JPH0540215A - Photocoupler - Google Patents

Abstract

PURPOSE:To provide a photocoupler considerably improving the productivity of an array-shaped module. CONSTITUTION:Assuming that light is made incident from an array-shaped single mode optical fiber 14, the array-shaped single mode optical fiber 14 and an array-shaped second lens 13 are arranged and integrated so that a beam formed after emission from the array-shaped second lens can be a spread array beam and on the other hand, an array-shaped semiconductor optical waveguide 11 and an array-shaped first lens 12 are arranged so that light emitted from the array-shaped semiconductor optical waveguide 11 can be a narrowed-down beam array after passage through the array-shaped first lens 12. Then, the spot size and the positions for the virtual image of the spread array beam from the array-shaped second lens and the real image of the spread array beam from the array-shaped first lens are coincident with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low loss and manufacturable optical coupling device for coupling light from an array type light emitting element to an array type light incident element.

[0002]

2. Description of the Related Art Various configurations have been proposed as an optical coupling system for coupling light emitted from a semiconductor laser (also referred to as an LD) to a single-mode optical fiber. In addition to proposing a pseudo confocal compound lens system having a low tolerance in manufacturing, the characteristics of the module were previously proposed [JP-A-60-
61707, and Kono, "Basics and Applications of Optical Coupling Systems" (Hyundai Engineering Co., Ltd.)].

FIG. 2 shows a schematic view of a semiconductor laser module using a pseudo confocal compound lens system, and FIG. 3 shows the principle of optical coupling in the pseudo confocal compound lens system.
In these figures, 1 is a semiconductor laser, 2 is a first lens, 3 is a housing in which the first lens 2 is provided, 4
Is a second lens, 5 is a single mode optical fiber, 6 is a core to which the single mode optical fiber is fixed, 7 is an integrated holder in which the core 6 and the second lens 4 are integrated, 8 is an integrated holder 7
Is a guide for attaching the optical fiber 5 to the housing 3 so as to be movable in the axial direction, and 9 is a nylon cord.
In optical coupling using such a pseudo confocal compound lens system, the distance between the light emitting surface of the semiconductor laser 1 and the first lens 2 is larger than the focal length of the first lens 2, and the semiconductor laser having a spot size of W _LD . Emitting light from 1
The first lens 2, which is a rod lens, is adapted to convert the beam to a slightly narrow beam having a spot size of W _LD ′. On the other hand, the core 6 to which the single mode optical fiber 5 having the spot size W _F is fixed is previously integrated with the second lens 4 and the integrated holder 7 which are shorter than, for example, 1/4 pitch. When it is assumed that light is incident on the two lenses 4, the beam becomes a beam with a slight spread. That is, considering that light is injected from the single-mode optical fiber 5 into the second lens 4, this integrated portion can be regarded as a virtual fiber having a spot size of W _F ′.

In the optical coupling shown in FIGS. 2 and 3, a beam with a spot size of W _LD ′, which is slightly narrowed, is incident on a virtual fiber with a spot size of W _F ′, so that the emitted light of the semiconductor laser 1 is separated. It can be made incident on the one-mode optical fiber 5. This is the beam after the exit of the first lens 2 having the spot size W _LD ′ and the spot size W _F ′.
Can be thought of as coupling with a virtual fiber. Therefore, if the two spot sizes of W _LD ′ and W _F ′ are designed to match, high coupling efficiency can be realized.

Here, consider a case where two Gaussian beams having a spot size W are offset from each other by X in the direction perpendicular to the optical axis and are coupled by being offset by θ. The coupling efficiency η at this time is expressed as η = exp (−X ² / W ² −π ² W ² θ ² / λ ² ). As can be seen from this equation, the larger the spot size W is, the smaller the deterioration of the coupling efficiency due to the axial displacement amount X in the direction perpendicular to the optical axis becomes. Therefore, an appropriate spot size (for example, about 13 μm) may be selected.

Since the above-mentioned spot size represented by the spot sizes W _LD ′, W _F ′ is larger than the spot size W _F of the single mode optical fiber, the tolerance of the axial deviation of the integrated portion, that is, the virtual fiber is relaxed. Therefore, the manufacturability of the semiconductor laser module is significantly eased.

[0007]

However, in the conventional optical coupling shown in FIG. 2, the first lens 2 and the second lens 4 are used.
Are both individual lenses. Therefore, if this conventional example is applied to coupling an array type semiconductor optical waveguide, which has been actively researched and developed in recent years, such as a waveguide type semiconductor optical switch, and a plurality of single mode optical fibers, the array type semiconductor optical waveguide is Since the first lens and the virtual fiber are coupled to each of the optical waveguides inside, it is practically difficult to form a module.

In view of such circumstances, it is an object of the present invention to provide an optical coupling device in which the manufacturability of an array type module is greatly improved.

[0009]

An optical coupling device according to the present invention that achieves the above object has an array type light emitting element in which at least two or more light emitting elements are integrated, and at least two or more lenses are integrated. An array type first lens, an array type second lens in which at least two or more lenses are integrated, and an array type light incident element in which at least two or more light incident elements are integrated; When light is incident on the array-shaped second lens from the beam-shaped light-incident element, the light formed after the array-shaped second lens exits is expanded so as to be an array beam with a slight spread or an array beam with a slight stop. The array type second lens and the array type light incident element are positioned and integrated to form an array type integrated portion, while the light emitted from the light emitting element is The array type first lens is arranged with respect to the array type light emitting element so as to form an array beam with a slight aperture or an array beam with a slight spread after passing through the array type first lens. Virtual image of array beam slightly expanding from lens or real image of array beam slightly squeezing and real image of array beam slightly squeezing from array-type first lens or real image of array beam slightly expanding, each beam waist spot The array-type first lens and the array-type integrated portion are arranged so that the size and position match.

[0010]

The spot size and position of the beam waists of the virtual image of the array beam with a slight spread from the array type second lens and the real image of the array beam with a slight aperture from the first lens of the array type are the same or the array size is the same. Array-shaped first lens by matching the spot size and position of the beam waists of the real image of the array beam from the second lens Since the array-shaped integrated portion is optically coupled to each other and the spot size for alignment is large, high coupling efficiency is realized.

[0011]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 shows a plan view and a sectional view of an optical coupling device according to the present embodiment. In the figure, 11 is an array type semiconductor waveguide as an array type light emitting element, 12 is an array type second lens, 13 is an array type second lens, 14 is an array type single mode optical fiber as an array type light incident element, 15 is an array type semiconductor optical waveguide mount, 16 is an array type first lens holder, 17 is an array type first lens 1 lens mount, 18 is an array type second lens holder, 19 is an array type optical fiber holder, and 20 is an array type integrated portion mount.

The array-type semiconductor waveguide 11 is provided on the mount for the array-type semiconductor optical waveguide, while the array-type first lens 12 is provided with the array-type first lens mount 17 via the array-type first lens holder 16. The end faces of the respective waveguides of the array-type semiconductor waveguide 11 fixed to the above face the lenses of the array-type first lens 12, respectively, and the distance between them is larger than the focal length of the array-type first lens 12. There is. In other words, the light emitted from the array-type semiconductor waveguide 11 is arranged so as to become an array beam with a slight aperture after passing through the array-type first lens 12. On the other hand, the array-type second lens 13 is passed through the array-type first lens holder 18, and the array-type single-mode optical fiber 14 is passed through the array-type optical-fiber holder 19 so that each lens and each lens of the array-type single-mode optical fiber 14 are connected. It is fixed on the mount 20 for the array type integrated part so as to be in close contact with the end face of the one-mode optical fiber, and forms the array type integrated part. The array-type integrated portion has a tendency that the light formed after the array-type second lens 13 exits, assuming that light is incident from the array-type single-mode optical fiber 14 to the array-type second lens 13. It is set to be an array beam. The array type optical fiber holder 19 is formed by etching a V groove in Si.

The principle of optical coupling of the above-mentioned optical coupling device is the same as that of the pseudo confocal compound lens system shown in FIGS.
That is, one spot size W ₀ of the array-type semiconductor optical waveguide 11 is enlarged to W ₀ ′ as a real image by the array-type first lens 12, while the array-type second lens 13 and the array-type optical fiber holder 19 are The spot size W _F ′ of the array type virtual fiber in which the above are integrated is the spot size W of each optical fiber of the array type single mode optical fiber
Expanded compared to _F. Therefore, in order to obtain a high coupling efficiency in an actual module, it is sufficient to match the both. That is, also in the present invention, there is an advantage of the conventional pseudo confocal compound lens system, that is, there is an effect of mitigating the tolerance of the axis deviation due to the enlargement of the spot size. Further, in this embodiment, since the array-type first lens 12 and the array-type second lens 13 are used as the first lens and the second lens, the array-type semiconductor optical waveguide, which is difficult with the conventional confocal compound lens system, is used. There is an advantage that a coupling module of the waveguide 11 and the array type single mode optical fiber 14 can be easily manufactured.

In the description of the present embodiment, so-called plano-convex lenses each having one spherical surface are used as the array-type first lens 12 and the array-type second lens 13, but a flat-plate microlens having a refractive index distribution type may be used. Good. Further, it goes without saying that the array type fiber holder can be configured with a configuration other than the array type fiber holder in which the V groove is formed in Si. Furthermore, although an array type single mode optical fiber has been described as the optical fiber, an array type multimode optical fiber may be used.

In the above embodiment, the array type first
The spot size W ₀ ′ of the array beam emitted from the lens 12 is a real image, and the array type single mode optical fiber 1
Although the spot size W _F ′ incident upon the array-type second lens 13 from No. 4 is a virtual image, the distance between each optical waveguide end face of the array-type semiconductor optical waveguide 11 and the array-type first lens 12 is determined by the array. By making the focal length of the first lens 12 of the array type smaller than the focal length of the first lens 12 of the array type, the spot size W ₀ ′ is made into a virtual image as an array beam having a spread after being emitted from the first lens 12 of the array type, and the second lens 13 of the array type is formed.
And the array-type single-mode optical fiber 14 are assumed to have received light from the array-type single-mode optical fiber 14, the light formed after the array-type second lens 13 exits is an array beam with a slight aperture. The spot size W _F ′ may be made into a real image by being integrated so that these positions and sizes may be matched.

[0017]

As described above, according to the present invention, since the array-type first lens and the array-type second lens are used,
An array-type pseudo confocal compound lens system can be easily constructed for the array-type optical waveguide. Therefore, there is an effect that the manufacturability of the array type module is dramatically improved.

[Brief description of drawings]

FIG. 1 is a plan view and a cross-sectional view showing an optical coupling device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional pseudo confocal compound semiconductor laser module.

FIG. 3 is an explanatory diagram showing the principle of a pseudo confocal compound lens system.

[Explanation of symbols]

 11 array type semiconductor optical waveguide 12 array type first lens 13 array type second lens 14 array type single mode optical fiber 15 array type semiconductor optical waveguide mount 16 array type first lens holder 17 array type first lens mount 18 Array type second lens holder 19 Array type optical fiber holder 20 Array type integrated section mount

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Satoshi Sekine 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. An array type light emitting element in which at least two or more light emitting elements are integrated, an array type first lens in which at least two or more lenses are integrated, and an array in which at least two or more lenses are integrated. In a light coupling device including an array type light incident element in which at least two light incident elements are integrated, it is assumed that light is incident on the array type second lens from the array type light incident element. In such a case, the array-type second lens and the array-type light-incident element are positioned and integrated so that the light formed after being emitted from the array-type second lens becomes a spread-like array beam or an aperture-like array beam. As a result, the array-type integrated portion is formed, while the light emitted from the light-emitting element passes through the array-type first lens, and the array beam is slightly squeezed. Is arranged such that the array-type first lens is arranged with respect to the array-type light emitting element so as to form a diverging array beam, and a virtual image of the diverging array beam from the array-type second lens or a squeezed array image. The array-shaped first lens so that the real image of the array beam and the real image of the array beam slightly squeezed from the array-type first lens or the real image of the array beam slightly divergent are matched in spot size and position of each beam waist. An optical coupling device comprising: an array-type integrated portion;