JP2018061229A - Optical line changeover device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication changeover device capable of suppressing decline in coupling efficiency, even when used in tape fiber, while preventing blockage and interference of communication.SOLUTION: An optical line changeover device includes a third optical fiber group for relaying a part of a first optical fiber group and a second optical fiber group, a first light leakage coupling part for optically coupling the core propagation mode and space propagation mode of the first optical fiber group by flexing thereof, an optical transfer part for optically coupling the space propagation mode with the core propagation mode of the third optical fiber group, a photodetector for detecting the light passed through the optical transfer part, an alignment mechanism control section for adjusting the optical coupling state of the first and third optical fiber groups, and a line changeover section for blocking communication between an ONU and any one of first OLT or second OLT and, at the same time, opening communication between the ONU and the other of the first OLT and second OLT.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical line switching device.

  For example, Patent Literature 1 below proposes a line switching device that controls an optical line switch to switch a communication light distribution path from a first optical fiber line to a second optical fiber line. In this line switching device, it is intended to maintain a communication service by duplexing a single optical fiber line and switching to the second optical fiber line when an abnormality occurs in the communication of the first optical fiber line. Yes.

JP 2015-226108 A

  It is desired that the line switching device as proposed in Patent Document 1 can be applied to, for example, a tape fiber that is a multi-core optical fiber line. However, when the line switching device as described above is simply applied to the tape fiber, the coupling efficiency due to the difference in the geometric shape in each tape fiber (for example, the deviation of the core interval between the tape fibers). There is concern about the decline. Further, in the line switching device as described above, it is also required to prevent communication interruption and occurrence of interference when switching lines.

  An object of the present invention is to provide an optical communication switching device that can suppress a decrease in coupling efficiency even when used in a tape fiber, and can prevent communication interruption and interference.

  An optical line switching apparatus according to an aspect of the present invention includes a communication state between an ONU and a first OLT via a first optical fiber group, and an ONU via a part of the first optical fiber group and a second optical fiber group. Line switching device for switching the communication state between the first optical fiber group and the second OLT, a part of the first optical fiber group and a third optical fiber group that relays the second optical fiber group, and a tape included in the first optical fiber group A first light leakage coupling portion that optically couples the core propagation mode and the spatial propagation mode of each optical fiber of the first optical fiber group by bending the fiber, and each optical fiber included in the spatial propagation mode and the third optical fiber group An optical transfer unit that optically couples the core propagation modes of the first optical fiber, a light detection unit that detects light via the third optical fiber group and the optical transfer unit, and a light intensity detected by the light detection unit. An optical fiber group and a third optical fiber group; The alignment mechanism control unit that adjusts the optical coupling state and the communication between the ONU and one of the first OLT and the second OLT are interrupted, and at the same time, the communication between the ONU and the other one of the first OLT and the second OLT A line switching unit that opens the line.

  ADVANTAGE OF THE INVENTION According to this invention, even when it is a case where it uses for a tape fiber, while being able to suppress the fall of coupling efficiency, the optical communication switching apparatus which can prevent interruption | blocking of communication and interference can be provided.

FIG. 1 is a block diagram showing an optical line switching apparatus according to the first embodiment. FIG. 2 is a schematic cross-sectional view of the first optical fiber group. FIG. 3A is a schematic diagram illustrating the optical coupling unit according to the first embodiment, and FIG. 3B is a schematic diagram illustrating a part of FIG. 3A from a different angle. is there. FIG. 4 is a schematic diagram illustrating the connection switching unit. FIG. 5A is a schematic diagram illustrating the line blocking unit and the first optical fiber group, and FIG. 5B is a schematic diagram illustrating a state in which the first optical fiber group is blocked by the line blocking unit. FIG. FIG. 6 is a block diagram showing an optical line switching device according to the second embodiment. FIG. 7A is a schematic diagram showing a state in which the second optical fiber group is blocked by the second line blocking unit, and FIG. 7B is a diagram illustrating the first optical fiber by the first line blocking unit. It is a schematic diagram which shows the state by which the group is interrupted | blocked. FIG. 8 is a schematic diagram showing a line branching portion. FIG. 9 is a block diagram showing an optical line switching apparatus according to the third embodiment. FIG. 10 is a schematic diagram illustrating an optical coupling unit according to the third embodiment. FIG. 11 is a block diagram showing an optical line switching apparatus according to the fourth embodiment. FIG. 12 is a schematic diagram illustrating an optical coupling unit according to the fifth embodiment. FIG. 13 is a schematic diagram illustrating an optical coupling unit according to the sixth embodiment.

[Description of Embodiment of Present Invention]
First, the contents of the embodiment of the present invention will be listed and described.

  One embodiment of the present invention relates to a communication state between the ONU and the first OLT via the first optical fiber group, and between the ONU and the second OLT via a part of the first optical fiber group and the second optical fiber group. An optical line switching device for switching a communication state, wherein a part of the first optical fiber group and a third optical fiber group that relays the second optical fiber group, and bending of the tape fiber included in the first optical fiber group, A first light leakage coupling unit that optically couples a core propagation mode and a spatial propagation mode of each optical fiber of the first optical fiber group; a spatial propagation mode and a core propagation mode of each optical fiber included in the third optical fiber group; A first optical fiber group and a first optical fiber group based on the intensity of light detected by the light detection unit, a light detection unit for detecting light via the third optical fiber group and the light transfer unit, Adjust the optical coupling state with the three optical fibers. The line switching that opens the communication between the ONU and one of the first OLT and the second OLT at the same time that the communication between the aligning mechanism control unit and the ONU and either the first OLT or the second OLT is cut off. And an optical line switching device.

  In this optical line switching device, lateral input / output technology is adopted in communication between the ONU and the second OLT, and the first optical fiber group and the third optical fiber group are the first optical leakage coupling unit and They are optically coupled to each other via an optical transfer unit. Here, based on the intensity of the light that has passed through the third optical fiber group and the optical transfer unit detected by the light detection unit, the alignment mechanism control unit performs the light of the first optical fiber group and the third optical fiber group. The coupling state is adjusted. Thereby, even if it is a case where it uses for a tape fiber, the fall of the coupling efficiency resulting from the difference in the geometric shape of each optical fiber group can be suppressed. In addition, the line switching unit cuts off the communication between the ONU and one of the first OLT and the second OLT, and at the same time opens the communication between the ONU and one of the first OLT and the second OLT. Therefore, it is possible to satisfactorily suppress the interruption of communication and the occurrence of interference in the optical line switching device.

  The optical line switching device further includes a fourth optical fiber group connected to the light detection unit, and the line switching unit includes a connection between the third optical fiber group and the fourth optical fiber group, and the third optical fiber group and the third optical fiber group. You may have a connection switching part which switches the connection of 2 optical fiber groups. In this case, when adjusting the optical coupling state between the first optical fiber group and the third optical fiber group, the light output from the ONU and passing through the third optical fiber group is selectively input to the fourth optical fiber group. it can.

  The optical line switching device further includes a fourth optical fiber group connected to the light detection unit, and a line branching unit that branches the third optical fiber group into the second optical fiber group and the fourth optical fiber group. The line switching unit may bend one of the first optical fiber group and the second optical fiber group and simultaneously eliminate the other bend of the first optical fiber group and the second optical fiber group.

  The optical line switching device further includes an alignment light source unit that outputs alignment light, and a fifth optical fiber group that connects the alignment light source unit and the line switching unit, and the line switching unit includes a third The connection between the optical fiber group and the fifth optical fiber group and the connection between the third optical fiber group and the second optical fiber group are switched, and the light detection unit adjusts via the fifth optical fiber group and the third optical fiber group. You may detect the light for heart. In this case, for example, light traveling from the ONU to the second OLT can be selectively input to the second optical fiber group. In addition, by using the aligning light source unit, the aligning operation between the first optical fiber group and the third optical fiber group can be performed regardless of the communication state.

  The optical line switching device includes an alignment light source unit that outputs alignment light, a fifth optical fiber group that connects the alignment light source unit and the line switching unit, a second optical fiber group, and a fifth optical fiber group. A line branching unit that joins the first optical fiber group and the second optical fiber group, and the line switching unit bends one of the first optical fiber group and the second optical fiber group, and simultaneously The light detection unit may detect alignment light via the fifth optical fiber group and the third optical fiber group. In this case, the alignment operation between the first optical fiber group and the third optical fiber group can be performed regardless of the communication state by using the alignment light source unit.

  The optical line switching device is provided on the ONU side with respect to the first light leakage coupling unit, and optically couples the core propagation mode and the spatial propagation mode of each optical fiber included in the first optical fiber group. The light detection unit may detect alignment light via the first light leakage coupling unit and the second light leakage coupling unit.

  The wavelength of the light output from the aligning light source unit may be longer than 1625 nm. In this case, it can suppress that the light output from the alignment light source part interferes with the light for communicating ONU and 1st OLT or 2nd OLT.

  The optical line switching device further includes a bending angle adjusting unit that increases a bending angle of the first optical fiber group in the first light leakage coupling unit when communication between the ONU and the first OLT is interrupted, and adjusts the bending angle. The unit may be provided between the ONU and the first light leakage coupling unit. In this case, the ratio of light leaking from the first optical fiber group at the first light leakage coupling portion can be increased. Thereby, since light having sufficient intensity is transmitted from the ONU to the second OLT, a communication failure between the ONU and the second OLT can be suppressed.

  In the case where the optical line switching device includes the second light leakage coupling unit, the optical line switching device, when blocking the communication between the ONU and the first OLT, of the first optical fiber group in the first light leakage coupling unit. A bending angle adjustment unit that increases the bending angle may further be provided, and the bending angle adjustment unit may be provided between the first light leakage coupling unit and the second light leakage coupling unit. In this case, the ratio of light leaking from the first optical fiber group at the first light leakage coupling portion can be increased. Thereby, since light having sufficient intensity is transmitted from the ONU to the second OLT, a communication failure between the ONU and the second OLT can be suppressed.

  The bending angle adjusting unit may be arranged so as to be farther from the first light leakage coupling unit as the allowable bending radius of the first optical fiber group is larger. In this case, according to the allowable bending radius of the first optical fiber group, the bending angle of the first optical fiber group at the first light leakage coupling portion can be appropriately set.

[Details of the embodiment of the present invention]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same elements or elements having the same functions, and redundant description is omitted.

(First embodiment)
FIG. 1 is a block diagram showing an optical line switching apparatus according to the first embodiment. As shown in FIG. 1, the optical line switching device 1 includes a first optical fiber group F1, a second optical fiber group F2, a third optical fiber group F3, a fourth optical fiber group F4, an ONU 2 (Optical Network Unit), a first OLT 3 (Optical Line Terminal), a second OLT 4, an optical coupling unit 5, a light detection unit 6, an alignment mechanism control unit 7, and a line switching unit 8. The optical line switching device 1 includes a communication state between the ONU 2 and the first OLT 3 through the first optical fiber group F1, and the ONU 2 and the second optical fiber group F2 through the part F1a of the first optical fiber group F1 and the second optical fiber group F2. This is a device for switching the communication state with 2OLT4. The optical line switching device 1 is a device that switches the communication state using a side light input / output technology (details will be described later).

  FIG. 2 is a schematic cross-sectional view of the first optical fiber group F1. As shown in FIG. 2, the first optical fiber group F1 is a tape fiber including a multi-core optical fiber, and includes four optical fibers 11 to 14 and a tape portion 15 that bundles the optical fibers 11 to 14. Have. The optical fiber 11 includes a core 11a having a circular cross section, a clad 11b having a circular cross section surrounding the core 11a, and a resin cover 11c surrounding the clad 11b. Each of the resin cover 11c and the tape part 15 has translucency, for example, is formed from an acrylic resin. The optical fibers 12 to 14 also have the same configuration as the optical fiber 11. The core interval S between the optical fibers in the first optical fiber group F1 is, for example, 0.21 mm to 0.29 mm. Each of the second to fourth optical fiber groups F2 to F4 is a tape fiber including four optical fibers as in the first optical fiber group F1. Each of the first to fourth optical fiber groups F1 to F4 may have a different core spacing S or the like due to a difference in geometric shape.

  Returning to FIG. 1, the ONU 2 is a subscriber-side transmission device, for example, an optical line termination device provided in the subscriber's home. On the other hand, each of the first OLT 3 and the second OLT 4 is a carrier side transmission device, for example, an optical line termination device provided in a station building. The ONU 2 is connected to the first OLT 3 via the first optical fiber group F1, which is an active optical fiber line. The ONU 2 includes a part F1a of the first optical fiber group F1, a second optical fiber group F2 that is a bypass optical fiber line, and a part F1a of the first optical fiber group F1 and the second optical fiber group F2. It can be connected to the second OLT 4 via the third optical fiber group F3 to be relayed. In the first embodiment, the first OLT 3 is a main OLT and the second OLT 4 is a sub OLT. Note that the “connection” in this specification may be at least optically connected, and may not be physically connected.

  3A is a schematic diagram showing the optical coupling unit 5 according to the first embodiment, and FIG. 3B is a schematic diagram showing a part of FIG. 3A from a different angle. It is. As illustrated in FIGS. 3A and 3B, the optical coupling unit 5 includes a light leakage coupling unit 21 (first light leakage coupling unit) and a light transfer unit 22.

  The light leakage coupling portion 21 is a portion that optically couples the core propagation mode and the spatial propagation mode of each of the optical fibers 11 to 14 included in the first optical fiber group F1 by bending the first optical fiber group F1. The core propagation mode indicates a state in which light propagates in the core of each optical fiber, and the space propagation mode indicates a state in which light propagates in space. The light leakage coupling portion 21 includes a pressing member 23 having a circular cross section and a transparent block 24 provided with a recess 24 a that can be fitted to a side surface of the pressing member 23. The first optical fiber group F <b> 1 is disposed between the pressing member 23 and the transparent block 24. For this reason, when the pressing member 23 is fitted into the recess 24 a, the first optical fiber group F <b> 1 that is a tape fiber is sandwiched and bent between the pressing member 23 and the transparent block 24. Of the first optical fiber group F1 bent by the light leakage coupling part 21, the part on the ONU2 side from the light leakage coupling part 21 is a part F1a, and the part on the first OLT 3 side from the light leakage coupling part 21 is The other part is F1b. Moreover, the transparent block 24 has a refractive index higher than the refractive index of the resin cover 11c and the tape part 15, for example, is formed from optical glass or a polycarbonate.

  Here, the movement of light output from the ONU 2 to the first optical fiber group F1 when the first optical fiber group F1 is bent by the light leakage coupling portion 21 will be described. First, part of the light output from the ONU 2 and flowing through the optical fibers 11 to 14 leaks outside from the bending point of the first optical fiber group F1. The leaked light L1 propagates through the transparent block 24. And the light L1 which propagates the inside of the transparent block 24 leaks to external space from the slope 24b of the transparent block 24 which opposes a part F1b of a 1st optical fiber group. Thereby, the core propagation mode of light changes to the spatial propagation mode. A non-reflective film may be provided on the inclined surface 24b.

  The optical transfer unit 22 is an optical system that optically couples the spatial propagation mode to the core propagation mode of each optical fiber included in the third optical fiber group F3. The optical transfer unit 22 includes plano-convex lenses 25 and 26 and a condenser lens 27 connected to the third optical fiber group F3. The lens 25 is positioned closer to the light leakage coupling part 21 than the lens 26 and the condenser lens 27, and is a lens that adjusts the traveling direction of the light L1 leaked from the light leakage coupling part 21 into the space. The lens 26 is located between the lens 25 and the condenser lens 27 and is a lens that adjusts the traveling direction of the light L <b> 2 adjusted by the lens 25 in a direction to reach the condenser lens 27. The condensing lens 27 is connected to each optical fiber included in the third optical fiber group F3, and is a lens that condenses the light from the lens 26 onto the core of each optical fiber. At least one of the lens 26 and the condenser lens 27 is a biaxial translation mechanism (alignment mechanism), and is provided so as to be driven by a drive mechanism (not shown). Two axes are directions that intersect the traveling direction of light.

  Specifically, the light L 1 leaked from the inclined surface 24 b of the transparent block 24 in the light leakage coupling portion 21 to the external space first reaches the lens 25. Next, the light L <b> 2 whose traveling direction is adjusted by the lens 25 reaches the lens 26. Next, the light L <b> 3 whose traveling direction is further adjusted by the lens 26 reaches the condenser lens 27. The light L3 that has reached the condenser lens 27 is input to the core of each optical fiber of the third optical fiber group F3, whereby the spatial propagation mode of light changes to the core propagation mode. Note that at least one of the lens 26 and the condenser lens 27 translates along two axes according to the control of the alignment mechanism control unit 7. Thereby, it can adjust so that the loss amount in the change from the space propagation mode of light to core propagation mode may become low.

  Returning to FIG. 1, the light detection unit 6 is a part that detects light via the third optical fiber group F3. In the first embodiment, the light detection unit 6 is connected to a fourth optical fiber group F4 connected to a connection switching unit 31 (details will be described later) of the line switching unit 8. The light detection unit 6 is output from the ONU 2 and is transmitted through a part F1b of the first optical fiber group F1, the optical coupling unit 5, the third optical fiber group F3, the line switching unit 8, and the fourth optical fiber group F4. It is the part which detects the intensity of the. The light detection unit 6 is, for example, a photosensor that detects the intensity of light output from the optical fibers of the fourth optical fiber group F4.

  The alignment mechanism control unit 7 is a part that adjusts the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3 based on the intensity of light detected by the light detection unit 6. The alignment mechanism control unit 7 is, for example, a CPU (Central Processing Unit) mounted on the drive mechanism. The alignment mechanism control unit 7 adjusts the position of at least one of the lens 26 and the condenser lens 27 of the optical coupling unit 5 based on the detection result of the light detection unit 6. Thereby, the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3 is optimized. The optimization of the optical coupling state means, for example, maximizing the coupling efficiency between the optical fibers 11 to 14 of the first optical fiber group F1 and the optical fibers of the third optical fiber group F3. For example, the alignment mechanism control unit 7 maximizes the coupling efficiency by adjusting the position of each optical fiber of the third optical fiber group F3.

  The line switching unit 8 is a part that blocks communication between the ONU 2 and one of the first OLT 3 and the second OLT 4 and simultaneously opens communication between the ONU 2 and one of the first OLT 3 and the second OLT 4. The line switching unit 8 includes a connection switching unit 31 and a line blocking unit 32.

  FIG. 4 is a schematic diagram showing the connection switching unit 31. The connection switching unit 31 is an active element having a first condenser lens 34 and a second condenser lens 35 that are optically coupled to each other. The first condenser lens 34 includes lenses 34a to 34d connected to the optical fibers of the third optical fiber group F3, and lenses 34e to 34h that are not connected to any part in the optical line switching device 1. doing. The lenses 34a to 34d and the lenses 34e to 34h are alternately arranged along a direction orthogonal to the light traveling direction. The second condenser lens 35 includes lenses 35a to 35d connected to the optical fibers of the second optical fiber group F2, and lenses 35e to 35h connected to the optical fibers of the fourth optical fiber group F4. . Similarly to the first condenser lens 34, the lenses 35a to 35d and the lenses 35e to 35h are alternately arranged along the above-described direction orthogonal to the light traveling direction. The second condenser lens 35 is movable along the above direction with respect to the first condenser lens 34.

  In FIG. 4, the lenses 34a to 34d are optically coupled to the lenses 35e to 35h, respectively. For this reason, the third optical fiber group F3 is connected to the fourth optical fiber group F4 via the connection switching unit 31. Here, by moving the second condenser lens 35, the lenses 34a to 34d can be optically coupled to the lenses 35a to 35d. At this time, the third optical fiber group F3 is connected to the second optical fiber group F2 via the connection switching unit 31. By such movement of the second condenser lens 35, the connection between the third optical fiber group F3 and the fourth optical fiber group F4 and the connection between the third optical fiber group F3 and the second optical fiber group F2 can be switched. it can. In other words, by using the connection switching unit 31, the light output from the third optical fiber group F3 can be output to only one of the second optical fiber group F2 and the fourth optical fiber group F4.

  FIG. 5A is a schematic diagram showing the line blocking unit 32 and the first optical fiber group F1, and FIG. 5B shows the first optical fiber group F1 blocked by the line blocking unit 32. It is a schematic diagram which shows a state. The line blocking unit 32 shown in FIGS. 5A and 5B is a part that blocks the other part F1b of the first optical fiber group F1. The line blocking section 32 has pressing members 32a to 32c and pressing members 32d and 32e that are circular in cross section and arranged in order. Each pressing member 32a to 32e is movable in a direction perpendicular to the first and second optical fiber groups F1 and F2. In the direction, the first optical fiber group F1 is located between the pressing members 32a to 32c and the pressing members 32d and 32e. That is, the pressing members 32a to 32c and the pressing members 32d and 32e are separated from each other with the first optical fiber group F1 in the above direction.

  When the first optical fiber group F1 is blocked by the line blocking unit 32, the pressing members 32a to 32c and the pressing members 32d and 32e move in a direction in contact with the first optical fiber group F1. Then, as shown in FIG. 5B, the pressing members 32a to 32e are in contact with the first optical fiber group F1. Thereby, the first optical fiber group F1 is sandwiched and bent by the pressing members 32a to 32c and the pressing members 32d and 32e.

  The blocking of the first optical fiber group F1 by the line blocking unit 32 is performed at the same time as the third optical fiber group F3 is connected to the second optical fiber group F2 via the connection switching unit 31. In other words, the connection switching unit 31 opens the connection state between the ONU 2 and the second OLT 4, and at the same time, the line blocking unit 32 blocks the connection state between the ONU 2 and the first OLT 3. As described above, the line switching unit 8 having the connection switching unit 31 and the line blocking unit 32 opens one of the first optical fiber group F1 and the second optical fiber group F2 and blocks the other, whereby the ONU 2 and the first A connection state with only one of the 1 OLT 3 and the second OLT 4 is secured.

  According to the optical line switching device 1 according to the first embodiment described above, the side input / output technology is adopted in the communication between the ONU 2 and the first OLT 3, and the first optical fiber group F1 and the third optical fiber switching device 1 are connected. The optical fiber group F3 is optically coupled to each other via an optical coupling unit 5 having a light leakage coupling unit 21 and an optical transfer unit 22. Here, based on the intensity of the light that has passed through the third optical fiber group F3 and the optical transfer unit 22 detected by the light detection unit 6, the alignment mechanism control unit 7 performs the first optical fiber group F1 and the third light. The optical coupling state with the fiber group F3 is adjusted. Thereby, even if it is a case where it uses for a tape fiber, the fall of the coupling efficiency resulting from the shift | offset | difference of the core space | interval in each tape fiber, etc. can be suppressed.

  In addition, the line switching unit 8 cuts off communication between the ONU 2 and one of the first OLT 3 and the second OLT, and simultaneously opens communication between the ONU 2 and one of the first OLT 3 and the second OLT 4. For example, during the adjustment of the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3 by the alignment mechanism control unit 7, the communication between the ONU 2 and the first OLT 3 is kept open, while the ONU 2 Communication with the second OLT 4 can be maintained. Thereby, generation | occurrence | production of the interruption | blocking of the communication in the optical line switching apparatus 1 can be suppressed favorably. Furthermore, after the adjustment of the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3 by the alignment mechanism control unit 7 is finished, the line switching unit 8 immediately switches between the ONU 2 and the first OLT 3. The communication between the ONU 2 and the second OLT 4 can be opened simultaneously. Thereby, generation | occurrence | production of the communication interference in the optical line switching apparatus 1 can also be suppressed favorably.

  The optical line switching device 1 includes a fourth optical fiber group F4 connected to the light detection unit 6, and the line switching unit 8 includes a connection between the third optical fiber group F3 and the fourth optical fiber group F4, and a third light. A connection switching unit 31 that switches connection between the fiber group F3 and the second optical fiber group F2 is provided. For this reason, when adjusting the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3, the light output from the ONU 2 and passing through the third optical fiber group F3 is transmitted to the fourth optical fiber group F4. You can enter it selectively. Therefore, the interruption of communication and the occurrence of interference in the optical line switching device 1 can be suppressed better.

(Second Embodiment)
Hereinafter, an optical line switching apparatus according to the second embodiment will be described. In the description of the second embodiment, descriptions overlapping with the first embodiment are omitted, and only the parts different from the first embodiment are described. In other words, the description of the first embodiment may be used as appropriate for the second embodiment within the technically possible range.

  FIG. 6 is a block diagram showing an optical line switching device according to the second embodiment. As shown in FIG. 6, the line switching unit 8A of the optical line switching device 1A does not include the connection switching unit 31, and is provided with a first line blocking unit 32A and a second line blocking unit 33. . In addition, the optical line switching device 1A includes a line branching unit 41 that branches the third optical fiber group F3 into the second optical fiber group F2 and the fourth optical fiber group F4.

  Similarly to the line blocking unit 32, the first line blocking unit 32A is a part that blocks or opens the other part F1b of the first optical fiber group F1. The second line blocking unit 33 is a part that blocks or opens the second optical fiber group F2. The first line blocking unit 32A and the second line blocking unit 33 operate complementarily. For this reason, when one of the first line blocking unit 32A and the second line blocking unit 33 is blocking the corresponding tape fiber, the other of the first line blocking unit 32A and the second line blocking unit 33 is the corresponding tape. The fiber is open. The first line blocking unit 32A and the second line blocking unit 33 may be integrated.

  FIG. 7A is a schematic diagram showing a state in which the second optical fiber group F2 is blocked by the second line blocking unit 33, and FIG. 7B is a diagram illustrating the first line blocking unit 32A. It is a schematic diagram which shows the state by which 1 optical fiber group F1 is interrupted | blocked. As shown in FIGS. 7A and 7B, the first line blocking section 32A has only pressing members 32a to 32c, and the second line blocking section 33 has a circular cross section and is arranged in sequence. The pressing members 33a to 33c are provided. Further, either one of the first line blocking unit 32A and the second line blocking unit 33 includes pressing members 36a and 36b having a circular cross section and arranged in order. Each pressing member 32a-32c, 33a-33c, 36a, 36b is movable in the direction orthogonal to the first and second optical fiber groups F1, F2. In this direction, the pressing members 36a and 36b are located between the pressing members 32a to 32c and the pressing members 33a to 33c. Further, in this direction, the first optical fiber group F1 is located between the pressing members 32a to 32c and the pressing members 36a and 36b, and the second optical fiber group F2 includes the pressing members 33a to 33c and the pressing member. 36a and 36b.

  For example, when the state changes from the state in which the second optical fiber group F2 is blocked to the state in which the first optical fiber group F1 is blocked, the pressing members 32a to 32c and the pressing members 36a and 36b mutually receive the first light. It moves in the direction in contact with the fiber group F1. As a result, the pressing members 36a and 36b that have been in contact with the second optical fiber group F2 in FIG. 7A are separated from the second optical fiber group F2, and as shown in FIG. One optical fiber group F1 is contacted. Thereby, the first optical fiber group F1 is sandwiched and bent by the pressing members 32a to 32c and the pressing members 36a and 36b. On the other hand, the pressing members 33a to 33c that have been in contact with the second optical fiber group F2 in FIG. 7A are separated from the second optical fiber group F2. Thereby, the bending of the second optical fiber group F2 is eliminated, and the second optical fiber group F2 is opened. Thus, the line switching unit 8A having the first line blocking unit 32A and the second line blocking unit 33 opens one of the first optical fiber group F1 and the second optical fiber group F2 and blocks the other. The connection state between the ONU 2 and one of the first OLT 3 and the second OLT 4 is ensured.

  FIG. 8 is a schematic diagram showing the line branch portion 41. The line branch portion 41 includes passive elements 41a to 41d connected to the respective optical fibers of the third optical fiber group F3. Each of the passive elements 41a to 41d is connected to a corresponding optical fiber of the second optical fiber group F2 and a corresponding optical fiber of the fourth optical fiber group F4. The passive elements 41a to 41d are, for example, optical fiber couplers or spectral filters. Even if the intensity of light input to the second optical fiber group F2 via the line branching portion 41 is significantly larger than the intensity of light input to the fourth optical fiber group F4 via the line branching portion 41, Good. For example, the ratio of the intensity of light input to the second optical fiber group F2 via the line branching portion 41 and the intensity of light input to the fourth optical fiber group F4 via the line branching portion 41 is 9 : 1 may be sufficient.

  In such an optical line switching device 1A according to the second embodiment, the same effects as those of the first embodiment are exhibited. Further, by using the line branching unit 41 instead of the connection switching unit 31, unlike the first embodiment, a mechanism for driving the connection switching unit 31 can be omitted. Therefore, light detection by the light detection unit 6 and communication between the ONU 2 and the second OLT 4 can be realized with a simpler configuration than the first embodiment. In addition, the ONU 2 and the second OLT 4 can communicate with each other while adjusting the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3.

  The line switching unit 8A bends one of the first optical fiber group F1 and the second optical fiber group F2 by the first line blocking unit 32A and the second line blocking unit 33, and at the same time, the first optical fiber group The other bending of F1 and the second optical fiber group F2 is eliminated. In this case, it is possible to easily block communication between the ONU and one of the first OLT and the second OLT and to open communication between the ONU and the other of the first OLT and the second OLT.

(Third embodiment)
Hereinafter, an optical line switching device according to the third embodiment will be described. In the description of the third embodiment, the description overlapping with the first and second embodiments is omitted, and only parts different from the first and second embodiments are described. In other words, the descriptions of the first and second embodiments may be used as appropriate in the third embodiment within the technically possible range.

  FIG. 9 is a block diagram showing an optical line switching apparatus according to the third embodiment. As shown in FIG. 9, the optical line switching device 1 </ b> B includes a fifth optical fiber group F <b> 5 and a aligning light source unit 51. Instead, unlike the first and second embodiments, the optical line switching device 1B does not include the fourth optical fiber group F4.

  The alignment light source unit 51 is a light emitting element that outputs alignment light. The presence / absence of light output from the aligning light source unit 51 is controlled by the aligning mechanism control unit 7A. For example, the alignment light source unit 51 outputs light during alignment between the first optical fiber group F1 and the third optical fiber group F3 (that is, during adjustment of the optical coupling state). Further, after the alignment of the first optical fiber group F1 and the third optical fiber group F3, the light output of the alignment light source unit 51 is stopped by the control of the alignment mechanism control unit 7A. The wavelength of the alignment light output from the alignment light source 51 is longer than the wavelength of the communication light, for example, longer than 1625 nm. Thereby, it is possible to satisfactorily prevent interference between alignment light and communication light. The ONU 2 or the like may include a band reflection filter that reflects alignment light, for example. This band reflection filter is a filter that reflects light having a wavelength of about 1625 nm centered at, for example, 1650 nm.

  The fifth optical fiber group F5 is a light source fiber that connects the aligning light source unit 51 and the line switching unit 8. More specifically, each optical fiber of the fifth optical fiber group F5 is connected to the lenses 35e to 35h of the corresponding connection switching unit 31 (see FIG. 4). For this reason, the connection switching unit 31 according to the third embodiment switches the connection between the third optical fiber group F3 and the fifth optical fiber group F5 and the connection between the third optical fiber group F3 and the second optical fiber group F2. .

  The light detection unit 6A according to the third embodiment detects the intensity of the alignment light output from the alignment light source unit 51. More specifically, the light detection unit 6A detects the intensity of alignment light via the fifth optical fiber group F5, the connection switching unit 31, the third optical fiber group F3, and the optical coupling unit 5A. In addition, the light detection unit 6A is not provided in the ONU 2 and is provided apart from the first optical fiber group F1. For this reason, the optical coupling unit 5A in the third embodiment is provided with a mechanism for leaking at least part of the alignment light output from the alignment light source unit 51.

  FIG. 10 is a schematic diagram illustrating the optical coupling unit 5A and the light detection unit 6A according to the third embodiment. As shown in FIG. 10, in addition to the light leakage coupling unit 21 and the light transfer unit 22, the light coupling unit 5A includes a light leakage coupling unit 61 (second light leakage) located on the ONU 2 side from the light leakage coupling unit 21. Coupling part). Similar to the light leakage coupling unit 21, the light leakage coupling unit 61 is configured such that the core propagation mode and the spatial propagation mode of each of the optical fibers 11 to 14 included in the first optical fiber group F1 by bending of the first optical fiber group F1. This is the part that optically couples. The light leakage coupling portion 61 includes a pressing member 62 having a circular cross section and a transparent block 63 provided with a recess 63 a that can be fitted to a side surface of the pressing member 62. The first optical fiber group F <b> 1 is disposed between the pressing member 62 and the transparent block 63. In addition, the cross-sectional diameter of the pressing member 62 is larger than the cross-sectional diameter of the pressing member 23. This is because the wavelength of alignment light is longer than the wavelength of communication light as described above. By setting the cross-sectional diameter of the pressing member 62 in this way, light for dimming can easily leak from the light leakage coupling portion 61 to the external space.

  Here, the movement of the light for dimming until it reaches the light detection unit 6A via the light leakage coupling units 21 and 61 will be described. First, the light output from the alignment light source unit 51 passes through the fifth optical fiber group F5, the connection switching unit 31, the third optical fiber group F3, and the light transfer unit 22, and the transparent block 24 of the light leakage coupling unit 21 is used. Is input. At least a part of the light propagated in the transparent block 24 is input to the optical fibers 11 to 14 of the first optical fiber group F1. Part of the light input to these optical fibers 11 to 14 leaks to the outside from the bending point of the first optical fiber group F1 in the light leakage coupling portion 61. This leaked light propagates through the transparent block 63. Then, the light propagating through the transparent block 63 leaks to the external space from the slope 63b of the transparent block 63 facing the light leakage coupling portion 21, and is input to the light detection portion 6A.

  In such an optical line switching device 1B according to the third embodiment, the same operational effects as those of the first and second embodiments are exhibited except that light traveling from the second OLT 4 to the ONU 2 is used. In addition, by using the aligning light source unit 51, the aligning operation of the first optical fiber group F1 and the third optical fiber group F3 can be performed regardless of the communication state.

  The wavelength of light output from the aligning light source unit 51 is longer than 1625 nm. For this reason, interference with the light output from the aligning light source unit 51 and the light for communicating the ONU 2 with the first OLT 3 or the second OLT 4 can be suppressed.

(Fourth embodiment)
Hereinafter, an optical line switching apparatus according to the fourth embodiment will be described. In the description of the fourth embodiment, the description overlapping with the first to third embodiments is omitted, and only parts different from the first to third embodiments are described. That is, the descriptions of the first to third embodiments may be appropriately used for the fourth embodiment within the technically possible range.

  FIG. 11 is a block diagram showing an optical line switching apparatus according to the fourth embodiment. As shown in FIG. 11, the optical line switching device 1C includes a line switching unit 8A and a line branching unit 71 that joins the second optical fiber group F2 and the fifth optical fiber group F5. Different from the third embodiment. The line branch portion 71 has the same configuration and function as the line branch portion 41 in the second embodiment. That is, the line branch portion 71 can be regarded as the same as the line branch portion 41. In such an optical line switching device 1C according to the fourth embodiment, the same function and effect as those of the third embodiment are exhibited. Further, by using the line branching unit 71 instead of the connection switching unit 31, a mechanism for driving the connection switching unit 31 can be omitted unlike the third embodiment. Therefore, light detection by the light detection unit 6A and communication between the ONU 2 and the second OLT 4 can be realized with a simpler configuration than in the third embodiment. In addition, the ONU 2 and the second OLT 4 can communicate with each other while adjusting the optical coupling state between the first optical fiber group F1 and the third optical fiber group F3.

(Fifth embodiment)
Hereinafter, an optical line switching apparatus according to the fifth embodiment will be described. In the description of the fifth embodiment, descriptions overlapping with the first to fourth embodiments are omitted, and only the portions different from the first to fourth embodiments are described. In other words, the descriptions of the first to fourth embodiments may be used as appropriate in the fifth embodiment within the technically possible range.

  12A and 12B are schematic views showing an optical coupling unit 5B according to the fifth embodiment. More specifically, FIG. 12A shows a state in which the ONU 2 and the first OLT 3 are communicating, and FIG. 12B shows a state in which the ONU 2 and the second OLT 4 are communicating. Yes. The optical line switching device according to the fifth embodiment has the same configuration as that of the optical line switching device 1 according to the first embodiment, except that the optical coupling unit 5B is provided instead of the optical coupling unit 5. .

  As shown in FIG. 12A, the optical coupling unit 5B is different from the optical coupling unit 5 shown in FIG. 3A, and the bending angle adjusting unit 81 is located between the light leakage coupling unit 21 and the ONU 2. Have The bending angle adjusting unit 81 is a member that increases the bending angle of the first optical fiber group F1 in the light leakage coupling unit 21 when the communication between the ONU 2 and the first OLT 3 is cut off. It has a circular shape. The cross-sectional diameter of the bending angle adjusting unit 81 is substantially the same as the cross-sectional diameter of the pressing member 62, for example. The bending angle adjustment unit 81 is disposed closer to the transparent block 24 than the first optical fiber group F1. Similar to the pressing member 23, the bending angle adjustment unit 81 is provided so as to be movable in a direction intersecting the first optical fiber group F1. The movement distance of the bending angle adjusting unit 81 in the direction is set to a predetermined value. As shown in FIG. 12B, when the communication between the ONU 2 and the first OLT 3 is interrupted, the bending angle adjustment unit 81 moves to the first optical fiber group F1, thereby the first optical fiber group F1. Turns. Specifically, when the communication between the ONU 2 and the first OLT 3 is interrupted, the bending angle adjustment unit 81 bends a part F1a of the first optical fiber group F1 in the vicinity of the light leakage coupling unit 21. The bend angle adjustment unit 81 may increase the bend angle at the same time as the communication between the ONU 2 and the first OLT 3 is interrupted, or after the communication between the ONU 2 and the first OLT 3 is interrupted. You may enlarge it. Note that the bending angle of the first optical fiber group F1 in the light leakage coupling part 21 is an angle formed by the part F1a side of the first optical fiber group F1 bent in the light leakage coupling part 21. The bending angle in the fifth embodiment is determined by bending the part F1a of the first optical fiber group F1 by the bending angle adjusting unit 81, for example, the bending angle of the first optical fiber group F1 in the first embodiment (FIG. 3 ( (see a)).

  The bending angle adjustment unit 81 is provided so as to be movable along the extending direction of the first optical fiber group F1. The bending angle adjusting unit 81 is arranged so as to be farther from the light leakage coupling unit 21 as the allowable bending radius of the first optical fiber group F1 is larger. In other words, the bending angle adjustment unit 81 is arranged on the ONU 2 side as the allowable bending radius of the first optical fiber group F1 is larger. This is because, for example, an optical fiber having an allowable bending radius of 15 mm and an optical fiber having an allowable bending radius of 30 mm have different rates of light leaking depending on the bending angle.

  The effects of using the optical coupling unit 5B according to the fifth embodiment will be described below. From the viewpoint of improving the communication accuracy between the ONU 2 and the first OLT 3, the insertion loss of the first optical fiber group F1 is set to 2 dB or less, for example. When the insertion loss of the first optical fiber group F1 is set as described above, when the ONU 2 and the second OLT 4 are communicated using the light leakage coupling unit 21, the coupling between the first optical fiber group F1 and the third optical fiber group F3 is performed. Efficiency can be reduced. In this case, for example, the loss of light transmitted from the ONU 2 to the second OLT 4 may increase. As a result, a communication failure may occur between the ONU 2 and the second OLT 4.

  In order to prevent the occurrence of communication failure between the ONU 2 and the second OLT 4, simply increasing the coupling efficiency between the first optical fiber group F1 and the third optical fiber group F3 results in an insertion loss of the first optical fiber group F1 of 2 dB. May be exceeded. As a result, the communication accuracy between the ONU 2 and the first OLT 3 deteriorates. Thus, there is a trade-off relationship between the insertion loss and the coupling efficiency.

  In contrast, in the fifth embodiment, when the communication between the ONU 2 and the first OLT 3 is interrupted, the bending angle adjustment unit 81 increases the bending angle of the first optical fiber group F1 in the light leakage coupling unit 21. doing. For this reason, the ratio of the light leaking from the 1st optical fiber group F1 in the light leak coupling part 21 can be increased. Thereby, for example, even if the insertion loss of the first optical fiber group F1 is set to 2 dB or less, light having sufficient intensity is transmitted from the ONU 2 to the second OLT 4. Therefore, it is possible to suppress the occurrence of a communication failure between the ONU 2 and the second OLT 4 while preventing deterioration in communication accuracy between the ONU 2 and the first OLT 3. In addition, the bending angle adjusting unit 81 is arranged so as to be farther from the light leakage coupling unit 21 as the allowable bending radius of the first optical fiber group F1 is larger. For this reason, according to the allowable bending radius of the first optical fiber group F1, the bending angle of the part F1a of the first optical fiber group F1 in the light leakage coupling portion 21 can be appropriately set.

  As described above, the optical line switching device according to the fifth embodiment is the same as the optical line switching device 1 according to the first embodiment, except that the optical coupling unit 5B is provided instead of the optical coupling unit 5. It has a configuration. For this reason, in 5th Embodiment, in addition to the said effect, the effect similar to the said 1st Embodiment is show | played.

(Sixth embodiment)
Hereinafter, an optical line switching apparatus according to the sixth embodiment will be described. In the description of the sixth embodiment, the description overlapping with the first to fifth embodiments is omitted, and only parts different from the first to fifth embodiments are described. In other words, the descriptions of the first to fifth embodiments may be used as appropriate for the sixth embodiment within the technically possible range.

  FIGS. 13A and 13B are schematic views showing an optical coupling unit 5C according to the sixth embodiment. More specifically, FIG. 13A shows a state where the ONU 2 and the first OLT 3 are communicating, and FIG. 13B shows a state where the ONU 2 and the second OLT 4 are communicating. Yes. The optical line switching device according to the sixth embodiment has the same configuration as that of the optical line switching device 1B according to the third embodiment, except that the optical coupling unit 5C is provided instead of the optical coupling unit 5. .

  As shown in FIG. 13A, the optical coupling portion 5C is different from the light leakage coupling portion 21A and the light leakage coupling portion 61 which are different from the light leakage coupling portion 21 of the optical coupling portion 5A shown in FIG. 61 A of light leak coupling parts and the bending angle adjustment part 81 are provided. In the light leakage coupling portion 21A, a part of the protruding portion constituting the concave portion 24a of the transparent block 24A is cut away. Specifically, the protrusion on the ONU 2 side of the transparent block 24A is cut away. Similarly, in the light leakage coupling portion 61A, the protruding portion on the first OLT 3 side of the transparent block 63A is cut out. Further, in the light leakage coupling portion 61A, the pressing member 62 is disposed closer to the pressing member 23 than the first optical fiber group F1, and the transparent block 63A is disposed closer to the transparent block 24A than the first optical fiber group F1. Has been. The position of the light detection unit 6A in the optical coupling unit 5C is different from the position of the light detection unit 6A in the optical coupling unit 5A. Specifically, the position of the light detection unit 6A in the optical coupling unit 5C is arranged closer to the transparent block 24 than the first optical fiber group F1.

  In the sixth embodiment, the bending angle adjustment unit 81 is provided between the light leakage coupling units 21A and 61A. As shown in FIG. 13 (b), when the communication between the ONU 2 and the first OLT 3 is interrupted, the bending angle adjustment unit 81 causes a part F1a of the first optical fiber group F1 in the vicinity of the light leakage coupling unit 21A. Bend. Further, the bending angle adjusting unit 81 is provided between the light leakage coupling units 21A and 61A so as to be movable along the extending direction of the first optical fiber group F1.

  When such an optical coupling unit 5C according to the sixth embodiment is used, the same effects as those of the fifth embodiment are achieved. In addition, as described above, the optical line switching device according to the sixth embodiment includes the optical coupling unit 1C according to the third embodiment, except that the optical coupling unit 5C is provided instead of the optical coupling unit 5. It has the same configuration. For this reason, in 6th Embodiment, in addition to the said effect, the effect similar to the said 3rd Embodiment is show | played.

  The optical line switching apparatus according to the present invention is not limited to the above-described embodiment, and various other modifications are possible. For example, the first OLT 3 and the second OLT 4 may be the same OLT. In this case, the first optical fiber group F1 and the second optical fiber group F2 are connected to different terminals in the OLT.

  The number of optical fibers in each optical fiber group in the above embodiment is not limited to four. Each optical fiber group only needs to include two or more, that is, a plurality of optical fibers. In the above embodiment, the second to fifth optical fiber groups F2 to F5 are not necessarily tape fibers but may be multi-fiber optical fiber lines. At least a part of the first optical fiber group F1 may be a tape fiber.

  In the above embodiment, a system for monitoring the state of each optical fiber group may be introduced. In this case, monitoring light is input to each optical fiber group. This monitoring light has a longer wavelength than the communication light. In the third embodiment, the fourth embodiment, and the sixth embodiment, the monitoring light may be light output from the alignment light source unit 51. In this case, it is possible to satisfactorily prevent interference between the communication light and the monitoring light.

  You may combine the said embodiment suitably. For example, the second embodiment and the fifth embodiment may be combined, or the fourth embodiment and the sixth embodiment may be combined.

  DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C ... Optical line switching device, 2 ... ONU, 3 ... 1st OLT, 4 ... 2nd OLT, 5, 5A, 5B, 5C ... Optical coupling part, 6, 6A ... Photodetection part, 7, 7A Alignment mechanism control unit, 8, 8A ... Line switching unit, 11-14 ... Optical fiber, 21, 21A ... Light leakage coupling unit (first light leakage coupling unit), 22 ... Light transfer unit, 31 ... Connection switching unit 32 ... Line blocking unit, 32A ... First line blocking unit, 33 ... Second line blocking unit, 41 ... Line branching unit, 51 ... Aligning light source unit, 61, 61A ... Light leakage coupling unit (second light leakage coupling unit) Part), 71 ... line branching part, 81 ... bending angle adjusting part, F1 ... first optical fiber group, F2 ... second optical fiber group, F3 ... third optical fiber group, F4 ... fourth optical fiber group, F5 ... 5th optical fiber group.

Claims (10)

An optical line for switching a communication state between the ONU and the first OLT via the first optical fiber group and a communication state between the ONU and the second OLT via a part of the first optical fiber group and the second optical fiber group. A switching device,
A third optical fiber group that relays the part of the first optical fiber group and the second optical fiber group;
A first light leakage coupling portion that optically couples the core propagation mode and the spatial propagation mode of each optical fiber of the first optical fiber group by bending of the tape fiber included in the first optical fiber group;
An optical transfer unit that optically couples the spatial propagation mode and the core propagation mode of each optical fiber included in the third optical fiber group;
A light detection unit for detecting light via the third optical fiber group and the light transfer unit;
An alignment mechanism control unit that adjusts an optical coupling state between the first optical fiber group and the third optical fiber group based on the intensity of the light detected by the light detection unit;
A line switching unit that interrupts communication between the ONU and one of the first OLT and the second OLT, and simultaneously opens communication between the ONU and the other of the first OLT and the second OLT; ,
An optical line switching device comprising: A fourth optical fiber group connected to the light detection unit;
The line switching unit includes a connection switching unit that switches connection between the third optical fiber group and the fourth optical fiber group and connection between the third optical fiber group and the second optical fiber group. An optical line switching device according to claim 1. A fourth optical fiber group connected to the light detection unit;
A line branching portion for branching the third optical fiber group into the second optical fiber group and the fourth optical fiber group;
Further comprising
The line switching unit bends one of the first optical fiber group and the second optical fiber group, and at the same time eliminates the other bending of the first optical fiber group and the second optical fiber group. Item 4. The optical line switching device according to Item 1. An alignment light source unit that outputs alignment light;
A fifth optical fiber group connecting the aligning light source unit and the line switching unit;
Further comprising
The line switching unit switches between the connection of the third optical fiber group and the fifth optical fiber group, and the connection of the third optical fiber group and the second optical fiber group,
2. The optical line switching device according to claim 1, wherein the light detection unit detects the alignment light via the fifth optical fiber group and the third optical fiber group. An alignment light source unit that outputs alignment light;
A fifth optical fiber group connecting the aligning light source unit and the line switching unit;
A line branching section for joining the second optical fiber group and the fifth optical fiber group;
Further comprising
The line switching unit bends one of the first optical fiber group and the second optical fiber group, and at the same time eliminates the other bending of the first optical fiber group and the second optical fiber group,
2. The optical line switching device according to claim 1, wherein the light detection unit detects the alignment light via the fifth optical fiber group and the third optical fiber group. A second light leakage coupling portion provided on the ONU side of the first light leakage coupling portion and optically coupling a core propagation mode and a spatial propagation mode of each optical fiber included in the first optical fiber group; ,
6. The optical line switching device according to claim 4, wherein the light detection unit detects the alignment light via the first light leakage coupling unit and the second light leakage coupling unit. The wavelength of the light output from the aligning light source unit is longer than 1625 nm.
The optical line switching apparatus as described in any one of Claims 4-6. A bending angle adjustment unit that increases a bending angle of the first optical fiber group in the first light leakage coupling unit when communication between the ONU and the first OLT is interrupted;
The optical line switching device according to any one of claims 1 to 7, wherein the bending angle adjusting unit is provided between the ONU and the first light leakage coupling unit. A bending angle adjustment unit that increases a bending angle of the first optical fiber group in the first light leakage coupling unit when communication between the ONU and the first OLT is interrupted;
The optical line switching device according to claim 6, wherein the bending angle adjustment unit is provided between the first light leakage coupling unit and the second light leakage coupling unit.   10. The optical line switching device according to claim 8, wherein the bending angle adjusting unit is arranged to be separated from the first light leakage coupling unit as the allowable bending radius of the first optical fiber group is larger.

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