JP2000193846A - Connection method of optical waveguide to optical fiber, and optical waveguide module to be formed using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide module which is capable of unifying the total loss of a connection set of an optical waveguide to an optical fiber as much as possible, compact in size, and low in cost. SOLUTION: An optical fiber array 12 is connected to the emission side of a waveguide chip 11 in which the optical transmission loss of continuously provided optical waveguides is increased from the continuously provided center side to the continuously provided end side. The waveguide chip 11 and the optical fiber array 12 are curved in the direction orthogonal to the arranging direction of an optical output waveguide 6 and an optical fiber 7, and both continuously provided optical output waveguides 6 and continuously provided optical fibers 7 are continuously provided so that the axial deviation in the direction orthogonal to the continuous arrangement relative to both continuous provided ends is increased toward the center side. Connection end faces 8, 9 of the optical output waveguides 6 to the corresponding optical fibers 7 are opposite to each other so that the axial deviation in the direction orthogonal to the continuous arrangement is increased toward the continuous arrangement center side to collectively connect the optical output waveguides 6 to the corresponding optical fibers 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting an optical fiber and an optical fiber used for optical communication and the like, and an optical waveguide module formed by using the method.

[0002]

2. Description of the Related Art At present, in the field of optical communication, a flat optical waveguide circuit (PLC; Pl) in which a plurality of optical waveguides are juxtaposed on silicon and quartz wafers from the viewpoint of cost reduction and high integration.
anere Light-wave Circuit)
Is being put to practical use. Optical waveguide components such as PLC
When the (waveguide chip) is used for optical communication, an optical fiber array in which a plurality of optical fibers are accurately arranged in parallel is connected to an optical waveguide component and used as an optical waveguide module.

FIG. 6 shows a configuration of a 16-branch optical splitter as an example of an optical waveguide circuit formed on an optical waveguide component. The slab waveguide 13 is connected to the output side of the optical input waveguide 2, and 16 optical output waveguides 6 are connected to the output side of the slab waveguide 13.

In this split optical splitter, the light incident from the optical input waveguide 2 spreads in the slab waveguide 13 and enters each optical output waveguide 6.
Has a light intensity distribution, whereby the light intensity incident on the light output waveguide 6 and propagating therefrom tends to decrease from the juxtaposed center to the juxtaposed end. In other words, the optical waveguide component having the optical waveguide circuit shown in the drawing has the optical output waveguide 6 with the position parallel to the central side of the optical output waveguide 6 toward the both ends. Each of the optical output waveguides 6 has a port a, a port b
When the port a is expressed in order from the port a to the port p such as a port, the light transmission loss of each of the ports a to p is as shown in FIG. 7, for example.

That is, as is apparent from FIG. 1, in this 16-branch optical splitter, (8 to
Compared to the light transmission loss of the h port and the i port (9th port), the light transmission loss of the a port and the p port at
It is about 3 dB larger.

FIG. 8 shows a configuration of a 32-branch array waveguide type diffraction grating as another example of an optical waveguide circuit formed on an optical waveguide component.
The input side slab waveguide 3 is connected to the output side of the 32 parallel optical input waveguides 2, and a plurality of side by side arrayed waveguides 4 are connected to the output side of the input side slab waveguide 3. The output side slab waveguide 5 is connected to the output side of the plurality of arrayed waveguides 4, and 32 parallel output optical waveguides 6 are connected to the output side of the output side slab waveguide 5. It is formed.

[0007] The arrayed waveguide 4 propagates light derived from the input side slab waveguide 3 and has different lengths from each other. The array waveguide 4 is
Usually, a large number of such waveguides are provided, for example, 100. In FIG. 1, the number of arrayed waveguides 4 is simply shown for simplification of the figure.

A transmission-side optical fiber is connected to the optical input waveguide 2 so that wavelength-division multiplexed light is introduced into the optical input waveguide 2, and is introduced into the input-side slab waveguide 3 through the optical input waveguide 2. The emitted light is spread by the diffraction effect, enters each of the plurality of arrayed waveguides 4, and propagates through each of the arrayed waveguides 4. The light propagating through each array waveguide 4 reaches the output side slab waveguide 5 and is further condensed and output to the optical output waveguide 6, but the lengths of the array waveguides 4 are different from each other. Therefore, after the light propagates through each of the arrayed waveguides 4, the phase of each light is shifted, and the wavefront of the converged light is tilted in accordance with the amount of the shift, and the angle of inclination is determined by the tilt angle. The light converging positions are different from each other, and by forming the light output waveguide 6 at that position, light with different wavelengths can be output from different light output waveguides 6 for each wavelength.

Further, when light is incident on the output side slab waveguide 5 from the array waveguide 4, the diffraction effect differs depending on the direction in which the light is diffracted, and the intensity of the light differs. Similarly to the branch optical splitter, the intensity of light output from each optical output waveguide 6 tends to decrease from the central side of the juxtaposition to the end side of the juxtaposition.

Therefore, in the above-mentioned arrayed waveguide type diffraction grating, if the port numbers of the respective optical output waveguides 6 are (1) to (32) in order from the upper side in FIG.
The wavelength dependence of the light transmission loss of (32) is as shown in FIG. 9, and also in the arrayed waveguide type diffraction grating, the light transmission loss is changed from the central side of the optical output waveguide 6 to the parallel end. It gets bigger toward the side. The difference between the maximum value of the minimum peak value of the light transmission loss (the peak value of the light transmission loss at the ports (16) and (17)) and the minimum value (the peak value of the light transmission loss at the ports (1) and (32)). May be, for example, 3 dB to 4 dB.

[0011]

In the case where an optical waveguide module having a plurality of optical waveguides as described above is used for optical communication, for example, the optical waveguide module connected to each of the plurality of optical output waveguides 6 may be used. It is required that the intensity of the light output from the fiber be uniform, in other words, that there be no difference in light transmission loss between ports constituting the optical waveguide module.

However, as described above, optical waveguide components such as a branch optical splitter and an arrayed waveguide type diffraction grating are:
The light intensity output from the juxtaposed optical output waveguides 6 decreases from the juxtaposed center to the juxtaposed end, and the difference in light transmission loss between the ports in the optical waveguide component is reduced. Since the center side and the side of the juxtaposed end may be as high as 3 dB to 4 dB, if the optical waveguide component is simply connected to the optical fiber to form the optical waveguide module, the above requirement can be met. Can not.

Therefore, conventionally, by using an attenuator or the like to suppress the transmission characteristic of the light output from the optical output waveguide 6 on the central side, the total of the optical waveguide and the optical fiber in the optical waveguide module is reduced. Although the difference between the maximum value and the minimum value of the loss (loss of the light transmission loss of the optical waveguide plus the connection loss between the optical waveguide and the optical fiber) was reduced, as described above, when an attenuator or the like is used, This leads to an increase in the size and cost of the optical waveguide module, which is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. A first object of the present invention is to provide three or more optical waveguides juxtaposed to an optical waveguide component and an optical fiber array. By providing a method for connecting an optical waveguide and an optical fiber, the total loss between the optical waveguide and the optical fiber can be made as uniform as possible when the three or more optical fibers are collectively optically connected. A second object of the present invention is to provide an optical waveguide module in which the total loss difference of the connection group is small, and which is small and inexpensive by using such a method for connecting an optical waveguide and an optical fiber. Is to do.

[0015]

In order to achieve the above-mentioned object, the present invention has the following structure to solve the problem. That is, the first invention of a method for connecting an optical waveguide and an optical fiber includes a method in which three or more optical waveguides juxtaposed in an optical waveguide component and three or more optical fibers juxtaposed in an optical fiber array are packaged together. A method of connecting an optical waveguide and an optical fiber for optical connection, wherein at least one side of the side-by-side optical waveguide and the side-by-side optical fiber is axially shifted in a direction perpendicular to the side of the side-by-side direction toward the center of the side-by-side direction. The connection ends of the optical waveguides and the corresponding optical fibers are opposed to each other so that the axial deviation in the juxtaposed orthogonal direction increases toward the center of the juxtaposition. This is a means for solving the problem with a configuration in which the optical waveguide and the corresponding optical fiber are collectively optically connected.

According to a second aspect of the present invention, there is provided a method for connecting an optical waveguide and an optical fiber, wherein at least one of the optical waveguide component and the optical fiber array includes an optical waveguide or an optical fiber array. By bending in a direction perpendicular to the direction, at least one side of the juxtaposed optical waveguide and the juxtaposed optical fiber is juxtaposed so that the axial deviation in the juxtaposed orthogonal direction to the juxtaposed ends increases toward the juxtaposed center. This configuration is a means of solving the problem.

Further, a third invention of a method for connecting an optical waveguide to an optical fiber is a method for connecting three or more optical waveguides juxtaposed to an optical waveguide component and three or more optical fibers juxtaposed to an optical fiber array. The optical waveguide and the optical fiber are connected collectively, and at least one of the parallel spacing of the connection end faces of the optical waveguides and the parallel spacing of the connection end faces of the optical fibers is not uniform. Then, the optical waveguides are opposed to each other so that the amount of deviation between the position of the connection end surface of the optical waveguide and the position of the corresponding connection end surface of the optical fiber becomes larger toward the center of the juxtaposition of the optical waveguide and the optical fiber. This is a means for solving the problem with a configuration in which the optical path and the corresponding optical fiber are collectively optically connected.

Further, a first invention of the optical waveguide module is an optical waveguide module formed by using any one of the first to third inventions of the method for connecting the optical waveguide and the optical fiber, The optical waveguide components are formed so that the optical transmission loss of the optical waveguide increases as the juxtaposition position with respect to the optical waveguide on the central side toward the both ends increases. When the total value of the connection loss between the optical fiber and the corresponding optical fiber is defined as the total loss of the connection pair of the optical waveguide and the optical fiber, the difference between the maximum value and the minimum value of the total loss of the connection pair is the optical waveguide. The structure is formed to be smaller than the difference between the maximum value and the minimum value of the light transmission loss of the present invention.

Further, in the second invention of the optical waveguide module, in addition to the configuration of the first invention, the difference between the maximum value and the minimum value of the total loss of the connection set of the optical waveguide and the optical fiber is substantially zero. With this configuration, the means to solve the problem is used.

In the method for connecting an optical waveguide and an optical fiber according to the present invention having the above-described structure, first, at least one side of the side-by-side optical waveguide and the side-by-side optical fiber has a parallel axis shift in a direction perpendicular to the both ends. The juxtaposition may be such that the juxtaposition increases as it approaches the installation center side, or at least one of the juxtaposition intervals of the connection end faces between the optical waveguides and the juxtaposition intervals of the connection end faces between the optical fibers may be formed non-uniformly. Thereafter, the connection end faces of the optical waveguide and the corresponding optical fiber are arranged side by side and face each other so that the displacement becomes larger toward the center side, and the optical waveguide and the corresponding optical fiber are collectively optically connected. I do.

Incidentally, examples of the optical waveguide component having three or more optical waveguides arranged side by side include a branch optical splitter and an arrayed waveguide type diffraction grating. In these optical waveguide components, the optical waveguide component is used. The optical transmission loss of the optical waveguide is increased as the juxtaposed position approaches the both end sides with respect to the optical waveguide on the central side of the juxtaposition.

Therefore, in connecting these optical waveguide components and the optical fiber array, as described above, the displacement between the optical waveguide and the optical fiber corresponding to the optical waveguide is caused by the central difference between the optical waveguide and the optical fiber. In the present invention, in which the optical waveguide and the optical fiber are collectively connected by facing each other so as to become larger toward the side, the value obtained by adding the connection loss between the optical waveguide and the corresponding optical fiber to the light transmission loss of the optical waveguide. Is the total loss of the connection set of the optical waveguide and the optical fiber, the difference between the maximum value and the minimum value of the total loss of the connection set is the difference between the maximum value and the minimum value of the light transmission loss of the optical waveguide. Can also be reduced.

When the optical fiber and the optical waveguide face each other, the relative position between the optical waveguide and the optical fiber to be connected to each other cancels out the difference in light transmission loss due to the difference in the juxtaposed position of the optical waveguide. In order to obtain an appropriate value, an optical waveguide juxtaposition position juxtaposed to the optical waveguide component and an optical fiber juxtaposition position juxtaposed to the optical fiber array are formed.
By performing the above connection, the difference between the maximum value and the minimum value of the total loss of the connection set of the optical waveguide and the optical fiber can be made substantially zero.

Therefore, unlike the related art, there is no need to interpose an attenuator or the like, and it is possible to reduce the size and cost of an optical waveguide module formed by connecting an optical waveguide component and an optical fiber array. It becomes possible and the above-mentioned problem is solved.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same parts as those in the conventional example, and the duplicate description thereof will be omitted. FIG. 1 is a perspective view showing an embodiment of an optical waveguide module formed by using the method for connecting an optical waveguide and an optical fiber according to the present invention. The optical waveguide module shown in FIG. 1 is formed by connecting an optical fiber array 12 to one end of a waveguide chip 11 and connecting an optical fiber fixing component 18 to the other end.

The waveguide chip 11 forms the waveguide pattern of the 16-branch optical splitter shown in FIG.
A glass plate 15 is provided on the upper side of the optical input waveguide 2 and the optical output waveguide 6 of the 16-branch optical splitter.

The optical fiber fixing component 18 inserts and fixes one optical fiber 17 for inputting light into one V-groove (not shown) formed in the optical fiber aligner 24. An optical fiber holding member 26 for holding the optical fiber 17 is provided on the front surface side.
Are optically connected to the optical input waveguide 2 formed on the waveguide chip 11.

The optical fiber array 12 has sixteen V-grooves (not shown in FIG. 1) formed in the optical fiber arrangement tool 14.
Each optical fiber 7 for optical output is inserted and fixed one by one, and an optical fiber holding member 16 for holding the optical fiber 7 is provided on the surface side of the optical fiber arrangement tool 14, and each optical fiber 7 is formed. Are optically connected to the respective optical output waveguides 6 formed on the waveguide chip 11.

The connection end face of the optical fiber 17 is polished together with the connection end face 31 of the optical fiber fixing part 18, and similarly, the connection end face of the optical fiber 7 is polished together with the connection end face 29 of the optical fiber array 12. The connection end faces of the optical input waveguide 2 and the optical output waveguide 6 are polished together with the connection end faces 30 and 28 of the waveguide chip 11.
Then, the connection end face 31 of the optical fiber fixing component 18 and the connection end face 30 of the waveguide chip 11 are fixed with an adhesive, and the connection end face 28 of the waveguide chip 11 and the connection end face 29 of the optical fiber array 12 are fixed with an adhesive. Fixed.

A feature of this embodiment is that 16 optical output waveguides 6 arranged in parallel with the waveguide chip 11 and 16 optical fibers 7 arranged in parallel with the optical fiber array 12 are connected. The method is that the waveguide chip 11 is formed by connecting by the following specific connection method.

That is, both the juxtaposed optical output waveguide 6 and the juxtaposed optical fiber 7 are juxtaposed such that the axial deviation in the juxtaposed orthogonal direction with respect to the juxtaposed ends increases toward the juxtaposed center. Thereafter, the connection ends 8 and 9 of the optical output waveguides 6 and the corresponding optical fibers 7 are opposed to each other so that the axial deviation in the juxtaposed orthogonal direction increases toward the center of the juxtaposition. Optical fiber 7 corresponding to waveguide 6
And are collectively optically connected.

In this embodiment, as shown in FIG. 2, the waveguide chip 11 and the optical fiber array 12 are connected to the optical output waveguide 6 or the optical fiber 7 in the Y direction orthogonal to the arrangement direction (X direction in the figure). In addition, it is curved in an arc shape,
Both the juxtaposed optical output waveguides 6 and juxtaposed optical fibers 7 are juxtaposed so that the axial deviation in the juxtaposed orthogonal direction with respect to the juxtaposed ends increases toward the juxtaposed center. The waveguide chip 11 is curved so as to have a convex shape on the upper side of the figure,
The optical fiber array 12 is curved so as to have a downwardly convex shape.

Waveguide chip 11 and optical fiber array 12
Is formed in this manner, in the present embodiment, as described above, the connection end faces 8, 9 between the optical output waveguide 6 and the corresponding optical fiber 7 are arranged side by side toward the central side. The optical output waveguide 6 and the corresponding optical fiber 7 are collectively optically connected so as to face each other so as to increase the axial deviation.

By connecting the waveguide chip 11 and the optical fiber array 12 by such a connection method to form an optical waveguide module, the optical waveguide module of the present embodiment has the following characteristics. . That is, the value obtained by adding the light transmission loss of the optical output waveguide 6 of the optical waveguide module to the connection loss between the optical output waveguide 6 and the corresponding optical fiber 7 is determined as the connection between the optical output waveguide 6 and the optical fiber 7. When the total loss of the pair is set, the difference between the maximum value and the minimum value of the total loss of the connection set is smaller than the difference (3 dB) between the maximum value and the minimum value of the light transmission loss of the optical output waveguide 6. Have been.

More specifically, as described above, the light output waveguides 6 of the 16-branch optical splitter of the waveguide chip 11 are sequentially arranged from the left side (rear side) of FIG. , A port to p port, the amount of axial deviation between the connection end face 8 of each optical output waveguide 6 of each of the ports a to p and the connection end face 9 of the corresponding optical fiber 7 is represented by a characteristic line B in FIG. In the vicinity of the center ports h and j, the amount of the axial deviation is about 4.25 μm.

The connection loss between each optical output waveguide 6 of each of the ports a to p and the corresponding optical fiber 7 is as shown by a characteristic line C in FIG. Note that the characteristic line C is a result of a simulation based on the characteristic line B, with the axis deviation coefficient between the optical output waveguide 6 and the optical fiber 7 being 0.17 which is a general value. The connection loss between the optical output waveguide 6 and the optical fiber 7 near j is about 3 dB.

On the other hand, as described above, the light transmission loss of each optical output waveguide 6 of each of the ports a to p is, as shown by the characteristic line A in FIG. Since the light transmission loss of the light output waveguide 6 increases as the juxtaposed position moves toward both ends, the difference between the maximum value and the minimum value of the light transmission loss is about 3 dB. The total loss of the connection set between the optical output waveguide 6 and the optical fiber 7 is as shown by a characteristic line D in FIG.

That is, as shown by a characteristic line D in FIG.
The difference between the maximum value and the minimum value of the total loss of each connection group is
0.1 dB or less (almost zero), and the optical output waveguide 6
Is much smaller than 3 dB which is the difference between the maximum value and the minimum value of the light transmission loss of the optical transmission loss.

According to the present embodiment, as described above, the light transmission loss of the light output waveguide 6 becomes larger as the juxtaposition position becomes closer to both ends with respect to the light output waveguides 6 arranged side by side. A waveguide chip 11 having a 16-branch optical splitter;
When the optical fiber array 12 is connected, both the juxtaposed optical output waveguide 6 and the juxtaposed optical fiber 7 are arranged such that the axial displacement in the juxtaposed orthogonal direction with respect to the juxtaposed ends increases toward the juxtaposed center. The axial displacement between the optical output waveguide 6 and the optical fiber 7 that are arranged side by side and connected to each other in the direction perpendicular to the juxtaposition becomes larger toward the center of the juxtaposition of the optical output waveguide 6 and the optical fiber 7. Optical output waveguide 6 and optical fiber 7
Are connected to face each other, the difference between the maximum value and the minimum value of the total loss of the connection set of the optical output waveguide 6 and the optical fiber 7 is determined by the maximum value and the minimum value of the light transmission loss of the optical output waveguide 6. Can be set to a value smaller than the difference.

In particular, in this embodiment, when the optical fiber 7 and the optical output waveguide 6 are opposed to each other, the relative position between the optical output waveguide 6 and the optical fiber 7 that are to be connected to each other is determined by the optical waveguide. The waveguide chip 1 has an appropriate value so as to offset the difference in light transmission loss due to the difference in the juxtaposed positions.
The optical output waveguide 6 and the optical fiber are formed by forming the juxtaposed position of the optical output waveguide 6 juxtaposed to the optical fiber array 1 and the juxtaposition position of the optical fiber 7 juxtaposed to the optical fiber array 12. The difference between the maximum value and the minimum value of the total loss of the connection set with No. 7 can be made substantially zero.

Therefore, according to the present embodiment, the optical waveguide module can be formed without an intervening attenuator or the like as in the prior art, so that a small-sized and low-cost optical waveguide module can be obtained.

According to this embodiment, the waveguide chip 11 and the optical fiber array 12 are curved in an arc shape in a direction perpendicular to the direction in which the optical output waveguides 6 or the optical fibers 7 are arranged. Both the connection end face 8 of the side-by-side optical output waveguide 6 and the connection end face 9 of the side-by-side optical fiber 7 are designed so that the axial deviation in the side-by-side orthogonal direction with respect to the side-by-side ends increases toward the center of the side-by-side arrangement. In addition, both the connection end face 8 of the side-by-side optical output waveguide 6 and the connection end face 9 of the side-by-side optical fiber 7 can very easily adjust the amount of axial misalignment with respect to both side-by-side directions. Such an excellent optical waveguide module can be manufactured very easily.

The present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, in the above-described embodiment, both the juxtaposed optical output waveguides 6 and the juxtaposed optical fibers 7 are so arranged that the axial deviation in the juxtaposed orthogonal direction with respect to the respective juxtaposed ends increases toward the juxtaposed center. Although one of the juxtaposed optical output waveguide 6 and the juxtaposed optical fiber 7 is juxtaposed, the axial deviation in the juxtaposed orthogonal direction with respect to the juxtaposed ends increases toward the center of the juxtaposition. You may.

Also in this case, the connection end faces 8, 9 of the optical output waveguide 6 and the corresponding optical fiber 7 are opposed to each other so that the axial deviation in the juxtaposed orthogonal direction becomes larger toward the juxtaposition center. Optical output waveguide 6 and corresponding optical fiber 7
Are collectively optically connected, the same effect as in the above embodiment can be obtained.

The connection end face 8 of the side-by-side optical output waveguide 6 and the connection end face 9 of the side-by-side optical fiber 7 are arranged such that the axial deviation in the side-by-side orthogonal direction with respect to the side-by-side ends increases toward the center side. For example, as shown in FIG. 4, at least one of the juxtaposed intervals of the juxtaposed intervals of the connecting end faces 8 of the optical output waveguides 6 and the juxtaposed intervals of the connecting end faces 9 of the optical fibers 7 is improper. The optical output waveguide 6 and the position of the connection end face 9 of the optical fiber 7 corresponding to the position of the connection end face 9 of the optical fiber 7 are later shifted by the center of juxtaposition of the optical output waveguide 6 and the optical fiber 7. The optical output waveguide 6 and the corresponding optical fiber 7 may be collectively optically connected so as to face each other so as to become larger toward the side.

In FIG. 4, the positions of the axes of the optical output waveguide and the optical fiber are shown as an optical output waveguide 6 and an optical fiber 7, respectively. The juxtaposed intervals on the connection end face 8 side are formed non-uniformly.

Further, in the above embodiment, the waveguide chip 11 and the optical fiber array 12 are curved to be opposite to each other in a direction orthogonal to the direction in which the optical output waveguides 6 or the optical fibers 7 are arranged. The bending directions of the waveguide chip 11 and the optical fiber array 12 may be the same, and the bending amounts may be different from each other. Also in this case, the connection end faces 8, 9 of the optical output waveguide 6 and the corresponding optical fiber 7 are opposed to each other so that the axial displacement in the juxtaposed orthogonal direction increases toward the juxtaposed center. If the optical output waveguide 6 and the corresponding optical fiber 7 are collectively optically connected, the same effect as in the above embodiment can be obtained.

Further, without bending the waveguide chip 11 or the optical fiber array 12, as shown in FIG. 5, the surface of the substrate 1 of the waveguide chip 11 is curved and the light output waveguide 6 is formed.
Are arranged in a curved line, or the optical fibers 7 are arranged in a curved line with the surface of the optical fiber arraying device 14 of the optical fiber array 12 being a curved surface. At least one side is arranged in such a manner that the axial misalignment with respect to the juxtaposed both ends becomes larger toward the center of the juxtaposition, and thereafter the connection end face between the optical output waveguide 6 and the corresponding optical fiber 7. The optical fibers 7 corresponding to the optical output waveguides 6 are opposed to each other so that the axial deviation in the direction perpendicular to the juxtaposition becomes larger toward the center of the juxtaposition.
May be collectively optically connected.

Further, the connection end surface 28 of the waveguide chip 11
Is a curved surface in which the central side of the optical output waveguide 6 is concave, or the connecting end surface 29 of the optical fiber array 12 is a curved surface in which the central side of the optical fiber 7 is concave. A gap is provided between the connection end face 8 on the central side of the optical fiber 7 and the connection end face 9 on the central side of the optical fiber 7 so as to correspond to the position of the connection end face 8 of the optical output waveguide 6. May be formed such that the amount of deviation from the position of the connection end face 9 increases toward the central side of the juxtaposition.

Further, by combining two or more of the above methods, the relative positions of the connection end faces 8 and 9 of the optical output waveguide 6 and the optical fiber 7 to be connected to each other become larger toward the center side. It may be shifted.

Then, in either case,
The amount of displacement of the connection end faces 8 and 9 when the optical output waveguide 6 and the optical fiber 7 face each other is determined in advance, and the optical output waveguide 6
By increasing the connection loss between the optical output waveguide 6 and the optical fiber 7 corresponding to the optical output waveguide 6 toward the central side of the juxtaposition of the optical output waveguide 6 and the optical fiber 7, the connection loss is increased as in the above embodiment. A waveguide chip 11 including a 16-branch optical splitter or the like in which the light transmission loss of the optical output waveguide 6 increases as the juxtaposed position moves toward both ends with respect to the central optical output waveguide 6, and an optical fiber array 12 and the difference between the maximum value and the minimum value of the total loss of the connection set of the optical output waveguide 6 and the optical fiber 7 is determined by calculating the difference between the maximum value and the minimum value of the optical transmission loss of the optical output waveguide 6. An optical waveguide module having a value smaller than the difference can be formed.

Further, in the above embodiment, the difference between the maximum value and the minimum value of the total loss of the connection set between the optical output waveguide 6 and the optical fiber 7 is set to 0.1 dB or less, and is set to a value close to zero. However, in the optical waveguide module of the present invention, the difference between the maximum value and the minimum value of the total loss of the connection set of the optical waveguide and the optical fiber is larger than the difference between the maximum value and the minimum value of the light transmission loss of the optical waveguide. The difference between the maximum value and the minimum value of the total loss of the connection set is, for example, 1.5.
It may be about dB.

Further, in the above embodiment, the waveguide chip 11 having the 16-branch optical splitter and the optical fiber array 12 are connected to form an optical waveguide module, but the waveguide chip 11 is not necessarily a 16-branch optical splitter. Is not necessarily provided, and may be provided with an optical splitter other than the 16-branch, or may be provided with, for example, an arrayed waveguide type diffraction grating other than the optical splitter.

[0054]

According to the connection method of the present invention, first, at least one side of the side-by-side optical waveguide and the side-by-side optical fiber has a larger axial deviation with respect to the side-by-side ends in the direction perpendicular to the side-by-side direction. In order to form a non-uniform arrangement of at least one of the juxtaposed interval between the connection end faces of the optical waveguides and the juxtaposed interval of the connection end faces between the optical fibers, it corresponds to the optical waveguide. The optical waveguides and the corresponding optical fibers can be collectively optically connected such that the connection end faces of the optical fibers are opposed to each other so that the displacement becomes larger as approaching the center side.

When such optical connection is made, the connection loss between the optical waveguide and the corresponding optical fiber can be increased toward the central side of the juxtaposition of the optical waveguide and the optical fiber.

For this reason, for example, as in the case of a branching optical splitter or an arrayed waveguide type diffraction grating, the light transmission loss of the optical waveguide increases as the juxtaposed position approaches the optical waveguide on the juxtaposed central side of the optical waveguide components. By connecting an optical fiber array using the above connection method to an optical waveguide component formed so as to increase the connection loss between the optical waveguide and the corresponding optical fiber to the optical transmission loss of the optical waveguide. The difference between the maximum value and the minimum value of the sum (the total loss of the connection set) can be made smaller than the difference between the maximum value and the minimum value of the light transmission loss of the optical waveguide.

In the connection method of the present invention, when the optical fiber and the optical waveguide face each other, the relative position between the optical waveguide and the optical fiber to be connected to each other depends on the difference in the juxtaposed positions of the optical waveguide. An optical waveguide juxtaposition position juxtaposed to the optical waveguide component and an optical fiber juxtaposition position juxtaposed to the optical fiber array are formed so as to have an appropriate value to offset the difference in light transmission loss. Is performed, the difference between the maximum value and the minimum value of the total loss of the connection set between the optical waveguide and the optical fiber can be made substantially zero.

Therefore, by applying the connection method of the present invention, it is not necessary to interpose an attenuator or the like as in the prior art, and an optical waveguide module formed by connecting an optical waveguide component and an optical fiber array is formed. A reduction in size and cost can be achieved.

Further, as in the second invention of the method for connecting the optical waveguide and the optical fiber, at least one of the optical waveguide component and the optical fiber array is curved in a direction orthogonal to the arrangement direction of the optical waveguide or the optical fiber. Accordingly, if at least one side of the juxtaposed optical waveguide and the juxtaposed optical fiber is juxtaposed so that the axial deviation in the juxtaposed orthogonal direction with respect to the juxtaposed ends increases toward the juxtaposed center, the optical waveguide can be very easily formed. And the optical fiber can be juxtaposed in the above embodiment.

Further, according to the optical waveguide module of the present invention, since the optical waveguide module is formed by using the above connection method, the maximum value of the total loss of the connection set of the optical waveguide and the optical fiber is reduced as described above. The difference between the minimum value and the minimum value can be made zero, for example, and the difference between the maximum value and the minimum value of the light transmission loss of the optical waveguide can be made smaller. Are approximately equal, and a compact and low-cost optical waveguide module can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an optical waveguide module formed by using a method for connecting an optical waveguide and an optical fiber according to the present invention.

FIG. 2 is an explanatory view showing a connection end face (a) of a waveguide chip and a connection end face (b) of an optical fiber array in the optical waveguide module of the embodiment.

FIG. 3 is a diagram showing the optical transmission loss of each optical waveguide in the optical waveguide module of the embodiment, the amount of axial displacement of the connection end face between the optical waveguide and the optical fiber, the connection loss value between the optical waveguide and the optical fiber, and the optical waveguide. 6 is a graph showing a loss value obtained by adding a connection loss between the optical waveguide and a corresponding optical fiber to a transmission loss of the optical waveguide.

FIG. 4 is an explanatory view showing another embodiment of a method for connecting an optical waveguide and an optical fiber according to the present invention.

FIG. 5 is a waveguide chip connection end face in another embodiment of the method for connecting an optical waveguide and an optical fiber according to the present invention.
It is an explanatory view showing (a) and an optical fiber array connection end face (b).

FIG. 6 is an explanatory diagram showing a 16-branch optical splitter.

FIG. 7 is a graph showing an example of light transmission loss of each port in a 16-branch optical splitter.

FIG. 8 is an explanatory diagram showing an arrayed waveguide grating.

FIG. 9 is a graph showing an example of transmission loss characteristics of light output from each light output waveguide of the arrayed waveguide grating.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Optical input waveguide 3 Input side slab waveguide 4 Array waveguide 5 Output side slab waveguide 6 Optical output waveguide 7 Optical fiber 8, 9, 28, 29, 30 Connection end face 11 Waveguide chip 12 Optical fiber array 13 Slab waveguide 14, 24 Optical fiber arrangement device 15 Glass plate 16, 26 Optical fiber pressing member

Claims (5)

[Claims] A connection between an optical waveguide and an optical fiber for optically connecting three or more optical waveguides arranged in parallel to an optical waveguide component and three or more optical fibers arranged in parallel in an optical fiber array. A method, wherein at least one side of the juxtaposed optical waveguide and the juxtaposed optical fiber is juxtaposed so that the axial deviation in the juxtaposed orthogonal direction with respect to the juxtaposed ends increases toward the juxtaposed center side, and thereafter, The connection ends of the optical fiber and the corresponding optical fiber are opposed to each other so that the axial deviation in the orthogonal direction becomes larger toward the center toward the central portion. A connection method between an optical waveguide and an optical fiber, wherein the connection is performed. 2. A side-by-side optical waveguide and at least one side of a side-by-side optical fiber are juxtaposed by curving at least one of the optical waveguide component and the optical fiber array in a direction orthogonal to the arrangement direction of the optical waveguide or the optical fiber. 2. The method for connecting an optical waveguide and an optical fiber according to claim 1, wherein the optical waveguide and the optical fiber are arranged side by side so that the axial deviation in the direction perpendicular to the both ends increases toward the center of the side. 3. An optical waveguide and optical fiber connection, which collectively optically connect three or more optical waveguides juxtaposed in an optical waveguide component and three or more optical fibers juxtaposed in an optical fiber array. A method, wherein at least one of the juxtaposed spacing of the connection end faces of the optical waveguides and the juxtaposed spacing of the connection end faces of the optical fibers are formed unevenly, and then correspond to the position of the connection end face of the optical waveguide. The optical waveguide and the corresponding optical fiber are collectively optically connected by facing each other so that the amount of deviation from the position of the connection end face of the optical fiber becomes larger toward the central side of the juxtaposition of the optical waveguide and the optical fiber. Characteristic connection method between optical waveguide and optical fiber. 4. An optical waveguide module formed by using the method for connecting an optical waveguide to an optical fiber according to claim 1, wherein the optical waveguide component is arranged side by side. The light transmission loss of the optical waveguide is increased as the juxtaposed position with respect to the optical waveguide toward both ends, and the light transmission loss of the optical waveguide is connected to the optical fiber and the corresponding optical fiber. When the value obtained by adding the losses is the total loss of the connection set of the optical waveguide and the optical fiber, the difference between the maximum value and the minimum value of the total loss of the connection set is the maximum value of the light transmission loss of the optical waveguide. An optical waveguide module formed to be smaller than a difference from a minimum value. 5. The optical waveguide module according to claim 4, wherein the difference between the maximum value and the minimum value of the total loss of the connection set of the optical waveguide and the optical fiber is substantially zero.