start of the first step; and a third step of, after the second step, heating the optical fiber cores wrapped with the bundling member to a temperature equal to or higher than the melting point of the inclusion to break the inclusion.

[0006] Figure 1 is a cross-sectional view of an optical fiber cable according to this embodiment. Figure 2 is a schematic diagram of an optical fiber unit. Figure 3 is a schematic diagram illustrating the intersection of the first bundle material and the second bundle material. Figure 4 is a cross-sectional view of the first bundle material, the second bundle material, and the intervening material at the intersection. Figure 5 illustrates an example of an optical fiber unit manufacturing apparatus. Figure 6 illustrates the state of the core wire group after the first and part of the second process have been performed. Figure 7 illustrates the state of the core wire group after the remaining process of the second process has been performed.

[0007] (Problems this disclosure aims to solve) If the bundling material wrapped around bundled optical fiber cores shifts, the optical fiber cores become more likely to unravel. Furthermore, even if the bundled optical fiber cores are wrapped around and secured with bundling material, it would be desirable for the optical fiber cable to be easily disassembled.

[0008] (Effects of this disclosure) This disclosure aims to provide an optical fiber cable that achieves both resistance to fraying of optical fiber cores and ease of disassembly in the optical fiber cable.

[0009] (Description of Embodiments of the Disclosure) Embodiments of the Disclosure will be described first by listing them. (1) An optical fiber cable according to one aspect of the Disclosure comprises a group of optical fiber cores formed by bundling together a plurality of optical fiber cores, at least one bundle material wound around the group of optical fiber cores, and an intervening made of a different material from the bundle material and provided inward of at least one of the bundle materials in a cross section perpendicular to the longitudinal direction.

[0010] According to the above-described optical fiber cable, the bundle material is formed from a different material, and an intervening material is provided in a cross section perpendicular to the longitudinal direction, positioned inside at least one of the bundle materials. This makes it difficult for the bundle material in contact with the intervening material to shift relative to the optical fiber. As a result, the bundle material is less likely to loosen, and the optical fiber cores are less likely to fray. Furthermore, because the bundle material is less likely to move in the longitudinal direction, it does not need to be welded to other components, making it easier to disassemble the optical fiber cable when some of the optical fiber cores are removed. Thus, the optical fiber cable achieves both resistance to fraying of the optical fiber cores and ease of disassembly.

[0011] (2) In the optical fiber cable described in (1) above, the intervening material includes a plurality of intervening material pieces formed by intermittently breaking the intervening material in the longitudinal direction of the optical fiber core, and each of the intervening material pieces may be provided inside at least one of the bundle material in a cross section perpendicular to the longitudinal direction.

[0012] According to the above-mentioned fiber optic cable, the bundle material is less likely to shift due to the intervening pieces placed in multiple locations, thus preventing the fiber optic cores from fraying.

[0013] (3) In the optical fiber cable described in (2) above, the intervening piece may include an intervening piece in which two or more intervening pieces are welded together.

[0014] According to the optical fiber cable described above, in an inclusion piece where two or more inclusions are welded together, the bundle material in contact with the inclusion piece becomes even less likely to shift relative to the optical fiber.

[0015] (4) In the optical fiber cable described in (2) or (3) above, the intervening piece may be formed when the intervening is broken by thermal shrinkage.

[0016] According to the optical fiber cable described above, multiple inclusion fragments are formed in a simple manner.

[0017] (5) In the optical fiber cable described in (4) above, the melting point of the inclusion piece may be lower than the melting point of the bundle material.

[0018] According to the optical fiber cable described above, when heat is applied to cause thermal shrinkage of the intervening material, the effect of the heat on the bundle material is reduced.

[0019] (6) In the optical fiber cable described in (4) or (5) above, the melting point of the inclusion piece may be 100°C or more and 150°C or less.

[0020] According to the above-mentioned optical fiber cable, the inclusions have a low melting point, making it easy to thermally shrink them.

[0021] (7) In the optical fiber cable described in (6) above, the intervening piece may be formed by breaking a low-melting-point nylon thread due to thermal shrinkage.

[0022] According to the optical fiber cable described above, the inclusions are made of low-melting-point nylon threads, so the melting point of the inclusions is sufficiently low. Therefore, when heat is applied to cause thermal shrinkage of the inclusion pieces, the effect of the heat on the bundle material is reduced.

[0023] (8) In the optical fiber cable described in any of (2) to (7) above, the bundle material includes a first bundle material and a second bundle material wound around the group of core wires so as to overlap the first bundle material, wherein the direction in which the second bundle material is wound around the group of core wires is different from the direction in which the first bundle material is wound around the group of core wires, and the intervening piece may be provided so as to be sandwiched between the first bundle material and the second bundle material at the intersection where the first bundle material and the second bundle material intersect.

[0024] In the optical fiber cable described above, the intervening piece is positioned so as to be sandwiched between the first and second bundle materials. As a result, the second bundle material, which is wound over the first bundle material, is less likely to shift relative to the first bundle material. Therefore, the winding of the bundle materials is more stable, and the first and second bundle materials are less likely to shift relative to the core wire group.

[0025] (9) In the optical fiber cable described in any of (2) to (8) above, a portion of the intervening material may protrude outward from the bundle material in a cross section perpendicular to the longitudinal direction of the optical fiber cable.

[0026] In the optical fiber cable described above, a portion of the intervening material protrudes outward from the bundle material in a cross-section perpendicular to the longitudinal direction of the optical fiber cable, making it difficult for the bundle material to move in the longitudinal direction. This makes it less likely for the optical fiber cores to unravel.

[0027] (10) A method for manufacturing an optical fiber cable according to one aspect of the present disclosure is a method for manufacturing an optical fiber cable comprising: a group of optical fiber cores formed by bundling a plurality of optical fiber cores; at least one bundle material wound around the group of optical fiber cores; and an intervening material made of a different material from the bundle material and provided inside at least one of the bundle materials, the method comprising: a first step of winding the intervening material around the bundled plurality of optical fiber cores; a second step, after the start of the first step, winding at least one bundle material so that at least a portion of it overlaps the intervening material; and a third step, after the second step, heating the optical fiber cores around which the bundle material is wound to a temperature above the melting point of the intervening material to break the intervening material.

[0028] According to the above manufacturing method, multiple optical fiber cores, each wrapped with an intervening material and a bundle material partially overlapping the intervening material, are heated, causing the intervening material to break. As a result, multiple intervening material fragments are formed from the intervening material. At this time, since the intervening material fragments are formed on the inside of the bundle material, the bundle material becomes less likely to shift due to the intervening material fragments. This makes the bundle material less likely to loosen, and thus the optical fiber cores are less likely to fray. Furthermore, since the bundle material does not need to be welded to other components in order to prevent it from moving in the longitudinal direction, the optical fiber cable is easily disassembled when some of the optical fiber cores are removed. Thus, in an optical fiber cable, both resistance to fraying of the optical fiber cores and ease of disassembly are achieved.

[0029] (11) In the method for manufacturing an optical fiber cable described in (10) above, the first step and the second step may be performed simultaneously. According to the above manufacturing method, since the first step and the second step are performed simultaneously, the time required for manufacturing the optical fiber cable is shortened.

[0030] (Details of Embodiments of the Disclosure) Specific examples of optical fiber cables and methods for manufacturing optical fiber cables according to embodiments of the Disclosure will be described below with reference to the drawings. However, the Disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope of the equivalents of the claims, as indicated by the claims.

[0031] Referring to Figure 1, the optical fiber cable 1 according to this embodiment will be described. Figure 1 is a cross-sectional view of the optical fiber cable 1 according to this embodiment. As illustrated in Figure 1, the optical fiber cable 1 comprises an optical fiber unit 10, an outer sheath 20, a tensile strength member 30, and a tear cord 40.

[0032] The optical fiber unit 10 is formed by bundling together multiple optical fiber cores 11. Five optical fiber units 10 are housed in the optical fiber cable 1 of this embodiment. The optical fiber unit 10 of this embodiment may include, for example, 12 to 288 optical fiber cores 11. The optical fiber cores 11 may be housed in the optical fiber cable 1 as an optical fiber ribbon formed by connecting multiple optical fiber cores 11 in parallel in a direction perpendicular to the longitudinal direction.

[0033] The outer sheath 20 covers the periphery of the optical fiber unit 10. The resin forming the outer sheath 20 may have a Young's modulus of, for example, 500 MPa or more. The outer sheath 20 may also contain a lubricant such as silicone. When the diameter of the optical fiber cable 1 is, for example, 22 mm, the thickness of the outer sheath 20 may be 1.5 mm.

[0034] The tensile strength members 30 are arranged along the longitudinal direction of the optical fiber cable 1 along the multiple optical fiber cores 11. Multiple tensile strength members 30 are embedded in the outer sheath 20. In this embodiment, two tensile strength members 30 are embedded in the outer sheath 20. The diameter of the tensile strength members 30 is, for example, 0.5 mm. The tensile strength members 30 are formed from fiber-reinforced plastic (FRP) such as aramid FRP, glass FRP, or carbon FRP. The tensile strength members 30 may also be formed from liquid crystal polymer. It is preferable that the tensile strength members 30 are non-inductive.

[0035] The tearing strings 40 are provided for tearing the outer sheath 20. The tearing strings 40 are arranged along the longitudinal direction of the optical fiber cable 1 in layers of the outer sheath 20, along with a plurality of optical fiber cores 11. In this embodiment, two tearing strings 40 are provided.

[0036] Figure 2 is a schematic diagram of an optical fiber unit 10. The optical fiber unit 10 has a core group 11A formed by bundling together a plurality of optical fiber cores 11, and at least one bundle material wound around the core group 11A. In this embodiment, the bundle material includes a first bundle material 12A and a second bundle material 12B. In the following description, the first bundle material 12A and the second bundle material 12B may be collectively referred to as bundle materials 12A and 12B. The first bundle material 12A and the second bundle material 12B are wound spirally around the core group 11A, and the second bundle material 12B is wound so as to overlap the first bundle material 12A. The first bundle material 12A and the second bundle material 12B are made of polyester colored yarn or the like. The direction of the spiral in which the second bundle material 12B is wound around the core group 11A may be different from the direction of the spiral in which the first bundle material 12A is wound around the core group 11A. In this case, the first bundle material 12A and the second bundle material 12B intersect at various points along the longitudinal direction of the optical fiber cable 1. The portion where the first bundle material 12A and the second bundle material 12B intersect is referred to as the intersection 12C.

[0037] Figure 3 is a schematic diagram of the first bundle material 12A and the second bundle material 12B. In Figure 3 and subsequent figures, the core wire group 11A is schematic to make the bundle materials 12A and 12B easier to see. Specifically, the individual optical fiber cores 11 of the core wire group 11A are not shown.

[0038] The optical fiber unit 10 further includes an inclusion piece 13. The inclusion piece 13 is made of a different material from the first bundle material 12A and the second bundle material 12B. The inclusion piece 13 is located inside at least one of the bundle materials 12A, 12B, or both. In this embodiment, the inclusion piece 13 is positioned between the first bundle material 12A and the second bundle material 12B. The inclusion piece 13 may also be located inside the first bundle material 12A. Furthermore, the inclusion piece 13 may be formed by welding two or more inclusions together.

[0039] In this embodiment, an inclusion piece 13 is provided at each intersection 12C scattered in the longitudinal direction. The inclusion piece 13 is provided so as to be sandwiched between the first bundle material 12A and the second bundle material 12B. The inclusion piece 13 is formed of, for example, a low-melting-point nylon yarn. The melting point of the inclusion piece 13 may be 100°C or more and 150°C or less. The inclusion piece 13 may be formed by intermittently breaking a single inclusion 13A (see Figures 6 and 7) due to thermal shrinkage. The fineness of the inclusion piece 13 may be 1000 dtex or less. Alternatively, the fineness of the inclusion piece 13 may be 5% or more and 50% or less of the fineness of the bundle materials 12A and 12B. For example, the fineness of the first bundle material 12A and the second bundle material 12B is 1000 dtex, and the fineness of the inclusion piece 13 is 110 dtex.

[0040] Figure 4 is a cross-sectional view of the first bundle material 12A, the second bundle material 12B, and the inclusion piece 13 at the intersection 12C. As illustrated in Figure 4, the end of the inclusion piece 13 rises up, so that a portion of the inclusion piece 13 protrudes outward from the second bundle material 12B, which overlaps the radially outer side of the inclusion piece 13 in a cross-section perpendicular to the longitudinal direction of the optical fiber cable 1.

[0041] Next, a method for manufacturing the optical fiber unit 10 illustrated in Figures 2 and 3 will be described. Figure 5 illustrates a manufacturing apparatus 100 for the optical fiber unit 10. The manufacturing apparatus 100 for the optical fiber unit 10 includes a core wire group feeding unit 110, a winding unit 120, and a hot air device 130. The core wire group feeding unit 110 is a device that bundles a plurality of optical fiber cores 11 to form a core wire group 11A, and feeds out the core wire group 11A, which has a first bundle material 12A and an inclusion 13A (see Figures 6 and 7) that will become the basis of the inclusion piece 13 wound around it, in the direction to the right in Figure 5 (downstream side of the manufacturing line). Alternatively, the first bundle material may be wound around the core wire group 11A with the inclusion 13A attached vertically. The winding unit 120 winds a second bundle material 12B around the core wire group 11A fed out by the core wire group feeding unit 110. The hot air device 130 is a device that heats the core wire group 11A, which has a first bundle material 12A, a second bundle material 12B, and an inclusion material 13A wrapped around it, in order to manufacture the inclusion material piece 13.

[0042] The method for manufacturing the optical fiber cable 1 comprises a first step, a second step, and a third step. The first step is to wrap an intervening material 13A around a bundle of multiple optical fiber cores 11, which is a core group 11A. There may be multiple intervening materials 13A. The second step is to wrap at least one bundle material 12A, 12B around the intervening material 13A after the start of the first step, such that at least a portion of it overlaps the intervening material 13A. The third step is to heat the core group 11A (optical fiber cores 11) around which either or both of the bundle materials 12A, 12B are wrapped, to a temperature above the melting point of the intervening material piece 13, thereby causing the intervening material 13A to break. Note that the first and second steps may be performed simultaneously. In this embodiment, the first step and the step of wrapping the first bundle material 12A, which is part of the second step, are performed simultaneously.

[0043] FIG. 6 illustrates an example of the state after a part of the first step and the second step have been performed on the core wire group 11A. As illustrated in FIG. 6, in a part of the first step and the second step, a first bundling material 12A and an inclusion 13A are wound around the core wire group 11A. In the first step of the present embodiment, the inclusion 13A that is simultaneously wound around the core wire group 11A is a single thread formed of low-melting nylon thread, and is the material before being broken to form inclusion pieces 13. The inclusion 13A is wound so as to overlap the first bundling material 12A. Further, the inclusion 13A may be wound linearly in a longitudinal application manner, or may be wound along the first bundling material 12A.

[0044] FIG. 7 illustrates an example of the state after the remaining steps of the second step have been performed on the core wire group 11A. In the remaining step of the second step, the winding section 120 winds a second bundling material 12B around the core wire group 11A on which the first bundling material 12A and the inclusion 13A have been wound. The second bundling material 12B is wound around the core wire group 11A in a spiral direction opposite to the direction in which the first bundling material 12A and the inclusion 13A are wound around the core wire group 11A.

[0045] In the third step, the core wire group 11A, around which the first bundling material 12A, the second bundling material 12B and the inclusion 13A are wound, is sent to a hot air device 130 and heated. The hot air device 130 heats the core wire group 11A wound with the inclusion 13A, the first bundling material 12A, and the second bundling material 12B such that the heating temperature is not lower than the melting point of the inclusion 13A and lower than the melting points of the first bundling material 12A and the second bundling material 12B. When the inclusion 13A is formed of a low-melting nylon thread having a melting point of 120°C, the hot air device 130 heats the core wire group 11A to, for example, 120°C or higher. Since the inclusion 13A thermally shrinks when heated to a temperature not lower than its melting point, the inclusion 13A breaks in places, and as illustrated in FIG. 3, inclusion pieces 13 are formed near the intersection 12C. The inclusion pieces 13 are crimped by thermal shrinkage, and as illustrated in FIG. 4, in a cross-section perpendicular to the longitudinal direction of the optical fiber cable 1, the ends of the inclusion pieces 13 are formed so as to protrude outward beyond the second bundling material 12B.

[0046] By providing the inclusion piece 13, at the intersection 12C, the second bundle material 12B overlapping the inclusion piece 13 is less likely to be displaced relative to the first bundle material 12A. In particular, when the inclusion piece 13 is crimped, the second bundle material 12B is even less likely to be displaced. That is, since the winding of the bundle materials 12A and 12B between each other is easily stabilized, the first bundle material 12A and the second bundle material 12B are less likely to be displaced relative to the core wire group 11A. Further, the inclusion piece 13 is not welded to the first bundle material 12A and the second bundle material 12B, and the inclusion piece 13 can be easily separated from the first bundle material 12A and the second bundle material 12B, for example, by an operator's fingers. Therefore, when taking out a part of the optical fiber core wires 11 from the optical fiber cable 1, the optical fiber cable 1 is easily disassembled, which facilitates the disassembly work.

[0047] As described above, according to the above-described optical fiber cable 1 and the manufacturing method thereof, at the intersection 12C where the inclusion piece 13 is present between the first bundle material 12A and the second bundle material 12B, the first bundle material 12A and the second bundle material 12B are less likely to be displaced from each other. Since the winding of the bundle materials 12A and 12B between each other is easily stabilized, the first bundle material 12A and the second bundle material 12B are less likely to be displaced relative to the core wire group 11A. Therefore, the bundle materials 12A and 12B are less likely to loosen, and the optical fiber core wires 11 are less likely to come apart. Further, since the bundle materials 12A and 12B do not need to be welded to prevent displacement, it is easy for an operator to remove the bundle materials 12A and 12B from the optical fiber unit 10 to separate the optical fiber core wires 11 from the bundled state, or to shift the spirally wound state of the bundle materials 12A and 12B to take out a desired optical fiber core wire 11. Therefore, when taking out a part of the optical fiber core wires 11 from the optical fiber cable 1, the optical fiber cable 1 is easily disassembled. This achieves both the difficulty of the optical fiber core wires 11 coming apart and the disassemblability of the optical fiber cable 1.

[0048] When the fineness of the inclusion piece 13 is 1000 dtex or less, the lateral pressure applied to the optical fiber core wires 11 is sufficiently low, so that microbend loss of the optical fiber core wires is less likely to occur.

[0049] Although this disclosure has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of this disclosure. Furthermore, the number, position, shape, etc. of the components described above are not limited to the embodiments described above and can be changed to a number, position, shape, etc. that is suitable for carrying out this disclosure.

[0050] The intervening piece 13 is positioned so as to overlap the intersection 12C, which is expected to reduce the likelihood of displacement for both the first bundle material 12A and the second bundle material 12B. However, the intervening piece 13 does not necessarily have to be located at the intersection. Even if the intervening piece 13 is located at a position other than the intersection, the bundle material wrapped around the intervening piece will be less likely to shift relative to the core wire group, thus reducing the likelihood of the optical fiber cores 11 unraveling.

[0051] In this embodiment, an inclusion piece 13 is manufactured by severing one inclusion 13A, but an inclusion piece 13 may be manufactured from two inclusions 13A. For example, the first bundle material 12A may be wound so as to overlap the first inclusion wound around the core wire group 11A, the second inclusion may be wound so as to overlap the first bundle material 12A, and the second bundle material 12B may be wound so as to overlap the second inclusion. When heated in this state to manufacture an inclusion piece, the inclusion piece manufactured from the first inclusion makes it difficult for the first bundle material 12A to shift relative to the core wire group 11A, and the inclusion piece manufactured from the second inclusion makes it difficult for the second bundle material 12B to shift relative to the first bundle material 12A. In addition, the first and second inclusions may be welded together.

[0052] For example, in this embodiment, a method of rupturing the inclusion 13A by thermal shrinkage was described, but the inclusion 13A may also be ruptured by chemicals, ultraviolet light, or the like.

[0053] In this embodiment, a loose-tube type optical fiber cable 1 as illustrated in Figure 1 is used as an example, but other types of optical fiber cables may be used. For example, the contents of this disclosure may be applied to a slot-type optical fiber cable.

[0054] 1 Optical fiber cable 10 Optical fiber unit 11 Optical fiber core 11A Core group 12A First bundle material 12B Second bundle material 12C Intersection 13 Filler piece 13A Filler 20 Sheath 30 Tension-resistant material 40 Tear string 100 Manufacturing equipment 110 Core group feeding section 120 Winding section 130 Hot air device

Claims

1. An optical fiber cable comprising: a group of optical fiber cores formed by bundling together multiple optical fiber cores; at least one bundle material wound around the group of optical fiber cores; and an intervening material made of a different material from the bundle material, provided inward of at least one of the bundle materials in a cross section perpendicular to the longitudinal direction.

2. The optical fiber cable according to claim 1, wherein the intervening material comprises a plurality of intervening material pieces formed by intermittently fracturing the intervening material in the longitudinal direction of the optical fiber core, and each of the intervening material pieces is located inside at least one of the bundle material in a cross section perpendicular to the longitudinal direction.

3. The optical fiber cable according to claim 2, wherein the inclusion piece includes an inclusion piece in which two or more inclusions are welded together.

4. The optical fiber cable according to claim 2 or 3, wherein the inclusion piece is formed by the inclusion being fractured by thermal shrinkage.

5. The optical fiber cable according to claim 4, wherein the melting point of the inclusion piece is lower than the melting point of the bundle material.

6. The optical fiber cable according to claim 5, wherein the melting point of the inclusion piece is 100°C or higher and 150°C or lower.

7. The optical fiber cable according to claim 6, wherein the inclusion piece is formed by breaking a low-melting-point nylon thread due to thermal shrinkage.

8. The optical fiber cable according to any one of claims 2 to 7, wherein the bundle material includes a first bundle material and a second bundle material wound around the group of core wires so as to overlap the first bundle material, the direction in which the second bundle material is wound around the group of core wires is different from the direction in which the first bundle material is wound around the group of core wires, and the intervening piece is provided so as to be sandwiched between the first bundle material and the second bundle material at the intersection where the first bundle material and the second bundle material intersect.

9. The optical fiber cable according to any one of claims 2 to 8, wherein a portion of the intervening piece protrudes outward from the bundle material in a cross section perpendicular to the longitudinal direction.

10. A method for manufacturing an optical fiber cable comprising: a group of optical fiber cores formed by bundling together a plurality of optical fiber cores; at least one bundle material wrapped around the group of optical fiber cores; and an intervening material made of a different material from the bundle material and provided inside at least one of the bundle materials, the method comprising: a first step of wrapping the intervening material around the bundled plurality of optical fiber cores; a second step, after the start of the first step, of wrapping at least one bundle material so that at least a portion of it overlaps the intervening material; and a third step, after the second step, of heating the optical fiber cores around which the bundle material is wrapped to a temperature above the melting point of the intervening material to break the intervening material.

11. The method for manufacturing an optical fiber cable according to claim 10, wherein the first step and the second step are performed simultaneously.

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