JPH0990159A - Optical module and its assembly method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module which can protect a semiconductor laser and the end face of a GI type optical fiber from a damage at the time of assembly and which can collectively and easily adjust a focal distance at the time of connection with optical parts and to provide an assembly method. SOLUTION: In the optical module 1, a GI type optical fiber array 4 where the grated index type optical fibers 4a are arranged at pitches equal to the optical parts is arranged between array-type optical parts 2 where the plural optical parts 2a are arranged on a substrate 2b at the prescribed pitches and an optical fiber array 3 where the plural optical fibers are arranged at pitches equal to the optical parts. A spacer 5 is arranged at least on the array-type optical parts-side of the GI-type optical fiber array 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module and its assembling method.

[0002]

2. Description of the Related Art Due to the complexity of optical communication systems, array type optical modules have been developed in which optical components such as semiconductor lasers, light receiving elements, and optical fibers are arranged in parallel. As an array type optical module in which a plurality of optical components are coupled with high coupling efficiency, an optical module coupling circuit using a GI (graded index) type optical fiber as a lens component is disclosed.
-194506.

Here, the GI type optical fiber has a refractive index distribution in which the refractive index distribution parameter α is 1 ≦ α <3, the refractive index is maximum at the center of the core, and the refractive index becomes smaller as it approaches the cladding. An optical fiber having a parabolic refractive index distribution, which acts as a lens when cut into a predetermined length.

[0004]

In the optical module coupling circuit disclosed in the above publication, a predetermined length (= several 100 μm to 10 mm) is provided between the plurality of optical waveguides and the semiconductor laser.
GI type optical fibers (outer diameter 125 μm) are installed with their optical axes aligned to enhance the coupling efficiency as an optical module.

By the way, the optical module coupling circuit is
GI is provided between the corresponding optical waveguide and the semiconductor laser.
The optical fiber is placed and assembled. Therefore, the optical module coupling circuit easily damages the end faces of the semiconductor laser and the GI type optical fiber at the time of assembly, and must be coupled with the semiconductor laser while adjusting the focal length of each GI type optical fiber individually. However, there is a problem that the joining work is complicated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a semiconductor laser and a GI are assembled at the time of assembly.
An object of the present invention is to provide an optical module that can protect the end face of a mold optical fiber from damage and can easily adjust the focal length at the time of coupling with an optical component, and an assembling method thereof.

[0007]

According to the present invention, in order to achieve the above object, an array type optical component in which a plurality of optical components are arranged on a substrate at a predetermined pitch, and a plurality of optical fibers are the optical components. GI in which a plurality of graded index type optical fibers of a predetermined length are arranged at the same pitch as that of the optical component between the optical fiber array arranged at the same pitch.
In the optical module where the optical fiber array is placed,
A spacer is arranged at least on the array type optical component side of the GI type optical fiber array.

Preferably, the spacer is a film-shaped transparent body. Further preferably, the spacer is a frame body in which a window is formed in a portion corresponding to at least a plurality of GI type optical fibers. Further, according to the optical module assembling method of the present invention for achieving the above object, an array type optical component in which a plurality of optical components are arranged at a predetermined pitch on a substrate,
A GI type optical fiber array in which a plurality of graded index type optical fibers of a predetermined length are arranged at the same pitch as the optical parts between the optical parts and the optical fiber array in which the plurality of optical fibers are arranged at the same pitch as the optical parts. In this configuration, a spacer is arranged at least on the side of the array type optical component, and the spacers are positioned and coupled by a plurality of fitting pins.

If a spacer is arranged at least on the array type optical component side of the GI type optical fiber array, the end faces of the semiconductor laser and the GI type optical fiber are protected from damage during the assembly of the optical module, and the focal length of the optical component is improved when the optical component is coupled. Adjustments can be made collectively and easily. At this time, if the spacer is a film-shaped transparent body or a frame body on which a window is formed,
The difference in refractive index in the optical path can be suppressed small.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to FIGS. The optical module 1
An array type optical component 2, an optical fiber array 3 and a GI type optical fiber array 4 are provided, and the GI type optical fiber array 4 is arranged between the array type optical component 2 and the optical fiber array 3.

In the array type optical component 2, a plurality of semiconductor lasers 2a are arranged on a substrate 2b at a predetermined pitch (= 250 μm), and pin holes 2c, 2c are formed on both sides in the width direction. Each semiconductor laser 2a is connected to a metal lead pattern 2e on the substrate 2b by a bonding wire 2d. The optical fiber array 3 has a plurality of single mode or multimode optical fibers (not shown) of 250 μm.
A multi-core connector having tape fibers 3a arranged in parallel at a pitch, with fitting pins 3b, 3b provided on both sides in the width direction.
Array type optical component 2 and GI type optical fiber array 4
Combined with.

In the GI type optical fiber array 4, the graded index type optical fiber 4a is a semiconductor laser 2a.
Are arranged in the synthetic resin 4b at the same pitch (= 250 μm), and pin holes 4c, 4c are provided on both sides. Further, the GI type optical fiber array 4 has a plurality of optical fibers 4a which are polished by micro-lapping or the like on both sides facing the array type optical component 2 and the optical fiber array 3.
Spacers 5 made of a film-shaped transparent body are provided on both surfaces where the is exposed. Here, the length of each optical fiber 4a is set to several tens of μm to several mm within a range where it acts as a lens.

The spacer 5 protects the end faces of the semiconductor laser 2a and the optical fiber 4a from damage, and is made of a material having a low transmission loss, such as glass or a transparent resin having a refractive index close to that of glass. As the transparent resin, for example, fluoride polyimide, fluoride polycarbonate, transparent epoxy or the like can be used. At this time, if the spacers 5 are provided on both surfaces of the GI type optical fiber array 4, the focal length of each of the graded index type optical fibers 4a having a lens action changes, and the focal length becomes longer than that in the case of air. This change depends on the refractive index of the spacer 5. Therefore, the spacer 5
When arranged on the array type optical component 2 side, the refractive index of the semiconductor laser 2a is about 3.5 and the refractive index of the optical fiber 4a is 1.
When it is arranged in the middle of 46 on the optical fiber array 3 side, it is set to the same degree as the refractive index of the optical fiber of the tape fiber 3a. However, the spacer 5 and the array type optical component 2
If they are separated from each other, the focal length of each optical fiber 4a on the optical fiber array 3 side becomes shorter. When the spacer 5 having an appropriate refractive index is arranged between the GI type optical fiber array 4 and the array type optical component 2 or the optical fiber array 3 as described above, the difference in the refractive index between them can be suppressed to a small value.
The reflection of the light transmitted between them is suppressed, and the coupling efficiency is improved.

The spacer 5 has a thickness of 0.6 mm on the array type optical component 2 side and 3.8 mm on the optical fiber array 3 side.
When the distance is set to mm, the coupling efficiency is maximized, but the coupling efficiency depends on the optical fiber 4a having a lens effect.
Therefore, the spacer 5 has a thickness of 0.01 to 1 mm on the array type optical component 2 side and 3 to 8 m on the optical fiber array 3 side.
It is desirable to set in the range of m. However, spacer 5
If the thickness is too thick, the coupling efficiency will be significantly reduced due to the angle shift. Therefore, the GI type optical fiber array 4
It is desirable to use an optical fiber having a large core diameter instead of using the ordinary optical fiber 4a.

Here, in addition to the above-mentioned film-shaped transparent body, the spacer has a plurality of optical fibers 4a of the GI type optical fiber array 4 opened, for example, a spacer 6 at the center as shown in FIG. It may be a frame body in which the window portion 6a is formed. In this case, since the spacer 6 has the open portion of the optical fiber 4a, the difference in refractive index cannot be suppressed to a small value, but it is sufficient to protect the end faces of the semiconductor laser 2a and the optical fiber 4a from damage.

The optical module 1 configured as described above
Arranges a GI type optical fiber array 4 having spacers 5 on both sides between the array type optical component 2 and the optical fiber array 3, and connects the optical fiber array 3 to the array type optical components 2 and GI.
The optical fiber array 4 side is pressed, and the fitting pins 3b are fitted into the pin holes 4c and 2c while being positioned by the corresponding pin holes 4c and 2c.

Therefore, in the optical module 1, the GI
Since the spacers 5 are provided on both surfaces of the mold optical fiber array 4, the focal lengths of the plurality of optical fibers 4a can be adjusted at once. Here, in the optical module 1, the light emitted from the semiconductor laser 2a of the array type optical component 2 is reflected when entering the corresponding optical fiber 4a of the GI type optical fiber array 4, and the characteristics of the semiconductor laser 2a are reflected. The end surface of the optical fiber 4a facing the semiconductor laser 2a may be processed into a convex surface so as not to deteriorate it. The processing to the convex surface can be easily performed by etching the end surface of the optical fiber 4a with an etchant such as hydrofluoric acid or an aqueous solution of ammonium fluoride. The tip of the optical fiber 4a thus processed into a convex surface is pressed against the spacer 5 when a soft transparent resin other than glass is used,
Alternatively, the optical module 1 is assembled using the spacer 6 formed of the frame body shown in FIG.

The optical module 1 includes an optical fiber array 3 and a GI type optical fiber array 4 as shown in FIG.
It is also possible to process the end faces that abut each other into an inclined surface inclined by an angle θ (= about 8 degrees). With such an inclined surface,
At the end faces of the optical fibers, reflection of transmitted light can be suppressed to be small. In the above embodiment, spacers were provided on both sides of the GI type optical fiber array 4. However, the spacer is a GI optical fiber array 4
It suffices that it is arranged at least on the array type optical component 2 side.

[0019]

As is apparent from the above description, according to the optical module and the method of assembling the optical module of the present invention, the end face of the semiconductor laser or the GI type optical fiber can be protected from damage when the optical module is assembled, The focal length can be easily adjusted in a lump at the time of coupling with the optical component.

At this time, if the spacer is a film-shaped transparent body or a frame body in which a window is formed, the difference in refractive index in the optical path can be suppressed small.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an optical module for explaining an optical module of the present invention and an assembling method thereof.

FIG. 2 is a perspective view showing another example of a spacer.

FIG. 3 is a cross-sectional view showing a modified example of the optical module.

[Explanation of symbols]

1 Optical Module 2 Array Optical Components 2a Semiconductor Laser 2b Substrate 2c Pin Hole 3 Optical Fiber Array 3a Tape Fiber 3b Fitting Pin 4 GI Optical Fiber Array 4a Optical Fiber (Graded Index Type) 4b Synthetic Resin 4c Pin Hole 5 Spacer 6 Spacer 6a Window

Claims (4)

[Claims] 1. A predetermined length between an array type optical component in which a plurality of optical components are arranged on a substrate at a predetermined pitch and an optical fiber array in which a plurality of optical fibers are arranged at the same pitch as the optical component. In an optical module in which a GI type optical fiber array in which a plurality of graded index type optical fibers are arranged at the same pitch as the optical component is arranged, a spacer is arranged at least on the array type optical component side of the GI type optical fiber array. An optical module characterized by the above. 2. The optical module according to claim 1, wherein the spacer is a film-shaped transparent body. 3. The optical module according to claim 1, wherein the spacer is a frame body in which a window is formed in a portion corresponding to at least a plurality of GI type optical fibers. 4. A predetermined length is provided between an array type optical component in which a plurality of optical components are arranged on a substrate at a predetermined pitch, and an optical fiber array in which a plurality of optical fibers are arranged at the same pitch as the optical component. A spacer is arranged on at least the array type optical component side of a GI type optical fiber array in which a plurality of graded index type optical fibers are arranged at the same pitch as the optical component, and the spacers are positioned and coupled by a plurality of fitting pins. A method for assembling an optical module, characterized in that