JP2004334057A - Optical waveguide and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide such that the formation state of a coupling end surface 6 of the optical waveguide 1 can be inspected without detaching the optical waveguide 1 from a fixing tool 70, and to provide a method for manufacturing the optical waveguide. <P>SOLUTION: This optical waveguide 1 has a core 4 and a clad 3 and is constituted by providing a mark 5 for confirming formation angles θ1 and θ2 of the coupling end surface 6 and a formation position L from a direction wherein the coupling end surface 6 can be viewed on the coupling end surface 6 where an end part 40 of the core 4 is present. The mark 5 consists of a plurality of parallel linear mark elements 50, whose exposure-side end parts 51 are sequentially shifted in position toward the inner side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical waveguide having a core and a clad, for example, by visually observing the number of marks formed on the end face of the optical waveguide with a microscope, so that the state of formation of the end face can be inspected. The present invention relates to a structure of an optical waveguide and a manufacturing method thereof.
[0002]
[Prior art]
As the conventional optical waveguide 100, there is one as shown in FIG. FIG. 17A is a plan view of the optical waveguide 100, and FIG. 17B is a side view thereof. In FIG. 17, 101 is a substrate made of quartz or silicon, etc., 102d and 102u are claddings provided on the substrate 101, 103 is a core provided in the substrates 102d and 102u for confining and propagating light. , 103a are branch portions provided on the core 103, and 104 is a cover glass. In this figure, reference numeral 105 denotes a fiber array having an optical fiber 105b, which is joined to a coupling end face 106 of the optical waveguide 100 via a filter 105a.
[0003]
Next, a process of manufacturing the optical waveguide 100 will be described with reference to FIG. The steps of manufacturing the optical waveguide 100 include a step of forming a chip of the optical waveguide 100, a step of polishing the coupling end face 106 of the optical waveguide 100, and a step of inspecting the state of formation of the polished coupling end face 106. Consists of
[0004]
First, a step of forming a chip of the optical waveguide 100 will be described. As shown in FIG. 18, first, a flat substrate 101 made of quartz, silicon, or the like is prepared, and a UV curable resin 102a is dropped on the upper surface thereof (FIG. 18A). Irradiation forms a lower clad 102d having a core recess 102b (FIG. 18B). Then, the core concave portion 102b formed by the lower clad 102d is filled with a core material having a higher refractive index than the clad 102d to form the core 103 (FIG. 18C). Next, the cladding resin 102a is dropped on the core 103 and pressed by the cover glass 104 to form the upper clad 102u in the same manner (FIG. 18D). Thus, the optical waveguide 100 is obtained.
[0005]
Then, in the step of polishing the optical waveguide 100, polishing is performed so that the coupling end face 106 of the optical waveguide 100 forms a predetermined angle and the coupling end face 106 is formed at a predetermined position near the branch portion 103a. More specifically, the angle θ2 in FIG. 17B is polished to about 82 degrees in order to suppress the influence on the core due to the reflection of light generated at the coupling end face 106, and the coupling efficiency with the fiber array 105 is reduced. In order to improve the shape, the angle θ1 in FIG. Also, in order to minimize the coupling loss of the reflected light that changes depending on the distance between the branch portion 103a and the filter 105a, the coupling end face 106 is similarly formed at a position suitable for the core pattern with respect to the cutting position in the direction perpendicular to the optical axis. Polish so that This polishing operation is performed using a polishing apparatus, and is performed by attaching the optical waveguide 100 to a jig and rotating the polishing plate and the coupling end surface 106 in contact.
[0006]
FIG. 19 shows the configuration of this jig. 19A is a plan view of the jig 70, FIG. 19B is a front view thereof, and FIG. 19C is a cross-sectional view taken along line MM of FIG. 19B. In FIG. 19, reference numeral 70 denotes a disk-shaped jig attached to the polishing apparatus, and 71 denotes a concave portion for attaching the optical waveguide 100. Then, in the step of polishing the coupling end face 106 of the optical waveguide 100, first, as shown in FIG. 19C, the coupling end face 106 of the optical waveguide 100 is mounted so as to protrude into the concave portion 71 of the jig 70, The bonded end face 106 is directed downward to contact a polishing plate (not shown) of the polishing apparatus. Then, by rotating the jig 70, the coupling end face 106 of the optical waveguide 100 is polished.
[0007]
The step of inspecting the state of formation of the coupling end face 106 is performed by bringing the objective lens 8 of the microscope close to the coupling end face 106. Specifically, the angle θ1 between the side face 107 and the coupling end face 106 in FIG. 17B, the angle θ2 between the upper surface 108u or the bottom surface 108d and the coupling end surface 106 is actually measured, and the cutting position of the branch portion 103a is inspected from its core pattern or the like.
[0008]
However, while holding the optical waveguide 100 in the jig 70, the objective lens 8 of the microscope indicated by a broken line is brought closer to the inside than the outer peripheral portion of the jig 70 as shown in FIGS. Cannot focus on the microscope. For this reason, conventionally, as shown in FIG. 20, the optical waveguide 100 is removed from the jig 70, and the optical waveguide 100 is placed on the microscope stage, and the formation state of the coupling end face 106 is inspected one by one. I had to.
[0009]
On the other hand, as a solution to such a problem, there is one disclosed in Patent Document 1 below.
[0010]
[Patent Document 1]
JP-A-2002-214468
[0011]
The optical waveguide disclosed in Patent Document 1 is formed by depositing a plurality of marks perpendicular to the optical axis direction on a substrate and observing the degree of removal of the marks in a polishing process. By doing so, it is possible to confirm the formation state of the coupling end face without actually measuring the value of θ1.
[0012]
[Problems to be solved by the invention]
However, in the optical waveguide described in Patent Literature 1, since the mark can be visually recognized only in a plan view, only the angle θ1 in a plan view in FIG. 17A can be inspected. In addition, when trying to observe the mark with the jig attached, the objective lens of the microscope cannot be closer than the outer periphery of the jig. The state of formation must be examined.
[0013]
In view of the above, the present invention has been made in view of the above problems, and provides an optical waveguide capable of inspecting the state of formation of an end face of the optical waveguide without removing the optical waveguide from a jig, and a method of manufacturing the optical waveguide. It is intended for that purpose.
[0014]
[Means for Solving the Problems]
That is, in order to solve the above-mentioned problems, an optical waveguide according to the present invention includes a core and a clad. In the optical waveguide, an angle of the end face from the direction in which the end face is visible to the end face where the end of the core exists. And a mark for confirming the position.
[0015]
With this configuration, since the mark is provided so as to be visible from the coupling end face, when polishing the coupling end face, the objective lens of the microscope can be brought close to the end face while the optical waveguide is mounted on the jig. In addition, the angle and the position of the end face can be inspected without removing the optical waveguide from the jig as in the related art.
[0016]
Further, in such a configuration of the optical waveguide, when the side of the mark exposed from the end face of the optical waveguide is an exposed end, the exposed end may be provided at a different position along the light traveling direction. . As such a method, for example, when a mark is formed by a linear mark element, a method in which the exposed end of the mark element is sequentially inclined stepwise in the depth direction can be considered.
[0017]
With this configuration, for example, if the coupling end face cannot be formed perpendicularly to the side surface in plan view, the number of mark elements exposed from the coupling end face changes, and the state of the mark is only observed with a microscope. Thus, the state of formation of the connection end face can be easily grasped.
[0018]
Further, in such a configuration, marks may be provided on both sides of the core.
[0019]
With this configuration, the joint end face can be formed uniformly and accurately at a predetermined angle with the core as a center. In addition, as a form of this arrangement, a method of providing the same shape across the core or a method of providing the same shape across the core can be considered.
[0020]
In addition, when such a mark is provided, the mark may be composed of a plurality of linear mark elements, and the form of the mark element may be changed every predetermined number. As a form of changing the mark element, for example, changing the thickness of the linear mark for each predetermined number is conceivable.
[0021]
With this configuration, for example, when counting the number of exposed marks, if the form of the mark is changed every predetermined number, the number can be easily counted.
[0022]
Further, an end of the mark opposite to the end on the exposed side may be provided so as to be aligned on a line orthogonal to the light traveling direction.
[0023]
With this configuration, the intensity of light incident from the end opposite to the exposed end can be made uniform, and uniform light suitable for inspection can be output from the exposed end. Become like
[0024]
In such a configuration, a plurality of blocks having a step along the traveling direction of light may be provided, and a step in each block may be provided so as to be different from a step in another block.
[0025]
According to this configuration, when recognizing the cutting state of the mark element, the dimension of the cutting position can be precisely grasped by grasping the exposure state of the step. That is, for example, as shown in FIG. 14, blocks composed of thick linear mark elements are sequentially provided from the core to the side, and the exposed ends of the line elements in each block are arranged along the light traveling direction. To provide a step corresponding to the line width. In such a configuration, the rough cutting position of the end face can be grasped by grasping the cutting state of the mark element having a large step, and further by grasping the cutting state of the thin mark element. Also, it becomes possible to grasp a cutting position having a small size.
[0026]
Further, this mark may be provided on the same layer as the layer having the core.
According to this structure, in the process of manufacturing the optical waveguide, the mark can be formed simultaneously with the step of forming the core on the lower clad layer, and the mark can be easily formed.
[0027]
Furthermore, when forming a mark in this way, the mark may be provided with the same material as the core.
[0028]
According to this structure, in the step of forming the mark, for example, a core concave portion and a mark concave portion are formed on the lower cladding layer, and the core material is filled on these concave portions. Can be simultaneously formed. Thereby, the mark can be formed more easily.
[0029]
Further, when manufacturing an optical waveguide having a core and a clad, on the clad, a concave portion for forming a core and a concave portion for forming a mark capable of confirming a forming angle or a forming position of a coupling end face are simultaneously provided, These concave portions are filled with a core material, and a clad is provided thereon.
[0030]
According to this structure, since the core and the mark can be provided at the same time, the relative positional accuracy of each of the stampers can be increased in the pressing step.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
Hereinafter, the configuration of the optical waveguide 1 according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of an optical waveguide 1 according to the first embodiment, FIG. 2 is a front view thereof, and FIG. 3 is a side view thereof. In FIGS. 1 to 3, 2d is a substrate made of quartz or silicon or the like, 3 is a clad composed of a lower clad layer 3d and an upper clad layer 3u, 4 is a core provided on the lower clad layer 3d, and 2u is this clad layer. 3 shows a cover glass provided on the upper surface of the cover 3. As is well known, the refractive index of the core 4 is made higher than the refractive index of the cladding 3 so that light is confined in the core 4 and propagated. Although the optical waveguide 1 is provided with the branch portion 41 in the core 4, the present invention can be applied to all optical waveguides that require precision in the state of formation at the end of the core.
[0032]
In such a case, in the present embodiment, the mark 5 is provided so that the formation state of the coupling end surface 6 (see FIG. 2) where the end portion 40 of the core 4 exists can be inspected. The mark 5 allows the inspection of the formation angle θ1 of the coupling end face 6 in FIG. 1, the angle θ2 of the coupling end face 6 in FIG. 3, and the formation position of the coupling end face 6 with respect to the optical axis direction. By inspecting the exposure pattern of the mark 5 exposed from 6, the angles θ1, θ2 and the formation position can be inspected.
[0033]
For this reason, the mark 5 is configured by providing a plurality of linear mark elements 50 that allow the exposed end 51 located on the exposed side to be visible from the coupling end face 6 side. The mark elements 50 each have a rectangular cross section, and have the same length in parallel with the optical axis direction. Further, the exposed side end portion 51 of the mark element 50 is positioned so as to be stepped so that the exposure pattern of the mark 5 can be changed depending on the formation angles θ1 and θ2 and the formation position of the coupling end surface 6. That is, the mark element 50 is provided so that the required cutting position CL is substantially at the center thereof, and as shown in FIG. 1, is symmetrical about a line parallel to the optical axis passing through the end 40 of the core 4. Of the mark elements 50, the side closer to the core 4 is provided on the back side from the coupling end face 6, and the exposed side ends 51 are sequentially coupled as the mark elements 50 move away from the core 4 in a direction perpendicular to the optical axis. It is located on the end face 6 side.
[0034]
FIG. 4 is an enlarged view of the X part of FIG. As shown in FIG. 4, the mark element 50 has the largest width W3 of the mark element 50 at the required cutting position CL and changes its exposed form so that the required cutting position CL can be smoothly recognized in the inspection process. ing. Further, the line width of the other mark elements 50 is relatively reduced, and the line width is increased at predetermined intervals so that the number of exposed mark elements 50 can be easily counted. The width, interval, and angle of these mark elements 50 are set as follows.
[0035]
First, CL is a required cutting position in plan view, L1 is the distance between the exposed side end 51 provided closest to the coupling end face 6 (+ side) and CL, and L2 is the rearmost (− side) from the coupling end face 6. ), The distance between the exposed side end 51 of the mark element 50 and the CL is
[0036]
L1> Design allowable range length in + direction
L2>-Design allowable range length in the direction
[0037]
Set so that As a result, the mark 5 can be exposed from the joint end face 6 with respect to a deviation from the required cutting position CL within the design allowable range length.
[0038]
When the length of the line segment of the mark element 50 is L3,
[0039]
L1 ≦ L3
L2 ≦ L3
[0040]
And Thus, when the coupling end face 6 is formed near the required cutting position CL, the number of mark elements 50 exposed from the coupling end face 6 can be increased as much as possible.
Further, the width of the thinnest mark element 50 is W1, the distance between the mark elements 50 is W4, the step of the exposed end 51 of each mark element 50 is L4, and the allowable design angle in one direction with respect to the formation angle θ1 is D. In the case of inspecting only the positional accuracy, L4 is set to the minimum resolution required for the inspection, and in the case of inspecting the angle θ1,
[0041]
D ≧ θ1
tan θ1 = L4 / (W1 + W4)
[0042]
L4, W1, and W4 are set so that If each parameter is set so as to satisfy all of these relationships, the angle θ1 and the cutting position L can be inspected simultaneously by inspecting only the exposure pattern of the mark 5.
[0043]
Next, a method for manufacturing the optical waveguide 1 will be described with reference to FIGS. First, when manufacturing the optical waveguide 1, as shown in FIG. 5, a planar substrate 2d made of quartz, silicon, or the like is prepared, and a UV curable resin 3a is dropped on the upper surface thereof (see FIG. )) The lower clad layer 3d having the core recess 30 and the mark recess 31 is formed by pressing with a stamper (not shown) and irradiating ultraviolet rays (FIG. 5B). Then, the core concave portion 30 and the mark concave portion 31 formed on the lower cladding layer 3d are filled with a core material having a high refractive index to form the core 4 and the mark 5 simultaneously (FIG. 5C). Next, a cladding resin 3a is dropped on the core 4 and the mark 5, and pressed with a cover glass 2u to similarly form an upper cladding layer 3u (FIG. 5D). Thus, the optical waveguide 1 is obtained.
[0044]
Next, the coupling end face 6 of the optical waveguide 1 is polished. As shown in FIG. 6, the optical waveguide 1 is mounted in the concave portion 71 of the jig 70 such that the coupling end face 6 protrudes upward. Then, the joint end face 6 is polished so that the joint end face 6 faces downward and comes into contact with a polishing plate of a polishing device (not shown). In this polishing, polishing is performed so that the angle θ1 between the traveling direction of light and the coupling end surface 6 in FIG. 1 is 90 degrees, and the angle θ2 between the coupling end surface 6 and the upper surface in FIG. It is formed so as to have a slightly smaller predetermined inclination angle (for example, 82 degrees). Further, polishing is performed so that the distance from the end of the branch portion 41 becomes a predetermined distance.
[0045]
Then, in this polishing step, after performing polishing for a predetermined time, the jig 70 is removed from the polishing apparatus, and the jig 70 is placed so that the coupling end face 6 faces upward and faces the objective lens 8 of the microscope. With the optical waveguide 1 attached to the jig 70, the formation state of the coupling end face 6 is inspected from above. This inspection process is performed by visual inspection using a microscope, but in this embodiment, it is not necessary to make the inspection by bringing the objective lens 8 close to the outer peripheral portion of the jig 70, and FIG. The inspection can be performed by bringing the objective lens 8 directly close to the coupling end face 6 as shown in c). FIGS. 7 and 8 show views of the exposure pattern of the mark 5 visually observed in this inspection process.
[0046]
FIG. 7 shows an exposure pattern of a mark when cutting is performed by changing θ1 and L in FIG. 1, and shows cutting states in lines CL, A1, and A2, respectively.
[0047]
As shown by CL in FIG. 1, when the coupling end face 6 is formed at a regular formation position perpendicular to the light traveling direction and at 90 degrees to the light traveling direction having the regular formation angle θ1. As shown in FIG. 7A, the same number of marks 5 are exposed at positions symmetrical about the core 4 in the left-right direction. In addition, as shown by A1 in FIG. 1, when the polishing is performed in a state where the angle is shifted from the normal angle by a predetermined angle (θ1 <90 degrees), as shown in FIG. A different number of lines will be exposed at asymmetric positions. Further, as shown by A2 in FIG. 1, even when θ1 = 90 degrees, if the polishing is performed at a position different from the regular position CL, the number of marks 5 exposed from the joint end face 6 increases or decreases. For this reason, the number of exposed mark elements 50 in the allowable design range is indicated to the inspector in advance, and the polishing operation is repeated so that the number of mark elements 50 is exposed symmetrically about the core 4 in the left-right direction.
[0048]
FIG. 8 shows an exposure pattern of the mark when the angle θ2 in FIG. 3 is changed.
[0049]
When the coupling end face 6 is formed at the regular angle θ2 in FIG. 3, the mark element 50 is exposed in a predetermined rectangular shape as shown in FIG. When the coupling end face 6 is formed at an angle larger than the regular angle θ2, as shown in FIG. 8B, the exposed mark element 50 becomes smaller than the vertical dimension of the regular mark element 50, and Approach shape. On the other hand, when the coupling end face 6 is formed at an angle smaller than the regular angle, as shown in FIG. 8C, the vertical dimension of the exposed mark element 50 is longer than the vertical dimension of the regular mark element 50. . For this reason, the length of the exposed end portion at the regular angle θ2 is shown to the inspector in advance, and the polishing operation is repeated so as to have substantially the same length.
[0050]
As described above, according to the first embodiment, the formation state of the coupling end surface 6 from the direction in which the coupling end surface 6 where the end of the core 4 exists can be viewed, that is, the forming angles θ1, θ2, and the forming position L Are formed, the formation state of the coupling end face 6 can be inspected while the optical waveguide 1 is attached to the jig 70.
[0051]
Further, in this embodiment, since the linear mark elements 50 are provided in parallel with the optical axis, the formation angle θ1 and the formation position L can be determined only by counting the number of mark elements 50 exposed from the coupling end face 6. You will be able to understand.
[0052]
Further, in this embodiment, the core concave portion 30 and the mark concave portion 31 are provided on the upper surface of the lower cladding layer 3d, and the mark 5 is simultaneously formed in the step of forming the core 4, so that the mark 5 is simplified. It can be formed, and the relative positional accuracy between the core 4 and the mark 5 can be increased.
[0053]
At this time, the mark 5 is formed by filling the mark concave portion 31 with the same material as that of the core 4, so that the process of forming the mark 5 can be further simplified.
[0054]
(Second embodiment)
Next, the configuration of the optical waveguide 1a according to the second embodiment of the present invention will be described. FIG. 9 shows a plan view of an optical waveguide 1a according to the second embodiment. In this figure, components denoted by the same reference numerals as those of the first embodiment are configured in the same manner as those of the first embodiment, and are manufactured through the same steps as those of the first embodiment, unless otherwise specified. You.
[0055]
In this embodiment, the mark 5a is composed of a plurality of parallel linear mark elements 50 having the same line segment length, and the widths W1, W2, W3 of the mark elements 50 and the distance between the mark elements 50. W4, the step L4 at the exposed end 51 of the mark element 50, and the like are set in the same manner as in the first embodiment. However, in the second embodiment, the mark elements 50 are provided to be inclined in the same direction with the core 4 interposed therebetween.
[0056]
Also in the second embodiment, the formation angle θ1 and the formation position L of the coupling end face 6 can be inspected only by counting the number of the mark elements 50 exposed from the coupling end face 6, and similarly, By inspecting the cross-sectional shape of the exposed mark element 50, the formation angle θ2 can be inspected.
[0057]
(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 10 shows a plan view of an optical waveguide 1b according to the third embodiment. In this figure, components denoted by the same reference numerals as those of the first embodiment are configured in the same manner as those of the first embodiment, and are manufactured through the same steps as those of the first embodiment, unless otherwise specified. You.
[0058]
In the third embodiment, the mark element 50b does not extend the opposite end 52b to the coupling end surface 6 on the side of the ports 40a, 40b of the core 4 in FIG. The ends 52b are aligned on a line that is substantially perpendicular. With this configuration, when the pattern of the mark 5 is inspected with a microscope by transmitting light from the microscope stage and transmitted through the microscope stage, the transmitted light irradiated from the microscope stage is the end opposite to the exposed end 51 of the mark element 50b. For the mark element 50b which is uniformly weakened by the clad before reaching the part and is not exposed from the coupling end face 6 side, the mark element 50b is further removed by the cladding existing between the exposed end 51 and the coupling end face 6. The transmitted light is weakened. On the other hand, as for the mark element 50 b exposed from the coupling end face 6, since no cladding exists on the tip side of the exposed side end 51, the transmitted light is not weakened and the exposed side end 51 is separated from the coupling end face 6. The transmitted light is observed with a relatively larger light amount than the unexposed mark element 50b. This makes it possible to make a difference in the amount of transmitted light between the mark element 50b exposed from the coupling end face 6 and the mark element 50b that is not exposed, so that the presence or absence of the exposure of the mark element 50b can be easily confirmed. it can.
[0059]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 11 shows a plan view of an optical waveguide 1c according to the fourth embodiment. Also in this figure, unless otherwise specified, those denoted by the same reference numerals as those of the first embodiment are configured in the same manner as the first embodiment, and are manufactured through the same steps as those of the first embodiment. Is done.
[0060]
In this embodiment, the mark 5c is constituted by a plurality of parallel linear mark elements 50, and the widths W1, W2, W3 of the mark elements 50c, the distance W4 between the mark elements 50c, the exposure of the mark elements 50c. The step L4 of the side end 51c and the like are set in the same manner as in the first embodiment. However, in this embodiment, the mark element 50c is provided so as to be line-symmetric with respect to the required cutting position CL. Specifically, the length of the mark element 50c is set to be the same in the front-rear direction with the required cutting position CL as the central axis, and the length in the front-rear direction is sequentially increased in the width direction.
[0061]
According to this configuration, in the step of extracting the optical waveguide 1 of one chip from the wafer, the mark exposure pattern of the chip piece on the tip side cut off is compared with the exposure pattern of the mark on the optical waveguide 1 side, thereby making the die easier. The condition such as the thickness of the blade can be checked.
[0062]
(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. FIGS. 12 and 13 are plan views of two types of optical waveguides 1d and 1e according to the fifth embodiment. In FIGS. 12 and 13, components denoted by the same reference numerals as those in the first embodiment are configured in the same manner as in the first embodiment, and the same processes as those in the first embodiment, unless otherwise specified. It is manufactured through
[0063]
In this embodiment, the marks 5d and 5e are configured so that the linear mark elements 50d and 50e are brought into close contact with each other to form a block, and furthermore, the exposed side ends 51d of the contacted mark elements 50d and 50e are formed. 51e is provided so that it may be stepped in the front-back direction. In this case, since the exposed patterns of the marks 5d and 5e on the joint end face 6 are block-shaped, the number of linear mark elements 50d and 50e cannot be counted, and the exposed size of the block must be measured. Since the area of the portion exposed from the end face becomes large, it becomes easy to find the exposed portion. Further, since the marks 5d and 5e are formed into blocks, the marks 5 can be easily manufactured. On the other hand, with respect to the problem that the size of the mark 5 has to be measured, this problem can be solved by setting the size to a level that can be visually recognized.
[0064]
When a block-shaped mark is provided, as shown in FIG. 13, the exposed end 51e and the opposite end 52e are aligned on a line orthogonal to the optical axis direction, as in the third embodiment. May be provided. With this configuration, as in the third embodiment, when inspecting an exposure pattern with a microscope, it is possible to eliminate unevenness in irradiation light.
[0065]
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. FIG. 14 shows a plan view of the sixth embodiment. Also in this figure, unless otherwise specified, those denoted by the same reference numerals as those of the first embodiment are configured in the same manner as the first embodiment, and are manufactured through the same steps as those of the first embodiment. Is done.
[0066]
In this embodiment, a plurality of blocks 5f1, 5f2, 5f3 in which linear mark elements 50f1, 50f2, 50f3 having the same length in the front-rear direction with the required cutting position CL as the central axis are provided. The linear mark elements 50f1, 50f2, and 50f3 are provided so as to have different line widths from different blocks 5f1, 5f2, and 5f3. Further, the linear mark elements 50f1, 50f2, and 50f3 in the blocks 5f1, 5f2, and 5f3 are provided. Both ends are provided with steps so as to be longer by the line width of the adjacent mark elements 50f1, 50f2, 50f3.
[0067]
FIG. 15 is an enlarged view of the mark 5f. FIG. 15 shows that when the step formation limit of the mark elements 50f1, 50f2, and 50f3 is 1 micrometer, the step of the first block 5f1 is 1 micrometer, the step of the second block 5f2 is 2 micrometer, The configuration when three blocks 5f3 are provided as 3 micrometers is shown.
[0068]
In such a case, for example, when the joint end face 6 is cut along the Z line shown in FIG. 15 and the joint end face 6 is formed there, as in the fifth embodiment, the mark 5f exposed on the joint end face 6 is formed. By measuring the size of the mark or by visually observing the cut state of the mark 5 from the upper surface of the optical waveguide 1, only the linear mark element 500 on the leftmost side of the first block 5f1 is not exposed to the coupling end face 6. I understand. For this reason, it can be seen that there is a shift of 0.5 μm or more, which is half of 1 μm, which is one side of the cutting request position CL, and the second 501 linear mark element 50f1 of this block 5f1 is connected. Since it is exposed on the end face 6, it can be understood that the range of the deviation is in the range of 0.5 micrometers to 1.5 micrometers. Also, when looking at the exposed pattern of the joint end face 6 in the second block 5f2, the leftmost linear mark element 502 in this block 5f2 is not exposed to the joint end face 6, and the second 503 linear mark element Since the mark element 50f2 is exposed on the coupling end face 6, it can be seen that the range of the deviation is in the range of 1.0 μm to 3.0 μm. Furthermore, when the exposure pattern of the coupling end face 6 in the third block 5f3 is viewed, the linear mark element 504 on the leftmost end protrudes to the coupling end face 6, so that the range of displacement is 0 to 1.5 micron. It turns out that it is meters. Then, if these AND conditions are taken, it can be seen that the range of the deviation is in the range of 1.0 to 1.5 micrometers.
[0069]
As described above, the mark 5f of this embodiment forms the blocks 5f1, 5f2, 5f3 by the plurality of linear mark elements 50f1, 50f2, 50f3, and the mark elements 50f1, 50f2 in the respective blocks 5f1, 5f2, 5f3. , 50f3 are made different from the step sizes of the mark elements 50f1, 50f2, 50f3 of the other blocks 5f1, 5f2, 5f3, so that it is possible to measure even a minute size exceeding the manufacturing limit of the steps. become.
[0070]
Note that the present invention is implemented by the above-described embodiments, but the present invention is not limited to these embodiments.
[0071]
For example, in the above embodiment, the description has been given of the case where the marks 5, 5b to f are provided on one of the coupling end surfaces 6, but as shown in FIG. A mark 5g may be provided so that the formation angle or formation position of the joint end face 6 can be confirmed from a visible direction.
[0072]
Further, in the above embodiment, the mark 5 is formed from the same material as the core material, but the mark 5 may be formed from a different material. At this time, the mark 5 may be colored so as to have a color different from that of the clad 3 in order to easily distinguish the mark 5 from the clad 3, or the mark 5 may be formed of a colorless and transparent core material having a different refractive index and a different material. It may be formed.
[0073]
Further, in the above-described embodiment, the mark 5 is provided on the same layer as the lower clad layer 3d having the core 4, but the mark 5 may be provided on a different layer. At this time, as long as the mark 5 can be visually recognized from the coupling end face 6 side, the cross-sectional shape of the mark 5 is not limited to a rectangular shape, and may be a circular shape, an elliptical shape, a thick line shape, or the like. Various shapes can be adopted.
[0074]
In the above embodiment, in the sixth embodiment shown in FIG. 15, the widths of the linear mark elements 50f1, 50f2, and 50f3 are 1 micrometer, 2 micrometers, and 3 micrometers, respectively. However, the pitch width can be set to 1 μm, 1.5 μm, 2 μm, etc., corresponding to the required accuracy.
[0075]
【The invention's effect】
According to the present invention, the end face where the end of the core is present is provided with a mark for confirming the formation angle or the formation position of the end face from a direction in which the end face can be visually recognized, so that the optical waveguide is removed from the jig. The state of formation of the end face can be inspected without the need.
[Brief description of the drawings]
FIG. 1 is a plan view of an optical waveguide according to a first embodiment of the present invention.
FIG. 2 is a front view of FIG.
FIG. 3 is a side view of FIG. 1;
FIG. 4 shows an arrangement state of mark elements in FIG. 1;
FIG. 5 shows a manufacturing process of the optical waveguide according to the first embodiment of the present invention.
FIG. 6 shows a jig mounted on the polishing apparatus according to the present invention.
FIG. 7 illustrates an exposure pattern of a mark corresponding to a formation state in a front view.
FIG. 8 shows an exposure mode of a mark corresponding to a formation state in a side view.
FIG. 9 is a plan view of an optical waveguide according to a second embodiment.
FIG. 10 is a plan view of an optical waveguide according to a third embodiment.
FIG. 11 is a plan view of an optical waveguide according to a fourth embodiment.
FIG. 12 is a plan view of an optical waveguide according to a fifth embodiment.
FIG. 13 is a plan view of another optical waveguide according to the fifth embodiment.
FIG. 14 is a plan view of an optical waveguide according to a sixth embodiment.
FIG. 15 shows an enlarged view of the mark in FIG. 14 (a) and its cut state (b).
FIG. 16 is a plan view of an optical waveguide in which marks are provided on both coupling end faces.
FIG. 17 shows a configuration of a conventional optical waveguide.
FIG. 18 is a diagram showing a conventional optical waveguide manufacturing process.
FIG. 19 shows a conventional state of inspection of a joint end face.
FIG. 20 shows a state of an inspection using a conventional microscope.
[Explanation of symbols]
1, 1b-1f ... optical waveguide
3 ... Clad
3d: Lower cladding layer
4 ・ ・ ・ Core
5 ... mark
6 ・ ・ ・ Connection end face
40 ... End of core
50, 50b to 50f ... mark element
51, 50b to 50f... Exposed end of mark element
70 ・ ・ ・ Jig

Claims (9)

In an optical waveguide having a core and a clad, a mark is provided on an end face where an end of the core exists, from a direction in which the end face can be visually recognized, so that a formation angle or a formation position of the end face can be confirmed. An optical waveguide. 2. The optical waveguide according to claim 1, wherein the mark has a side that can be exposed from the end face as an exposed side end, and the exposed side end is provided at a different position along an optical axis direction. 3. 2. The optical waveguide according to claim 1, wherein the marks are provided on both sides of the core. The optical waveguide according to claim 1, wherein the mark is configured by a plurality of linear mark elements, and the mark elements are provided by changing the form for each predetermined number. The optical waveguide according to claim 1, wherein the mark is provided such that an end opposite to the exposed end is aligned in a direction orthogonal to an optical axis. The light guide according to claim 2, wherein the mark is constituted by a plurality of blocks having steps along the optical axis direction, and a step size in each block is provided so as to be different from a step size in another block. Wave path. The optical waveguide according to claim 1, wherein the mark is provided on the same layer as a layer having a core. 2. The optical waveguide according to claim 1, wherein the mark is formed of the same material as the core. In a method of manufacturing an optical waveguide having a core and a clad, a concave portion for forming a core on the clad and a concave portion for forming a mark capable of confirming a forming angle or a forming position of an end face where an end of the core exists. Simultaneously, a step of filling these recesses with a core material, and a step of providing a cladding layer on the filled core material.

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