JPH1039173A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate positioning of a light emission element to an optical waveguide element by providing a connection part formed on an electrode and electrically connected to only a light emission element opposite to the light incident surface of the optical waveguide element existing in the corresponding relation to the electrode. SOLUTION: A support groove 4 supporting the optical waveguide element 3 and the electrode 5 are arranged on the same straight line to be formed on a substrate 2, and a light emission element array 7 arranging end surface light emitting type light emission elements smaller than the light incident surface 3a of the optical waveguide element 3 in an array shape is provided in the direction orthogonally intersecting with the opposite direction between the optical waveguide element 3 and the electrode 5, and the connection part 5a electrically connected to only the light emission element opposite to the light incident surface of the optical waveguide element 3 existing in the answering relation to the electrode 5 is formed on the electrode 5. Then, even when the position of the light emission element array 7 in the arranging direction of the light emission element is deviated slightly, it is made possible that at least one light emission element is connected to the connection part 5a of the electrode 5 arranged on the straight line passing through the center of the support groove 4, that is, the center of the optical waveguide element 3. Thus, only the light emission element opposite to the central part of the light incident surface 3a among the light emission elements arranged on the array is made to light emit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module in which an edge-emitting light emitting device and an optical waveguide device are supported on the same substrate so as to face each other.

[0002]

2. Description of the Related Art Conventionally, a light emitting element of an edge emitting type and an optical waveguide element such as an optical fiber are arranged on the same substrate so as to face each other, and light emitted from an end face (light emitting surface) of the light emitting element is transmitted by the optical waveguide element. There is an optical module for guiding to a desired site.
In such an optical module, it is important to fix the optical waveguide element and the light emitting element such that the centers of the end faces of the optical waveguide element and the light emitting element are exactly coincident with each other, but the alignment is not easy. For this purpose, various proposals have been made regarding the positioning structure between the light emitting element and the optical waveguide element.

As one example, Japanese Patent Application Laid-Open No. 6-16067 entitled "Method of Manufacturing Semiconductor Laser Module"
There is an invention described in Japanese Patent Application Publication No. 6 (1994). Hereinafter, description will be made with reference to FIG. In the semiconductor laser module 100 shown here, a groove 103 for positioning and fixing an optical fiber 102 (optical waveguide element) on a surface of a substrate 101 and a groove marker 104 located on a central extension of the groove 103 are provided. At the same time, the surface of the substrate 101 is made a mirror surface, and markers 107 are formed on both sides of the active layer 106 on the back surface of the semiconductor laser 105 (light emitting element). Is observed and the position corresponding to the groove marker 104 on the substrate 101 is determined.

[0004]

The method shown in FIG.
It is said that the semiconductor laser 105 and the optical fiber 102 can be accurately aligned in the direction orthogonal to the facing direction on the order of 1 μm. Such highly accurate alignment is performed by microscopic observation. Since a precise alignment process is required, there is a problem in productivity. In addition, since the surface of the substrate 101 needs to be formed in a mirror surface state, there is a problem that the material of the substrate is limited.

[0005]

According to the first aspect of the present invention,
An optical waveguide element having a light incident surface on which light is incident on an end face, a substrate in which a support groove in which the optical waveguide element is fixedly supported and an electrode corresponding to the optical waveguide element are formed on the same straight line; A light emitting element array in which edge emitting light emitting elements smaller than the light incident surface are arranged in an array in a direction orthogonal to a direction in which the optical waveguide element and the electrode face each other, and formed on the electrode; A connection portion electrically connected only to the light emitting element facing the light incident surface of the optical waveguide element corresponding to the electrode. Therefore, as for the light emitting element on the light emitting element array, only the light emitting element facing the light incident surface of the optical waveguide element is connected to the substrate corresponding to the optical waveguide element.

According to a second aspect of the present invention, in the first aspect of the present invention, the light emitting element array includes a current injection range restricting portion for suppressing a current injected to the driven light emitting element from spreading in the light emitting element array direction. . Therefore, the light emitting region from the light emitting element is limited to a small region.

According to a third aspect of the present invention, in the first aspect of the present invention, the light emitting element array has a cross-sectional shape in which a light emitting surface retreats in a direction away from the optical waveguide element than an opposing surface on the optical waveguide element side. Having. Therefore, when a light emitting element array formed by arranging a large number of light emitting elements equal to or more than the number of light emitting elements necessary for one optical module is collectively formed, and this is cut into a length required for one optical module, Thus, cutting can be performed without causing the cutting tool to interfere with the light emitting surface.

According to a fourth aspect of the present invention, in the third aspect of the invention, at least one of the optical waveguide element and the light emitting element has an optical axis with respect to the surface of the substrate according to a light amount distribution of light from the light emitting element. Are arranged facing each other in a state of being relatively inclined. Therefore, light incident from the light emitting surface of the light emitting element to the light incident surface of the optical waveguide element is light that is directly incident from the light emitting surface,
It becomes light that combines light that is incident after being reflected on the substrate,
The peak of the combined light is directed in a direction inclined with respect to the surface of the substrate, but the inclination of the optical axis causes the peak of the combined light to be directed to the center of the light incident surface of the optical waveguide element.

According to a fifth aspect of the present invention, in the first aspect, a crystal substrate having a predetermined orientation is used as the substrate, the support grooves are formed by anisotropic etching, and the electrodes are formed in a thin film forming process. Is formed. Therefore, the relative position between the support groove and the electrode is accurately determined.

According to a sixth aspect of the present invention, in the first aspect, the optical waveguide element is an optical fiber having a light incident surface formed into a spherical or aspherical shape. Therefore,
It becomes possible to have a lens function on the light incident surface of the optical fiber.

[0011]

FIG. 1 shows a first embodiment of the present invention.
A description will be given with reference to FIG. First, FIG. 1 shows the entire structure of the optical module 1. In the figure, reference numeral 2 denotes a substrate. In the present embodiment, the substrate 2 has a fixed orientation (for example, (10
(0) plane).
An optical fiber 3 as an optical waveguide element is provided on the surface of the substrate 2.
A plurality of V-shaped support grooves 4 for positioning and fixing the electrodes, a plurality of electrodes 5 positioned on the center line of each of the support grooves 4, and an electrode 6 arranged on the side of the substrate 1 are formed. Have been. The support groove 4 is formed by an anisotropic etching technique. Specifically, first, an oxide film (SiO ₂ ) is formed on the entire surface of the substrate 2, and then a portion other than the portion where the support groove 4 is to be formed is patterned by patterning by a normal photolithography method, and KOH is formed. By performing anisotropic etching with an aqueous solution to remove a part of the substrate 2 that is not masked, the support groove 4 is accurately positioned and formed.

The electrodes 5 and 6 are formed by a thin film forming process similar to a process for forming various semiconductors. At each end of the plurality of electrodes 5, a connection portion 5a connected to a light emitting element described later is formed.
The connection portion 5a is formed of, for example, a patterned conductive adhesive or solder bump so as to protrude from the surface within the width of the electrode 5.

The substrate 2 is provided with a light emitting element array 7 connected to the electrodes 5 and 6. As shown in FIG. 2, the light emitting element array 7 has an elongated light emitting element substrate (n-
On one surface of a GaAs substrate 8, there are provided a large number of edge emitting light emitting elements 9. As shown in FIG. 4, the light emitting device 9 includes an n-AlGaAs cladding layer 10 on one surface of a light emitting device substrate 8.
A p-GaAs active layer 11, a p-AlGaAs cladding layer 12, and a p-GaAs cap layer 13 are formed.
It has a double hetero structure formed by laminating a stripe electrode 14 on a GaAs cap layer 13 via an oxide film (not shown) patterned.
The width and arrangement interval of the stripe electrodes 14 are set to a width of several μm. As a result, each light emitting element 9 is narrower than the width of the electrode 5 and further smaller than the light incident surface 3a of the optical fiber 3.

In such a configuration, since the light emitting elements 9 smaller than the light incident surface 3a are arranged in an array, when the light emitting element array 7 is connected to the substrate 2, the surface on which the stripe electrode 14 is formed is removed. When placed on the connection portion 5a of the electrode 5 of the substrate 2, even if the position of the light emitting element array 7 in the longitudinal direction (the arrangement direction of the light emitting elements 9) is slightly shifted, at least one connection portion 5a of the electrode 5 is provided. The stripe electrodes 14 of the two light emitting elements 9 are connected. The light emitting element 9
Is located on the electrode 5 formed on a straight line passing through the center of the support groove 4 that supports the optical fiber 3, and thus faces the center of the light incident surface 3 a of the optical fiber 3. In this case, among the light-emitting elements 9 arranged in an array, there are light-emitting elements 9 located at positions deviated from the center of the light incident surface 3a. Since it is not supplied, it has no effect on light transmission.

Therefore, the width direction of the optical fiber 3 (FIG. 1)
It is not necessary to strictly align the light emitting element 9 with respect to the (X direction). Light emitting element 9 in Y direction in FIG.
The position of the support groove 4 is precisely formed with the support groove 4 and the connection portion 5a.
And the accurate film thickness of the electrode 5 containing The position of the light emitting element 9 in the Z direction in FIG.
The opposing surface 7a on the optical fiber 3 side of the light emitting element array 7 is abutted against the light incident surface 3a, or the light emitting element array 7
Forming a mark for alignment on the surface facing the substrate 2 and
The positioning is performed by connecting the light emitting element 9 to the electrode 5 in accordance with the mark. The positioning in the Z direction, which is the direction of the optical axis, does not require much rigor.

Then, a desired light emitting element 9 is
When a voltage is applied to the optical fiber 3, light from the light emitting surface 15 of the light emitting element 9 (the end surface of the active layer 11 in FIG. 4) is incident on the light incident surface 3a of the optical fiber 3.

A modification in which a support groove is formed in a substrate will be described. As a first modification, a ceramic substrate may be used as the substrate, and the support groove may be formed by mechanical cutting. Further, the substrate 2 provided with the support groove 4 formed by the method described in the previous embodiment is used as a master,
A mold may be manufactured by an electroforming method, the mold may be set in an injection molding machine, and a substrate having a support groove may be formed by injection molding. The accuracy of the duplicated substrate is slightly lower than that of the original substrate 2 as a master, but there is no problem in accuracy in the case of an optical module using an optical fiber having a large diameter.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment and the subsequent embodiments, the same portions as those described with reference to FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof will be omitted. The light emitting element array 7 includes a current injection range limiting unit that suppresses a current injected into the driven light emitting element 9 from spreading in the light emitting element array direction. As shown in FIG. 5A, the specific configuration of the current injection range limiting section is as follows.
This is a deleted portion 16 between the light emitting elements 9 in the case where the layer forming 4 is deleted and the plurality of light emitting elements 9 are configured in a mesa shape. Alternatively, as shown in FIG.
Is a buried layer 17 disposed at the boundary of the buried layer. This buried layer 17
The material is an insulating resin such as polyimide, and a semiconductor thin film configured to form a pn reverse bias layer.

Therefore, when a current is injected into the electrode 5 in order to cause the light emitting element 9 to emit light, the spread of the current in the direction of the adjacent light emitting element 9 is prevented by the deleted portion 16 or the buried layer 17, and Can be made smaller. Thereby, the arrangement density of the light emitting elements 9 can be increased to reduce the size, and the power consumption can be reduced.

The layers 10 to 13 and the stripe electrode 14 are formed on one surface of the substrate 2, and desired ions are diffused between the light emitting elements 9 to form a high resistance portion (current injection limiting portion). However, the same effect can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG. In the light emitting element array 7 according to the present embodiment, the light emitting surface 15 (see FIGS. 4 and 5) of the light emitting element 9 is smaller than the facing surface 7a on the optical fiber 3 side.
It has a cross-sectional shape that recedes in the direction away from it. Specifically, after laminating the layers 10 to 13 and the stripe electrode 14 on the light emitting element substrate 8, the opposing surface 7 on the optical fiber 3 side is formed.
By removing a part of the vicinity of the edge where the “a” intersects the surface on the substrate 2 side, including the laminated layers 10 to 13 and the stripe electrode 14 by etching, the light emitting surface 15 of the light emitting element 9 can emit light from the opposing surface 7 a. It is retracted in a direction away from the fiber 3.

In such a configuration, a large number of light emitting elements 9 more than the number of light emitting elements 9 necessary for one optical module 1 are provided.
Is formed on a semiconductor wafer (light emitting element substrate 8) in a lump, which is advantageous in terms of manufacturing efficiency. When the light emitting element array 7 is cut into a length required for one optical module 1,
Since the light emitting surface 15 is retracted from the opposing surface 7a, the cutting can be performed without causing the cutting tool to interfere with the light emitting surface 15. Thus, there is no possibility that the light emitting surface 15 is damaged by the cutting tool, and the yield at the time of manufacturing can be improved.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, as described in FIG. 6, the light emitting element array 7 has the light emitting surface 15 of the light emitting element 9 higher than the opposing surface 7a on the optical fiber 3 side.
When the optical fiber 3 (see FIGS. 4 and 5) has a sectional shape that recedes in a direction away from the optical fiber 3, the optical fiber 3 and the light emitting element 9 are separated from each other by the substrate 2 according to the light amount distribution of light from the light emitting element 9. Are arranged so that the optical axis is relatively inclined with respect to the surface. Specifically, the support groove 4 of the substrate 2
By forming a V-shaped stepped recess 4a, which is narrower and shallower than the support groove 4, at the tip of the optical fiber 3, the tip of the optical fiber 3 is supported by the stepped recess 4a.
The optical axis at the end on the light emitting element 9 side is inclined with respect to the surface of the substrate 2.

In such a configuration, since there is an interval between the light incident surface 3a of the optical fiber 3 and the light emitting surface 15 of the light emitting element 9, light incident on the light incident surface 3a from the light emitting element 9 is small. And light that is directly incident from the light emitting element 9 and light that is incident after being reflected on the surface of the substrate 2.
As a result, the peak of the combined light is directed in a direction inclining away from the substrate 2 with respect to the surface of the substrate 2, but the light incident surface 3 a of the substrate 2 is Since the light is displaced in a direction away from the surface, the peak of the combined light is directed to the center of the light incident surface 3a, and the light use efficiency can be increased.

The configuration for tilting the optical axis at the end of the optical fiber 3 is not limited to the configuration described above. Also,
When the axis of the optical fiber 3 is kept straight, the same effect can be obtained even if the light emitting element array 7 is inclined.

FIG. 9 shows a fifth embodiment of the present invention.
It will be described based on. This embodiment is an example in which a spherical or aspherical light incident surface 3a is formed on the end face of the optical fiber 3 on the light emitting element 9 side. Therefore, the light incident surface 3a of the optical fiber 3 can have a lens function. As a result, the light emitting element 9 can be
Light from the sun can be taken in efficiently.

[0027]

According to the first aspect of the present invention, the support groove and the electrode to which the optical waveguide element is fixed are arranged on the same straight line and are formed on the substrate, and the optical element array is formed from the light incident surface of the optical waveguide element. It has an edge-emitting light-emitting element arranged in an array in a direction orthogonal to the direction in which the light guide element and the electrode face each other, and emits light that faces the light incident surface of the light guide element that is in correspondence with the electrode. Since the connection portion electrically connected only to the element is formed on the electrode, even if the position of the light emitting element array in the light emitting element array direction is slightly shifted, at least one light emitting portion is provided at the connection portion of the electrode. The element is connected, and the light emitting element is located on an electrode located on a straight line passing through the center of the support groove for supporting the optical waveguide element, and thus faces the center of the light incident surface of the optical waveguide element. Therefore, the relative position between the light emitting element and the optical waveguide element can be accurately determined without performing the operation of strictly aligning the light emitting element in the width direction of the optical waveguide element.

According to a second aspect of the present invention, in the first aspect of the present invention, the light emitting element array includes a current injection range limiting section for suppressing a current injected to the driven light emitting element from spreading in the light emitting element array direction. Therefore, when the light emitting element emits light, the spread of the current in the direction of the adjacent light emitting element is prevented by the current injection range limiting portion, and the light emitting region from the light emitting element can be reduced. Accordingly, the arrangement density of the light-emitting elements can be increased, the size can be reduced, and the power consumption can be reduced.

According to a third aspect of the present invention, in the first aspect of the present invention, the light emitting element array has a cross-sectional shape in which a light emitting surface is receded in a direction away from the optical waveguide element than an opposing surface on the optical waveguide element side. Therefore, a light emitting element array formed by arranging a large number of light emitting elements equal to or more than the number of light emitting elements necessary for one optical module is collectively formed, and this is cut into a length required for one optical module. In this case, cutting can be performed without causing the cutting tool to interfere with the light emitting surface. This eliminates the risk of damaging the light emitting surface with the cutting tool,
The yield at the time of manufacturing can be improved.

According to a fourth aspect of the present invention, in the third aspect of the invention, at least one of the optical waveguide element and the light emitting element has an optical axis with respect to the surface of the substrate in accordance with the light quantity distribution of light from the light emitting element. Are arranged facing each other in a state of being relatively inclined. Therefore, light incident from the light emitting surface of the light emitting element to the light incident surface of the optical waveguide element is light that is directly incident from the light emitting surface,
It becomes light that combines light that is incident after being reflected on the substrate,
The peak of the combined light is directed in a direction inclined with respect to the surface of the substrate, but the inclination of the optical axis directs the peak of the combined light toward the center of the light incident surface of the optical waveguide element, thereby increasing the light use efficiency. Can be increased.

According to a fifth aspect of the present invention, in the first aspect, a crystal substrate having a predetermined orientation is used as the substrate, the support grooves are formed by anisotropic etching, and the electrodes are formed in a thin film forming process. Therefore, the relative position between the support groove and the electrode can be accurately determined. Since the arrangement density of the support grooves and the electrodes can be increased by the improvement of the dimensional accuracy, the size can be reduced.

According to a sixth aspect of the present invention, in the first aspect, the optical waveguide element is an optical fiber having a light incident surface formed into a spherical or aspherical shape. Therefore,
The light incident surface of the optical fiber can have a lens function. Thereby, light from the light emitting element can be efficiently taken in by utilizing the light condensing action of the lens.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing the entire structure of an optical module according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a light emitting element array.

FIG. 3 is a partially enlarged side view.

FIG. 4 is a partially enlarged front view.

FIG. 5 is a partially enlarged front view showing a second embodiment of the present invention.

FIG. 6 is a partially enlarged side view showing a third embodiment of the present invention.

FIG. 7 is a partially enlarged side view showing a fourth embodiment of the present invention.

FIG. 8 is a partial plan view showing a relationship between an optical waveguide element in a support groove and an electrode.

FIG. 9 is a partially enlarged side view showing a fifth embodiment of the present invention.

FIG. 10 is an exploded perspective view showing a conventional example.

[Explanation of symbols]

 2 Substrate 3 Optical waveguide element 3a Light incident surface 4 Support groove 5 Electrode 5a Connection part 7 Light emitting element array 9 Light emitting element 15 Light emitting surface 16, 17 Current injection range limiting part

Claims (6)

[Claims] 1. An optical waveguide element having an end face having a light incident surface on which light is incident, a support groove in which the optical waveguide element is fixedly supported, and an electrode corresponding to the optical waveguide element are arranged on the same straight line. A formed substrate, a light-emitting element array in which edge-emitting light-emitting elements smaller than the light-incident surface are arranged in an array in a direction orthogonal to a facing direction of the optical waveguide element and the electrode, and An optical module, characterized in that the optical module further comprises a connection portion formed only on the light-emitting element facing the light-incident surface of the optical waveguide element corresponding to the electrode. 2. The optical module according to claim 1, wherein the light emitting element array includes a current injection range limiting unit that suppresses a current injected into a light emitting element to be driven from spreading in a light emitting element array direction. 3. The light-emitting element array has a cross-sectional shape in which a light-emitting surface retreats in a direction away from the optical waveguide element than an opposing surface on the optical waveguide element side.
An optical module as described. 4. At least one of the optical waveguide element and the light emitting element is arranged to face the surface of the substrate in a state where the optical axis is relatively inclined with respect to the light amount distribution of light from the light emitting element. The optical module according to claim 3, wherein: 5. The substrate according to claim 1, wherein a crystal substrate having a predetermined orientation is used, the support grooves are formed by an anisotropic etching technique, and the electrodes are formed by a thin film forming process. Optical module. 6. An optical module, wherein the optical waveguide element is an optical fiber having a light incident surface formed into a spherical or aspherical shape.