CN115097573A - An isolation device and optical communication system - Google Patents

Abstract

Embodiments of the present application disclose an isolation device and an optical communication system, including: a first optical fiber including at least two first fiber cores; a second optical fiber including at least two second fiber cores, the second fiber cores being connected to The first fiber cores are in one-to-one correspondence; the isolation core piece is arranged between the first optical fiber and the second optical fiber in the axial direction, and the isolation core piece is configured as the first fiber The optical signal in the core is unidirectionally transmitted to the corresponding second fiber core through the isolation core; and a capillary tube, the capillary tube is sleeved near the first fiber core and/or the second fiber core on one end of the isolation core. The isolation device and the optical communication system according to the embodiments of the present application have the advantages of low cost and compact size.

Description

An isolation device and an optical communication system

technical field

The present application relates to an isolation device and an optical communication system in particular.

Background technique

The optical isolator is an important optical passive device used to eliminate or suppress the reverse light in the fiber channel. For example, an optical isolator must be added to the laser, because the reflected light in the optical path will cause the peak wavelength of the laser to drift, causing the laser transmission power to fluctuate greatly and phase noise to occur, resulting in spectral broadening. The transmission of high rate is extremely disadvantageous; in the long-distance optical communication system, a large number of relay amplifiers are required, and the existence of reflected light causes the gain of the optical amplifier to change and generate self-excitation, which causes the entire optical fiber communication system to fail to work normally. In order for the amplifier to operate stably, an isolator must be used across the amplifier to eliminate the effects of returning light.

With the rapid development of optical fiber communication technology, optical isolators continue to develop towards miniaturization, especially for each optical signal path after multi-wavelength wavelength division multiplexing, the use of optical isolators alone is not only expensive, but also unfavorable for volume reduction.

SUMMARY OF THE INVENTION

In view of this, the embodiments of the present application are expected to provide an isolation device and an optical communication system with a high degree of integration and a small volume.

In order to achieve the above purpose, the technical solutions of the embodiments of the present application are implemented as follows:

An isolation device comprising:

a first optical fiber, including at least two first fiber cores;

The second optical fiber includes at least two second fiber cores, and the second fiber cores are in one-to-one correspondence with the first fiber cores;

an isolation core, the isolation core is axially disposed between the first optical fiber and the second optical fiber, and the isolation core is configured so that the optical signal in the first fiber core passes through the isolation core The pieces are unidirectionally transmitted to the corresponding second fiber core;

and a capillary tube, the capillary tube is sleeved on one end of the first fiber core and/or the second fiber core close to the isolation core piece.

Further, the isolation device includes a first lens and a second lens, the first lens is disposed between the first optical fiber and the isolation core, and the second lens is disposed between the isolation core and the isolation core. between the second optical fibers;

the first optical fiber, the first lens, the isolating core piece, the second lens and the second optical fiber are arranged in sequence along the axial direction;

The first lens is configured to collimate the optical signal; the second lens is configured to converge the optical signal.

Further, the isolation device includes two of the capillaries;

The first fiber core passes through one of the capillaries in the axial direction until it is flush, the end of the first fiber core is attached to the first lens, and the second fiber core passes through the other one in the axial direction. One of the capillaries is flush, and the end of the second fiber core fits the second lens.

Further, the isolation device includes a first needle cannula and a second needle cannula;

The first pin sleeve is sleeved on the first lens and the peripheral side of the capillary tube through which the first fiber core is penetrated to form a first pin assembly;

The second pin sleeve is sleeved on the peripheral side of the second lens and the capillary tube through which the second fiber core is penetrated to form a second pin assembly.

Further, the isolation device includes an outer sleeve; the isolation core is fixed in the middle of the outer sleeve; the first pin assembly and the second pin assembly are at least partially inserted into the outer sleeve ; The first pin assembly and the second pin assembly are respectively arranged on both sides of the isolation core piece.

Further, the outer diameters of the first lens and the second lens are equal to the capillary tube.

Further, the end of the capillary tube away from the isolation core in the axial direction has an inclined surface, and the inclined surface is coated with a planar anti-reflection film.

Further, the outer diameter of the capillary is 0.5-5mm, and the inner diameter of the capillary is 50um-300um.

Further, the isolation core includes two wedge angle pieces and a Faraday rotation piece, wherein one of the wedge angle pieces, the Faraday rotation piece and the other wedge angle piece are stacked in sequence in the axial direction.

Further, the first optical fiber includes a first coating layer and seven first fiber cores, and the seven first fiber cores are arranged in a circle in the first coating layer;

The second optical fiber includes a second coating layer and seven second fiber cores, and the seven second fiber cores are arranged in a circle in the first coating layer.

An optical communication system includes the above isolation device.

An isolation device and an optical communication system according to the embodiments of the present application are arranged between a first optical fiber and a second optical fiber in the axial direction by setting an isolation core piece, and the isolation core piece is configured so that the optical signal in the first fiber core passes through the isolation core piece One-way transmission to the corresponding second fiber core, multiple optical signal channels can be formed in the isolation device, and the optical signals of multiple channels are unidirectionally transmitted through the isolation core, avoiding the need for each optical signal channel. The unidirectional isolator is configured separately, which reduces the cost and can reduce the volume; in addition, the capillary can be sleeved on the end of the first fiber core and/or the second fiber core close to the isolation core to effectively obtain protection against the first fiber The core and/or the second core is broken in the isolation device, improving product quality.

Description of drawings

FIG. 1 is a schematic structural diagram of an isolation device according to an embodiment of the present application;

2 is a schematic cross-sectional view of a first optical fiber according to an embodiment of the present application;

3 is a schematic diagram of a connection relationship between a first optical fiber and a second optical fiber according to an embodiment of the application;

FIG. 4 is a schematic structural diagram of an isolation device according to another embodiment of the present application;

FIG. 5 is a schematic structural diagram of an isolation core according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a connection relationship of an optical communication system according to an embodiment of the present application, wherein from left to right is the direction of optical signal transmission.

Detailed ways

It should be noted that the embodiments in this application and the technical features in the embodiments may be combined with each other without conflict. Improper restrictions on applications.

In the description of the embodiments of the present application, "up", "down", "left", "right", "front", "rear" orientation or positional relationship are based on the orientation or positional relationship shown in FIG. It is understood that these orientation terms are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a reference to the present application. limit.

An isolation device 300 , as shown in FIG. 1 to FIG. 6 , includes: a first optical fiber 10 , a second optical fiber 20 , an isolation core 30 and a capillary 40 .

The first optical fiber 10 and the second optical fiber 20 are both single-mode multi-core optical fibers. The first optical fiber 10 includes at least two first cores 11 ; the second optical fiber 20 includes at least two second cores 21 . The extension direction of the first optical fibers 10 is the axial direction, and the second optical fibers 20 and the first optical fibers 10 are arranged coaxially in the isolation device 300 to facilitate optical signal transmission.

The capillary 40 can be sleeved on one end of the first fiber core 11 and/or the second fiber core 21 close to the isolation core 30 . That is to say, the capillary 40 can be sleeved on the end of the first fiber core 11 or the second fiber core 21 close to the isolation core 30 alone, or the capillary 40 can be sleeved on the first fiber core 11 and/or the first fiber core 11 at the same time. The two fiber cores 21 are located on one end of the isolation core 30 . By passing the first fiber core 11 and the second fiber core 21 in the capillary tube 40, protection can be effectively obtained to prevent the first fiber core 11 and/or the second fiber core 21 from being broken in the isolation device 300, thereby preventing the The path of the optical signal is disconnected, which leads to the scrapping of the isolation device 300 as a whole, and finally improves the quality of the product.

The isolation core 30 is axially disposed between the first optical fiber 10 and the second optical fiber 20 , and the isolation core 30 is configured so that the optical signal in the first fiber core 11 is unidirectionally transmitted to the corresponding second fiber through the isolation core 30 . The optical signal in the second optical fiber core 21 cannot be allowed to pass through the isolation core 30 to be transmitted into the first optical fiber core 11, so as to realize unidirectional isolation on the optical signal channel.

The isolation device uses the first optical fiber 10 and the second optical fiber 20 of the multi-core optical fiber as a channel for optical signal transmission. The second fiber cores 21 are in one-to-one correspondence with the first fiber cores 11 , that is, the optical signal transmitted in any one of the first fiber cores 11 is unidirectionally transmitted to the corresponding second fiber core 21 through the isolation core 30 . . For the first optical fiber 10 having a plurality of first fiber cores 11, and for the second optical fiber 20 having a plurality of second fiber cores 21, a plurality of channels of optical signals may be formed in the isolation device 300, and the plurality of channels are The optical signals of the optical signal are all transmitted in one direction through the isolation core 30, which avoids configuring a one-way isolator separately for each optical signal channel, reduces the cost and can simplify the volume.

It should be understood that, in this embodiment, the optical signal is input from the first optical fiber 10, passes through the isolation core 30 in one direction, and is output from the second optical fiber 20, while the optical signal is input from the second optical fiber 20, and is in the isolation core Under the reverse blocking of 30, the optical signal cannot reach the first optical fiber 10; of course, the unidirectional isolation of the isolation core 30 can also be set in reverse, that is to say, the optical signal is input from the second optical fiber 20, and is isolated in one direction. The core member 30 is output from the first optical fiber 10 , and when the optical signal is input from the first optical fiber 10 , the optical signal cannot reach the second optical fiber 20 under the reverse blocking of the isolation core member 30 . For ease of understanding, in other embodiments, unless otherwise specified, the installation direction of the isolation core 30 is determined, the incoming optical signal is the first optical fiber 10 , and the outgoing optical signal is the second optical fiber 20 .

A possible embodiment, as shown in FIG. 1 , FIG. 4 and FIG. 6 , the isolation device 300 includes a first lens 51 and a second lens 52 , and the first lens 51 is disposed between the first optical fiber 10 and the isolation core 30 , the second lens 52 is disposed between the isolation core 30 and the second optical fiber 20 ; that is, the isolation core 30 is disposed between the first lens 51 and the second lens 52 .

The first lens 51 is configured to collimate the optical signal, and the second lens 52 is configured to converge the optical signal; the first lens 51 and the second lens 52 are commonly used as a G lens or a C lens; the first lens 51 and the second lens The outer diameter of the 52 can be any one of 1.0mm and 1.8mm, and other outer diameters can also be customized according to needs. The materials of the two can be glass, metal or plastic. In order to facilitate the installation of the first pin sleeve 53 and the second pin sleeve 54 , the outer diameters of the first lens 51 , the second lens 52 and the capillary 40 can be designed to be equal in size.

The first optical fiber 10 , the first lens 51 , the isolation core 30 , the second lens 52 and the second optical fiber 20 are arranged in sequence along the axial direction.

The optical signals in the plurality of first fiber cores 11 input from the external light source 100 (mentioned below) to the first optical fiber 10 are collimated by the first lens 51 and then enter the isolation core 30 , and the isolation core 30 allows them to pass in one direction. , and enters the second lens 52 and then converges again into the corresponding second fiber core 21 in the second fiber 20. The optical signal in the second fiber core 21 is then input to the external fan-out device 400 and multi-channel power detection. In the module 500 (mentioned below); when the optical signal in the second fiber core 21 is reflected back to the second lens 52 and enters the isolation core 30, it is isolated by the isolation core 30 to prevent the optical signal from being transmitted back to the first The optical fiber 10 and the light source 100 realize the one-way transmission of the optical signals of multiple channels through the isolation core 30, and the minimum volume can reach Φ3mm*23.5mm, which avoids the need to separately configure a one-way isolator for each optical signal channel. , reducing the cost and reducing the size.

In addition, the axial ends of the first lens 51 and the second lens 52 may be coated with a planar anti-reflection film, so as to improve the efficiency of transmitting optical signals and reduce or eliminate the stray light of the system.

A possible embodiment, as shown in FIG. 1 to FIG. 5 , the isolation device 300 includes two capillary tubes 40 ; one capillary tube 40 is sleeved on the end of the first fiber core 11 close to the first lens 51 ; the other capillary tube 40 It is sleeved on one end of the first fiber core 11 close to the first lens 51 to protect it.

Specifically, the first core 11 of the first optical fiber 10 passes through one of the capillary tubes 40 in the axial direction, and the end face of the capillary tube 40 should be flush with the end face of the first core 11 so that the first core 11 will not be exposed. , the first fiber core 11 is better protected by the capillary 40 to prevent breakage; the end face of the first fiber core 11 and the capillary 40 flush with the first lens 51 should be attached to the first lens 51, so that the input from the first fiber 10 is more The optical signals in each of the first fiber cores 11 can better enter the first lens 51 to complete collimation, thereby completing the optical signal transmission process of multiple channels.

Similarly, another capillary tube 40 is inserted through the second core 21 of the second optical fiber 20 in the axial direction. The end face of the capillary tube 40 and the end face of the second core 21 should be flush with each other, so that the second core 21 will not be exposed. , the second fiber core 21 is better protected by the capillary 40 to prevent breakage, and the end of the second fiber core 21 is attached to the second lens 52, so that the optical signal converged and output from the second lens 52 can be better Enter the second fiber core 21 corresponding to the first fiber core 11, thereby completing the optical signal transmission process of multiple channels.

In a possible embodiment, as shown in FIGS. 1 to 6 , the isolation device 300 includes a first needle cannula 53 and a second needle cannula 54 . The first cannula 53 and the second cannula 54 may be glass, metal or plastic.

The first pin sleeve 53 is sleeved on the first lens 51 and the peripheral side of the capillary 40 through which the first fiber core 11 is inserted to form the first pin assembly; the second pin sleeve 54 is sleeved on the first Two lenses 52 and the peripheral side of the capillary 40 through which the second fiber core 21 passes to form a second pin assembly;

Between the first needle sleeve 53 and the first lens 51 and the capillary 40; between the second needle sleeve 54 and the second lens 52 and the capillary 40; can be fixed by glue, through the first needle sleeve 53. The second pin sleeve 54 plays a protective role to prevent the first lens 51, the first core 11 in the capillary 40, the second lens 52, and the second core 21 in the other capillary 40 from being installed during the installation process. Damage occurs.

The inner apertures of the first pin sleeve 53 and the second pin sleeve 54 can generally be slightly larger or equal according to the outer diameters of the first lens 51, the capillary 40, and the second lens 52, and the gaps are filled with glue , to prevent shaking.

In addition, as shown in FIGS. 1 to 6 , the isolation device 300 may further include an outer sleeve 60; the outer sleeve 60 may be used to fix the first pin assembly and the second pin assembly; the material may be glass, metal or plastic .

In the axial direction, the isolation core 30 is fixed in the middle of the inner cavity of the outer sleeve 60, and the isolation core 30 and the inner wall of the outer sleeve 60 can be fixed by materials such as silica gel; the first pin assembly and the second pin assembly are at least Parts are inserted into the outer sleeve 60 ; the first pin assembly and the second pin assembly are respectively arranged on both sides of the isolation core 30 .

In a possible embodiment, as shown in FIG. 1 and FIG. 4 , the end of the capillary 40 away from the isolation core 30 in the axial direction has an inclined surface 43 , and the inclined surface 43 here refers to no transverse plane perpendicular to the axial direction. In cross section, the inclination angle of the inclined surface 43 can be 5-15° according to the design requirements, and the inclined surfaces 43 of the two capillaries 40 are adapted to the ends of the first lens 51 and the second lens 52 respectively. The first fiber cores 11 are axially penetrated to be flush with the inclined surface 43 of the capillary 40; , in order to facilitate the transmission of optical signals of multiple channels. The inclined surface 43 may be correspondingly coated with a planar anti-reflection film to improve the efficiency of transmitting optical signals and reduce or eliminate the stray light of the system.

A possible embodiment, as shown in FIG. 1 to FIG. 6 , the outer diameter of the capillary 40 is φ0.5-5mm, specifically φ0.5mm, φ0.8mm, φ1.0mm, φ1.8mm, φ2. 5mm, φ4mm, and φ5mm are usually close to or equal to the inner diameters of the first needle cannula 53 and the second needle cannula 54 . The first needle cannula 53 and the second needle cannula 54 play a protective role to prevent the capillary 40 from being damaged during the installation process.

The inner diameter of the capillary 40 is 50um-300um, specifically, the inner diameter of the capillary 40 can be φ50um, φ100um, φ150um, φ250um, φ300um, etc. The specific selection can be based on the number and different diameters of the first core 11 and the second core 21 to actually decide.

The first optical fiber 10 and the second optical fiber 20 are single-mode multi-core optical fibers; a plurality of cores share an outer cladding, which can be single-mode multi-core optical fibers with any number of cores, and the number and arrangement of optical fibers are in any shape.

In the embodiment shown in FIGS. 2 and 3 , the first optical fiber 10 includes a first coating layer 12 and seven first fiber cores 11 , and the seven first fiber cores 11 are circular in the first coating layer 12 Arrangement; the second optical fiber 20 includes a second coating layer 22 and seven second cores 21 corresponding to the first core 11 one-to-one, and the seven second cores 21 are circular in the first coating layer 12 shape arrangement. Usually, only the first fiber core 11 and the second fiber core 21 are left after the first coating layer 12 / the second coating layer 22 is peeled off and then penetrated into the capillary 40 .

The inner diameter B of the capillary 40 is 150um, and the outer diameter C is 1.8mm. At this time, the outer diameters of the first lens 51 and the second lens 52 can also be designed to be 1.8mm. The inner diameter B of the capillary 40 accommodates seven first fibers. The cores 11 and the seven first fiber cores 11 can be arranged in a circle, and the gap A between them is 41.5um; The cores 11 correspond to ensure the transmission of optical signals of multiple channels.

The first fiber cores 11 and the second fiber cores 21 are in one-to-one correspondence, and the seven first fiber cores 11 are sorted according to No. 1 to No. 7, and the seven second fiber cores 21 are sorted according to No. 1 to No. 7. A mirror (not shown) is placed on one side of the 51 and the second lens 52, the first lens 51 and the second lens 52 are placed on both sides of the normal line of the mirror, and the optical signal is passed through, and the three-way monitoring access method is adopted. , that is, the corresponding No. 1, No. 5, No. 6, or No. 2, No. 3, and No. 7 in the seven first fiber cores 11 are coarsely adjusted, and then each channel is finely adjusted to check that the three-way insertion loss is satisfied. If the difference is less than the predetermined value, it can be determined that the matching installation of the first optical fiber 10 and the second optical fiber 20 is qualified. Otherwise, it is considered that the matching installation of the first optical fiber 10 and the second optical fiber 20 is unqualified, and it is necessary to continue debugging. Usually, the predetermined value can be set is 0.05-0.3dB. In this way, between the No. 1 first core 11 and No. 7 second core 21 , between No. 2 first core 11 and No. 6 second core 21 , and No. 3 first core 11 and 5 between the No. 2 second core 21, No. 4 first core 11 and No. 4 second core 21, No. 5 first core 11 and No. 3 second core 21, No. 6 first fiber Between the core 11 and the No. 2 second fiber core 21 , and between the No. 7 first fiber core 11 and the No. 1 second fiber core 21 , seven optical signal transmission paths are formed.

A possible embodiment, as shown in FIG. 1 , FIG. 4 and FIG. 5 , the isolation core 30 includes two wedge angle pieces 31 and Faraday rotating pieces 32 , one of which is wedge angle piece 31 , Faraday rotating piece 32 and the other The wedge-angle pieces 31 are stacked in sequence along the axial direction. That is to say, along the transmission direction of the optical signal, the first optical fiber 10, the first lens 51, one of the wedge-angle plates 31, the Faraday rotating plate 32, the other wedge-angle plate 31, the second lens 52 and the Two optical fibers 20 . The Faraday rotating plate 32 usually adopts a 45° Faraday rotating plate to realize the function of forward passage of optical signals and reverse isolation.

Specifically, the optical signals in the plurality of first fiber cores 11 input from the external light source 100 (mentioned below) to the first optical fiber 10 enter the isolation core 30 after being collimated by the first lens 51 , and pass through one of the wedges in sequence The angle piece 31 , the Faraday rotating piece 32 , and the other wedge angle piece 31 , the isolating core piece 30 allows it to pass in one direction, and enters the second lens 52 and then converges again and then enters the corresponding second fiber core in the second optical fiber 20 21, the optical signal in the second fiber core 21 is input to the external fan-out device 400 and the multi-channel power detection module 500 (mentioned below); when the optical signal in the second fiber core 21 is reflected back to the second lens 52 , and enters the isolation core 30, and the Faraday rotating plate 32 realizes light blocking isolation, preventing the optical signal from being transmitted back to the first optical fiber 10 and the light source 100, so that the optical signals of multiple channels are all unidirectional through the isolation core 30. For transmission, it is avoided to separately configure a one-way isolator for each optical signal channel, thereby reducing the cost and reducing the volume.

The present application further provides an optical communication system including the above-mentioned isolation device 300 .

As shown in FIG. 1 to FIG. 6 , along the direction of optical signal transmission, it sequentially includes: a light source 100 , a fan-in device 200 , an isolation device 300 , a fan-out device 400 , and a multi-channel power detection module 500 .

The fan-in device 200 may be a 1*N beam splitter, the fan-out device 400 may be an N*1 beam splitter (both are also called multi-core splitters, Fan-in and Fan-out Device), the light source 100 is injected into the seven-core isolation device 300 through the fan-in device 200 , and then output to the fan-out device 400 , and finally branched out to the multi-channel power detection module 500 .

The various embodiments/implementations provided in this application may be combined with each other under the condition that no contradiction arises.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims (11)

1. An isolation device, comprising:

a first optical fiber (10) comprising at least two first cores (11);

a second optical fiber (20) including at least two second cores (21), the second cores (21) corresponding to the first cores (11) one to one;

-an isolating core member (30), the isolating core member (30) being axially arranged between the first optical fiber (10) and the second optical fiber (20), the isolating core member (30) being configured such that optical signals in the first cores (11) are unidirectionally transmitted through the isolating core member (30) into the corresponding second cores (21);

and the capillary tube (40), the said capillary tube (40) is fitted over said first fiber core (11) and/or said second fiber core (21) near one end of the said insulating core piece (30).

2. The isolating device according to claim 1, characterized in that it comprises a first lens (51) and a second lens (52), said first lens (51) being arranged between said first optical fiber (10) and said isolating core member (30), said second lens (52) being arranged between said isolating core member (30) and said second optical fiber (20);

the first optical fiber (10), the first lens (51), the isolating core member (30), the second lens (52) and the second optical fiber (20) are arranged in this order in the axial direction;

the first lens (51) is configured to collimate an optical signal; the second lens (52) is configured to focus the optical signal.

3. The isolation device according to claim 2, characterized in that it comprises two of said capillaries (40);

the first fiber core (11) penetrates through one of the capillaries (40) along the axial direction until the capillaries are flush, the end part of the first fiber core (11) is attached to the first lens (51), the second fiber core (21) penetrates through the other capillary (40) along the axial direction until the capillaries are flush, and the end part of the second fiber core (21) is attached to the second lens (52).

4. The isolating device according to claim 3, characterized in that it comprises a first pin sleeve (53) and a second pin sleeve (54);

the first pin sleeve (53) is sleeved on the first lens (51) and the periphery of the capillary (40) with the first fiber core (11) penetrating through to form a first pin component;

the second pin sleeve (54) is sleeved on the second lens (52) and the periphery side of the capillary (40) penetrating the second fiber core (21) to form a second pin assembly.

5. The isolation device of claim 4, wherein the isolation device comprises an outer sleeve (60); the isolating core member (30) is fixed in the middle of the outer sleeve (60); the first pin assembly and the second pin assembly are at least partially inserted into the outer sleeve (60); the first and second pin assemblies are disposed on either side of the isolating core member (30).

6. An isolation device according to claim 2, wherein the first lens (51), the second lens (52) and the capillary (40) have the same outer diameter.

7. An insulation device according to any of the claims 1-6, wherein the ends of the capillaries (40) axially remote from the insulation core member (30) have inclined faces (43), which inclined faces (43) are coated with a planar antireflection coating.

8. An isolation device according to any of claims 1 to 6, wherein the outer diameter of the capillary (40) is 0.5-5mm and the inner diameter of the capillary (40) is 50-300 um.

9. An isolation device as claimed in any one of claims 1 to 6, characterized in that the isolation core member (30) comprises two wedge segments (31) and a Faraday rotator (32), wherein one of the wedge segments (31), the Faraday rotator (32) and the other wedge segment (31) are stacked in axial sequence.

10. The isolation device according to any of claims 1 to 6, wherein the first optical fiber (10) comprises a first coating layer (12) and seven first cores (11), the seven first cores (11) being arranged in a circle within the first coating layer (12);

the second optical fiber (20) comprises a second coating layer (22) and seven second fiber cores (21), and the seven second fiber cores (21) are arranged in a circle in the first coating layer (12).

11. An optical communication system comprising an isolation device as claimed in any of claims 1 to 10.

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