WO2019017587A1

WO2019017587A1 - Active optical cable

Info

Publication number: WO2019017587A1
Application number: PCT/KR2018/006349
Authority: WO
Inventors: 유태경
Original assignee: 주식회사 루멘스
Priority date: 2017-07-19
Filing date: 2018-06-04
Publication date: 2019-01-24
Also published as: KR20190009664A

Abstract

Disclosed is an active optical cable. The active optical cable comprises a VCSEL array having a plurality of VCSEL elements emitting a combined optical beam; and an optical fiber having an input end for receiving the combined optical beam from the VCSEL array, wherein the input end is spaced apart from the VCSEL array at a predetermined interval, and for efficient coupling of the input end of the optical fiber and the combined optical beam, the VCSEL array and the optical fiber are arranged such that the input end and the combined optical beam are coaxially aligned.

Description

Active optical cable

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active optical cable, and more particularly, to an active optical cable, in which an active optical cable can be used for an active optical cable capable of efficiently coupling a maximum light intensity of a light beam emitted from a VCSEL (Vertical Cavity Surface Emitting Laser) Optical cable.

Copper cables, which are generally used for signal transmission, are not suitable for high-capacity, high-quality voice and video signals (A / V signals) for long distance transmission.

Recently, 4K UHD broadcasting and HD content transmission are becoming active (4K UHD broadcasting has started in the metropolitan area and some regions in 2017 and 4K UHD broadcasting is planned to be implemented nationwide in 2020) , The demand for active optical cables (AOC or AOC cables) is increasing, and as the supply of related equipment increases, the use and demand of such AOC cables are also expected to continue to increase.

The most basic feature of the AOC cable is that there is a photoelectric conversion part on a printed wiring board (PWB) or a printed circuit board (PCB) and an optical cable as a transmission medium . An example of an AOC cable structure using a conventional vertical cavity surface emitting laser (VCSEL) array and a photodiode (PD) array is schematically illustrated in FIG. Vertical cavity surface-emitting laser (VCSEL) is a type of semiconductor laser diode that emits laser in the vertical direction to the upper surface.

Referring to FIG. 1, the basic structure of the AOC cable will be described. Electric components and optical components are mounted on the PWB 16, which is not shown in detail in the drawings. For example, Electric parts and optical parts having both the transmitting and receiving functions can be mounted. For example, in the case of the 12-channel bidirectional type, the electric parts and the optical parts having the transmitting and receiving functions can be respectively disposed on two different PWBs. The transmission electric signal is input to the transmission driver IC 13 through the electric transmission line on the PWB, and the VCSEL element 11 is current-modulated, so that the optical signal can be outputted and transmitted through the optical cable 12. [

As shown in FIG. 1, focusing on the path where light from the VCSEL array travels in a general AOC cable, focusing on the side of the transmitter 10 (Tx) The lens 14 is located and the light focused by the focusing lens 14 is converted by the prism 15 or the reflecting mirror 15. The path-converted light travels through the plastic optical fiber 12, (20, Rx). On the receiving end 20 side, the photodiode 21 detects light traveling through the plastic optical fiber. In the structure of such an AOC cable, components such as a focusing lens 14, a prism 15 and a separate alignment structure 18 are required at each of the transmitting end and the receiving end, There is a problem in that the center of the optical fiber having a very small diameter and the center of the VCSEL element must be precisely aligned through a lens coupling process and the coupling with the input side of the optical fiber is not properly performed even if the core is used . Therefore, there is a need in the art for a solution that can solve this problem.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the need for a lens and a prism in each of a transmitting end and a receiving end in an AOC cable and to avoid a lens coupling process for precisely aligning a center of a cable and a VCSEL, Since the light input to the input end of the optical fibers is not an optical beam emitted from one VCSEL element but a combined optical beam emitted from a plurality of VCSEL elements, an improved structure of the AOC cable .

According to an aspect of the present invention, there is provided an active optical cable including: a VCSEL array having a plurality of VCSEL elements emitting a combined optical beam; Wherein the VCSEL array and the optical fiber are arranged such that the optical fiber is connected to the VCSEL array and the optical fiber, And the input end and the combined optical beam are coaxially aligned.

According to one embodiment, the active optical cable comprises a VCSEL mounting substrate for mounting the VCSEL array, a printed circuit board mounting a driver IC for driving the VCSEL elements, and allowing the VCSEL mounting substrate to be secured .

According to one embodiment, the VCSEL mounting substrate is fixed in a direction orthogonal to the printed circuit board.

According to one embodiment, the diameter of the combined optical beam emitting region may be the same as the diameter of the core of the optical fiber.

According to one embodiment, VCSEL elements adjacent to each other in the VCSEL array are spaced apart from each other by at least a reference interval, and the reference interval may be determined depending on the amount of light of adjacent VCSEL elements in the VCSEL array.

According to one embodiment, three VCSEL elements adjacent to each other in the VCSEL array may be spaced apart at equal intervals.

According to one embodiment, three VCSEL elements adjacent to each other in the VCSEL array may be arranged to form a triangle.

According to one embodiment, the four VCSEL elements adjacent to each other in the VCSEL array may be arranged in a shape of either a square shape or a rectangular shape.

According to another aspect of the present invention, there is provided an active optical cable including a plurality of VCSEL element groups, each of the VCSEL element groups including a plurality of VCSEL elements emitting a combined optical beam, And a plurality of optical fibers, each of the optical fibers corresponding to each of the VCSEL element groups and having an input end, and the input end of each of the optical fibers receives a combined optical beam from a corresponding group of VCSEL elements - and spaced apart from the VCSEL group array by a predetermined distance, and for efficient coupling of a combined optical beam emitted from a VCSEL element group corresponding to each of the input ends of the optical fibers and each of the optical fibers, , A VCSEL element group corresponding to each of the optical fibers and each of the optical fibers, The keombain de optical beam emitted from the VCSEL element group corresponding to each of the optical fibers, each of the input stage and the optical fiber and is arranged such that coaxial alignment (coaxially aligned).

According to one embodiment, the active optical cable comprises a VCSEL mounting substrate for mounting the VCSSEL group array, a printed circuit board (PCB) mounting a driver IC for driving the VCSEL elements, And the VCSEL mounting substrate is fixed in a direction orthogonal to the printed circuit board.

According to one embodiment, the diameter of the combined optical beam emitting region in each of the VCSEL groups may be equal to the diameter of the core of the corresponding optical fiber.

According to one embodiment, VCSEL elements adjacent to each other in each of the VCSEL groups are spaced apart from each other by at least a reference interval, and the reference interval may be determined depending on the light amount of VCSEL elements adjacent to each other in each of the VCSEL groups .

According to one embodiment, three VCSEL elements adjacent to each other in each of the VCSEL groups may be spaced apart at equal intervals.

According to one embodiment, three VCSEL elements adjacent to each other in each of the VCSEL groups may be arranged to form a triangle.

According to one embodiment, the four VCSEL elements adjacent to each other in each of the VCSEL groups may be arranged in any one of a square shape and a rectangular shape.

The present invention provides an AOC cable that not only eliminates the need to use lens and prism components in each of the transmitting or receiving ends, but also eliminates the need for a lens coupling operation to precisely align the core of the cable with the center of the VCSEL It is effective. In addition, since the light input to the input end of a plurality of optical fibers is not an optical beam emitted from one VCSEL element but a combined optical beam emitted from a plurality of VCSEL elements, the coupling operation can be facilitated .

1 is a view showing an example of a conventional active optical cable (AOC)

2 is a diagram showing a characteristic part of an active optical cable according to an embodiment of the present invention,

3A and 3B are views for explaining a VCSEL array in an active optical cable according to an embodiment of the present invention,

4 is a view for explaining a VCSEL group array in an active optical cable according to an embodiment of the present invention,

FIG. 5 is a view illustrating examples of arrangements of a plurality of VCSEL elements spaced correspondingly to an optical fiber in an active optical cable according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the accompanying drawings and embodiments are illustrated and simplified for those of ordinary skill in the art with a view to facilitating understanding of the present invention.

3 is a view for explaining a VCSEL array in an active optical cable according to an embodiment of the present invention, and FIG. 4 is a view for explaining a VCSEL array in an active optical cable according to an embodiment of the present invention. FIG. 5 is a diagram illustrating a structure of a plurality of VCSEL elements arranged correspondingly to an optical fiber in an active optical cable according to an exemplary embodiment of the present invention, Fig.

The VCSEL used in the active optical cable of the present invention is basically made of GaAs or AlGaAs material, and is composed of an n-type DBR (Distributed Bragg Reflector) as a bottom mirror, a p-type DBR as a top mirror, And a gain region located between the n-type DBR and the p-type DBR. In this gain region, free photons are pumped to form a laser diode having an emission wavelength of approximately 650 nm to 1300 nm.

Referring to FIGS. 2, 3A, and 3B, an active optical cable according to an exemplary embodiment of the present invention includes a VCSEL array 110 and an optical fiber 120. As shown in FIGS. 3A and 3B, the VCSEL elements 130 constituting the VCSEL array 110 are mounted on the VCSEL mounting substrate 111. FIG. As shown in FIG. 3B, a driver IC 190 for electrically connecting the VCSEL elements in the VCSEL array 110 to convert an electrical signal into an optical signal, and various wiring patterns and other components for electrical connection Are mounted on a printed circuit board (160). The VCSEL mounting substrate 111 is fixed to the printed circuit board 160, and a fixing member 180 may be used. Other submounts and optical fiber guides may be provided on the printed circuit board 160 side, but are not shown as they are not essential components of the present invention.

A plurality of

VCSEL elements

130a, 130b and 130c 130 are disposed in the VCSEL array 110 and a plurality of VCSEL elements 130 emits a combined optical beam 132. [ A plurality of VCSEL elements 130 in the VCSEL array 110 are disposed correspondingly spaced apart from the optical fibers 120 and a combined optical beam 132 emitted from the plurality of VCSEL elements 130 is disposed on one optical fiber 120 . That is, the light emitted from each of the plurality of VCSEL elements 130 is combined to form a combined optical beam 132, and the combined optical beam 132 thus formed is incident on the input end 126 of the optical fiber 120) .

The optical fiber 120 has an input end 126 and a combined optical beam 132 from the VCSEL array 110 is input through the input end 126. The combined optical beam 132 is input to the optical fiber 120, Lt; RTI ID = 0.0 > 122 < / RTI >

In order to allow the maximum luminous intensity of the combined optical beam 132 emitted from the plurality of VCSEL elements 130 in the VCSEL array 110 to be input smoothly into the input end 126 of the optical fiber 120, The beam 126 and the input end 126 of the optical fiber 120 are coupled such that they are coaxially aligned. More specifically, the center of the combined optical beam 132 emitted from the plurality of VCSEL elements 130 in the VCSEL array 110 (the center of the incident surface S1 having the diameter R1 in FIG. 2 or 3A) Is coaxially aligned with the center of the core 122 located at the center of the input end 126 of the optical fiber 120 (the center of the cross section of the core having the diameter R2 in Fig. 2), so that the combined optical beam 132 and the optical fiber 120 are configured to be coaxially aligned. This allows the intensity of the combined optical beam 132 emitted from the plurality of VCSEL elements 130 in the VCSEL array 110 to be substantially maximally input to the input end 126 of the optical fiber 120. The incident surface S1 may be represented by a circle circumscribing the beams emitted by each of the VCSEL elements 130, as shown in FIG. Thus, the combined optical beam 132 has a predetermined diameter R1.

The combined optical beam emitted by the plurality of VCSEL elements 130 is input to the input end 126 side of the optical fiber 120. In the combined optical beam 132, (S1 in FIG. 3A) is defined as the combined optical beam emitting region, the diameter R1 of the combined optical beam emitting region (S1 in FIG. 3A) is equal to the diameter R2 of the core 122 of the optical fiber The distance between the VCSEL array 110 and the input end 126 of the optical fiber 120, the number of VCSEL elements 130 in the VCSEL array 110, and the spacing distance between the VCSEL elements 130 can be appropriately adjusted . Reference numeral 124 denotes a cladding layer of the optical fiber 120.

Further, adjacent VCSEL elements (e.g., 130a and 130b) in the VCSEL array 110 are spaced apart from each other by at least a reference interval. The reference spacing can be determined depending on the amount of light of the VCSEL elements (e.g., 130a and 130b) that are adjacent to each other in the VCSEL array 110. [ The spacing of the VCSEL elements in the VCSEL array 110 may be determined by considering the size of the VCSEL elements or the pitch width of the upper electrode wiring (p-type electrode wiring).

3A, the incident surface S1 of the VCSEL elements 130, that is, the combined optical beam emitting region can be bounded by a combination of the emitted light of each of the VCSEL elements as mentioned above, The combined optical beam emission region has a diameter R1. In arranging the VCSEL array 110 and the optical fiber 120 (see FIG. 2), the center of the optical fiber core is substantially aligned with the center of the combined optical beam emitting region (see C1, C2, and C3 in FIG. 5) The combined optical beam and the input end 126 of the optical fiber 120 can be efficiently coupled. Compared with the conventional case, even if a focusing lens, a prism, an alignment structure, or the like is used, the coupling operation between the core portion of the optical fiber and the optical beam becomes much more errory, and the present invention can overcome this disadvantage .

3B, the VCSEL mounting substrate 111 may be coupled to the printed circuit board 160 in a direction orthogonal to the VCSEL mounting substrate 111. As shown in FIG. 1, the substrate 16 and the VCSEL array are parallel to each other. In the active optical cable of the present invention, the printed circuit board 160 and the VCSEL array are orthogonal to each other. In this respect, the conventional type can be regarded as a horizontal type, and the present invention can be regarded as a vertical type.

FIG. 5 is a view illustrating examples of arrangements of a plurality of VCSEL elements spaced correspondingly to an optical fiber in an active optical cable according to an embodiment of the present invention. (a) shows a case where three

VCSEL elements

130a, 130b and 130c are arranged in a regular triangle in a VCSEL array, (b) and (c) show four

VCSEL elements

130d, 130e, 130f and 130g (B) is a structure arranged in a square, and (c) is a structure arranged in a rectangle. S2 and S3 are the incident faces incident on the core side of the optical fiber and C1, C2 and C3 are the center of each of the incident faces S1, S2 and S3, to be. In coupling the VCSEL array (110 in FIG. 2) and the optical fiber (120 in FIG. 2), the centers of these incident planes (C1, C2, C3) coaxially align with the center of the core 122 of the optical fiber. In FIG. 5, the incident planes S1, S2, and S3 are represented by a circumscribed circle drawn so as to include all the optical beams emitted from the respective VCSEL elements as shown in the figure, and the centers of these incident planes Coaxially aligned to coincide with the center of the cross section of the core of the optical fiber. In FIG. 5, reference numerals 132a to 132k denote outer edges of the optical beams emitted from the respective VCSEL elements. In (c), d4 is an interval wider than the reference interval d3.

As described above, the VCSEL array and the core of the optical fiber are coaxially aligned, and the diameter of the incident surface, that is, the diameter of the combined optical beam, is equal to the diameter of the core of the optical fiber between the incident surface of the VCSEL array and the optical fiber So as to be located at a predetermined position.

A plurality of VCSEL elements may be appropriately arranged in various forms in the VCSEL array to form a combined optical beam as shown in FIGS. 5A, 5B, and 5C, Is determined by the amount of light of adjacent VCSELs (e.g., 130a and 130b, or 130d and 130e, or 130h and 130i). Further, the present invention is not limited to the example shown in FIG. 5, but a larger number of VCSEL elements can be arranged in a more extended structure with such a structure as a unit unit.

Finally, referring to FIG. 4, a VCSEL group array in an active optical cable according to an embodiment of the present invention will be described. The active optical cable of the present invention is capable of inputting the combined optical light emitted by a plurality of VCSEL elements to one optical fiber as in the above-described example, and further, in the embodiment described with reference to FIG. 4 The VCSEL element groups may be spaced apart from the

optical fiber bundles

120a, 120b, 120c and 120d and correspond to the optical fibers in the

optical fiber bundles

120a, 120b, 120c and 120d. A VCSEL group array in which a plurality of

VCSEL element groups

110a, 110b, 110c, and 110d are arranged, and an optical fiber bundle.

Each of the

VCSEL element groups

110a, 110b, 110c, and 110d includes a plurality of VCSEL elements that emit a combined optical beam. An example of one VCSEL element group 110a may be the structure shown in FIG.

The optical fiber bundle has a plurality of

optical fibers

120a, 120b, 120c, and 120d and is spaced apart from the corresponding VCSEL group array at predetermined intervals. Each of the

optical fibers

120a, 120b, 120c, and 120d corresponds to each of the VCSEL element groups. Each of the optical fibers has an input end, and the input end receives a combined optical beam from the corresponding group of VCSEL elements.

In FIG. 4, the

VCSEL element groups

110a, 110b, 110c, and 110d are shown mounted on the respective VCSEL mounting substrates, but they may be mounted on one VCSEL mounting substrate, And can be fixed in a vertical type on the printed circuit board 160 using the fixing member 180, as shown in Figs.

The relationship between one optical fiber in the optical fiber bundle and the corresponding VCSEL element group is substantially the same as the VCSEL array and optical fiber described above with reference to Fig. As well as. Although the optical cables in the optical fiber bundle in Fig. 4 are illustrated as four, they may be extended in different numbers and may be arranged in a matrix as well as a structure arranged in a row or in a row. In this arrangement, a plurality of VCSEL elements in the VCSEL element group corresponding to one optical fiber may be used.

By doing so, it is not necessary to use a focusing lens, a prism, or the like in order to accurately transmit the optical beam emitted from the VCSEL device to the input end of the optical fiber core as in the prior art. It is possible to prevent failures from occurring in the transfer of data through the optical cable even if one VCSEL device is not correctly aligned with the core.

While the present invention has been described with reference to the exemplary embodiments, it is to be understood that the scope of the present invention is defined by the appended claims.

110: VCSEL array

120: Optical fiber

130: VCSEL element

Claims

A VCSEL array having a plurality of VCSEL elements emitting a combined optical beam; And

An input end for receiving the combined optical beam from the VCSEL array, the input end being spaced apart from the VCSEL array by a predetermined distance,

Characterized in that for efficient coupling of the input end of the optical fiber and the combined optical beam the VCSEL array and the optical fiber are arranged such that the input and the combined optical beam are coaxially aligned, cable.
The active optical cable according to claim 1,

A VCSEL mounting substrate for mounting the VCSEL array; And

Further comprising: a printed circuit board mounting a driver IC for driving the VCSEL elements and allowing the VCSEL mounting substrate to be secured.
The active optical cable according to claim 2, wherein the VCSEL mounting substrate is fixed in a direction orthogonal to the printed circuit board.
The method according to claim 1,

And the diameter of the combined optical beam emitting region is equal to the diameter of the core of the optical fiber.
The method according to claim 1,

Wherein the VCSEL elements adjacent to each other in the VCSEL array are spaced apart from each other by at least a reference interval and the reference interval is determined depending on a light amount (?) Of VCSEL elements adjacent to each other in the VCSEL array. .
The method of claim 5,

Wherein three VCSEL elements adjacent to each other in the VCSEL array are spaced apart at equal intervals.
The method of claim 5,

And the three VCSEL elements adjacent to each other in the VCSEL array are arranged to form a triangle.
The method of claim 5,

Wherein the four VCSEL elements adjacent to each other in the VCSEL array are arranged in a shape of either a square or a rectangle.
A plurality of VCSEL element groups, each of said VCSEL element groups including a plurality of VCSEL elements emitting a combined optical beam; And

A plurality of optical fibers, each of the optical fibers corresponding to each of the VCSEL element groups and having an input end, the input end of each of the optical fibers receiving a combined optical beam from a corresponding VCSEL element group, An optical fiber bundle spaced a predetermined distance from the array,

The VCSEL element group corresponding to each of the optical fibers and each of the optical fibers is connected to the input end of each of the optical fibers and the group of VCSEL elements corresponding to each of the optical fibers, Characterized in that each of the input ends and the combine optical beams emitted from the group of VCSEL elements corresponding to each of the optical fibers are coaxially aligned.
10. The active optical cable according to claim 9,

A VCSEL mounting substrate for mounting the VCSEL group array; And

Further comprising: a printed circuit board mounting a driver IC for driving the VCSEL elements and allowing the VCSEL mounting substrate to be secured.
11. The active optical cable of claim 10, wherein the VCSEL mounting substrate is fixed in a direction orthogonal to the printed circuit board.
The method of claim 9,

Wherein the diameter of the combined optical beam emission region in each of the VCSEL groups is equal to the diameter of the core of the corresponding optical fiber.
The method of claim 9,

Wherein the VCSEL elements adjacent to each other in the VCSEL groups are spaced apart from each other by at least a reference interval and the reference interval is determined depending on the amount of light of the VCSEL elements adjacent to each other in each of the VCSEL groups. cable.
14. The method of claim 13,

And three VCSEL elements adjacent to each other in each of the VCSEL groups are spaced apart at equal intervals.
14. The method of claim 13,

And the three VCSEL elements adjacent to each other in each of the VCSEL groups are arranged to form a triangle.
14. The method of claim 13,

And the four VCSEL elements adjacent to each other in each of the VCSEL groups are arranged in a shape of either a square or a rectangle.