JPH01319708A - Method of aligning optical waveguide and optical parts used therein - Google Patents

Abstract

PURPOSE:To decrease the number of measurements and to provide the method of aligning an optical waveguide which can efficiently execute aligning operations with a decreased number of measurements and the optical parts used in said method by executing the aligning operation in the transverse direction after executing registration in the thickness direction by the slab waveguide provided near the intrinsic optical waveguide. CONSTITUTION:The slab waveguide 46 having the refractive index higher than the refractive index of a glass substrate 40 and the refractive index lower than the refractive index in the core part of the intrinsic three-dimensional optical waveguide 42 is formed on the glass substrate 40 at the same level as the level of the optical waveguide 42. The registration with optical fibers 14a, 14b,... in the thickness direction of the substrate is first executed by using the slab waveguide 46 at the time of optically coupling the optical parts 10 having such structure and the optical fibers 14a, 14b,.... The optical fibers 14a, 14c,... are then moved toward arrows M, N direction in the horizontal direction of the substrate from this position and the rough alignment is executed by using the intrinsic optical waveguide 42. The optical parts and the fibers are then coupled by executing the precise aligning in the final.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an alignment technique for aligning the optical axes of optical parts such as optical branching/coupling devices and optical waveguides such as optical fibers. be.

More specifically, the present invention uses a slab waveguide as one optical component near the original optical waveguide to be optically coupled, and performs alignment in the thickness direction using the slab waveguide. The present invention relates to an optical waveguide alignment method and optical components used therein.

[Prior Art] For example, as shown in FIG. 3, an optical waveguide 12 of an optical component 10
optical fibers 14a, 14b for each end 12a, 12b, 12c, respectively.

When optically coupling 14C, it is necessary to align the optical axes of the optical waveguides of both optical components.

Such alignment work is performed using a device as shown in FIG. The optical component 10 is mounted on a fixed stage 16. One optical fiber 14a is fixed within block 1B and attached to fine movement stage 20. the other 2
The optical fibers 14b and 14c are similarly fixed to the block 22 and attached to the fine movement stage 24.

Both fine movement stages 20.24 move in the vertical direction (Y direction),
The left-right direction (X direction) and the perspective direction with respect to the optical component 1o (
X direction), and the movement thereof is controlled by a stage control device 26. Optical fiber 14 on the input side
A light source 28 is connected to the end of a, and an optical power meter 30 is connected to the output side optical fiber 14b.

First, each end 12a, . . . , 12c of the optical waveguide 12 formed in the optical component IO is visually observed using a microscope or the like.
and the optical fiber 14a,...

The optical waveguide (core) of 14c is aligned within the range of the outer diameter of the optical fiber. Fine movement stage 2 centering on that position
0.24 in the X direction and Y direction within a predetermined range (search area), the light emitted from the optical fiber 14a enters the optical waveguide end 12a, and the light emitted from the optical fiber 14a enters the optical waveguide end 12a.
Rough alignment is performed to find the position where the light is emitted from the optical fiber 14b and enters the optical fiber 14b.

For example, if the coarse centering search area is set to about 100 μm x 100 μm, then 1
The fine movement stage 20° 24 is automatically finely moved by the stage control device 26 at a pitch of about 0 μm to perform coarse alignment to maximize the optical output, and then fine alignment to obtain optimal optical coupling near that position. I do.

[Problem to be solved by the invention] In order to find the position where the optical output is maximum during coarse alignment, it is necessary to: ■ move the optical fiber on the input side, ■ move the optical fiber on the output side, ■ change the output of the output side optical fiber. It is necessary to repeat the four steps of measurement and evaluation of output measurement values at each measurement point within the grid-like search area. It depends on the output evaluation method, but
In order to find the optimal position of the human output optical fiber where the optical output of the output side optical fiber shows the maximum value within the search area, the number of measurements is (number of optical fiber movement points in the input side search area) x (
The number of optical fiber moving points within the output side search area) is enormous.

For example, in the case of the search method described in the prior art, the number of moving points is 100 on each of the incident side and the exit side, so the total number of measurements reaches 10,000. For this reason, there is a drawback that the alignment work takes a very long time. This makes it difficult to expand the search area, so a high level of accuracy is required for initial positioning by visual inspection using a microscope, etc.
There were also problems such as the need for skill to perform the work.

The purpose of the present invention is to provide an optical waveguide alignment method devised to eliminate the above-mentioned drawbacks of the prior art, to reduce the number of measurements, and to perform alignment work efficiently and quickly, and to provide an optical component used therein. It is about providing.

[Means for Solving the Problems] The present invention, which can solve the above-mentioned technical problems, uses a slab waveguide as one optical component in the vicinity of the original optical waveguide to be optically coupled. By performing alignment work limited to the thickness direction using a slab waveguide, we can indirectly align the optical axis of the original optical waveguide and the optical axis of the other optical component in the vertical direction. This is an alignment technique that then moves in the width direction to the original optical waveguide, performs alignment work limited to the width direction, and finally aligns with the target optical waveguide.

Here, the slab waveguide refers to a two-dimensional waveguide that has a width sufficiently wider than the width of the original optical waveguide that will ultimately be optically coupled.
This slab waveguide for alignment is formed at the same level of the substrate as the original optical waveguide to be optically coupled. In other words, the original optical waveguide is located within the plane in which the slab waveguide is formed. Therefore, when creating a buried optical waveguide by performing two-step ion exchange on a glass substrate, a slab waveguide may be formed around it, or a slab waveguide may be formed around it to differentiate it from the original optical waveguide. It may also be a structure in which slab waveguides are arranged in parallel.

In the present invention, the other optical component may be any optical component including an optical fiber, an optical fiber array, or the like.

[Function] According to the present invention, the optical axes of the optical waveguides are aligned using a two-dimensional slab waveguide for alignment of one optical component, so that the light incident on the slab waveguide is It emits light with a spread distribution in the width direction as well. Therefore, when setting the initial position to start coarse alignment by visual inspection using a microscope, etc., the alignment accuracy in the width direction of the slab waveguide does not need to be as precise as it is for three-dimensional optical waveguides. Even if there is some deviation in the width direction, sufficient alignment in the thickness direction can be achieved.

In the present invention, the position where the optical output is maximum can be detected by searching on a straight line in both directions orthogonal to the optical axis, so the number of measurement points is significantly reduced compared to the conventional search using grid-like movement. I will do it.

[Example] FIG. 1 shows an example of an optical component 10 used in the present invention. This optical component 10 has a structure in which an original optical waveguide 42 to be optically coupled and a slab waveguide 46 for alignment are formed on the same level on a glass substrate 40. The optical waveguide 42 has two
This is an embedded type vehicle-mode two-branch optical waveguide fabricated by step ion exchange. In this embodiment, an optical fiber is used as the other optical component to be aligned. Optical waveguide 42
An optical fiber 14a is located facing the input end 42a of the optical waveguide 42, and an optical fiber 14b is located at the output ends 42b and 42c of the optical waveguide 42, respectively.

14C is facing. The end of optical fiber 14a is fixed to block 18, and optical fiber 14b.

14C are arranged and fixed on the block 22 in accordance with the output end pinch of the waveguide 42. These are similar to those shown in FIG.

The optical component 10 described above is manufactured by performing first-stage ion exchange using Tlo, C3", Ag", etc. on a glass substrate 40 in a predetermined waveguide pattern, and then performing second-stage ion exchange. The loss of the optical waveguide 42 is reduced by embedding the optical waveguide 42 inside. By this second stage ion exchange, a three-dimensional optical waveguide 42 with a refractive index higher than that of the glass substrate 40 is formed around the intended original three-dimensional optical waveguide 42.
A slab waveguide (with a refractive index lower than the core refractive index of
A two-dimensional optical waveguide) 46 is formed.

In addition, as shown in FIG. 2, the optical component 10 used in the present invention includes an original optical waveguide 42 to be optically coupled, and an alignment slab waveguide 48 adjacent to the original optical waveguide 42 on a glass substrate 40. It may also be a structure formed in the following manner.

In any case, in the optical components used in the present invention, the original optical waveguide to be optically coupled is located in the slab waveguide or on the extension of the slab waveguide, in other words, they are formed at the same level of the substrate. Any structure may be used as long as the width of the slab waveguide is sufficiently wider than the original optical waveguide to which optical coupling is to be performed.

The method of the present invention can be carried out using a conventionally used alignment device as shown in FIG. Therefore, an optical component 10 and an optical fiber 14a having a structure as shown in FIG.
, . . . , 14c will be explained as an example. First, when optically coupling the optical fiber 14a and the optical fibers 14b and 14c to the two-branch optical waveguide 42, the slab waveguide 46 is used to connect the optical fiber 14a to the two-branch optical waveguide 42, as shown by the imaginary line in FIG.
+..., 0 to align with 14c in the substrate thickness direction (Y direction) Then, from that position, optical fiber 14a
,..., 14C in the board horizontal direction (X direction) with arrow M,
Move as shown by N and use the original optical waveguide 42 to
Coarse alignment is performed in the direction, and finally fine alignment is performed to join.

The specific steps are as follows. The optical fiber 14a is fixed to the block 18 and attached to the fine movement stage 20. One end of the optical fiber 14a is connected to a light source 28. The optical fibers 14b and 14c are arranged and fixed on the block 22 at the output end pitch of the optical waveguide 42, and then attached to the fine movement stage 24. An optical power meter 30 is connected to the end of one selected optical fiber (for example, 14b). The optical component 10 provided with the optical waveguide 42 and the slab waveguide 46 is mounted on the fixed stage 16. At this time, optical component 1
0 so that the surface of the fine movement stage 20.24 and the X-direction movement axis of the fine movement stage 20.24 are parallel to each other.

Next, by visual observation using a microscope etc., the fine movement stage 20 is
．． 24 to bring the block 18 22 into close contact with the optical component 10, and each optical fiber +4a, . . . , 14
C and the end face of the slab waveguide 46 are aligned. in this case,
As shown in FIG. 1B, an optical waveguide 42 and a slab waveguide 46
Since the slab waveguide 46 is formed in contact with
The incident light also propagates to the slab waveguide on the side sandwiching the optical waveguide 42, but here, the core positions of the optical fibers 14a, 14b on the input side and output side are at the optical waveguide ends 42a, 42b.
Align it so that it is slightly shifted from the (+) side in the X-axis direction.

In order to emit the light incident on the slab waveguide 46 with a distribution spread in the width direction (X direction), the optical fiber 14a
, 14b do not need to sandwich the glass substrate 40 and face each other accurately.

From this state, the fine movement stage 20.24 is automatically finely moved by the stage control device 26 to perform positioning in the Y direction. First, in order to create a slight gap between the block 18.22 and the optical component 10, the fine movement stage 20.24 is moved in the X direction. Fine movement stage 20.24 centered on that position
is moved stepwise in the Y direction within the search area on a straight line as shown in FIG. Search for the location. The search area in this case is
For example, the range is set to 100 μm, which is the same as the region in the Y direction in the coarse alignment work according to the prior art, and step movement is performed within that range at a pitch of 10 μm. Measuring the optical output by alternately moving the input side optical fiber 14a and the output side optical fiber 14b,
Find the position where it has the maximum value.

Next, move the fine movement stage 20.2 to the position where the light output is maximum.
Move 4. Fine movement stage 20.2 in the X direction as it is
4 to oppose each optical fiber 14a, . . . , 14C near the respective end face 42a, .

A search area on a straight line in the X direction as shown in FIG. 6B is set around this position, and the fine movement stages 20 and 24 are moved step by step to roughen the steel core in the X direction. In this case, as in the Y direction, the search range is 100 μm, and the search pitch is 10
Find the position where the optical output shows the maximum value in μm. In this way, the optical waveguide is roughly aligned.

When coarse alignment is completed, an optical power make is also connected to the output side optical fiber 14c, and the fine movement stage is moved at a finer pitch to achieve precise alignment and coupling.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the configuration of the embodiments as described above. Various changes can be made to the optical waveguide substrate, waveguide pattern, formation state of the slab waveguide, search area during coarse alignment, search movement method, movement pinch, etc.

[Effects of the Invention] As described above, the present invention uses a slab waveguide formed in the vicinity of the original optical waveguide to be optically coupled to first perform indirect alignment in the thickness direction, and then perform the original alignment. Since this is a two-step alignment method that uses an optical waveguide to perform alignment in the width direction, it is possible to use a linear search method in each of the two directions, which greatly reduces the number of measurements required for alignment work. This has the effect of reducing work time. Incidentally, if a search area of 10 steps is set on each of the X side and Y side, the number of measurements would be 10,000 with the conventional technology because optical components such as optical fibers are moved alternately on the input side and the output side. However, in the present invention, it is only 200, which is simply calculated and reduced to 11,500.

This means that the search area can be expanded compared to the conventional technology, and the accuracy of initial position setting required for visual alignment during alignment work can be lowered, making it easier even for non-experts. It becomes possible to perform alignment work.

[Brief explanation of the drawing]

1 UjJA, B are a perspective view and an end view showing one embodiment of the optical component according to the present invention, FIGS. 2 A, B are a perspective view and an end view showing another embodiment of the optical component, and FIG. 3 A, B is a perspective view and an end view showing an example of a conventional optical component. Further, FIG. 4 is a configuration diagram of the alignment device, FIG. 5 is an explanatory diagram of a search area in the prior art, and FIG. 6A. B is an explanatory diagram showing a search area in the present invention. 10-... Optical component, 14a, 14b, 14cm--optical fiber, 40... Glass substrate, 42... Optical waveguide,
46.48...Slab waveguide. Patent applicant: Nippon Sheet Glass Co., Ltd. Agent: Shigeru Mi 1 Figure 1 i2゜

Claims (1)

[Claims] 1. In a method of aligning the optical axes of optical waveguides of optical components in two directions orthogonal to the optical axes, a slab is placed near the original optical waveguide to be optically coupled as one optical component. A device having a waveguide is used, the slab waveguide is used to perform alignment in the thickness direction, and then the optical waveguide is moved in the width direction to the original optical waveguide to perform alignment in the width direction. A method for aligning optical waveguides. 2. An optical component characterized in that an original optical waveguide to be optically coupled and a slab waveguide for alignment are formed on the same level of a glass substrate.