JPWO2006137451A1 - Optical parts - Google Patents

Abstract

An optical component with higher reliability is provided by preventing destructive peeling of an adhesive portion by an adhesive. According to the present invention, in an optical component in which an optical fiber is sandwiched between a substrate and a lid and fixed with an adhesive, the adhesive stress of the adhesive is unevenly distributed so that the internal stress at the time of curing is alleviated. To. In this way, a part with weak adhesive force is intentionally produced, and when the internal stress occurs, the part is partially peeled to absorb or relieve the stress, such as temperature change or humidity change. It is possible to prevent destructive peeling of the substrate and lid due to external stress. Such uneven adhesion can be achieved by adding additives to the adhesive, chemically treating the adhesive surface of the substrate or lid with the adhesive, or physically processing it. it can.

Description

  The present invention relates to an optical component in which an optical fiber between a substrate and a lid is fixed with an adhesive.

  Optical fiber-based optical communication technology supports the increase in communication traffic accompanying the explosive spread of the Internet. In particular, with the recent progress in broadbandization, music and video transmission / reception and real-time communication using the FTTH access network have been realized.

  Communication using such an optical fiber requires an interface for connecting the optical fiber and the optical device. Normally, optical fibers are handled in the form of a tape fiber that is coated in parallel with a plurality of optical fibers. For connection between the fiber and the device, an optical fiber is disposed on a substrate having a V-groove and is fixed by a lid. Optical components such as fiber arrays are used. This optical fiber array is required to have an accurate optical alignment with an optical device such as a planar optical circuit (PLC), for example, and the connection portion must have strength enough to withstand use.

  FIG. 36 shows an example of such an optical component. As shown in FIG. 36, the optical component 100 has a structure for connecting the optical fiber 2 or the optical fiber array 3 to the PLC 1 using the V-groove substrate 20 and the lid 10. In this case, the optical fiber or the optical fiber array is sandwiched between the V-groove substrate and the lid and fixed with an adhesive. FIG. 37 is a side view showing another example of such an optical component. As shown in the figure, the optical component 200 has a structure in which the optical fiber 2 is connected to the PLC 1 using the silicon bench 20 and the lid 10 in which the V-groove is formed. Also in this case, the optical fiber is sandwiched between the silicon bench and the lid and fixed with an adhesive. A conventional structure of such an optical component is described in Patent Document 1, for example.

  However, in the conventional structure, peeling may occur between the lid and the optical fiber, between the optical fiber and the substrate, and between the lid and the substrate due to external factors such as temperature change and humidity change. This peeling has caused a positional shift or peeling at the connection portion between the optical fiber and the optical device, and in some cases, an optical disconnection, which is a cause of damaging the optical characteristics.

  When such an optical component is actually subjected to a reliability test, particularly an accelerated test under high temperature and high humidity, the peeling phenomenon appears prominently, not only the interface peeling between the adherend and the adhesive, but also cohesive failure and Mixed destruction occurs at the same time.

  Further, a method is known in which the adhesive strength of the roughened adhesive surface is strengthened by roughening the adhesive surface of the substrate so as not to cause such peeling between the lid and the substrate (Patent Document 2). . However, if the bonding surface of the substrate is further reduced due to a demand for downsizing of the optical component, sufficient bonding strength may not be obtained between the substrate and the lid even if the bonding surface is roughened. Furthermore, in a highly integrated and high-density optical component, there has been a problem that the mechanical strength of the substrate and the lid is reduced due to scratches and chips in dicing during manufacture.

JP-A-7-209547 JP-A-11-142673

  The present invention has been made in view of such problems, and an object of the present invention is to provide a more reliable optical component by preventing destructive peeling of an adhesive portion by an adhesive. .

  In order to achieve the above object, according to an embodiment of the present invention, in an optical component in which an optical fiber is sandwiched between a substrate and a lid and fixed with an adhesive, the adhesive is bonded. Forces are distributed unevenly, thereby relieving the internal stress of the adhesive due to external stress.

  Moreover, according to one Embodiment of this invention, in said optical component, the adhesive force of an adhesive agent can be made non-uniform | heterogenous by adding an additive to an adhesive agent.

  According to one embodiment of the present invention, in the above optical component, the adhesive force of the adhesive can be made nonuniform by attaching an organic substance or an inorganic substance to at least one of the bonding surfaces of the substrate and the lid. .

  According to one embodiment of the present invention, in the above optical component, the adhesive force of the adhesive can be made non-uniform by modifying the adhesive surface of at least one of the substrate and the lid by surface treatment. .

  According to one embodiment of the present invention, in the above optical component, the adhesive force of the adhesive can be made uneven by providing irregularities on at least one of the bonding surfaces of the substrate and the lid.

  According to one embodiment of the present invention, in the above optical component, the adhesive force of the adhesive can be made non-uniform by roughening at least one of the bonding surfaces of the substrate and the lid.

FIG. 1 is a cross-sectional view showing a state where an adhesive having a normal amount of silane coupling agent added is filled between a V-groove substrate and a lid. FIG. 2 is a cross-sectional view showing a state in which an adhesive to which a silane coupling agent less than a normal amount is added is filled between the V-groove substrate and the lid. FIG. 3 is a cross-sectional view showing a state where an adhesive to which more silane coupling agent than a normal amount is added is filled between the V-groove substrate and the lid. FIG. 4A is a perspective view showing a state in which a silane coupling agent is applied in a circular pattern to the adhesion surface of the V-groove substrate. FIG. 4B is a perspective view showing a state in which a silane coupling agent is applied to the bonding surface of the lid with a circular pattern. FIG. 5 is a cross-sectional view showing a state where an optical fiber is fixed between the V-groove substrate of FIG. 4A and the lid of FIG. 4B and is filled with an adhesive. FIG. 6A is a diagram illustrating a process of applying a photosensitive resin when a photosensitive resin is produced with a desired pattern on an adhesive surface. FIG. 6B is a diagram illustrating a step of exposing with a mask when a photosensitive resin is formed on a bonding surface with a desired pattern. FIG. 6C is a diagram illustrating a process of developing a pattern when a photosensitive resin is formed on the adhesive surface with a desired pattern. FIG. 7A is a diagram illustrating a process of applying a resist when performing plasma treatment on a bonding surface with a desired pattern. FIG. 7B is a diagram illustrating a process of exposing with a mask when performing plasma treatment on a bonding surface with a desired pattern. FIG. 7C is a diagram illustrating a process of developing a pattern when performing plasma treatment on a bonding surface with a desired pattern. FIG. 7D is a diagram illustrating a process of performing plasma treatment when performing plasma treatment on a bonding surface with a desired pattern. FIG. 7E is a diagram showing a step of removing a resist when performing plasma treatment on a bonding surface with a desired pattern. FIG. 8A is a diagram showing a step of applying a resist when forming irregularities on a bonding surface with a desired pattern. FIG. 8B is a diagram showing a step of exposing with a mask when forming irregularities with a desired pattern on the bonding surface. FIG. 8C is a diagram illustrating a process of developing a pattern when forming irregularities with a desired pattern on the bonding surface. FIG. 8D is a diagram illustrating a process of performing ion milling when forming irregularities with a desired pattern on the bonding surface. FIG. 8E is a diagram showing a step of removing the resist when forming irregularities with a desired pattern on the bonding surface. FIG. 9A is a plan view showing irregularities of a lattice pattern formed on the bonding surface of the lid. FIG. 9B is a plan view showing the unevenness of the grid pattern formed on the adhesion surface of the V-groove substrate. FIG. 10A is a plan view showing irregularities of a lattice point pattern formed on the bonding surface of the lid. FIG. 10B is a plan view showing the unevenness of the lattice point pattern formed on the bonding surface of the V-groove substrate. FIG. 11 is a diagram showing the relationship between the bonding strength of the substrate and the lid after the high-temperature and high-humidity test with respect to the depth of the concave and convex portions formed on the bonding surface of the V-groove substrate and the lid. FIG. 12 is a cross-sectional view showing a state in which an optical fiber array is fixed and an adhesive is filled between a V-groove substrate having an uneven surface and a lid. FIG. 13 is a cross-sectional view showing a state in which an optical fiber array is fixed and an adhesive is filled between a V-groove substrate on which concavities and convexities are formed other than an adhesive surface in contact with the optical fiber array and a lid. FIG. 14 is a cross-sectional view showing a step of forming fine grooves on the bonding surface of the V-groove substrate or lid with a dicing saw. FIG. 15A is a plan view showing a lid in which fine grooves are formed on the bonding surface with a dicing saw. FIG. 15B is a plan view showing a V-groove substrate in which fine grooves are formed on the bonding surface with a dicing saw. FIG. 16A is a plan view showing a lid in which grooves are formed in a plurality of directions on an adhesive surface. FIG. 16B is a plan view showing a V-groove substrate in which grooves are formed in a plurality of directions on the bonding surface. FIG. 17A is a diagram illustrating a process of heating and softening a substrate and pressing a mold when forming irregularities using a nanoimprint technique. FIG. 17B is a diagram illustrating a process of forming a V-groove and unevenness on the substrate simultaneously by pressing a mold when forming unevenness using the nanoimprint technology. FIG. 18 is a cross-sectional view showing a state in which an optical fiber array is fixed and an adhesive is filled between a substrate having a roughened adhesive surface and a lid. FIG. 19 is a diagram showing a relationship between the surface roughness Ra and the adhesive strength between the substrate and the lid after the high-temperature and high-humidity test. FIG. 20A is a plan view showing a lid in which a large number of random thin wires are produced on a bonding surface using a scriber, a diamond cutter, or the like. FIG. 20B is a plan view showing a V-groove substrate in which a large number of random fine wires are produced on the bonding surface by a scriber, a diamond cutter, or the like. FIG. 21A is a plan view showing a lid in which fine wires are randomly formed in a plurality of directions on a bonding surface using a scriber, a diamond cutter, or the like. FIG. 21B is a plan view showing a V-groove substrate in which fine wires are randomly formed in a plurality of directions on a bonding surface using a scriber, a diamond cutter, or the like. FIG. 22 is a perspective view of an optical component in which fixing members are bonded to both side surfaces of the substrate and the lid. FIG. 23 is a perspective view of an optical component in which a fixing member is bonded to one side surface of the substrate and the lid. FIG. 24 is a perspective view of an optical component in which a fixing member is bonded to one side surface of the substrate and the lid, and the bonding area between the lid and the substrate on the other side is increased. FIG. 25 is a perspective view of an optical component in which a plurality of fixing members are selectively bonded to locations where the substrate and the lid are liable to peel off. FIG. 26 is a perspective view of an optical component having a fixing member bonded over the entire side surface of the substrate. FIG. 27 is a perspective view of an optical component in which a semi-cylindrical fixing member is bonded to the side surfaces of the substrate and the lid. FIG. 28 is a perspective view of an optical component in which a trapezoidal fixing member is bonded to the side surfaces of the substrate and the lid. FIG. 29 is a perspective view of an optical component in which a U-shaped fixing member is mounted on the side surface of the substrate and the lid and the bottom surface of the substrate. FIG. 30 is a perspective view of an optical component in which a U-shaped fixing member is attached to the side surface of the substrate and the lid and the upper surface of the lid. FIG. 31 is a perspective view of an optical component in which a U-shaped fixing member is mounted on the side surface of the substrate, the lid, and the upper surface of the lid so as to cover the fiber core wire. FIG. 32 is a perspective view of an optical component in which a U-shaped fixing member is attached to one side surface of the substrate and the lid, the bottom surface of the substrate, and the top surface of the lid. FIG. 33 is a cross-sectional view of an optical component in which a U-shaped fixing member is attached to one side surface of the substrate and the lid, a part of the bottom surface of the substrate, and a part of the lid. FIG. 34 is a perspective view of an optical component in which a square-shaped fixing member is mounted on the substrate and the lid so as to cover all four surfaces. FIG. 35A is a plan view of the optical component for explaining the width of the flat portion outside the V groove on the substrate. FIG. 35B is a cross-sectional view of the tape fiber taken along line XXXVB in FIG. 35A. FIG. 35C is a cross-sectional view of the substrate and the lid taken along line XXXVC in FIG. 35A. FIG. 36 is a perspective view showing an example of an optical component. FIG. 37 is a perspective view showing another example of the optical component.

  In the structure of an optical component in which an optical fiber is sandwiched between a substrate and a lid and fixed with an adhesive, peeling or breakage may occur when a reliability test is performed as described above. However, such a peeling phenomenon does not occur when the flat plate of the substrate and the lid is bonded to each other with an adhesive. Therefore, the peeling phenomenon between optical component components (substrate, optical fiber, lid) is not simply caused by the weak adhesive force of their adhesive surfaces, but the internal stress that occurs when the adhesive cures and shrinks. It seems to be deeply related. That is, when the adhesive is cured, the distance between the substrate and the lid is almost the same as the distance between the substrate and the lid because the optical fiber becomes a spacer, although the adhesive resin shrinks. It is considered that peeling occurs due to the concentration of the internal stress of the adhesive in the vicinity of the outer periphery of the adhesive. Due to this peeling, the fiber cannot be gripped or fixed between the substrate and the lid, the fiber is displaced, and the optical characteristics of the optical component are deteriorated.

  In the present invention, a part where the adhesive strength with the adhesive is weak is intentionally produced on the surface where the substrate and the lid are in contact with the adhesive, and when the internal stress is generated, the part is partially peeled off. , Absorb or relieve intrinsic stress. Thereby, the adhesive strength between the substrate and the lid is maintained, and destructive peeling is prevented. In the prior art, it has been devised not to cause partial peeling as well as destructive peeling. On the contrary, in the present invention, partial peeling is positively induced to prevent the occurrence of destructive peeling between the substrate, the lid and the optical fiber.

  In order to change the adhesive strength of the adhesive, in the present invention, an additive can be added to the adhesive, or a chemical treatment or physical processing can be performed on the adhesive surface of the substrate and the lid. Since the purpose is to alleviate the internal stress in the resin of the adhesive, the pattern of change in adhesive force needs to be larger than the polymer molecules of the adhesive. However, if the change pattern of the adhesive force is too large, the adhesion area is reduced, and the overall adhesion strength of the substrate, the lid, and the optical fiber is lowered. Therefore, it is desirable that the actual interval between the change patterns is 0.1 μm to 100 μm.

  If the ratio of the adhesive with respect to the entire area where the adhesive strength is weak is small, the effect of relaxing the internal stress is small, and the effect of maintaining the adhesive strength is small. On the contrary, if the ratio is large, the effective bonding area between the adhesive and the adherend decreases, so that the lowering of the adhesive strength by the adhesive is more problematic than the effect of maintaining the adhesive strength by stress relaxation. Become. For this reason, it is desirable that the proportion of the practically weak portion of the adhesive force is 5% to 50%.

  This ratio can be confirmed visually with a microscope when the substrate or lid is made of a transparent material such as glass. Specifically, the site where the adhesive strength with the adhesive is weak can be observed as a bubble or a peeled state. However, in the normal state, it may not appear as a bubble or exfoliation state. In that case, by applying external stress for a short time, such as in an accelerated test at high temperature and high humidity, the bubble or exfoliation becomes obvious. Can be observed.

  Further, since stress is concentrated along the optical fiber at the bonded portion of the substrate, the optical fiber, and the lid, it is important to intentionally cause bubbles or peeling at this portion. When the adhesive layer is several μm to several tens of μm, it is empirically desirable that bubbles or delamination be distributed along the fiber in a region within 5 mm from the fiber.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  In the first embodiment of the present invention, by adding an additive in the adhesive, it is possible to create a region where the adhesive strength of the adhesive is not uniform on the adhesive surface between the substrate and the lid. Specifically, a silane coupling agent can be used as an additive. Silane coupling agents are usually used to improve adhesive strength. This is because the silane coupling agent is covalently bonded to an inorganic material by hydrogen bonding or dehydration reaction, and the silane coupling agent and the organic material are bonded by hydrogen bonding or intermolecular force, or are covalently bonded by chemical reaction. By doing so, strong adhesion can be obtained. Usually, when a silane coupling agent is added to the adhesive, the amount is adjusted so that the silane coupling agent uniformly adheres to the bonding surface of the substrate and the lid. This is shown in FIG. FIG. 1 shows a state where the adhesive 30 to which the silane coupling agent 40 is added is filled between the substrate 20 and the lid 10. Ideally, as shown in FIG. 1, the amount is adjusted so that only one molecular layer of functional silane uniformly adheres to the bonding surface of the substrate 20 and the lid 10.

  However, in the present invention, a region where the silane coupling agent does not adhere is created by reducing the addition amount instead of the addition amount where the molecular layer is uniformly attached only by one layer. This is shown in FIG. FIG. 2 shows a state in which an adhesive 30 in which the silane coupling agent 40 is adjusted to be less than usual is filled between the substrate 20 and the lid 10 according to an embodiment of the present invention. By adjusting in this way, the part of the adhesive surface to which the silane coupling agent 40 does not adhere has a weak adhesive force with the adhesive and is likely to cause partial peeling with respect to the internal stress. By making the addition amount 5% to 50% with respect to the ideal addition amount, a desirable stress relaxation effect can be obtained.

  Moreover, the same effect can be acquired also by making the quantity of a silane coupling agent larger than the ideal addition amount. This is shown in FIG. FIG. 3 shows a state in which the adhesive 30 in which the amount of the silane coupling agent 40 is adjusted more than usual is filled between the substrate 20 and the lid 10 according to an embodiment of the present invention. Thus, when the quantity of a silane coupling agent increases, the coupling | bonding of the molecules of a silane coupling agent will occur. This bond is generally weaker than the bond between adhesive molecules. Therefore, the portion where the molecules of the silane coupling agent are bonded to each other easily causes partial peeling with respect to the internal stress.

  In this embodiment, the silane coupling agent is described as an example of the additive, but the same result can be obtained by adding another appropriate additive. Usually, the additive is used for the purpose of adjusting the viscosity of the adhesive, but in the present invention, it is used to make the adhesive strength of the adhesive non-uniform. Therefore, any additive for achieving this object may be used. For example, silica, quartz, plastic, wood, metal, graphite, carbon nanotube, and the like can be used, but are not limited thereto.

  It is desirable that the total area of the partial peeling or weak adhesion strength caused by the additive is 5% to 50% of the area of the bonding surface of the substrate or lid. In addition, it is desirable that the portion where the peel strength or the adhesive strength is weak exists along the fiber at a portion within a distance of 5 mm from the fiber.

  In the second embodiment of the present invention, a chemical surface treatment is performed on the bonding surface of the substrate and the lid, so that a region where the adhesive force of the adhesive is not uniform can be formed on the bonding surface of the substrate and the lid. Specifically, a silane coupling agent is applied to the bonding surface between the substrate and the lid by an ink jet method to form a circular pattern with an interval of 3 μm. This is shown in FIGS. 4A and B. FIG. 4A and 4B show states in which the silane coupling agent 42 is applied to the adhesion surface of the substrate 20 and the lid 10 with a circular pattern, respectively. FIG. 5 shows a state in which the optical fiber 2 is mounted in the V-groove 21 between the substrate 20 on which the silane coupling agent 42 is applied in a circular pattern and the lid 10 and the adhesive 30 is filled.

  When a silane coupling agent is applied to the surface of a substrate such as glass or silicon or a lid and dried, the wettability and compatibility with the adhesive is improved in the portion where the silane coupling agent is applied, and the surface and A strong bonding surface is obtained by covalent bonding or hydrogen bonding with the adhesive. On the other hand, the part where the silane coupling agent is not applied is in a state in which such a mechanism does not work and peeling easily occurs. As a result, the part that has not been surface-treated is easily peeled and absorbs or relaxes the stress, and the part that has been surface-treated becomes difficult to peel off. As a result, it is resistant to external stress such as high temperature and high humidity. Thus, destructive peeling can be prevented and optical fiber position shift, pitch shift, and disconnection can be effectively prevented.

  Note that the application pattern of the adhesive surface does not need to be circular, and may be an ellipse, a triangle, a polygon, or an arbitrary irregular shape. The size of the pattern can also be set to a desired change in adhesive strength. Moreover, in said embodiment, although the space | interval which apply | coats a silane coupling agent was 3 micrometers, the space | interval of the part (part where the adhesive strength of an adhesive agent becomes weak) where the silane coupling agent is not apply | coated is as above-mentioned. Further, it may be in the range of 0.1 μm to 100 μm, and preferably 1 μm to 10 μm. When this interval is less than 1 μm, the pattern for applying the silane coupling agent becomes fine, which makes it difficult to produce. On the other hand, when the thickness exceeds 10 μm, sufficient stress relaxation is not performed in the adhesive layer.

  Further, the total area of the portion where the silane coupling agent is not applied is desirably 5% to 50% of the bonding surface of the lid or the substrate. The uncoated part is peeled off in the uncoated part by subjecting this part to a high temperature and high humidity accelerated test (for example, 130 ° C. and 90% RH) for 1 hour, and the area of the part is visually evaluated. be able to. In addition, it is desirable that the part having a weak peel or adhesive force exists along the fiber within a distance of 5 mm from the fiber.

  In the above embodiment, the case where a silane coupling agent is used as the coating agent has been described as an example. However, any material that can change the adhesive force may be used. Silazane (for example, hexamethyldisilazane), optical fiber Even if an organic substance (epoxy, acrylic, polyimide, silicone, PMMA, PC, BCB, urethane, etc.) other than the adhesive used for adhesion is applied, the same effect can be obtained, but it is not limited thereto. In addition, the material may not be a material that improves the adhesive strength like a silane coupling agent, and a material that lowers the adhesive strength like a fluorine-containing resin may be used to make it easier to peel off the applied part. Good. The material for changing the adhesive force is not an organic material, but an inorganic material such as a metal may be used, and the pattern as described above may be formed on the adhesion surface by vapor deposition and lift-off. For example, when Au is used, the Au surface becomes a portion with poor adhesive strength and weak adhesive strength.

  In the above embodiment, the organic material is applied using the inkjet method, but any method that can apply a desired material may be used, and mist is generated by spraying, ultrasonic waves, bubbling, etc. A mist spraying method in which the adhesive surface is exposed and adhered to a gas, or a method in which a photosensitive resin is applied, pattern exposure and development can be used, but is not limited thereto. FIGS. 6A to 6C show an example of a process of applying a photosensitive resin, performing pattern exposure and developing. First, as shown in FIG. 6A, a photosensitive resin 50 is applied to the lid 10 (or the substrate 20). Next, as shown in FIG. 6B, the photosensitive resin 50 is exposed using a mask 60 having a desired pattern. Finally, as shown in FIG. 6C, the exposed photosensitive resin 50 is developed to obtain a desired pattern. Thereby, the photosensitive resin 50 can be made to adhere to a bonding surface of the lid or the substrate with a desired pattern.

  Furthermore, in one embodiment of the present invention, the wettability of the adhesive surface may be changed without applying a resin to the adhesive surface. For example, the adhesive surface may be plasma-treated with a desired pattern. An example of such a plasma treatment is shown in FIGS. First, as shown in FIG. 7A, a resist 52 is applied to the lid 10 (or the substrate 20). Next, as shown in FIG. 7B, the resist 52 is exposed using a mask 60 having a desired pattern. Next, as shown in FIG. 7C, the exposed resist 52 is developed to obtain a desired pattern. Next, as shown in FIG. 7D, the lid 10 having a resist pattern is exposed to plasma. Finally, as shown in FIG. 7E, the resist pattern is removed, and the lid 10 having the plasma-treated portion 54 is obtained. As a result, the wettability of the adhesive 30 is different between the plasma-treated portion 54 and the portion that is not, so that the bonding surface can have a non-uniform adhesive force.

  In the third embodiment of the present invention, a region where the adhesive force of the adhesive is not uniform can be formed on the adhesive surface of the V-groove substrate and the lid by performing physical treatment on the adhesive surface of the substrate and the lid. . Specifically, a physical pattern can be formed by applying resist, applying pattern exposure, developing, and performing ion milling using wafer-like glass or silicon as a substrate and lid. An example of such a process is shown in FIGS. First, as shown in FIG. 8A, a resist 52 is applied to the lid 10 (or the substrate 20). Next, as shown in FIG. 8B, the resist 52 is exposed using a mask 60 having a desired pattern. Next, as shown in FIG. 8C, the exposed resist 52 is developed to obtain a desired pattern. Next, as shown in FIG. 8D, the lid 10 having a resist pattern is etched by Ar ion milling. Finally, as shown in FIG. 8E, the resist pattern is removed, and the lid 10 having the irregularities 12 formed by etching is obtained.

  As shown in FIGS. 9A and 9B, the pattern of the unevenness 12 of the lid 10 and the V-groove substrate 20 is, for example, a lattice pattern with an interval of 1 μm, or a lattice point pattern as shown in FIGS. 10A and 10B, respectively. be able to. Thereby, since the adhesive force of an adhesive agent differs in a recessed part and a convex part, it can give a non-uniform adhesive force to an adhesive surface.

  FIG. 11 shows the relationship between the lid and the substrate manufactured as described above, and the bonding strength of the substrate and the lid after the high-temperature and high-humidity test with respect to the depth of the recess. From this figure, it can be seen that there is no effect when the depth of the recess is 0.1 μm or less. On the other hand, when the depth of the recess exceeds 10 μm, it becomes difficult to ensure the accuracy of the V-groove and the pitch accuracy of the fiber when the optical fiber is mounted. Therefore, the etching depth is desirably 0.1 μm to 10 μm. Further, the etching depth can be adjusted by the thickness of the adhesive layer and the curing shrinkage rate. For example, when the thickness of the adhesive layer is 20 μm, the appropriate etching depth is 0.5 μm to 5 μm, and preferably 1 to 2 μm.

  FIG. 12 shows a cross-sectional view of an optical component in which the fiber array is fixed using the V-groove substrate 20 and the lid 10 having such irregularities. In the recesses formed by etching or the like, the curing shrinkage rate of the adhesive is large, and peeling easily occurs. In response to temperature change or humidity change, peeling occurs in this portion, and the internal stress is relieved. As a result, as in the case of the above embodiment, destructive peeling between the V-groove substrate and the lid can be prevented, and the optical fiber can be prevented from being displaced or disconnected. However, after etching, if residues are generated or the surface is roughened to increase the effective bonding area, or if an increase in bonding strength occurs due to the anchor effect, etc., bonding will occur through the recesses. The strength does not necessarily decrease, and curing shrinkage and their effects may be traded off or reversed.

  The total area of the recesses produced by etching is desirably 5% to 50% of the area of the bonding surface between the substrate and the lid. In the case of a material with poor wettability, these portions are in a state in which bubbles remain in the recesses, and a stress relaxation effect is obtained at the time of curing. In addition, when the adhesive penetrates into the concave portion, the stress relaxation effect can be obtained by curing and shrinking the adhesive. Needless to say, even if peeling does not occur at the time of curing shrinkage, the same effect can be obtained if peeling occurs at the stage where external stress is applied.

  When holding the optical fiber with the uneven lid 10, if the unevenness 12 of the lid is large, proper fixing of the fiber 2 may be hindered. For this reason, as shown in FIG. 13, the bonding surface with which the fiber contacts may not be provided with unevenness.

  In this embodiment, an Ar ion milling method is used as an etching method. However, similar effects can be obtained even if the etching is performed by acid or alkali wet etching or reactive ion etching (RIE). In addition to etching, a fine groove may be formed by a dicing saw 70 as shown in FIG. As a result, as shown in FIG. 15A (or FIG. 15B), many fine grooves 13 can be formed on the bonding surface of the lid 10 (or the substrate 20), and the same effect as in the case of etching can be obtained. . As shown in FIGS. 16A and 16B, the groove to be manufactured can obtain a higher stress relaxation effect by forming the groove 14 in a plurality of directions. In any case, it is desirable to form grooves or irregularities in the direction along the fiber within a range of 5 mm from the fiber.

  In the case where the V-groove substrate and the lid are materials that can be heat-processed, the unevenness can be produced using a nanoimprint technique. FIGS. 17A and 17B show a process for forming irregularities using such a technique. As shown in FIG. 17A, the substrate 20 made of a material such as glass or plastic is heated and softened, and the mold 80 is pressed against the substrate. Thereby, the desired unevenness | corrugation 12 is obtained in the adhesion surface of the board | substrate 20 by FIG. 17B. Further, as shown in the figure, if the irregularities 12 are produced in the same process as the production of the V groove 21 of the substrate 20, the number of processes and the production time can be reduced.

  As another embodiment of the present embodiment, a region where the adhesive strength of the adhesive is not uniform can be formed on the adhesive surface of the V-groove substrate and the lid by physically roughening the adhesive surface of the substrate and the lid. . Specifically, the adhesion surface of the V-groove substrate and the lid is roughly polished with # 200. FIG. 18 shows a state in which the optical fiber 2 is fixed between the substrate 20 and the lid 10 whose surface is roughened in this way and the adhesive 30 is filled. The random depressions 15 as shown in FIG. 18 can change the adhesive force, cause partial peeling, and relieve internal stress due to external stress. In this embodiment, the adhesion surface can be characterized by the surface roughness Ra defined by JIS, not by the pattern interval and the etching amount described above. By performing rough polishing so that the surface roughness Ra is 1 to 5 μm, an appropriate stress relaxation effect can be obtained, and it is desirable to perform rough polishing so that the surface roughness is 1 to 2 μm. .

  FIG. 19 shows the relationship between the surface roughness Ra and the adhesive strength between the substrate and the lid after the high-temperature and high-humidity test. As can be seen from FIG. 19, sufficient adhesive strength is maintained in a region where the surface roughness Ra exceeds 1 μm. However, if the surface roughness Ra exceeds 5 μm, stable fixing of the optical fiber is hindered, and a positional shift or a pitch shift may occur. Therefore, the range of the surface roughness Ra is suitably 1 μm to 5 μm.

  It should be noted here that it is important to create a recess that weakens the adhesive force between the V-groove substrate or the lid and the adhesive, and this recess causes stress relaxation of the adhesive and causes external stress. In contrast, the overall adhesive strength is maintained. Therefore, the effect is not obtained on any surface as long as the surface roughness Ra is in the range of 1 μm to 5 μm. For example, on a surface in which protrusions having a height of 10 μm are arranged at intervals of 10 μm and the other portions are flat, the adhesion effect can be improved by increasing the anchor effect or the adhesion area, but the adhesion strength is weak. Since the portion is hardly formed, the relaxation effect of the internal stress of the adhesive is low, and the degree of maintaining the adhesive strength against external stress is also low.

  For this reason, it may replace with the depth of the recessed part used in FIG. 11, and you may make it characterize an adhesive surface by the ten-point average roughness Rz defined by JIS. The ten-point average roughness Rz is preferably 0.25 ≦ Rz / t ≦ 2.5, where t is the thickness of the adhesive layer between the substrate and the lid. When t is 20 μm, the ten-point average roughness Rz is 5 μm to 50 μm. In this case, when the ten-point average roughness Rz is less than 5 μm, partial peeling at the recesses is difficult to occur, and the stress relaxation effect is low. On the other hand, if Rz exceeds 50 μm, positional deviation and pitch deviation are likely to occur when the optical fiber is mounted. In addition, when the positional deviation or pitch deviation of the optical fiber causes a problem due to the unevenness of the surface, the surface of the lid that is in contact with the optical fiber may not be subjected to rough polishing.

  As a method for roughening the bonding surface, the substrate or the lid may be directly rough-polished, or may be mirror-polished and then roughened by blasting or the like. Also, as shown in FIGS. 20A and 20B, the same effect can be obtained even if a large number of random thin wires 16 are produced on the bonding surface of the V-groove substrate 20 and the lid 10 by scriber or diamond cutter instead of polishing. It is done. Moreover, as shown in FIGS. 21A and 21B, thin wires 17 may be randomly formed on the bonding surface in a plurality of directions.

  In any of the above cases, it is desirable that the total area of the weakened adhesive force between the substrate with the roughened adhesive surface and the lid adhesive be 5% to 50% of the bonded area between the substrate and the lid. The portion with weak adhesive strength can be visually observed as partial peeling or bubbles when the adhesive is cured. When they do not appear as peeling or bubbles, they can be exposed to an external stress such as a high-temperature and high-humidity test for a short time to reveal the peeling or bubbles and make visual observation. Further, it is desirable that such a portion having a low adhesive strength exists along the fiber within a distance of 5 mm from the fiber.

  When the optical fiber array mounting component according to each of the above embodiments was manufactured and subjected to a high-temperature and high-humidity accelerated test, destructive peeling of the bonded portion was suppressed and high compared to conventional optical fiber array mounting components. It was confirmed that the adhesive strength can be maintained. Further, when an optical device using the optical fiber array mounting component of the present invention was subjected to a high-temperature and high-humidity accelerated test, higher reliability was obtained than before, and the effectiveness of the present invention was confirmed.

  As miniaturization of optical components progresses, the area of the bonding surface of the substrate having the V-groove decreases, and the adhesive force with the lid decreases. Further, in the production of a small optical component, a process such as dicing causes scratches or chips on the substrate or lid of the optical component, thereby reducing the mechanical strength of the optical component. Therefore, in the fourth embodiment of the present invention, by supporting the substrate and the lid with a fixing member, the adhesive strength between the substrate and the lid for gripping the optical fiber is enhanced, and the mechanical strength of the optical component is reinforced. Can do.

  FIG. 22 shows the structure of an optical component according to the fourth embodiment of the present invention. This optical component includes a substrate 20 having a V-groove, an optical fiber array 3 having a core wire disposed in the V-groove, a lid 10 mounted on the substrate so as to fix the core wire to the V-groove, and both sides of the substrate and the lid. And a fixing member 90 bonded to the surface. By adhering the fixing member, the adhesive strength between the V-groove substrate and the lid can be increased. Furthermore, the mechanical strength of the optical component can be reinforced by supporting the side surfaces of the substrate and the lid with a fixing member. Here, the V-groove has been described as an example of the groove. However, as long as the fiber can be accurately fixed, a U-shaped groove or a U-shaped groove may be used, and the shape of the groove is not limited.

  In FIG. 22, the fixing members 90 are bonded to both side surfaces of the substrate and the lid. However, when sufficient strength is obtained, the fixing members 90 may be bonded only on one side as shown in FIG. . In this case, the optical component can be further downsized.

  Also, if there is a difference in bonding strength between the left and right sides of the lid, as shown in FIG. 24, the area of the bonding surface between the substrate and the lid on the side where the fixing member is not bonded is set to the side where the fixing member 90 is bonded. You may enlarge it. By adjusting in this way, the left and right adhesive strength can be balanced.

  Also, the peeling of the lid due to external stress is likely to occur at the end of the lid on the tape fiber side or the opposite end. For this reason, as shown in FIG. 25, a plurality of fixing members 91 may be selectively arranged at a place where peeling is likely to occur.

  In general, a fiber protective agent is applied to the core portion of the fiber. Therefore, as shown in FIG. 26, the protective agent can be prevented from flowing out by adhering to both the lid and the substrate and further adhering the fixing member 92 over the entire side surface of the substrate.

  The above embodiment relates to a plate-like fixing member, but it can be formed in any shape according to the shape of the optical component package. For example, when the optical component package is cylindrical, a semi-columnar fixing member 93 can be used as shown in FIG. Similarly, when mounting in a package at an angle, a trapezoidal fixing member 94 can be used as shown in FIG. As described above, the shape of the fixing member can be arbitrarily changed according to the form of the package and the mounting method.

  Further, instead of using separate fixing members on both sides of the substrate and the lid, for example, a U-shaped integrated fixing member 95 can be used as shown in FIG. Thereby, the number of parts on mounting can be reduced. In this case, the fixing member 95 may be attached from the substrate side as shown in FIG. 29, or the fixing member 95 may be attached from the lid side as shown in FIG. In particular, when it is necessary to protect the fiber, it is preferable to use a fixing member 96 that is attached from the lid side and covers the fiber core wire as shown in FIG.

  Furthermore, as shown in FIG. 32, a fixing member 97 shaped to cover three sides of the side surface of the optical component, the lower surface of the substrate, and the upper surface of the lid can be used. In this case, the lid can be mechanically reinforced against peeling. Here, as shown in FIG. 33, it is not necessary that the U-shaped fixing member is in direct contact with the lid and the V-groove substrate, and the gap 30 can be filled with, for example, an adhesive 30. As shown in FIG. 33, the U-shaped fixing member does not need to cover the entire upper surface of the lid and the entire bottom surface of the substrate, and may be attached to a part of the lid and the substrate.

  The U-shaped fixing member as shown in FIGS. 29 to 33 can be produced by, for example, cutting out a member such as glass or silicon, but if it is produced by molding or the like using plastic or metal. It is easier. In the above embodiment, the U-shaped fixing member has been described as an example. However, the shape is not limited to the U-shape as long as the fiber array component is fixed from three sides. .

  Furthermore, as shown in FIG. 34, a square shape 98 may be formed so as to cover all four surfaces of the substrate and the lid. Thereby, the effects described with reference to FIGS. 29 to 33 can be obtained at a time.

  In the above embodiment, the substrate and the lid are reinforced by the fixing member, so that a smaller optical component can be provided while maintaining the adhesive strength between the substrate and the lid. However, when a tape fiber is used for the optical component, the width of the optical component may be smaller than the width of the tape fiber. This is not a problem when assembling optical components one by one, but mounting a plurality of tape fibers on a substrate on which a plurality of V-groove groups are fabricated, assembling a plurality of optical components, and then dicing, etc. In the case of dividing by, there may be a problem in the dicing process.

  FIG. 35A shows a top view of the fiber array optical component, FIG. 35B shows a cross-sectional view of the tape fiber along line XXXVB, and FIG. 35C shows a cross-sectional view of the substrate and lid portions along line XXXVC. As shown in the figure, the width x (FIG. 35C) of the flat portion outside the V-groove on the substrate needs to be larger than the coating thickness d (FIG. 35B) of the tape fiber, and more than 2d It is desirable that Further, if x ≦ W with respect to the width W (FIG. 35C) of the V-grooved portion of the V-groove substrate, it is possible to give sufficient adhesive strength without using a fixing member.

  In the above embodiment, the thermal expansion coefficient of the fixing member is the same as that of at least one of the substrate and the lid, or the same material, in order to give the optical component provided with the fixing member temperature resistance. Is preferred. For example, when the V-groove substrate is silicon and the lid is quartz glass, the fixing member is preferably made of silicon or quartz glass.

  When fixing the fixing member to the optical component with an adhesive, it is preferable to use the same adhesive as that used for bonding the substrate and the lid from the viewpoint of reliability. When the same adhesive is used, there is also an advantage that when the optical component is assembled, the fixing member can be bonded simultaneously in the bonding process between the substrate and the lid.

  Further, when at least one of the bonding surfaces of the fixing member, the substrate, and the lid is roughened, the bonding area can be substantially increased, and a higher bonding effect can be obtained. Roughening is more effective when the surface roughness Ra is 50 nm to 10 μm.

  As the material of the fixing member, glass, silicon, plastic, metal, or the like can be used according to the optical component to be reinforced. In addition, when a material having UV transparency is used for at least one of the substrate, the lid, and the fixing member, a UV curable resin can be used during assembly, and the time of the assembly process can be shortened.

  Based on the above-described embodiment, a fiber array optical component smaller than the conventional one was manufactured and subjected to an acceleration test using high temperature and high humidity. As a result, the same reliability as the conventional one could be secured. By adopting the structure of the optical component according to the present embodiment, it is possible to reduce the size of the optical component while ensuring the reliability of the connection portion with the optical fiber.

The present invention has been described above with respect to several embodiments. However, in view of the many possible embodiments to which the principles of the present invention can be applied, the embodiments described herein are merely illustrative, It is not intended to limit the scope of the invention. The embodiments illustrated here can be modified in configuration and details without departing from the spirit of the present invention. Further, the illustrative components and procedures may be changed, supplemented, or changed in order without departing from the spirit of the invention.

Claims (29)

In an optical component in which an optical fiber is sandwiched between a substrate and a lid and fixed with an adhesive,
An optical component characterized in that the adhesive force of the adhesive is unevenly distributed, whereby internal stress of the adhesive due to external stress is relieved. The optical component according to claim 1,
The optical component according to claim 1, wherein the adhesive strength of the adhesive is unevenly distributed due to partial peeling or bubbles of the adhesive. The optical component according to claim 1,
An optical component characterized in that the adhesive force of the adhesive is unevenly distributed within 5 mm from the optical fiber. The optical component according to claim 1,
The optical component according to claim 1, wherein the adhesive force of the adhesive is unevenly distributed on or near at least one adhesive surface of the substrate and the lid. The optical component according to claim 4,
An optical component characterized in that an area of a portion where the adhesive strength of the adhesive is weak is 5% to 50% of an area of the entire adhesive surface. The optical component according to claim 4,
The optical component according to claim 1, wherein the adhesive force of the adhesive is periodically and unevenly distributed. The optical component according to claim 6,
The optical component characterized in that the periodic change of the adhesive force of the adhesive is 0.1 μm to 100 μm. The optical component according to claim 1,
The optical component according to claim 1, wherein the adhesive strength of the adhesive is made non-uniform by adding an additive to the adhesive. The optical component according to claim 1,
2. The optical component according to claim 1, wherein the adhesive force of the adhesive is made non-uniform by attaching an organic substance or an inorganic substance to at least one of the bonding surfaces of the substrate and the lid. The optical component according to claim 9, wherein
The optical component is a silane coupling agent or a fluorine-containing resin. The optical component according to claim 9, wherein
The optical component, wherein the inorganic substance is a metal. The optical component according to claim 1,
The optical component according to claim 1, wherein the adhesive force of the adhesive is made nonuniform by modifying a bonding surface of at least one of the substrate and the lid by a surface treatment. The optical component according to claim 1,
The optical component according to claim 1, wherein the adhesive force of the adhesive is made uneven by providing irregularities on at least one adhesive surface of the substrate and the lid. The optical component according to claim 13,
The depth of the unevenness is 0.1 μm to 10 μm. The optical component according to claim 13,
The depth d of the unevenness and the thickness t of the adhesive layer satisfy 0.01 ≦ d / t ≦ 0.2. The optical component according to claim 1,
The optical component according to claim 1, wherein the adhesive force of the adhesive is made non-uniform by roughening at least one adhesive surface of the substrate and the lid. The optical component according to claim 16, wherein
A surface roughness Ra of the roughened adhesive surface is 1 μm to 5 μm. The optical component according to claim 16, wherein
The optical component according to claim 10, wherein a ten-point average roughness Rz of the roughened adhesive surface and a thickness t of the adhesive layer satisfy 0.25 ≦ Rz / t ≦ 2.5. The optical component according to claim 1,
At least one of the substrate and the lid is made of glass, silicon, or plastic. The optical component according to claim 1,
An optical component comprising a fixing member bonded to at least one of the substrate and the side surface of the lid. The optical component according to claim 1,
An optical component, wherein a fixing member is mounted so as to cover three surfaces including at least one of the substrate and the side surface of the lid. The optical component according to claim 20,
The optical component, wherein the fixing member is a flat plate. The optical component according to claim 20 or 21,
The width x of the bonding surface between the substrate and the lid is d ≦ x ≦ W, where d is the thickness of the coating of the optical fiber and W is the width of the groove portion of the substrate. Optical parts. The optical component according to claim 20 or 21,
The optical component according to claim 1, wherein a thermal expansion coefficient of the fixing member is the same as that of one of the substrate and the lid. The optical component according to claim 20 or 21,
The material of the fixing member is the same as that of either the substrate or the lid. The optical component according to claim 20 or 21,
The optical component, wherein the fixing member, the substrate, and the lid are bonded with an adhesive, and the adhesive is the same as the adhesive between the substrate and the lid. The optical component according to claim 20 or 21,
The optical component, wherein the fixing member, the substrate, and the lid are bonded with an adhesive, and at least one of the bonding surfaces is roughened. The optical component according to claim 20 or 21,
The optical member according to claim 1, wherein the fixing member is made of glass, silicon, plastic, or metal. The optical component according to claim 20 or 21,
An optical component, wherein an ultraviolet curable adhesive is used for an adhesive surface between the fixing member, the substrate, and the lid, and at least one of the adhesive surfaces is ultraviolet transmissive.

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