JP2002350692A - Multi-unit optical fiber cable used for two-way full- duplex optical communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide one optical fiber for two-way full-duplex optical communication that makes good use of features of a multi-unit optical fiber cable by using an optical fiber cable which has many coated optical fibers which are not completely parallel to one another. SOLUTION: Optical transmitter receivers each consisting of a transmitter which transmits a light signal and a receiver which receives the transmitted light signal are optically connected to each other through one multi-unit optical fiber cable 1. The coated optical fibers (represented by numbers 1, 2, 3, etc.), in the optical fiber cable 1 are arranged concentrically in its section so that coated optical fibers arranged on even-numbered circumferences from the center are arranged in parallel to one another and coated optical fibers arranged on odd-numbered circumferences from the center are arranged in parallel to one another while those even-numbered coated optical fibers and odd-numbered coated optical fibers are rotated at a prescribed angle between one end and the other end of the optical fiber cable 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transceiver comprising a transmitter for transmitting an optical signal and a receiver for receiving a transmitted optical signal, which is optically connected to each other via one optical fiber cable. The present invention relates to a multi-core optical fiber cable used for bidirectional full-duplex optical communication.

[0002]

2. Description of the Related Art FIG. 1 shows a cross section of a conventional single-core optical fiber cable used in a bidirectional full-duplex optical communication system.
It is shown in FIG.

In a conventional single-core optical fiber cable 51, an optical signal (indicated by an arrow in the figure) output from a transmitter 61 a of its own transceiver 61 is reflected by a distal end 51 a of the optical fiber cable 51. And own transceiver 61
Of the receiver 61b to prevent it from being received again.

In this example, the following two main means are used to prevent an optical signal output from a transmitter from being received by a receiver.

One of them is that when an optical signal is incident on the optical fiber cable 51, the core 51b of the optical fiber cable 51 is used.
When light leaking out without entering the receiver is reflected at the peripheral portion, the light is prevented from going to the receiver 61b side.
(A), (B), and (C) show the shape and the light ray direction (this is referred to as Conventional Technique 1).

The other is to reduce the amount of light that enters the optical fiber cable 51 and is reflected by the opposite end 51c and returns, so that the reflected light is shifted in the direction deviated from the axis of the optical fiber cable 51. The shape of the end 51c on the opposite side is devised so as to face, and FIGS. 11 (D), (E), and (F)
Shows the shape and the beam direction (this is described in Related Art 2).
).

By combining these prior arts 1 and 2 (ie, combining (A) or (B) or (C) with (D) or (E) or (F)), The amount of returning light can be further reduced. In FIG. 11 (G), (A) and (E)
The example shown in FIG.

As another method, a multi-core optical fiber cable for transmitting and receiving an optical signal has been provided.

For example, Japanese Unexamined Utility Model Publication No. 58-13504 discloses that a plurality of cores 71 are provided in a common cladding 72 as shown in FIG. An optical fiber cable has been disclosed which improves the performance and transmission quality (this is referred to as prior art 3).

In Japanese Utility Model Application Laid-Open No. 58-13505, as shown in FIG. 12B, a plurality of cores 76 are provided in a common clad 75 and the surface of the optical fiber cable is provided. There is disclosed an optical fiber cable in which an identification body 77 is provided in parallel with the core so that the relative positions of the cores 76 can be easily identified (this is referred to as a prior art 4). .

Further, as shown in FIG. 12 (C), two multicore areas are provided to separate transmission and reception, thereby enabling bidirectional full-duplex optical communication with one optical fiber cable. An optical fiber cable has been disclosed (this is referred to as Prior Art 5).

Japanese Patent Application Laid-Open No. 8-299788 discloses that, as shown in FIG. 12D, the two optical fiber cables 81 and 82 are bent to widen the mutual distance, and light emission in the optical fiber module is performed. There is disclosed an optical fiber connector in which two optical fiber cables 81 and 82 are vertically arranged with respect to an element 83 and a light receiving element 84 so as to be optically coupled (this is referred to as prior art 6).

[0013]

However, the methods according to the above-mentioned prior arts 1 and 2 have a problem that the method of preparation is difficult because a complicated shape is required with high accuracy. Further, since a single-core optical fiber cable is used, it is required to use a multi-core optical fiber cable which is weak in bending and strong in bending and has good transmission quality. In addition, materials around the optical fiber cable (for example, coatings and plugs)
There is internally disturbing light slightly reflected at (Fig. 1 (A),
(See (B) and (C)), there is a problem that the internal disturbance light may be received by the receiver. Furthermore, the method shown in FIGS. 11D, 11E, and 11F has a problem that the effect is not exerted unless the optical fiber cable is long to some extent and cannot be applied to a short optical fiber cable.

In the method according to the prior art 3, since the inner cores are kept parallel to each other, the light emitted from the optical fiber cable has a bias with respect to the wavefront when the wavefront division method is adopted. However, there are directions in which communication is not possible with a connection that allows the optical fiber cable to rotate in the axial direction.
For this reason, there is a problem that bidirectional full-duplex optical communication using a multi-core optical fiber cable that is strong in bending while allowing rotation in the axial direction cannot be realized.

Further, the methods of the prior arts 4 to 6 are methods for performing bidirectional full-duplex optical communication with one cable. However, similar to the above-mentioned prior art 3, rotation in the axial direction is not allowed. There was a problem.

The present invention has been made in order to solve such a problem, and an object of the present invention is to use an optical fiber cable having a large number of cores that are not completely parallel to each other, thereby making the characteristics of a multi-core optical fiber cable possible. Take advantage of one bidirectional all 2
An object of the present invention is to provide an optical fiber cable for heavy optical communication.

[0017]

In order to solve the above-mentioned problems, a multi-core optical fiber cable used for bidirectional full-duplex optical communication according to the present invention includes a transmitter for transmitting an optical signal and a transmitted optical signal. An optical transceiver consisting of a receiving receiver and
It is characterized by being optically connected to one another via a multi-core optical fiber cable. According to the present invention having such features, by using a multi-core optical fiber cable, an optical signal generated as internal disturbance in the optical fiber cable can be cut off.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the positional relationship between the internal multi-cores is not always constant. According to the present invention having such characteristics, when an optical signal transmitted from a transmitter of an optical transceiver is incident on one end of the optical fiber cable, reflected light generated on the other end face is reflected by the optical transceiver. It is possible to reduce the possibility of returning to the receiver side of the device. In addition, by making the cores of the multi-core optical fiber cable different from each other (that is, they are not completely parallel), even when they are rotated in the axial direction in bidirectional full-duplex optical communication with one cable, The accuracy of full duplex optical communication can be kept constant.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the internal multi-core
It is characterized by being arranged concentrically on the cut surface and having different arrangements inside the cores on adjacent circumferences. According to the present invention having such features, the positional relationship between the cores can be easily understood.

Further, according to the multi-core optical fiber cable used for bidirectional full duplex optical communication of the present invention, the cores arranged on the same circumference are arranged so as to be parallel to each other. . According to the present invention having such features,
The positional relationship between the cores can be easily understood, and the method of producing the multi-core optical fiber cable can be facilitated.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the cores arranged on even-numbered circumferences from the center are arranged in parallel with each other, and The cores arranged on the odd-numbered circumference from the center are arranged so as to be parallel to each other, and the even-numbered core and the odd-numbered core are arranged at a predetermined angle between one end and the other end of the optical fiber cable. It is characterized by rotating. According to the present invention having such features, in performing bidirectional full-duplex optical communication with one cable, rotation in the axial direction is allowed, and when there is one set of the transmitter and the receiver, the position of the cores may be reduced. The relationship can be easily understood, and the method of producing the multi-core optical fiber cable can be facilitated.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, when an optical signal is transmitted from the same half circumference core on each circumference at one end of the optical fiber cable, The arrangement of each core is set so that an optical signal is emitted from the core dispersed from the other end in a circumferential shape. According to the present invention having such features,
The positional relationship between the cores can be easily understood, and the method of producing the multi-core optical fiber cable can be facilitated.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the optical fiber cable reproduces the arrangement of the cores on each circumference on a plane, and then reproduces them. And is formed by winding. According to the present invention having such a feature, the state of the core can be more accurately reflected by cutting out and arranging one end on a plane, instead of winding concentrically.

According to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the optical fiber cable has a period twice as long as an odd number of the length of the core cut out. It is characterized by. According to the present invention having such features, the optical fiber cable satisfying each of the above configurations can be mass-produced by having a period (2 / odd) times the length of the optical fiber cable from which the core arrangement is cut out. Can be

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the cutting position of the covering portion of the optical fiber cable is marked. According to the present invention having such features, when cutting an optical fiber cable, it is possible to cut out a pattern that satisfies each of the above configurations accurately.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, each core member has a double structure having a different refractive index. According to the present invention having such features, it is possible to reduce crosstalk between signals between cores.

Further, according to the multi-core optical fiber cable used for bidirectional full-duplex optical communication of the present invention, the multi-core gap of the double structure is filled with a light-impermeable material. According to the present invention having such features, it is possible to reduce crosstalk between signals between cores and to reduce reflected light at the far end (the other end).

That is, according to the multi-core optical fiber cable used in the bidirectional full duplex optical communication of the present invention, the reflected light generated when the optical signal transmitted from the transmitter of the optical transceiver enters the optical fiber cable. (Hereinafter referred to as internal light),
The rate of return light incident on the receiver of the optical transceiver can be reduced. Also, reflected light (far-end reflected light) generated at the other end after transmission through one optical fiber cable
Can be prevented from returning to the receiver of the optical transceiver. With such a feature, bidirectional full-duplex optical communication can be performed with one multi-core optical fiber cable.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] FIGS. 1 (D), (E),
(F) shows a cross-sectional structure of the multi-core optical fiber cable 1 of the first embodiment, and corresponds to claim 1. 11A, 11B, and 11C are optical fiber cables according to the prior art 1 (FIGS. 11A, 11B, and 11C) for comparison with the optical fiber cable 1 according to the first embodiment. (Corresponding to C)). Note that the arrows in the figure indicate the optical path of the internal disturbance light.

The optical fiber cable 1 of the first embodiment is
A large number of cores 2, 2...
It has a structure covered by. By using the multi-core optical fiber cable 1 having such a structure, FIG.
(A), (B), (C), it is possible to reduce the ambient light more than the prior art 1. That is, by using the multi-core optical fiber cable 1, each core 2, 2,... Blocks an unnecessary optical path, so that internal disturbance can be further reduced.

[Embodiment 2] FIGS. 2A and 2B show a multi-core optical fiber cable according to Embodiment 2 of the present invention.

As shown in FIG.
When a bidirectional optical signal is mixed in the single-core optical fiber cable 51, the optical signal is reflected on the far end face 51b of the optical fiber cable, and the optical signal emitted from the transmitter 61a of the own transceiver 61 is transmitted. Is received by the receiver 61b of the own transceiver 61. Therefore, the cores 2, 2,... Of the multi-core optical fiber cable 1 are assigned to roles for transmission or reception, so that the optical signal emitted by the optical fiber cable 1 is transmitted to the far end face 1b of the optical fiber cable 1. Even if it is reflected back and reflected, the returning optical signal is
As shown in FIG. 2 (A), the light returns through the core 2 on the emission side. That is, since the light does not pass through the receiving core, the returned light is not received by the receiver. This is the same even if the cores 2 and 2 in the optical fiber cable 1 are replaced on the way, as shown in FIG. As a result, in the second embodiment, FIG.
The optical fiber cable 1 having a multi-core structure can perform bidirectional full-duplex optical communication using light that permits rotation in the axial direction (the direction of the arrow X in the figure) by appropriately displacing the replacement as shown in FIG. It becomes feasible.

Third Embodiment FIG. 3 is an enlarged sectional view of a multi-core optical fiber cable according to a third embodiment, and corresponds to the first to fifth aspects.

FIG. 3A is a diagram schematically showing only the tip portion (end face) of the optical fiber cable 1 and enlarging the respective cores. Each of the cores has a structure in which the distance from the center is the same for both end faces and is alternately rotated by 180 ° in the axial direction (the direction of the arrow X in the figure). When an optical signal is applied to the optical fiber cable 1 having such a structure from only one end to only an area (hatched area) corresponding to a half circumference (right half in FIG. 3B) of the end face, the same figure is obtained. As shown in (B) and (C), light is alternately emitted from one end on the opposite side in a state where the light is concentrically shifted by 180 °, and the bias in the circumferential direction is reduced. Here, in FIGS. 7B and 7C, the core on which the optical signal is incident on the end face is x, the core on which the optical signal is emitted from the end face is ●, and no optical signal is incident on the end face on the side where the optical signal is transmitted. The core is indicated by triangles at both ends. Thereby, the optical fiber cable 1 having a multi-core structure that allows rotation in the axial direction can be realized.

FIGS. 3A to 3C show a case where the arrangement of the cores is quadruple concentrically, but this pattern can be repeated as long as the thickness of the optical fiber cable 1 permits. As the number of repetitions increases, a multi-core optical fiber cable having less deviation can be produced.

In the third embodiment, as shown in FIGS. 3 (A) to 3 (C), an example in which the center is rotated by 180 ° from the center toward the outer concentric core is shown, but it is not necessarily 180 °.
It is not necessary to rotate each time, and the angle can be set arbitrarily. By the way, FIG. 3 (D) is rotated by 120 °,
FIG. 3E shows a pattern of an optical signal emitted from the end face of the optical fiber cable 1 (that is, a core pattern) when the optical fiber cable 1 is rotated by 90 °. In this figure, a pattern in which light incident on the optical fiber cable after wavefront division is emitted is indicated by a black portion. That is, black portions in FIGS. 3D and 3E correspond to those in FIG.
(B) and (C) correspond to the position where ● is present.

Fourth Embodiment FIG. 4 shows a multi-core optical fiber cable 1 according to a fourth embodiment.
3, 6, and 7.

FIG. 4A is a diagram schematically showing only the cut surface of the optical fiber cable and enlarging the respective cores with numbers (1 to 8 in the fourth embodiment). On the cut surface, the cores are arranged concentrically, and when there are eight cores, numbers are assigned to the respective cores. FIG. 4 (B)
FIG. 4 illustrates a method using the method of claim 7 of the present invention.
It is a schematic diagram when the way of arrangement | positioning of the core of the part which has 8 cores of the optical fiber cable 1 shown to (A) is arranged vertically. That is, a certain end (the left end in FIGS. 4A and 4B)
In FIG. 4, the core numbers 1 to 8 are continuously arranged, and the other end (FIG. 4)
In (A) and (B), the right end portions)
And 5 to 8 are alternately arranged. By arranging in this way, (1, 2, 3, 4), (2, 3, 4, 5), (3,
Even if light enters one of the continuous patterns (4,5,6) and (4,5,6,7) from one end, no light is emitted from the four continuous cores from the other end. In other words, when an optical signal is incident only on a half-periphery region of one end of an optical fiber cable in the uniform wavefront division method, if the signal is received in the uniform wavefront division method, no matter how it rotates in the axial direction, An optical signal can be received.

[Fifth Embodiment] FIG. 5 is an explanatory view of a multi-core optical fiber cable according to a fifth embodiment, and corresponds to claims 1, 2, 3, 6, and 7.

In the above-described fourth embodiment, the case where there are eight cores on a concentric circle has been described. However, the method of the fourth embodiment satisfies the condition when there are five or more cores and the number of cores is large. The greater the number, the more uniform the variation of the optical signal emitted from the other end. In the fifth embodiment, a case where the number of cores is large will be described based on this.

First, consider the case where there are 4n cores. Then, numbers are assigned to each of 1 to 4n, and using the method of claim 7 of the present invention, it can be shown as in FIG. 5 (A). FIG. 5A shows the same notation as in FIG. 4B when the number of cores is 4n. In FIG. 5 (A), when optical signals are transmitted from the left side in the figure using the cores of numbers 1 to 2n, every other optical signal is emitted from the right side, resulting in uniform dispersion. Become. FIG.
(B) shows this, in which the tip of the core on which light is incident is indicated by x, the tip of the core on the exit side is indicated by ●, and the tip of the core which is not related to the incidence and emission of light is indicated by Δ.

Next, when an optical signal is transmitted from the left side in the figure using the cores of numbers 2 to 2n + 1, as shown in FIG. 5C, the optical signal emitted from the right side results in the number This means that there is only one shift from 1 to the number 2n + 1. This means that the optical signal is emitted every other except for the continuous portion of the numbers 2n + 1 and 2, and when n ≧ 2, the optical signal is not emitted in a half circle. Number 3-2
Similarly, in the case of n + 2, the optical signal emitted from the right side is shifted by one from number 2 to number 2n + 2. This means that every other optical signal is emitted except for a continuous part of numbers 2n + 2 and 3. Thereafter, by using the same concept, even if an optical signal is incident on a region where 2n lines are continuous on the left side, an optical signal that varies almost uniformly is emitted from the right side. This means that n
The greater the is, the greater the variation (ie, more evenly).

On the other hand, in the reverse direction, first, numbers 1 to n
5n, light signals are emitted from the right side and the light signals emitted from the left side are continuously emitted n times and then skipped continuously n times, as shown in FIG. 5D. After that, the light is emitted continuously n times. In this state,
In the case of receiving by the uniform wavefront division method, optical signals are always received from n cores. In the same way as in the case of FIG. 5C, as shown in FIG. 5E, when light signals are incident on the numbers 2 to n + 1 and the numbers 2n + 1 to 3n from the right side,
As a result, the optical signal emitted from the left side is shifted by one from number 1 to number 2n + 1. Also at this time, n ≧ 2
In the case of (1), the light is not deviated half the circumference. Number 2
The same applies to the case of 以降 n + 1, 2n + 2 to 3n + 1, and when n ≧ 2, the light is not deviated halfway.

In the case where there are 4n-2 cores, FIG.
As shown in (F), when numbers are assigned from 1 to 4n-2,
As in the case where there are 4n cores, a core that emits an optical signal and a core that does not emit an optical signal follow every other. That is, the core is 4n-2
In the case of a book, when transmitting an optical signal from the left side to the right side, exactly the same concept as in the case of 4n cores can be applied.

On the other hand, in the reverse direction, when an optical signal is sent from the right to the left, the number of cores into which the optical signal enters is 2n-1, and 1 to n (= n) and 2n to 3n-2 (= n). -1)
An optical signal will enter the In this case, the same concept can be applied as when the number of the cores is 4n. If the uniform wavefront division method is adopted, the reception light is continuously received from n or n-1 cores (see FIG. 5 ( G)). Similarly, 2
Ｎn and 2n〜3n, the core is 4n
The same concept as in the book can be adopted (see FIG. 5H).

When the core is 4n-1 or 4n-3, it is considered that there is no 4n core in FIG. 5A and that there is no 4n-2 core in FIG. 5F. Again, a similar idea can be employed. Therefore, if a uniform wavefront splitting method is adopted for the transceivers on both sides, there is no need to consider rotation in the axial direction when inserting the optical fiber cable into the transceiver.

When the core is thicker than the boundary between the transmission side area and the reception side area, there is a possibility that both transmission and reception optical signals are mixed in one core. Doing so can solve a significant portion. The central part is
In particular, the possibility of mixing is high. In this case, by filling the vicinity of the center with a material that does not allow light to pass through, the occurrence of mixing at the center can be eliminated.

Sixth Embodiment FIG. 6 is an enlarged sectional view of a multi-core optical fiber cable according to a sixth embodiment, and corresponds to the first, second, third, sixth, and seventh aspects.

In the sixth embodiment, an optical fiber cable 1 having a concentric quadruple multicore structure will be described based on the example of the fifth embodiment.

In the sixth embodiment, the states shown in FIGS. 5A and 5F are concentrically arranged in quadruple, and the numbers on the concentric cores are assigned (see FIG. 6A). . When an optical signal is applied to the optical fiber cable 1 having such a structure only in a region corresponding to a half circumference from one end and a wavefront splitting method is employed as shown in FIGS. 6B and 6C, rotation in the axial direction is reduced. An optical fiber cable 1 having a forgiving multi-core structure can be realized. Here, in FIGS. 6B and 6C, the core where the optical signal is incident on the end face is ×, the optical signal which is emitted from the end face is ●, and the core where the optical signal does not enter is the end face on which the optical signal is transmitted. Both ends are shown as 〇.

FIG. 6 shows an example of a structure in which the cores are arranged in a concentric quadruple, but this pattern can be repeated as long as the thickness of the optical fiber cable 1 permits. A multi-core optical fiber cable with less deviation can be produced. In addition, with respect to the bias as shown in FIG. 6C, the overall bias is reduced by repeatedly switching the center of the core halfway. FIG.
FIG. 6D shows a state in which the second and fourth cores from the center are switched left and right with respect to FIG.

[Seventh Embodiment] FIG. 7 is an explanatory view of a multi-core optical fiber cable according to a seventh embodiment, and corresponds to claims 7, 8, and 9.

First, similarly to the examples of the fourth and fifth embodiments, the arrangement of the cores on the circumference is reproduced on a plane by using the method of the eighth aspect of the present invention. Then, using the method of claim 8 of the present invention, reproduction is performed on a plane such that the arrangement of the cores has a period twice as long as an odd number of the cut length.

Here, fa (i) (i = 1,2 ... m) is
I from the top when the circumference closest to the ath from the center is arranged on a plane
The number of the wick is shown. For example, if the example of the fifth embodiment is adopted, when m = 4n, fa (1) = 1 and fa (2)
= 2n, fa (3) = 2, fa (4) = 2n + 1,... Fa (4n
-1) = 2n-1, and fa (4n) = 4n. If the example of the fourth embodiment is adopted, a certain circumference is fa (i) = i, and another circumference is fa (i) = i + m / 2 (when i ≦ m / 2),
fa (i) = i−2 / m (when i> 2 / m). Correspondingly, if fa ^-1 (i) is a pattern opposite to fa (i), it is assumed that fa ^-1 (fa (i)) = i holds. Here, having a period means fa (fa (... fa (i) ...))
= I, where fa is taken. In the present embodiment, the case where fa (fa (i)) = i is taken as an example.

If the method of claim 8 of the present invention is not used, patterns are accumulated as shown in FIG.
Creating long fiber optic cables for mass production becomes very complicated. Therefore, when the method of claim 8 of the present invention is adopted, a pattern as shown in FIG. 7C is obtained. As shown in FIG. This makes it easy to produce an optical fiber cable having a long length. In addition, by marking a position such as a marker at a position where the covering portion of the optical fiber cable is cut, it is possible to prevent cutting at an unauthorized portion.

[Eighth Embodiment] FIG. 8 is an explanatory view of a multi-core optical fiber cable according to an eighth embodiment, and corresponds to claims 8 and 9.

In FIG. 7 (D) shown in the seventh embodiment, the parts to be rearranged from i to fa (i) are A, and fa (i) to i
FIG. 8 (A) shows a portion to be rearranged as B.

In FIG. 8 (A), a mass-produced long optical fiber cable in which this pattern is repeated has a core arrangement of ABABAB ·
.. can be shown in succession. Therefore, AB is considered as one cycle, and one cycle is defined as a length 1 (m).

In this case, if the optical fiber cable is cut out in the state of “AB” of l (m), the pattern is maintained at “AB” as shown in FIG. When an optical signal enters the optical fiber cable,
The pattern of the optical signal emitted from the optical fiber cable (that is, the pattern of the core) does not vary evenly on the end surface (the end surface on the emission side) of the optical fiber cable. This means that no uniform variation can be obtained as long as it is cut out at a multiple of the period.

On the other hand, as shown in FIG.
"B", "ABA", "BAB", "ABABA" ...
・ So, (2j-1) × 1/2 (m) (j =
..), The inner core of the optical fiber cable can obtain the required uniform variation.
Utilizing this property, one kind of mass-produced optical fiber cable has a length of (2j-1) × 1/2 (m) (j
= 1, 2,...) Can be cut out.

[Embodiment 9] FIG. 9 shows a multicore optical fiber cable according to Embodiment 9 of the present invention.

FIGS. 9A and 9B show a state where an optical signal passes through two adjacent optical fiber cables. When each core of the multi-core optical fiber cable is a single core with the same refractive index, FIG.
As shown in FIG. 9, there is a possibility that crosstalk occurs between the adjacent cores 2, 2. However, by forming the cores 2, 2 into a double structure as shown in FIG. Generation can be prevented. The structure of the ninth embodiment is particularly effective when the cores in the optical fiber cable are entangled as in the present invention.

[Embodiment 10] FIG. 10 shows Embodiment 9 of the present invention.
12. The multi-core optical fiber cable 1 according to claim 11, wherein
It corresponds to.

That is, as shown in FIG. 10B, the multi-core optical fiber cable of the ninth embodiment has the
Double structure and the gap between these cores 2 and 2 (cladding)
3 has a structure filled with a light-impermeable material.

FIG. 10A shows a case where light is incident on an optical fiber cable which does not use such a structure, and shows a traveling state of a light beam when an optical signal is incident on a portion 4 other than the core 2. Is shown. In other words, since the gap 4 between the cores 2 is transparent, the light signal may return due to far-end reflection after being reflected by the internal core 2 a plurality of times. On the other hand, in FIG. 10B, which is the optical fiber cable of the tenth embodiment, by filling the gap (cladding) 3 between the cores 2 with a material that does not allow light to pass, such a long distance can be obtained. No edge reflection occurs.

[0067]

According to the present invention, by using a multi-core optical fiber cable, an optical signal generated as an internal disturbance in the optical fiber cable can be cut off. Also,
When an optical signal transmitted from the transmitter of the optical transceiver enters one end of the optical fiber cable, reflected light generated at the other end returns to the receiver side of the optical transceiver again. Can be reduced.

Further, according to the present invention, since the arrangement of the cores of the multi-core optical fiber cable is not completely parallel, the bidirectional full-duplex optical communication can be performed by one cable even if it is rotated in the axial direction. In addition, it is possible to reduce the difference in accuracy between two-way full-duplex optical communication.

According to the present invention, the inner cores are arranged concentrically on the end face and the arrangement of the inner cores on adjacent circumferences is made different from each other. It is possible to make it easy to understand the positional relationship between each other.

Further, according to the present invention, since the cores arranged on the same circumference are arranged so as to be parallel to each other, the positional relationship between the cores can be easily understood, and the multi-core light The method of producing the fiber cable can be simplified.

According to the present invention, the cores arranged on even-numbered circles from the center are arranged in parallel with each other, and the cores arranged on odd-numbered circles from the center are mutually aligned. The optical fibers are arranged so as to be parallel to each other, and the even-numbered core and the odd-numbered core are rotated by a predetermined angle between one end and the other end of the optical fiber cable. Accordingly, in performing bidirectional full-duplex optical communication with one cable, rotation in the axial direction is permitted, and when there is one set of a transmitter and a receiver, the positional relationship between the cores can be easily understood. At the same time, the method for producing the multi-core optical fiber cable can be facilitated.

Further, according to the present invention, when an optical signal is transmitted from the same half of the core on each circumference at one end of the optical fiber cable, the optical signal is transmitted from the circumferentially distributed core from the other end. Since the arrangement of the cores is set so that the light is emitted, the positional relationship between the cores can be easily understood, and the method of producing the multi-core optical fiber cable can be simplified.

Further, according to the present invention, the optical fiber cable is formed by reproducing the arrangement of the cores on each circumference on a plane, and then winding it. That is, instead of being wound concentrically, by cutting out and arranging one end on a plane, the state of the core can be more accurately reflected.

Further, according to the present invention, since the arrangement of the cores has a period that is (2 / odd) times the length of the optical fiber cable to be cut out, the optical fiber cable can be put into a mass-producible state.

Further, according to the present invention, by marking the cutting position of the covering portion of the optical fiber cable, a pattern satisfying the constitutional requirements of the present invention can be accurately cut when cutting the optical fiber cable.

According to the present invention, the crosstalk of signals between the cores can be reduced by forming each core material into a double structure having a different refractive index.

Further, according to the present invention, by filling the gap between the double cores of the double structure with a material that does not transmit light, it is possible to reduce the crosstalk of signals between the cores and to reduce the distance between the cores. The reflected light at the edge can be reduced.

[Brief description of the drawings]

FIGS. 1 (D), (E), and (F) show cross-sectional structures of a multi-core optical fiber cable according to a first embodiment, and FIGS. 1 (A), 1 (B), and 1 (C) show 1 shows a cross-sectional structure of an optical fiber cable according to the related art 1 for comparison with the optical fiber cable according to the first embodiment.

FIG. 2 is an explanatory diagram illustrating a multi-core optical fiber cable according to a second embodiment.

FIG. 3 is an explanatory diagram showing a multi-core optical fiber cable according to a third embodiment.

FIG. 4 is an explanatory diagram showing a multi-core optical fiber cable according to a fourth embodiment.

FIG. 5 is an explanatory diagram showing a multi-core optical fiber cable according to a fifth embodiment.

FIG. 6 is an explanatory diagram showing a multi-core optical fiber cable according to a sixth embodiment.

FIG. 7 is an explanatory diagram showing a multi-core optical fiber cable according to a seventh embodiment.

FIG. 8 is an explanatory diagram showing a multi-core optical fiber cable according to Embodiment 8;

FIG. 9 is an explanatory diagram showing a multicore optical fiber cable according to Embodiment 9;

FIG. 10 is an explanatory diagram showing a multi-core optical fiber cable according to Embodiment 10;

FIG. 11 is an explanatory diagram of prior arts 1 and 2.

FIG. 12 is an explanatory view of Conventional Techniques 3 to 6.

[Explanation of symbols]

 1 Optical fiber cable 2 Core 3 Core gap filled with light impermeable material (cladding)

Claims (11)

[Claims] 1. An optical transceiver comprising a transmitter for transmitting an optical signal and a receiver for receiving a transmitted optical signal, comprises:
A multi-core optical fiber cable used for bidirectional full-duplex optical communication, wherein the multi-core optical fiber cable is optically connected to each other via a multi-core optical fiber cable. 2. The bidirectional two-way communication system according to claim 1, wherein the positional relationship between the internal multicores is not always constant.
Multi-core optical fiber cable used for heavy optical communication. 3. The both of claim 1, wherein the inner multiple cores are arranged concentrically on the cut surface, and the arrangement of the inner cores on adjacent circumferences is different. Multi-core optical fiber cable used for full duplex optical communication. 4. The multi-core optical fiber cable used for bidirectional full-duplex optical communication according to claim 3, wherein the cores arranged on the same circumference are arranged so as to be parallel to each other. 5. Cores arranged on even-numbered circles from the center are arranged so as to be parallel to each other, and cores arranged on odd-numbered circles from the center are arranged so as to be parallel to each other. 4. The bidirectional full-duplex optical communication according to claim 3, wherein the even-numbered core and the odd-numbered core are rotated by a predetermined angle between one end and the other end of the optical fiber cable. Multi-core optical fiber cable used for 6. When an optical signal is transmitted from the same half of the core on each circumference of one end of the optical fiber cable, the optical signal is emitted from the core dispersed in the circumference from the other end. 3. The multi-core optical fiber cable used for bidirectional full duplex optical communication according to claim 2, wherein the arrangement of the cores is set. 7. The optical fiber cable according to claim 3, wherein the optical fiber cable is formed by reproducing an arrangement of the cores on each circumference on a plane, and then winding the reproduced arrangement. A multi-core optical fiber cable used for bidirectional full duplex optical communication according to any of the above. 8. The two-way optical fiber cable according to claim 1, wherein the optical fiber cable has a period twice as long as an odd number of the length of the core cut out. Multi-core optical fiber cable used for heavy optical communication. 9. The cutting position of the covering portion of the optical fiber cable is marked.
2. A multi-core optical fiber cable used for bidirectional full-duplex optical communication according to item 1. 10. The multi-core optical fiber cable used for bidirectional full-duplex optical communication according to claim 1, wherein each core has a double structure having a different refractive index. . 11. The multi-core optical fiber cable used for bidirectional full-duplex optical communication according to claim 10, wherein a gap between the multi-cores of the double structure is filled with a light-impermeable material.