JPH0769497B2 - Optical component mount - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Industrial field of application” The present invention relates to an optical axis between an end face of a waveguide in an optical component such as an optical switch and an optical modulator and an end face of an optical fiber to be connected to the optical component. The present invention relates to a mounting board for mounting with high precision matching, an optical component, and an optical fiber.

"Prior Art" FIG. 3 shows a conventional example of the optical component mounting body.

Reference numeral 1 is an optical component to be mounted. For example, when the optical component is formed of LiNbO ₃ , it can function as a modulator by applying a voltage. This optical component 1
Inside, a pair of linear waveguides 101 are provided in parallel with each other, and waveguide end faces 102 are formed at both ends of these waveguides 101 in a direction orthogonal to the optical axis of the waveguide 101. . The waveguide 101 is formed by a diffusion method from the upper surface of the optical component 1, and forms a part of a planar waveguide forming surface 103 on the upper surface of the optical component 1. Further, an electrode 104 made of, for example, a conductor foil as a printed pattern is formed in a region of the waveguide forming surface 103 that covers the waveguide 101 so that a voltage can be applied to the optical component 1.

On the other hand, reference numerals 2 and 3 are optical fibers to be connected to the optical component 1 (the core wire shown in the drawing is the one with its coating removed).
This is a Si positioning substrate for positioning 4.5. The substrates 2 and 3 are provided with V-grooves 20 provided in parallel with each other.
1 and 301 have a function of holding the optical fibers 4 and 5, respectively. In addition, the optical fibers 4 and 5
Has cores 401 and 501, respectively, and has end faces 402 and 502 perpendicular to the axis.

Reference numeral 6 is the optical component 1 and the positioning boards 2 and 3
A mount substrate on which is mounted, reference numeral 7 is a spacer interposed between the optical component 1, the positioning substrates 2 and 3 and the mount substrate 6.

A process of mounting work in the mounting body configured as described above will be described.

First, the coating of the optical fiber is removed to expose the core wire, which is adhesively fixed to the V groove 201 of the positioning substrate 2, and further, the positioning substrate 2 is fixed to a predetermined position of the mount substrate 6.

Next, the optical component 1 is placed on the mount substrate 6, and the optical axes of the core 401 of the optical fiber 4 and the end face of the waveguide 101 of the optical component are aligned. At this time, light is input from the other end face (not shown) of the optical fiber 4 so that the optical output detected by the output end face of the waveguide 101 of the optical component 1 is maximized.
Is moved (mainly in the X and Z axis directions in FIG. 3). In addition, in the case of FIG. 3, since two waveguides 101 are provided, it is necessary to correct a minute rotation around the Z axis, and the optical component 1 is moved along the X axis direction in the optical component 1. Since there are minute irregularities on the surface, it is necessary to correct the rotation around the Y axis. After the optical component 1 is moved in each of the above directions and positioned so that the maximum optical output can be obtained from the end faces of both waveguides 101, between the optical component 1 and the mount substrate 6 in order to maintain this positional relationship. The spacer 7 is inserted in and fixed in this state.

Further, the output-extracting optical fiber 5 from which the coating has been removed is fixed in the V groove 301 of the positioning substrate 3, and the positioning substrate 3
Is aligned with the output side end face of the optical waveguide 101. At this time, the positioning board 3 is not only positioned by moving in the X and Z axis directions, but also due to the non-uniformity of the thickness of the optical component 1, the spacer 7 is also provided at a plurality of positions for rotation around the X and Y axes. It needs to be inserted and adjusted.

[Problems to be Solved by the Invention] In the above-mentioned mounted body, the optical component 1 and the positioning substrate 3
Since it is essential to adjust many axial movements and rotations about each axis in mounting each, assembly with many parameters in this way involves many difficulties. . Further, if there are many parameters necessary for positioning, there is a risk that the optical axis will be displaced thereafter.

The present invention has been proposed in view of the above circumstances, and it is an object of the present invention to reduce the parameters related to positioning, to facilitate assembly, and to obtain a mounted body that is less likely to cause misalignment after assembly. is there.

[Means for Solving the Problem] In order to achieve the above object, a first invention of the present application is to provide an input side optical fiber and an output side optical fiber whose end faces are opposed to each other with a space therebetween,
In an optical package which is provided between these and an optical component which performs some processing on a signal from the input side optical fiber and outputs the signal to the output side optical fiber is mounted on a substrate, the lower surface of the optical component is A waveguide and contact portions provided at positions on both sides of the waveguide that respectively slightly project from the lower surface of the optical component and contact the upper surface of the substrate are provided, and the substrate has an input side and an output side. Groove having a V-shaped cross section for holding each of the optical fibers, and the contact portion is provided at at least two places on one side of the waveguide and at least one place on the other side of the waveguide. And the V-shaped groove is a sum of the distance from the lower surface of the optical component to the contact surface between the contact portion and the substrate and the distance from the lower surface of the optical component to the center of the waveguide. Only the distance equivalent to In order to support the center of the optical fiber by separating it from the surface of the substrate, the width dimension and the angle of the vertex are set, and the second invention of the present application makes contact with the contact portions on the lower surface of the optical component, respectively. On the surface of the substrate,
Reference marks are formed by crossing V-shaped grooves in a cross shape, and the reference marks have a distance in plan view from the center line of the V-shaped grooves that support the optical fiber. It is configured to be provided at a position equal to the distance between the center line of the waveguide and the center of the contact portion in a plan view. Furthermore, the third invention of the present application defines the range of contact with the contact portion of the optical component. This is a configuration in which a portion recessed from this surface is provided on the upper surface of the substrate in the area excluding the area that faces the electrode of the optical component.

[Operation] According to the configuration of the first invention, the optical axes of the input and output optical fibers can be made to coincide with each other only by inserting them into the V-grooves, and at the same time, one side of the waveguide in the optical component can be provided. The optical component can be positioned by contacting the optical component with the substrate at least at one location on the other side and at least two locations on the other side, and the optical fiber can be positioned on the substrate by the V-groove, thus And the optical fiber can be relatively positioned in the height direction.

According to the configuration of the second aspect of the invention, in addition to the operation of the first aspect of the invention, the center of the contact portion and the center of the reference mark are aligned with each other, so that the waveguide and the optical fiber are relatively aligned in the horizontal direction. The optical axes of the waveguide and both optical fibers can be aligned with each other as a result.

According to the configuration of the third invention, in addition to the operation of the first invention, for example, an electrode necessary for performing a predetermined function as an optical component is projected to the waveguide peripheral portion on the lower surface of the optical component. However, even if they are provided in the above, they are accommodated in the recess of the window, and thus the contact state of the contact portion with the substrate is maintained.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In the figure, the same parts as those of the conventional example shown in FIG. 3 are designated by the same reference numerals to simplify the description.

Reference numeral 1 is an optical component configured similarly to the conventional example. This optical component 1 is used with the optical waveguide 101 facing downward, and a vapor deposition pad 105 as a matching mark is formed on the waveguide forming surface 103 thereof. This evaporation pad 105
Is, for example, formed on the formation surface 103 at the same time in the process of vapor-depositing the electrode 104, and in the case of an embodiment, one diagonal line has a square planar shape oriented in a direction parallel to the waveguide 101. Have

Further, reference numeral 2A is a Si mounting substrate that has the functions of the positioning substrate 2 and 3 and the mounting substrate 6 in the conventional example. The mounting substrate 2A has a V groove 201 that holds the optical fibers 4 and 5. 201, a window 203 penetrating in the plate thickness direction, and a reference mark 204 used for alignment with the optical component 1 are provided.

The V-grooves 201 and 202 hold the optical fibers 4 and 5 in a state where the optical axes of the optical fibers 4 and 5 are aligned with the optical waveguide 101 of the optical component 1.
The dimensions are set as shown in FIG. That is, assuming that the surface of the mounting substrate 2A is the (100) plane of the Si crystal and the optical axis direction of the set optical fibers 4 and 5 is the <100> direction, the width of the opening of the V groove 201 in FIG. 2l (width dimension on the etching mask in manufacturing) is relative to the radius d of the optical fiber core wire, the inclination angle θ of the V groove slope, and the distance a between the center of the optical fiber core wire 4 and the upper surface of the mounting substrate 2A. Is given by l = (d / cos θ−a) / tan θ. Where θ is 54.7 ° as a value peculiar to the crystal, d is the nominal size 1/2 (125 μm), which is the radius of a general standard optical fiber, and a is the optical The sum of the distance from the surface of the component 1 to the center of the waveguide 101, the thickness of the metal foil forming the vapor deposition pad 105, and the thickness of the adhesive layer of the vapor deposition pad 105 is substituted as constants. From the above, the width 21 of the V groove 201, that is, the dimension of the mask required when the V groove 201 is formed by etching is determined, and the V groove 201 having a predetermined dimension can be obtained.

Even when the V groove 202 is formed, the V groove 201 is also formed.
If the outer diameters of the optical fibers 4 and 5 are the same, naturally, l also has the same value. Further, regarding the reference mark 204 having a cross-shaped planar shape, the V groove 2 is also used.
It can be formed by etching simultaneously with 01.

Further, the substrate 2A is provided with a window 203 in order to avoid contact with the electrode 104 protruding from the waveguide forming surface 103 of the optical component 1 to be mounted over a height corresponding to the thickness thereof. ,
In addition to the above purpose, the window 203 also has a function of reducing the dielectric constant ε of the portion facing the electrode 104.

Next, the relative relationship between the alignment mark 105 on the optical component 1 side and the reference mark 204 on the substrate 2A side will be described. The alignment mark 105 has a square shape in which one diagonal line is oriented in a direction parallel to the waveguide 101. And is made of, for example, a metal foil formed on the surface of the optical component 1 in the same manufacturing process as the electrode 104. Further, the reference mark 204 is an alignment mark on the waveguide side when the optical component 1 is placed on the substrate 2A.
Cross-shaped V-grooves (grooves having a V-shaped cross section), which are respectively coincident with the diagonal lines of 105, are formed at predetermined positions with respect to the center line of the V-grooves 201 for holding the optical fiber by means of anisotropic etching or the like. It will be. That is, the diagonal line of the alignment mark 105 extending in the direction orthogonal to the waveguide 101 and the line of the reference mark 204 extending in the direction orthogonal to the center line of the V groove 201 are
In the direction parallel to the axis of the waveguide 101 (the center line of the V-shaped groove 201), the diagonal line of the alignment mark 105 directed in the direction parallel to the waveguide 101 and the direction parallel to the center line of the V-shaped groove 201. The V-shaped groove of the reference mark 204 that faces the waveguide 1
01 and the V groove 201 are formed at the same distance from the center line. In addition, the V groove that constitutes the reference mark 204,
It is desirable that the diagonal lines of the matching marks 105 have the same length.

Mounting work in the optical mounter configured as described above is
The procedure is as follows.

First, the end faces of the optical fibers 4 and 5 are mirror-polished to form a V groove.
Insert into 201 and 301 respectively, and inject the adhesive from the gap between them to fix. At this time, the centers of the optical fibers 4 and 5 are arranged at positions apart from the upper surface of the substrate 2A by a distance a on the center lines of the V grooves 201 and 202.

Next, when the optical component 1 is placed on the substrate 2A with the surface on the side where the waveguide 101 is formed facing downward, the alignment mark 105 serves as a contact portion with the substrate 2A and is held in the V groove 201. Since the height of the center of the optical fibers 4 and 5 from the surface of the substrate 2A is set to a, that is, the value including the thickness of the alignment mark 105 as described above, the waveguide 101 and the optical fiber are set. The heights of the centers of 4 and 5 necessarily coincide. Further, the high component 1 is moved on a horizontal plane (the upper surface of the substrate 2A) to align the alignment mark 105 with the reference mark 204, thereby causing the waveguide 101 and the centers of the optical fibers 4 and 5 to be substantially aligned in the horizontal direction. be able to. In general, optical component 1
Since the material forming the mark is transparent or semi-transparent, the alignment mark 10 can be easily seen by visual observation from above the optical component 1.
The 5 and the reference mark 204 can be aligned.

Then, as in the conventional case, a light beam is made incident from the input side end of the optical fibers 4 and 5, and the output is measured by the photodetector at the output side end, and the optical component 1 is finely moved in the horizontal direction. The center of the waveguide 101 and the centers of the optical fibers 4 and 5 can be finally made coincident with each other by moving and finding the position where the output of the detector becomes maximum.

Then, after the positioning is performed as described above, an adhesive is injected between the optical component 1 and the substrate 2A using the V groove forming the reference mark 204.
5 and each reference point 204). It should be noted that the larger the installation interval of the reference marks 204 (the interval in the direction parallel to the axis of the optical fiber), the higher the stability of the optical component 1, but the amount of thermal expansion and contraction between the optical component 1 and the substrate 2A between the fixing points. In consideration of the strain caused by the difference of, it is desirable to make it as small as possible without impairing the stability.

As described above, in the mounted body of the embodiment, the optical component 1
By aligning the position of the vapor deposition mark 105 on the side and the reference mark 204 on the side of the substrate 2A, the optical component and the optical fiber can be positioned by a simpler process than in the case of the conventional mounting body without using a special spacer or the like. can do.

“Modified Example” a. Since the substrate supporting the optical fiber has a surplus space in the region except the region where the V groove is formed and the region where the optical component is mounted, the space is utilized. The circuit pattern of the electric circuit for driving the optical element may be directly formed on the substrate.

b. One embodiment shows an example in which there are two input / output optical fibers, but in the case of four input side and eight output side, or one input and one output, Of course, the present invention can be applied to the case of a different number of lines.

c. In one embodiment, two matching marks are provided on both sides of the substrate, but if one matching mark is provided at three positions, a similar function can be achieved.

d. When the optical component is made of an opaque material, it is impossible to observe the alignment mark and the reference mark from above through the optical component. (Formed by a metal foil with a thickness smaller than the mark) is provided so as to extend to the outside of the alignment mark in the direction parallel to the waveguide and the direction orthogonal to the waveguide, respectively. The V-grooves that form the marks are also extended in the same manner, and after mounting the optical components on the substrate, a manipulator or the like that can perform minute movements while observing the extended lines from the side with a microscope or the like. The two can be positioned by moving them relative to each other.

e. The window formed on the substrate is intended to reduce the inductivity ε of the portion facing the optical component, and therefore it is either a window that penetrates the substrate in the thickness direction or a window that does not penetrate the substrate. Alternatively, a required shape may be adopted according to the shape of the lower surface of the optical component, for example, the planar shape of the electrode.

"Effects of the Invention" As is apparent from the above description, according to each invention of the present application, the following effects can be obtained.

Since the V groove for positioning the input / output optical fiber is formed on the integrated substrate and is formed by the same mask in the same etching process, no special processing is required for input / output. The optical fiber can be positioned.

By setting the width of the V groove to a predetermined value, only by forming the V groove by a method such as etching, the center position of the optical fiber held in the V groove is set to a predetermined distance from the upper surface of the substrate. On the other hand, if the thickness of the contact portion is determined, the distance from the lower surface of the optical component to the center of the waveguide is also determined. The optical components can be positioned in the height direction only by placing the optical component on the substrate in a state of being in contact with the substrate via the adhesive layer in which the thickness is set.

Furthermore, since the waveguide and the optical fiber can be positioned in the horizontal direction by aligning the positions of the contact portion on the optical component side and the reference mark on the substrate side, in combination with the above effect, the The optical axes of the optical fiber and the waveguide can be made to substantially coincide with each other by a simple operation of placing the component on the substrate and moving it horizontally. Therefore, the maximum output from the optical fiber on the output side is then obtained by the photodetector. By precisely moving the optical component to the position where the position is obtained, accurate positioning can be easily performed.

Since the fixing point between the optical component and the substrate is at least one place on one side and at least two places on the other side,
Naturally, thermal stress does not occur on the side supported at one location, and by reducing the mutual distance between the fixed points on the side supported at two locations, the thermal stress between the substrate and the optical component is minimized. Can be suppressed.

Since the recessed portion is provided at a position excluding the range in which the optical component is contacted, the inductivity ε of this portion can be reduced, and for example, the electrical circuit provided to the optical component to perform various operations can be reduced. It is possible to prevent the adverse effect of the capacity.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
FIG. 1 is a perspective view with a part in section showing a mounting state, FIG.
The figure is a cross-sectional view showing the dimensional relationship between the V groove and the optical fiber,
FIG. 3 is a perspective view, partly in section, showing an example of a mounting state when a conventional mounting body is used. 1 ... Optical component, 101 ... Waveguide, 104 ... Electrode, 105 ...
Evaporation pad (match mark), 2A …… substrate, 201 ・ 202 ……
V groove, 203 ... Window, 204 ... Reference mark, 4 ... Input side optical fiber, 5 ... Output side optical fiber.

Claims (3)

[Claims] 1. An input-side optical fiber and an output-side optical fiber whose end faces are opposed to each other with a space between them, and an output-side optical fiber which is provided between them and which performs some processing on a signal from the input-side optical fiber. In an optical mounting body in which an optical component for outputting to a fiber is mounted on a substrate, a waveguide is provided on the lower surface of the optical component, and the waveguide is provided at positions on both sides of the waveguide so as to slightly project from the lower surface of the optical component. And a contact portion that contacts the upper surface of the substrate, and the substrate is provided with a groove having a V-shaped cross section for holding the optical fibers on the input side and the output side, respectively. Is
The V-shaped groove is provided at at least two places on one side of the waveguide and at least one place on the other side of the waveguide, and the V-shaped groove is provided from the lower surface of the optical component to the contact portion and the substrate. The distance to the contact surface of the optical component and the distance from the lower surface of the optical component to the center of the waveguide to support the center of the optical fiber at a distance from the surface of the substrate. And an optical component mounting body in which the angles of the vertices are set. 2. A reference mark formed by crossing V-shaped grooves in a cross shape is formed on each surface of the substrate that contacts the contact portion on the bottom surface of the optical component. The distance in plan view between the center line of the V-shaped groove supporting the fiber and the center line of the waveguide and the center of the contact portion is equal to the distance in plan view. An optical component mounting body according to claim 1, wherein: 3. A region recessed from this surface is provided on the upper surface of the substrate in a range excluding a range in contact with a contact portion of the optical component and facing an electrode of the optical component. The optical component mounting body according to claim 1.