Optical connector for multicore fiber

Abstract

To provide an optical connector capable of eliminating wrong connection between an optical transmitter and an optical receiver generated when the number of connections between the same type of end surfaces of a multicore optical fiber is odd.SOLUTION: An optical connector comprises: a first surface; a second surface from which a plurality of optical signals input to the first surface is output; and adjustment means for adjusting the output position of the plurality of output signal from the second surface so that the plurality of optical signals output from the second surface is in a mirror symmetric relation with the plurality of optical signals input to the first surface when viewed in a propagation direction of the plurality of optical signals.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a multicore fiber optical connector. [Background technology]

[0002] In order to increase transmission capacity, optical communication systems using multi-core optical fibers (MCFs) (hereinafter, MCF optical communication systems) have been attracting attention. MCFs are optical fibers with multiple cores, and the multiple cores are arranged at equal intervals at positions equidistant from the center of the MCF. Each core of the MCF is assigned a core number, and the core number is identified based on a marker provided on the MCF.

[0003] When two MCFs are connected, the relative rotational phase of the two MCFs is adjusted so that the same core numbers are connected, and then the fusion process is performed. However, due to an operational error or the like, the two MCFs may be connected in a state where the relative rotational phase of the two MCFs is shifted. Patent Document 1 discloses an optical connector for correcting the shift in rotational phase in such a case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7261778 Summary of the Invention [Problem to be solved by the invention]

[0005] FIG. 1(A) is a side view of a four-core MCF 50, and the left-right direction of FIG. 1(A) corresponds to the longitudinal direction of the MCF 50. The MCF 50 has two types of end faces, A end face and B end face. FIG. 1(B) shows the MCF 50 viewed toward the A end face, and FIG. 1(C) shows the MCF 50 viewed toward the B end face. As shown in FIG. 1(B) and FIG. 1(C), a marker 53 is provided on the MCF 50, and the core closest to the marker 53 has a core number of #1. On the A end face, the core numbers increase in the clockwise direction. On the other hand, on the B end face, the core numbers increase in the counterclockwise direction. In the following description, a core with a core number of #n (in this example, n is an integer from 1 to 4) is represented as core #n. The A end face and the B end face are determined by the positional relationship between the marker 53 and the reference core closest to the marker 53. In other words, the end face of marker 53 between the reference core and the core adjacent to the reference core in the clockwise direction is end face A, and the end face of marker 53 between the reference core and the core adjacent to the reference core in the counterclockwise direction is end face B.

[0006] FIG. 2 shows an example of an MCF optical communication system using an MCF 50. An optical device called a fan-in fan-out (FIFO) is used to input an optical signal #n transmitted by an optical transmitter (TX) #n (n is an integer from 1 to 4) to a core #n of an MCF 50. Similarly, a FIFO is used to input an optical signal #n from a core #n of an MCF 50 to an optical receiver (RX) #n. The end face of the FIFO #1 used on the transmitting side that connects to the MCF 50 is end face B, and the end face of the FIFO #2 used on the receiving side that connects to the MCF 50 is end face A. As shown in FIG. 2, an optical transmission path in an MCF optical communication system is generally configured by connecting multiple MCFs 50 (three in FIG. 2) in series. According to FIG. 2, end face B of the MCF 50-1 is connected to end face A of the MCF 50-2, and end face B of the MCF 50-2 is connected to end face A of the MCF 50-3. End face A of MCF 50-1 is connected to FIFO #1 having end face B, and end face B of MCF 50-3 is connected to FIFO #2 having end face A. By connecting as in Fig. 2, optical signal #n transmitted by TX #n reaches RX #n via core #n of each of MCFs 50-1 to 50-3.

[0007] Here, the MCF 50 is not laid alone between communication stations, but laid in the form of an optical cable accommodating multiple MCFs 50. FIG. 3 shows multiple MCFs 50 housed in an optical cable 70. In FIG. 3, the shaded rectangles are MCFs 50. As shown in FIG. 3, generally, the end faces of the multiple MCFs 50 housed in the optical cable 70 are not the same type, and end faces A and B are mixed. This means that when connecting two MCFs 50 housed in different optical cables, a situation arises in which end faces of the same type, such as end face A and end face A, or end face B and end face B, must be connected to each other.

[0008] 4 is a diagram similar to FIG. 2, but differs from FIG. 2 in that the B end face of MCF50-1 is connected to the B end face of MCF50-2, the A end face of MCF50-2 is connected to the B end face of MCF50-3, and the FIFO#1 having the B end face is used on the receiving side instead of the FIFO#2 having the A end face, and is connected to the A end face of MCF50-3. Note that at the connection point between the B end face of MCF50-1 and the B end face of MCF50-2, the core#1 of MCF50-1 and the core#1 of MCF50-2 are connected. Therefore, the core#2 of MCF50-1 and the core#4 of MCF50-2 are connected, the core#3 of MCF50-1 and the core#3 of MCF50-2 are connected, and the core#4 of MCF50-1 and the core#2 of MCF50-2 are connected. Therefore, optical signal #1 transmitted by TX#1 will reach RX#1, and optical signal #3 transmitted by TX#3 will reach RX#3, but optical signal #2 transmitted by TX#2 will reach RX#4 rather than RX#2, and optical signal #4 transmitted by TX#4 will reach RX#2 rather than RX#4.

[0009] 5 is a diagram similar to FIG. 2, but differs from FIG. 2 in that the B end face of MCF50-1 is connected to the B end face of MCF50-2, and the A end face of MCF50-2 is connected to the A end face of MCF50-3. Note that at the connection point between the B end face of MCF50-1 and the B end face of MCF50-2, the core #1 of MCF50-1 is connected to the core #1 of MCF50-2, and at the connection point between the A end face of MCF50-2 and the A end face of MCF50-3, the core #1 of MCF50-2 is connected to the core #1 of MCF50-3. Therefore, the core #2 of MCF50-1 is connected to the core #4 of MCF50-2, and the core #4 of MCF50-2 is connected to the core #2 of MCF50-3. Also, core #3 of MCF50-1 is connected to core #3 of MCF50-2, and core #3 of MCF50-2 is connected to core #3 of MCF50-3. Furthermore, core #4 of MCF50-1 is connected to core #2 of MCF50-2, and core #2 of MCF50-2 is connected to core #4 of MCF50-3. Therefore, optical signal #n transmitted by TX#n arrives at RX#n.

[0010] As is clear from the explanations of Figures 4 and 5, when the number of connections between end faces of the same type, such as the connection between end faces A and A, or the connection between end faces B and B, is an even number or 0, the optical signal #n transmitted by TX #n reaches RX #n. Note that in Figure 5, at the connection between end face B of MCF 50-1 and end face B of MCF 50-2, the core #1 of MCF 50-1 is connected to the core #1 of MCF 50-2, and at the connection between end face A of MCF 50-2 and end face A of MCF 50-3, the core #1 of MCF 50-2 is connected to the core #1 of MCF 50-3, but due to a shift in the relative rotation phase, such a connection may not be possible. However, in such a case, for example, the optical connector disclosed in Patent Document 1 can be used to eliminate the erroneous connection.

[0011] On the other hand, if the number of connections between end faces of the same type is odd, some optical signals sent by TX will not reach the intended RX. In other words, if the number of connections between end faces of the same type is odd, misconnections will occur between optical transmitters and optical receivers using the MCF optical communication system. Such misconnections cannot be resolved even by the optical connector disclosed in Patent Document 1.

[0012] The present disclosure provides an optical connector that eliminates erroneous connections between an optical transmitter and an optical receiver that occur when the number of connections between end faces of the same type of MCF is odd. [Means for solving the problem]

[0013] According to one aspect of the present disclosure, an optical connector comprises a first surface, a second surface from which a plurality of optical signals input to the first surface are output, and an adjustment means for adjusting output positions of the plurality of optical signals from the second surface so that, when viewed in the propagation direction of the plurality of optical signals, the plurality of optical signals output from the second surface are mirror-symmetric with respect to the plurality of optical signals input to the first surface. Effect of the Invention

[0014] According to the present disclosure, it is possible to eliminate erroneous connections between optical transmitters and optical receivers that occur when the number of connections between end faces of the same type of MCF is odd. [Brief description of the drawings]

[0015] [Figure 1] An explanatory diagram of MCF. [Diagram 2] FIG. 1 is a diagram showing an example of the configuration of an MCF optical communication system. [Diagram 3] FIG. 1 is a diagram showing an example of an MCF housed in an optical cable. [Figure 4] FIG. 13 is an explanatory diagram of an erroneous connection that occurs when there is an odd number of connection points between end faces of the same type. [Diagram 5] FIG. 11 is an explanatory diagram illustrating how incorrect connections do not occur when there is an even number of connection points between end faces of the same type. [Figure 6] FIG. 1 is a diagram showing an example of the configuration of an MCF optical communication system using an optical connector according to an embodiment. [Figure 7] FIG. 2 is an explanatory diagram of an optical connector according to an embodiment. [Figure 8] FIG. 2 is an explanatory diagram of an optical connector according to an embodiment. [Figure 9] A diagram showing two end faces of an MCF. [Figure 10] FIG. 2 is a diagram showing a configuration example of an optical connector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0017] FIG. 6 shows an MCF optical communication system using an optical connector 100 according to the present disclosure. In FIG. 6, the optical connector 100 is used at the connection point between the B end faces in order to eliminate the erroneous connection described in FIG. 4. FIGS. 7 and 8 are explanatory diagrams of the optical connector 100 according to this embodiment. In addition, although the optical connector 100 is shown as a rectangular parallelepiped in FIGS. 7 and 8, the shape of the optical connector 100 is not limited to a rectangular parallelepiped and may be any shape. The optical connector 100 has two faces 101 and 102 connected to the MCF 50. In the following description, the propagation direction of the optical signal, that is, the direction connecting the faces 101 and 102 in FIG. 7, is the Z direction, one direction in the plane perpendicular to the Z direction is the X direction, and a direction perpendicular to both the Z direction and the X direction is the Y direction. As an example, the face 101 is connected to the B end face of the MCF 50-1, and the face 102 is connected to the B end face of the MCF 50-2. An adjustment unit (not shown) is provided on the propagation path of a plurality of optical signals from surface 101 to surface 102 for adjusting the position of the optical signal output from surface 102. The process performed by the adjustment unit will be described below.

[0018] FIG. 8(A) shows the area of ​​the surface 101 where the optical signals #1 to #4 from the cores #1 to #4 on the B end surface of the MCF 50-1 are input. #1 to #4 in FIG. 8(A) show the optical signals #1 to #4. Note that FIG. 8(A) shows the view in the Z direction, that is, the view of the surface 101 from the outside of the optical connector 100. FIG. 8(B) shows the area of ​​the surface 102 where the optical signals #1 to #4 are output. #1 to #4 in FIG. 8(B) show the optical signals #1 to #4. Note that FIG. 8(B) shows the view in the Z direction, that is, the view of the surface 102 from the inside of the optical connector 100. Note that in FIG. 8(A) and FIG. 8(B), the black circles show the positions of the surface 101 and the surface 102 connected to the center of the MCF, and the dotted line is a line in the Y direction passing through the center, which will be referred to as the "reference line" below.

[0019] 8(A) and 8(B), the optical connector 100 converts an optical signal incident on the surface 101 so that the optical signal becomes a mirror image of the optical signal incident on the surface 101, and outputs the converted signal. That is, the optical connector 100 outputs the optical signal #1 and the optical signal #3 from the same position on the surface 102 as the incident position on the surface 101. On the other hand, the optical connector 100 outputs the optical signal #2 from a position on the opposite side in the X direction from the incident position on the surface 101 to the reference line, although the distance in the X direction between the incident position on the surface 101 and the reference line is the same. The same is true for the optical signal #4.

[0020] Therefore, optical signal #2 output from core #2 of MCF 50-1 is input to core #2 of MCF 50-2, and optical signal #4 output from core #4 of MCF 50-1 is input to core #4 of MCF 50-2, thereby eliminating the erroneous connection.

[0021] 9(A) and 9(B) show the A and B end faces of the MCF 50, respectively. Note that FIG. 9(A) shows the A end face of FIG. 1(B) rotated counterclockwise by 45 degrees, and FIG. 9(B) shows the B end face of FIG. 1(C) rotated clockwise by 45 degrees. In the explanation of FIG. 4, it is assumed that the core #1 of MCF 50-1 and the core #1 of MCF 50-2 are connected at the connection point between the B end face of MCF 50-1 and the B end face of MCF 50-2. For example, it is assumed that the core #1, the core #2, the core #3, and the core #4 of MCF 50-1 are connected to the core #2, the core #1, the core #4, and the core #3 of MCF 50-2 at the connection point between the B end face of MCF 50-1 and the B end face of MCF 50-2. In this case as well, the erroneous connection can be eliminated by using the optical connector 100 as shown in FIGS. 8(C) and 8(D).

[0022] FIG. 8(C) shows the area of ​​the surface 101 where the optical signals #1 to #4 are input from the cores #1 to #4 on the B end surface of the MCF 50-1 when connected as described above. #1 to #4 in FIG. 8(C) show the optical signals #1 to #4. Note that FIG. 8(C) shows the view in the Z direction, that is, the view of the surface 101 from the outside of the optical connector 100. FIG. 8(D) shows the area of ​​the surface 102 where the optical signals #1 to #4 are output. #1 to #4 in FIG. 8(D) show the optical signals #1 to #4. Note that FIG. 8(D) shows the view in the Z direction, that is, the view of the surface 102 from the inside of the optical connector 100. In addition, in Figures 8(C) and 8(D), the black circles indicate the positions of surfaces 101 and 102 connected to the center of the MCF, and the dotted line is a line in the Y direction passing through the center, which will be referred to as the "reference line" below.

[0023] 8(C) and 8(D), optical connector 100 outputs an optical signal incident on surface 101 such that surface 102 is a mirror image of the optical signal incident on surface 101. In other words, optical connector 100 outputs the positional relationship between optical signal #1 and optical signal #2 at the incident position on surface 101 after inverting it with respect to a reference line on surface 102. Similarly, optical connector 100 outputs the positional relationship between optical signal #3 and optical signal #4 at the incident position on surface 101 after inverting it with respect to the reference line on surface 102.

[0024] Therefore, the optical signal #n output from the core #n of the MCF 50-1 is input to the core #n of the MCF 50-2, and the erroneous connection is eliminated.

[0025] 6, the optical connector 100 is used at a position where end faces of the same type are connected to each other, but the position where the optical connector 100 is used may be another connection point, that is, the connection point between FIFO#1 and MCF5-1, the connection point between MCF50-2 and MCF50-3, or the connection point between MCF50-3 and FIFO#1. Furthermore, when the number of connections between end faces of the same type is odd, only one optical connector 100 is used, and it is not necessary to use the same number of optical connectors 100 as the number of connections between end faces of the same type.

[0026] FIG. 10 shows an example of the configuration of the adjustment unit of the optical connector 100. In FIG. 10(A), the adjustment unit is configured with the flat sides of two cylindrical lenses 103 facing each other. The surface 101 faces the convex side of one of the two cylindrical lenses 103, and the surface 102 faces the convex side of the other of the two cylindrical lenses 103. With this configuration, an optical signal that is mirror-symmetrical to the multiple optical signals incident on the surface 101 can be output from the surface 102. In FIG. 10(B), a mirror 104 that reflects light is used as the adjustment unit. In FIG. 10(B), the light is deflected by 90 degrees by the mirror 104. By reflecting the light by the mirror 104, an optical signal that is mirror-symmetrical to the multiple optical signals incident on the surface 101 can be output from the surface 102. As shown in FIG. 10B, the propagation direction of light in optical connector 100 (Z direction in FIG. 7) may be changed within the adjustment section.

[0027] As described above, the optical connector 100 according to the present embodiment can eliminate erroneous connections between optical transmitters and optical receivers that occur when the number of connections between the same type of end faces of MCFs becomes odd. In addition, the optical connector 100 according to the present embodiment can reduce the number of types of FIFOs to be installed in each station to one. That is, as shown in FIG. 2, the FIFO to be used is FIFO#1 or FIFO#2 depending on the type of end face of the MCF 50 to be connected. However, since the end faces of the MCF 50 housed in the optical cable are not the same, the type of FIFO to be used is determined immediately before the connection. Therefore, it was necessary to prepare two FIFOs, FIFO#1 and FIFO#2, in advance so that either end face can be handled. However, since the optical connector 100 can eliminate erroneous connections, the optical transmitter and the optical receiver can be properly connected by preparing only one of FIFO#1 and FIFO#2 in each station.

[0028] Note that Fig. 8(B) shows a view looking in the Z direction, that is, a state in which face 102 is viewed from inside optical connector 100, but when face 102 is viewed in the opposite direction to the propagation direction of the optical signals, that is, when face 102 is viewed from the outside of optical connector 100, the positions of the optical signals output from face 102 are the same as in Fig. 8(A). The same is true for Fig. 8(C). Therefore, optical connector 100 can also be said to be a device that makes the output positions of each optical signal from face 102 when viewed toward face 102 the same as the input positions of each optical signal to face 101 when viewed toward face 101.

[0029] Although the embodiment has been described using the MCF 50 with four cores as an example, the present invention can be applied to MCF 50 with any number of cores. In the case of connecting end faces of the same type, all cores of two MCFs 50 are connected 1:1 when the core arrangement when viewed toward the A end face is a mirror image of the core arrangement when viewed toward the B end face. Therefore, more specifically, the present invention can be applied to MCFs 50 with any number of cores as long as the two types of core arrangements are mirror images of the MCF 50. The optical connector 100 outputs an optical signal incident on a first position on the face 101 from a second position on the face 102. Here, when viewed toward the propagation direction of the optical signal, the distance in the X direction between the second position and the reference line and the distance in the X direction between the first position and the reference line are the same, but the second position is on the opposite side of the reference line from the first position in the X direction. The positions of the first position and the second position in the Y direction are the same.

[0030] The above configuration can eliminate incorrect connections between optical transmitters and optical receivers that occur when the number of connections between end faces of the same type of MCF is odd, making it possible to contribute to Goal 9 of the United Nations Sustainable Development Goals (SDGs) "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0031] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0032] 101, 102: surfaces, 103: cylindrical lens, 104: mirror

Claims

1. The first page and a second surface from which the plurality of optical signals input to the first surface are output; an adjustment means for adjusting output positions of the plurality of optical signals from the second surface so that the plurality of optical signals output from the second surface have a mirror symmetric relationship with the plurality of optical signals input to the first surface when viewed in a propagation direction of the plurality of optical signals; An optical connector comprising:

2. 2. The optical connector according to claim 1, wherein said adjustment means comprises reflecting means for reflecting said plurality of optical signals input to said first surface.

3. 3. The optical connector according to claim 2, wherein said reflecting means deflects said plurality of optical signals input to said first face by 90 degrees.

4. 2. The optical connector according to claim 1, wherein the adjustment means comprises two cylindrical lenses.

5. 5. The optical connector according to claim 4, wherein the flat surfaces of the two cylindrical lenses are disposed opposite each other.

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