JP4144427B2 - Optical waveguide and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an optical waveguide comprising 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, the formation state 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]
  A conventional optical waveguide 100 as shown in FIG. 17 exists. 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 formed of quartz or silicon, 102d and 102u are clads provided on the substrate 101, and 103 is a core provided in the substrates 102d and 102u for confining and propagating light. 103a is a branch portion provided in 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 bonded to the coupling end face 106 of the optical waveguide 100 through a filter 105a.
[0003]
  Next, a process for 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 surface 106 of the optical waveguide 100, and a step of inspecting the formation state of the polished coupling end surface 106. Consists of.
[0004]
  First, a process for forming the chip of the optical waveguide 100 will be described. As shown in FIG. 18, first, a flat substrate 101 such as quartz or silicon is prepared, and a UV curable resin 102a is dropped on the upper surface (FIG. 18 (a)) and pressed by a stamper (not shown) to emit ultraviolet rays. By irradiation, a lower clad 102d having a core recess 102b is formed (FIG. 18B). Then, the core 103 is formed by filling the core recess 102b formed by the lower clad 102d with a core material having a refractive index higher than that of the clad 102d (FIG. 18C). Next, the clad resin 102a is dropped onto the core 103 and pressed by the cover glass 104 to similarly form the upper clad 102u (FIG. 18D). In this way, 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 surface 106 of the optical waveguide 100 forms a predetermined angle and the coupling end surface 106 is formed at a predetermined position in the vicinity of the branching portion 103a. Specifically, in order to suppress the influence on the core based on the reflection of light generated at the coupling end face 106, the angle θ2 in FIG. 17B is polished to about 82 degrees, and the coupling efficiency with the fiber array 105 is increased. In order to improve, the angle θ1 in FIG. Further, in order to minimize the coupling loss of the reflected light that varies depending on the distance between the branching 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 to make. 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 with each other.
[0006]
  The configuration of this jig is shown in FIG. 19A is a plan view of the jig 70, FIG. 19B is a front view thereof, and FIG. 19C is a sectional view taken along line MM in FIG. In FIG. 19, reference numeral 70 denotes a disk-like jig attached to the polishing apparatus, and 71 denotes a recess for attaching the optical waveguide 100. 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 protruded and attached to the recess 71 of the jig 70. The coupling end face 106 is faced down and brought into contact with a polishing plate (not shown) of the polishing apparatus. Then, the coupling end face 106 of the optical waveguide 100 is polished by rotating the jig 70.
[0007]
  The step of inspecting the formation state of the coupling end surface 106 is performed by bringing the objective lens 8 of the microscope close to the coupling end surface 106. Specifically, the angle θ1 between the side surface 107 and the coupling end surface 106 in FIG. In addition, the angle θ2 between the upper surface 108u or the bottom surface 108d and the coupling end surface 106 in FIG. 17B is measured, and the cutting position of the branching portion 103a is inspected from the core pattern or the like.
[0008]
  However, if the optical waveguide 100 is held on the jig 70, the objective lens 8 of the microscope indicated by the wavy 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. Therefore, 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, where the formation state of the coupling end face 106 is inspected one by one. I had to.
[0009]
  On the other hand, there exists a thing as shown in the following patent document 1 as what solves this subject.
[0010]
[Patent Document 1]
  JP 2002-214468 A
[0011]
  The optical waveguide disclosed in Patent Document 1 is formed by vapor-depositing a plurality of marks orthogonal to the optical axis direction on a substrate, and observes the degree of removal of the marks in the polishing process. By doing so, the formation state of the coupling end face can be confirmed without actually measuring the value of θ1.
[0012]
[Problems to be solved by the invention]
  However, in such an optical waveguide described in Patent Document 1, since the mark can be visually recognized only in a plan view, only the angle θ1 in the plan view in FIG. 17A can be inspected. Moreover, if you try to observe the mark while attached to the jig, you cannot bring the microscope objective lens closer to the outer periphery of the jig. The state of formation must be inspected.
[0013]
  Therefore, the present invention has been made paying attention to the above problems, and provides an optical waveguide that can inspect the formation state of the end face of the optical waveguide without removing it from the jig, and a method of manufacturing the optical waveguide. It is for the purpose.
[0014]
[Means for Solving the Problems]
  That is, the optical waveguide of the present invention is to solve the above problems,An angle (θ1) formed between the coupling end surface and the side surface of the optical waveguide in a plan view, and the coupling end surface and the optical waveguide in a side view, formed on the coupling end surface on the side where the core is exposed from the cladding. Formation angle (θ2) with the upper surface and formation position of the coupling end surfaceAn optical waveguide having a mark capable of confirmingBecauseThe mark is composed of a plurality of mark elements that are parallel to the optical axis of the core and embedded in a concave portion of the cladding, and an exposed cross-section by the coupling end surface forms a predetermined rectangular shape, The plurality of end portions on the coupling end surface side and the coupling end surface are arranged at different distances, and are formed on both sides with the optical axis in between.
[0015]
  With this configuration, since the mark is provided so as to be visible from the coupling end surface, when the coupling end surface is polished, the objective lens of the microscope can be brought close to the end surface while the optical waveguide is mounted on the jig. As in the prior art, the angle and position of the end face can be inspected without removing the optical waveguide from the jig. In addition, the distance from the exposed side end of the mark element to the coupling end surface is different, and the cross-section of the mark element is a predetermined rectangleShape andBecause the joint end faceSide andIf it cannot be formed at right angles, the number of mark elements exposed from the joint end face changes, and the formation state of the joint end face can be easily grasped just by looking at the state of the mark with a microscope. become.Further, in such a configuration, since the marks are arranged on both sides of the core, the coupling end surface can be formed at a predetermined angle uniformly and accurately around the core. In addition, as a form of this arrangement, a method of providing symmetry so as to sandwich the core, a method of providing the same form with the core interposed, and the like can be considered.
[0016]
  Further, in such a configuration, marks may be provided on both sides of the core.
[0017]
  If comprised in this way, it will become possible to form a joint end surface in a predetermined angle uniformly and accurately centering on a core. In addition, as a form of this arrangement, a method of providing symmetry so as to sandwich the core, a method of providing the same form with the core interposed, and the like can be considered.
[0018]
  Also, the end on the opposite side of this mark from the exposed endAlign in the direction perpendicular to the optical axis.
[0019]
  If comprised in this way, the intensity | strength of the light which injects from the edge part on the opposite side to an exposure side edge part can be made uniform, and the uniform light suitable for a test | inspection can be output from an exposure side edge part. It becomes like this.
[0020]
  Further, in such a configuration, a plurality of blocks having steps along the light traveling direction may be provided, and the step size in each block may be different from the step size in the other blocks.
[0021]
  If comprised in this way, when recognizing the cutting state of a mark element, it will become possible to grasp | ascertain now the dimension of a cutting position exactly by grasping | ascertaining the exposure state of a level | step difference. That is, for example, as shown in FIG. 14, blocks each including thick line-shaped mark elements are provided sequentially from the core toward the side, and the exposed end portions of the line elements in each block are arranged along the light traveling direction. A step corresponding to the line width is provided. When configured in this way, it is possible to grasp the cutting position of the rough end face 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 the cutting position having a small size.
[0022]
  Furthermore, when forming a mark in this way, the mark may be provided with the same material as the core.
[0023]
  If comprised in this way, in the step of forming a mark, for example, if a concave portion for a core and a concave portion for a mark are formed on the lower clad layer and the core material is filled on these concave portions, the mark and the core are formed. Can be formed simultaneously. Thereby, it becomes possible to form the mark more easily.
[0024]
  Moreover, it has a core and a clad, and on the coupling end surface on the side where the core is exposed from the clad,Formation angle (θ1) between the coupling end surface and the side surface of the optical waveguide in plan view, formation angle (θ2) between the coupling end surface and the top surface of the optical waveguide in side view, and formation position of the coupling end surfaceA method of manufacturing an optical waveguide having a mark that can be confirmed, comprising: forming a plurality of recesses in a clad parallel to the optical axis of a core; and filling the recess with a material for forming a mark element Forming a mark element whose exposed cross section by a predetermined coupling end face forms a rectangular shape, and the distance between the end of the mark element on the coupling end face side and the coupling end face is different,A plurality of mark elements are formed on both sides of the optical axis of the core.
[0025]
ThisWith this configuration, since the core and the mark can be provided at the same time, the relative positional accuracy of each can be increased in the stamper pressing process.The
[0026]
DETAILED DESCRIPTION OF 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 the optical waveguide 1 in the first embodiment, FIG. 2 is a front view thereof, and FIG. 3 is a side view thereof. 1 to 3, 2d is a substrate made of quartz or silicon, 3 is a clad formed 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 3. As is well known, the refractive index of the core 4 is made higher than the refractive index of the clad 3 so that light is confined in the core 4 and propagated. In addition, although this optical waveguide 1 is provided with the branch part 41 in the core 4, it can be applied to all optical waveguides that require accuracy in the formation state at the end of the core.
[0027]
  In such a case, in the present embodiment, the mark 5 that can inspect the formation state of the coupling end face 6 (see FIG. 2) where the end portion 40 of the core 4 exists is provided. This mark 5 is formed so that the formation angle θ1 of the coupling end surface 6 in FIG. 1 and the angle θ2 of the coupling end surface 6 in FIG. 3 and the formation position of the coupling end surface 6 with respect to the optical axis direction can be inspected. In this case, the angles θ1, θ2, and the formation position can be inspected by inspecting the exposed pattern of the mark 5 exposed from 6.
[0028]
  For this reason, the mark 5 has a plurality of linear mark elements 50 in which the exposed end 51 located on the exposed side can be visually recognized from the coupling end face 6 side.ByComposed. Each of the mark elements 50 has a rectangular cross section and has the same length in parallel with the optical axis direction. Further, the exposed end 51 of the mark element 50 is positioned so as to be inclined in a stepwise manner so that the exposed pattern of the mark 5 can be changed according to the formation angles θ1 and θ2 and the formation position of the coupling end face 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, the mark element 50 is symmetrical with respect to a line parallel to the optical axis passing through the end portion 40 of the core 4. Of these mark elements 50, the side close to the core 4 is provided on the back side from the coupling end surface 6, and the exposed side end portions 51 are coupled sequentially as the distance from the core 4 in the direction perpendicular to the optical axis is increased. It is located on the end face 6 side.
[0029]
  FIG. 4 shows an enlarged view of the portion X in 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 to change its exposure form so that the required cutting position CL can be recognized smoothly in the inspection process. ing. Further, the other mark elements 50 are relatively thin in line width, 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.
[0030]
  First, CL is a required cutting position in a plan view, L1 is the distance between the exposed end 51 provided on the most coupling end surface 6 side (+ side) and CL, and L2 is the farthest (−side) from the coupling end surface 6 ), When the distance between the exposed end 51 of the mark element 50 provided in CL and CL is
[0031]
  Design tolerance length in the L1> + direction
  Design allowable range length in L2>-direction
[0032]
Set to be. Thereby, the mark 5 can be exposed from the coupling end face 6 with respect to the deviation within the design allowable range length from the required cutting position CL.
[0033]
  When the line length of the mark element 50 is L3,
[0034]
  L1 ≦ L3
  L2 ≦ L3
[0035]
And As a result, when the coupling end face 6 is formed in the vicinity of the required cutting position CL, the number of mark elements 50 exposed therefrom 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 side end 51 in each mark element 50 is L4, and the design allowable angle in one direction with respect to the formation angle θ1 is D. In the case where only the positional accuracy is inspected, L4 is set to the minimum resolution necessary for the inspection, and in the case where the angle θ1 is inspected,
[0036]
  D ≧ θ1
  tanθ1 = 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 exposed pattern of the mark 5.
[0037]
  Next, a method for manufacturing the optical waveguide 1 will be described with reference to FIGS. First, when the optical waveguide 1 is manufactured, as shown in FIG. 5, a planar substrate 2d formed of quartz, silicon, or the like is prepared, and a UV curable resin 3a is dropped on the upper surface thereof (FIG. )) Pressing with a stamper (not shown) and irradiating with ultraviolet rays forms the lower clad layer 3d having the core recess 30 and the mark recess 31 (FIG. 5B). Then, the core recess 30 and the mark recess 31 formed on the lower cladding layer 3d are filled with a core material having a high refractive index to simultaneously form the core 4 and the mark 5 (FIG. 5C). Next, the clad resin 3a is dropped onto the core 4 and the mark 5 and pressed by the cover glass 2u to form the upper clad layer 3u in the same manner (FIG. 5 (d)). In this way, the optical waveguide 1 is obtained.
[0038]
  Next, the coupling end face 6 of the optical waveguide 1 is polished. As shown in FIG. 6, the optical waveguide 1 is attached to the recess 71 of the jig 70 so that the coupling end face 6 side protrudes upward. Then, the coupling end surface 6 is attached so that the coupling end surface 6 faces downward and is brought into contact with a polishing plate of a polishing apparatus (not shown), and the coupling end surface 6 is polished. In this polishing, the polishing is performed so that the angle θ1 between the light traveling direction and the coupling end face 6 in FIG. 1 is 90 degrees, and the angle θ2 between the coupling end face 6 and the upper surface in FIG. It is formed so as to have a slightly small predetermined inclination angle (for example, 82 degrees). Furthermore, it grind | polishes so that the distance with the edge part of the branch part 41 may become predetermined distance.
[0039]
  In this polishing step, after performing polishing for a predetermined time, the jig 70 is removed from the polishing apparatus, and is placed so as to face the objective lens 8 of the microscope with the coupling end face 6 facing upward, While the optical waveguide 1 is 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, there is no need to inspect the objective lens 8 close to the outer peripheral portion of the jig 70, and FIG. As shown in c), the objective lens 8 can be inspected by being brought close to the coupling end face 6 directly. FIGS. 7 and 8 show exposure patterns of the marks 5 that are visually observed in the inspection process.
[0040]
  FIG. 7 shows the exposure pattern of the mark when cutting with varying θ1 and L in FIG. 1, and shows the cutting state on the CL, A1, and A2 lines, respectively.
[0041]
  As shown by CL in FIG. 1, when the coupling end face 6 is formed in a normal forming position perpendicular to the light traveling direction and a direction that forms 90 degrees with the light traveling direction that is the normal forming angle θ1, As shown in FIG. 7A, the same number of marks 5 are exposed at positions symmetrical with respect to the core 4. Further, as shown by A1 in FIG. 1, when polishing is performed in a state deviated from a normal angle by a predetermined angle (θ1 <90 degrees), the mark 5 is centered on the core 4 as shown in FIG. Different numbers are exposed at positions that are left-right asymmetric. Further, as indicated by A2 in FIG. 1, when the polishing is performed at a position different from the normal position CL even when θ1 = 90 degrees, the number of marks 5 exposed from the coupling end face 6 increases or decreases. For this reason, the number of mark elements 50 exposed in the design allowable range is shown to the inspector in advance, and the polishing operation is repeated so that this number of mark elements 50 is exposed symmetrically about the core 4.
[0042]
  FIG. 8 shows the mark exposure pattern when the angle θ2 in FIG. 3 is changed.
[0043]
  When the coupling end face 6 is formed at a regular angle θ2 in FIG. 3, the mark element 50 is exposed in a predetermined rectangular shape as shown in FIG. 8A. When the coupling end face 6 is formed at an angle larger than the normal angle θ2, as shown in FIG. 8B, the exposed mark element 50 becomes smaller than the vertical dimension of the normal mark element 50, and is square. It approaches the shape. On the other hand, when the coupling end face 6 is formed at an angle smaller than the regular angle, the vertically long dimension of the exposed mark element 50 is longer than the vertically long dimension of the regular mark element 50 as shown in FIG. . For this reason, the length of the exposed end portion at the normal angle θ2 is shown to the inspector in advance, and the polishing operation is repeated so as to have substantially the same length as this.
[0044]
  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 visually recognized, that is, the formation angles θ1, θ2, and the formation position L. Since the marks 5 that can be inspected are provided, the formation state of the coupling end face 6 can be inspected while the optical waveguide 1 is attached to the jig 70.
[0045]
  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. It becomes possible to grasp.
[0046]
  Further, in this embodiment, the core recess 30 and the mark recess 31 are provided on the upper surface of the lower clad layer 3d, and the mark 5 is simultaneously formed in the process of forming the core 4. Therefore, the mark 5 is simplified. In addition, the relative positional accuracy between the core 4 and the mark 5 can be increased.
[0047]
  At this time, since the mark 5 is formed by filling the same material as that of the core 4 into the mark recess 31, the process of forming the mark 5 can be further simplified.
[0048]
(Second embodiment)
  Next, the configuration of the optical waveguide 1a in the second embodiment of the present invention will be described. FIG. 9 is a plan view of the optical waveguide 1a according to the second embodiment. In this figure, unless otherwise indicated, the same reference numerals as those in the first embodiment are configured in the same manner as in the first embodiment, and are manufactured through the same steps as in the first embodiment. The
[0049]
  In this embodiment, the mark 5a is constituted by a plurality of parallel linear mark elements 50 having the same line segment length, and the distance between the width W1, W2, W3 of the mark element 50 and the mark element 50. W4, the step L4 of 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 element 50 is provided to be inclined in the same direction with the core 4 interposed therebetween.
[0050]
  In the second embodiment, the formation angle θ1 and the formation position L of the coupling end surface 6 can be inspected only by counting the number of mark elements 50 exposed from the coupling end surface 6, and similarly. By inspecting the cross-sectional shape of the exposed mark element 50, the formation angle θ2 can be inspected.
[0051]
(Third embodiment)
  Next, a third embodiment of the present invention will be described. FIG. 10 is a plan view of the optical waveguide 1b according to the third embodiment. In this figure, unless otherwise indicated, the same reference numerals as those in the first embodiment are configured in the same manner as in the first embodiment, and are manufactured through the same steps as in the first embodiment. The
[0052]
  In the third embodiment, the mark element 50b is not extended to the coupling end face 6 on the port 40a, 40b side of the core 4 in FIG. The end 52b is aligned on a line that is substantially perpendicular. With this configuration, when the transmitted light is incident from the microscope stage and the pattern of the mark 5 is inspected by the microscope, the transmitted light irradiated from the microscope stage is the end opposite to the exposed end 51 of the mark element 50b. The mark element 50b that is uniformly weakened by the clad before reaching the portion and is not exposed from the coupling end face 6 side is further removed by the clad existing between the exposed side end 51 and the coupling end face 6 Transmitted light is weakened. On the other hand, the mark element 50b exposed from the coupling end surface 6 has no cladding on the tip side of the exposed side end portion 51, so that the transmitted light is not weakened, and the exposed side end portion 51 is separated from the coupling end surface 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 mark element 50b can be easily confirmed. it can.
[0053]
(Fourth embodiment)
  Next, a fourth embodiment of the present invention will be described. FIG. 11 is a plan view of the optical waveguide 1c in the fourth embodiment. Also in this figure, unless otherwise indicated, the same reference numerals as those in the first embodiment are configured in the same manner as in the first embodiment, and manufactured through the same steps as in the first embodiment. Is done.
[0054]
  In this embodiment, the mark 5c is constituted by a plurality of parallel linear mark elements 50, and the width W1, W2, W3 of the mark element 50c, the distance W4 between the mark elements 50c, and the exposure of the mark element 50c. The level difference L4 and the like of the side end 51c is 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 made 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.
[0055]
  With this configuration, in the step of extracting the optical waveguide 1 of one chip from the wafer, the mark exposure pattern of the chip fragment on the tip side that has been cut off is compared with the exposure pattern of the mark on the optical waveguide 1 side. The state such as the thickness of the blade can be examined.
[0056]
(Fifth embodiment)
  Next, a fifth embodiment of the present invention will be described. 12 and 13 show plan views of two types of optical waveguides 1d and 1e in the fifth embodiment. In FIG. 12 and FIG. 13, unless otherwise indicated, the same reference numerals as in the first embodiment are configured in the same manner as in the first embodiment, and the same steps as in the first embodiment. It is manufactured through.
[0057]
  In this embodiment, the marks 5d and 5e are configured to be in a block shape by closely adhering the linear mark elements 50d and 50e, and further, the exposed side end portions 51d and 51d of the closely-adhered mark elements 50d and 50e, 51e is provided so as to be stepped in the front-rear direction. In this case, since the exposed pattern of the marks 5d and 5e on the coupling end face 6 is in a block shape, the number of the linear mark elements 50d and 50e cannot be counted, and the exposure size of the block must be measured. Since the area of the part exposed from the end surface becomes large, it becomes easy to find the exposed part. Moreover, since the marks 5d and 5e are blocked, the mark 5 can be easily manufactured. On the other hand, for the problem that the size of the mark 5 has to be measured, this problem can be solved by using a size that can be seen on the visual level.
[0058]
  When providing a block-shaped mark, 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. When configured in this manner, similarly to the third embodiment, when the exposure pattern is inspected with a microscope, it is possible to eliminate unevenness of the irradiation light.
[0059]
(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 indicated, the same reference numerals as those in the first embodiment are configured in the same manner as in the first embodiment, and manufactured through the same steps as in the first embodiment. Is done.
[0060]
  In this embodiment, a plurality of blocks 5f1, 5f2, 5f3 are provided 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 in close contact. The linear mark elements 50f1, 50f2, and 50f3 are provided so as to have different line widths in the different blocks 5f1, 5f2, and 5f3, and further, the linear mark elements 50f1, 50f2, and 50f3 in the blocks 5f1, 5f2, and 5f3 are provided. Both end portions are provided with steps so as to be longer by the line widths of the adjacent mark elements 50f1, 50f2, and 50f3.
[0061]
  FIG. 15 shows an enlarged view of the mark 5f. This FIG. 15 shows that when the mark element 50f1, 50f2, 50f3 has a step creation limit of 1 micrometer, the step of the first block 5f1 is 1 micrometer, the step of the second block 5f2 is 2 micrometers, A configuration when the third block 5f3 is provided as 3 micrometers is shown.
[0062]
  In such a case, for example, when the coupling end surface 6 is formed along the Z line shown in FIG. 15, the mark 5 f exposed on the coupling end surface 6 is formed as in the fifth embodiment. By measuring the size of the first block 5f1 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 is not exposed to the coupling end face 6 on the leftmost side of the first block 5f1. I understand. For this reason, it can be seen that the half of 1 micrometer, which is one part across the cutting request position CL, is shifted by 0.5 micrometer or more, and the linear mark element 50f1 of the second 501 of this block 5f1 is coupled. Since it is exposed at the end face 6, it can be seen that the range of deviation is in the range of 0.5 micrometers to 1.5 micrometers. When the exposed pattern of the coupling end surface 6 in the second block 5f2 is seen, the leftmost linear mark element 502 in the block 5f2 is not exposed on the coupling end surface 6, and the second 503 linear pattern is formed. Since the mark element 50f2 is exposed on the coupling end face 6, it can be seen that the range of deviation is in the range of 1.0 to 3.0 micrometers. Further, when the exposed pattern of the coupling end surface 6 in the third block 5f3 is seen, the leftmost linear mark element 504 protrudes to the coupling end surface 6, so the range of deviation is 0 to 1.5 micron. It turns out that it is a meter. And when these AND conditions are taken, it turns out that the range of deviation | shift is the range of 1.0-1.5 micrometers after all.
[0063]
  As described above, in the mark 5f of this embodiment, the plurality of linear mark elements 50f1, 50f2, 50f3 constitute the blocks 5f1, 5f2, 5f3, and the mark elements 50f1, 50f2 in the respective blocks 5f1, 5f2, 5f3. Since the step size of 50f3 is made different from the step size of the mark elements 50f1, 50f2, 50f3 of the other blocks 5f1, 5f2, 5f3, it is possible to measure a minute size exceeding the production limit of the step. become.
[0064]
  In addition, although this invention is implemented by embodiment as mentioned above, this invention is not limited to these embodiment.
[0065]
  For example, in the above embodiment, the case where the marks 5, 5b to f are provided on the one coupling end surface 6 side has been described. However, as shown in FIG. 16, the coupling end surfaces 6 are respectively provided on the coupling end surfaces 6 on both sides. You may make it provide the mark 5g which can confirm the formation angle or formation position of the joint end surface 6 from the direction which can be visually recognized.
[0066]
  Moreover, in the said embodiment, although the mark 5 was formed with the same material as a core material, you may make it form the mark 5 with 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 for easy identification from the clad 3, or the mark 5 is made of a material different from a core material having a colorless and transparent refractive index different from the core material. You may make it form.
[0067]
  Furthermore, in the above embodiment, the mark 5 is provided in the same layer as the lower clad layer 3d having the core 4, but the mark 5 may be provided in a different layer. At this time, if 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, but a circular shape, an elliptical shape, a thick line shape, or the like. Various shapes can also be adopted.
[0068]
  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 may be 1 μm, 1.5 μm, 2 μm, or the like corresponding to the required accuracy.
[0069]
【The invention's effect】
  According to the present invention, since the mark is provided so as to be visible from the coupling end surface, when polishing the coupling end surface, the objective lens of the microscope can be brought close to the end surface while the optical waveguide is mounted on the jig, As in the prior art, the angle and position of the end face can be inspected without removing the optical waveguide from the jig. Also, the distance from the exposed end of the mark element to the end face is different, and the cross-section of the mark element is a predetermined rectangleShape andTherefore, when the joint end face could not be formed at right angles to the side face, the number of mark elements exposed from the joint end face changes, and it is easy to form the joint end face just by looking at the state of the mark with a microscope. It becomes possible to grasp the state.Further, in such a configuration, since the marks are arranged on both sides of the core, the coupling end surface can be formed at a predetermined angle uniformly and accurately around the core.
[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;
4 shows an arrangement state of mark elements in FIG. 1. FIG.
FIG. 5 shows an optical waveguide manufacturing process 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 shows an exposure pattern of a mark corresponding to a formation state in a front view.
FIG. 8 shows an exposed form of a mark corresponding to a formation state in a side view.
FIG. 9 is a plan view of an optical waveguide according to the 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 is an enlarged view (a) of a mark in FIG. 14 and a cut state (b) thereof.
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 manufacturing process of an optical waveguide.
FIG. 19 shows a conventional state of inspection of the coupling end face.
FIG. 20 shows the state of inspection using a conventional microscope.
[Explanation of symbols]
1, 1b-1f ... Optical waveguide
3 ... Clad
3d ... Lower cladding layer
4 ... Core
5 ... mark
6 ... Join end face
40 ... End of core
50, 50b to 50f ... Mark elements
51, 50b to 50f... Exposed side end portion in the mark element
70 ... Jig

Claims (8)

An angle (θ1) formed between the coupling end surface and the side surface of the optical waveguide in a plan view, and the coupling end surface and the optical waveguide in a side view, formed on the coupling end surface on the side where the core is exposed from the cladding. forming angle formed between the upper surface (.theta.2) and, an optical waveguide comprising a mark that can confirm the formation position of the coupling end face,
The mark is parallel to the optical axis of the core and is embedded in a concave portion of the clad, and is composed of a plurality of mark elements whose exposed cross section by the coupling end surface forms a predetermined rectangular shape,
An optical waveguide characterized in that a plurality of the mark elements are arranged on both sides of the optical axis, and a plurality of the mark elements are arranged so that the distance between the end portion on the coupling end surface side and the coupling end surface is different. The optical waveguide according to claim 1, wherein the mark elements are provided by changing their forms every predetermined number. 2. The optical waveguide according to claim 1, wherein an end of the mark element opposite to the end of the coupling end face is aligned in a direction orthogonal to the optical axis. The mark is composed of a block composed of a plurality of linear mark elements provided in close contact with each other so as to have a step along the optical axis direction, and the step dimension along the optical axis direction of the mark element in each block is set. The optical waveguide according to claim 1, wherein the optical waveguides are different. The optical waveguide according to claim 1, wherein the mark is made of the same material as the core. An angle (θ1) formed between the coupling end surface and the side surface of the optical waveguide in a plan view, and the coupling end surface and the optical waveguide in a side view, formed on the coupling end surface on the side where the core is exposed from the cladding. A method of manufacturing an optical waveguide having a mark capable of confirming a formation angle (θ2) formed with an upper surface and a formation position of the coupling end surface ,
Forming a plurality of recesses in the clad parallel to the optical axis of the core;
Filling the concave portion with a material for forming a mark element, and forming a mark element having a rectangular cross section exposed by a predetermined coupling end face,
A method of manufacturing an optical waveguide , comprising: forming a plurality of mark elements on both sides of an optical axis of a core so that a distance between an end of the mark element on the coupling end face side and the coupling end face is different. The method for manufacturing an optical waveguide according to claim 6, wherein the step of forming the concave portion and the step of forming the concave portion for the core are performed simultaneously. The method for manufacturing an optical waveguide according to claim 6, wherein a material for forming the mark element is the same material as the core material.

Images