JP4167498B2 - Optical transmission component connection structure and optical connection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a connection structure of an optical transmission connection part obtained by mechanically optically connecting an optical transmission part and a connection method thereof.
[0002]
[Prior art]
[0003]
[Patent Document 1]
JP-A-8-114724.
[Patent Document 2]
Japanese Patent Laid-Open No. 11-101919.
[Patent Document 3]
Japanese Patent Laid-Open No. 2000-241660.
[0004]
When mechanically optically connecting optical transmission components such as optical fibers, usually, the optical fiber end faces are physically connected by applying an axial pressing force. In that case, since the optical fiber is generally brittle and weak, the optical fiber is inserted into a ferrule for protection, thereby enabling physical contact of the optical fiber end face (Patent Document). 1). In that case, the end face of the optical fiber and the ferrule are polished and a pressing force is applied to avoid Fresnel reflection caused by the air existing on the optical fiber joint surface, thereby reducing the connection loss and improving the physical coupling. Be complete.
[0005]
However, the above connection method requires a polishing process of the optical fiber and requires a sturdy housing and a pressure holding mechanism in order to apply a pressing force. This increases the number of parts, increases the size of the connection structure, and increases the cost of the parts. Further, since the ferrule and the optical fiber end face are mechanically brought into contact with each other and a pressing force is applied, the ferrule and the optical fiber end face are deformed to cause light loss.
[0006]
In order to solve these problems, without using a ferrule and without polishing, the end faces of the optical fibers are pressed against each other by applying axial pressure to the end faces of the cut optical fibers to buckle the optical fibers. The method of connecting them is being studied. However, also in this case, since it is necessary to apply a pressing force high enough to buckle the optical fiber, the above-described problem relating to component costs has not been solved. In addition, in order to obtain a constant optical fiber output, it is necessary to adjust the amount of buckling of the optical fiber due to the pressing force. For this purpose, the length of the optical fiber and the pressing force must be finely controlled. It was very difficult to obtain a constant light output. In addition, since the optical fiber end faces to be connected are connected by applying a pressing force, optical loss may occur due to the cutting surface inclination, cut surface chipping or burrs caused by cutting, and optical fiber damage may occur. There was also a problem that it was easy.
[0007]
Furthermore, a splicing method that optically connects the cut optical fiber without any buckling is applied to the end face of the cut optical fiber in the axial direction without using ferrules and polishing, as described above. (Patent Documents 2 and 3). In this system, a refractive index matching agent having a refractive index substantially equal to that of the core of the optical fiber is provided on the end face of the optical fiber to avoid Fresnel reflection caused by air existing on the optical fiber joint surface.
[0008]
However, even with this method, the above-mentioned problem relating to the component cost is still not solved because a pressing force is applied to the optical fiber. In addition, since the refractive index matching agent used in this case is generally a silicone-based or paraffin-based liquid or grease-like material, when a pressing force is applied in the axial direction of the optical fiber, the optical index matching agent is used. The distance between the fiber end faces cannot be kept constant. Eventually, the end faces of the optical fibers are connected in contact with each other. Therefore, the above-mentioned problem due to the abutment of the end face of the optical fiber is still not solved. In addition, it is very difficult to apply a certain amount of liquid and grease-like refractive index matching agent to the end face of an optical fiber having a very small area. Contamination around the connector and adhesion of dust and the like due to the matching agent become a problem. Therefore, the use of a liquid or grease-like refractive index matching agent is not preferable in the optical connection field.
[0009]
Furthermore, in general, it is easier to connect and remove optical components. However, if a refractive index matching agent in the form of a liquid or grease is used and the connection is made detachable, it will be refracted every time it is detached. The process of cleaning and re-applying the rate matching agent is required, and there is a problem that it is difficult to always obtain a constant and stable light output.
[0010]
[Problems to be solved by the invention]
As described above, the above-described various problems have occurred in the method of applying pressure to the current optical fiber and abutting and connecting the end surfaces of the optical fibers and the method using a liquid or grease-like refractive index matching agent. .
The present invention has been made in view of the aforementioned problems. That is, the object of the present invention is to have a simple and inexpensive structure without damage to the optical transmission parts to be connected in the mutual connection of the optical transmission parts, the work at the time of connection is simple, and a stable light output. Another object of the present invention is to provide an optical transmission component connection structure and an optical connection method that can be obtained and can be repeatedly connected.
[0011]
[Means for Solving the Invention]
  In order to achieve the above object, the present inventors have examined the connection structure of the optical transmission component.A refractive index matching agent is supported on a porous substrate selected from polyethylene, polypropylene and polyvinylidene fluorideBy using the refractive index matching sheet, it has been found that the above problems in the prior art are solved, and the present invention has been completed.
  Therefore, the connection structure of the optical transmission component of the present invention is substantially the same as the pair of optical transmission components in which the optical transmission portions face each other with a gap of 1 to 100 μm in width and the optical transmission portion inserted in the gap. And a refractive index matching sheet having a refractive index ofA connection structure for optical transmission components, wherein the refractive index matching sheet has a refractive index matching agent supported on a porous substrate selected from polyethylene, polypropylene, and polyvinylidene fluoride.It is characterized by that.
[0012]
  In the optical connection method of the optical transmission component of the present invention, the optical transmission parts of a pair of optical transmission parts are faced with a gap of 1 to 100 μm in width, and the refractive index is substantially the same as that of the optical transmission part. Insert a refractive index matching sheet withAn optical connection method for an optical transmission component, wherein the refractive index matching sheet has a refractive index matching agent supported on a porous substrate selected from polyethylene, polypropylene, and polyvinylidene fluoride.It is characterized by this. Thereby, it is possible to perform optical connection without directly contacting the end faces of the optical transmission parts of the optical transmission component.
[0013]
  In the present invention, as an optical transmission component having a transmission unit, for example, an optical fiber, an optical waveguide, an optical lens, or the like is used. Further, the refractive index matching sheet may be a sheet-like material having a refractive index substantially equal to the refractive index of the transmission part of the optical transmission component and can maintain the connection interval of the optical transmission component constant. The thickness of the refractive index matching sheet may be any thickness as long as it can be inserted into the gap between the optical transmission components of 1 to 100 μm. Furthermore, the material constituting the refractive index matching sheet isSelected from polyethylene, polypropylene and polyvinylidene fluorideA porous base material carrying a refractive index matching agentIs. Furthermore, the refractive index matching sheet may be a cartridge structure that can be easily attached and detached.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view for explaining an example of a connection structure when an optical fiber is used as an optical transmission component. In FIG. 1, the optical fiber 1 and the optical fiber 2 are abutted with a gap, the refractive index matching sheet 3 is inserted into the gap, and the optical fiber and the refractive index matching sheet are fixed by the adhesive 12. The optical fibers 1 and 2 are mechanically optically connected. In this connection structure, since a refractive index matching sheet having a constant thickness is inserted in the gap between the optical fibers, the optical fiber connection interval is kept constant, and the optical fiber is prevented from being broken and stable. Light output can be obtained.
[0015]
FIG. 2 is a partially broken plan view (FIG. 2A) and sectional view (FIG. 2B) for explaining another example of the connection structure when an optical fiber is used as an optical transmission component. In FIG. 2, four optical fibers 1 a to 1 d and the same four optical fibers 2 a to 2 d from which the coating of the tip portion has been removed are inserted into through holes provided in the alignment member 4 and the alignment member 5, respectively. A concave portion 6 is provided on the end surface of the alignment member 5 so that a gap having a certain width is formed when the alignment member 4 is abutted against the alignment member 4. Next, the alignment members 4 and 5 are butted together, the refractive index matching sheet 3 is inserted into the gap formed by the recess 6, and the alignment members 4 and 5 are fixed by the clip 13. The optical fiber is fixed with an adhesive 12. Thereby, a connection structure is formed in which the multi-fiber optical fibers 1a to 1d and 2a to d are mechanically optically connected. In this case, since a refractive index matching sheet having a constant thickness is inserted in the gap between the multi-fibers, the connection interval of the multi-fibers is kept constant, and damage to the optical fibers is prevented. In addition, a stable light output can be obtained, and the alignment member is provided with a recess, so that the refractive index matching sheet can be easily inserted, and the connection operation and the replacement operation can be easily performed.
[0016]
FIG. 3 is a drawing for explaining an example of a connection structure when optical connection is performed using an optical waveguide and an optical fiber as an optical transmission component. FIG. 3 is a plan view in which the connection structure is partially crushed. 4A to 4C are plan views of various refractive index matching sheet cartridges used in the connection structure of FIG. In FIG. 3, two optical fibers 1 a and 1 b from which the coating of the optical fiber tip is removed are inserted into through holes provided in the alignment member 7 and fixed by an adhesive 12. The optical fiber is optically connected to the optical waveguide 8 via the refractive index matching sheet 3. The optical connection is performed as follows. That is, the refractive index matching sheet cartridge having the structure in which the support frame 9 shown in FIG. 4 is provided on the end face of the refractive index matching sheet 3 is placed in the gap between the alignment member 7 and the optical waveguide 8 facing each other with a certain gap. After that, the optical fiber and the optical waveguide are fixed by the clip 13, thereby forming a connection structure in which the refractive index matching sheet 3 is inserted into the gap where the optical fiber 1 and the optical waveguide 8 face each other. The In the case of the refractive index matching sheet cartridge having the structure of FIG. 4A, the support frame 9a is configured to be set on the support frame 9 after inserting the refractive index matching sheet. As in the case of FIG. 3, even in the optical connection between different types of optical transmission components, by inserting a refractive index matching sheet having a certain thickness into the gap, the connection interval of the optical transmission components is kept constant. Damage to the optical transmission component is prevented. Further, since the refractive index matching sheet is made into a cartridge, the cartridge can be easily attached and detached, the connection and replacement workability is improved, and the light output is stable.
[0017]
FIG. 5 is a diagram for explaining an example of an optical connection method for forming the connection structure of the present invention, and FIG. 6 is a plan view and one view of various refractive index matching sheet cartridges used in the connection structure of FIG. FIG. As shown in FIG. 5, first, the optical fibers 1 from which the coatings of the tip portions are removed are respectively inserted into the through holes of the two alignment members 10 provided with the engagement grooves 10a, and the two alignment members 10 are fixed. Face each other so as to maintain a gap of width (w) (FIG. 5A). Next, a refractive index matching sheet cartridge having a structure in which the refractive index matching sheet 3 is fitted to the support frame 11 provided with the latch portion 11a shown in FIG. 6 is inserted into the gap w, and the latch portion 11a is inserted into the engaging groove 10a. The alignment members 10 and the cartridge are fixed by being engaged. Thereafter, the end face of the optical fiber 1 is pressed against the refractive index matching sheet 3, and the optical fiber is fixed to the alignment member 10 with the adhesive 12 to form an optical fiber connection structure (FIG. 5B). According to the above method, it is possible to form a simple connection structure in which the two optical fibers maintain a constant connection distance, and the optical fiber is not damaged during the connection work. It is possible to connect the fibers easily.
[0018]
When performing the above optical connection, it is preferable to use a passive alignment such as a method of providing a V-shaped structure or a rectangular groove in the alignment member for the alignment of the optical transmission component. A known alignment method can also be used.
[0019]
FIG. 7 is a diagram for explaining another example of the optical connection method for forming the connection structure of the present invention. The optical connection of the optical transmission component in this figure uses an optical fiber and an optical waveguide. FIG. 7A is a plan view showing a state before connection, and FIG. 7B is a connection state. It is a partially broken side view shown. As shown in FIG. 7, first, two optical fibers 1a and 1b from which the coating of the tip portion has been removed are inserted into the through-holes of the alignment member 7 provided with the engagement grooves 7a, and the light having the engagement grooves 8a. It faces to the end face of the waveguide 8 so as to keep a gap of a certain width (w) (FIG. 7A). Next, a refractive index matching sheet cartridge having a structure similar to that shown in FIG. 6, that is, a refractive index matching sheet cartridge having a structure in which the refractive index matching sheet 3 is fitted in the support frame 11 provided with the latch portion 11a, The alignment member 7 and the optical waveguide 8 are fixed to the cartridge by inserting the latch portion 11a into the engagement grooves 7a and 8a. Thereafter, the optical fiber 1 is pressed against one surface of the refractive index matching sheet 3, and at the same time, the other surface of the refractive index matching sheet is pressed against the end surface of the optical waveguide 8. And an optical fiber is fixed to the alignment member 7 with the adhesive agent 12, and the connection structure of an optical fiber and an optical waveguide is formed (FIG.7 (b)). According to the above method, since the connection structure is very simple, it is possible to easily connect the two optical fibers and the optical waveguide while maintaining a constant connection distance.
[0020]
FIG. 8 is a diagram for explaining another example of the optical connection method for forming the connection structure of the present invention. The optical connection of the optical transmission component in this figure uses an optical fiber and an optical lens array. As shown in FIG. 8, first, four optical fibers 1 a to 1 d from which the coating of the tip portion has been removed are inserted into the through holes of the alignment member 4, and the end face of the optical lens array 14 and a certain width (w). Face each other so as to hold the gap (FIG. 8A). Next, the refractive index matching sheet 3 is inserted into the gap, and then the optical fiber and the optical lens array are pressed against the refractive index matching sheet. The optical fiber and the alignment member, and the alignment member, the refractive index matching sheet, and the optical lens array Are each fixed with an adhesive 12 to form a connection structure between the optical fiber and the optical lens (FIG. 8B). According to the above method, it is possible to easily form a connection structure in which the four optical fibers and the optical lens maintain a constant connection distance, and the optical fiber is broken during the connection work. It is possible to easily connect the optical fiber to the optical lens.
[0021]
FIG. 9 is a diagram for explaining another example of the optical connection method for forming the connection structure of the present invention. The optical connection of the optical transmission component in this figure uses an optical waveguide and an optical lens array. As shown in FIG. 9, first, the both end faces of the optical waveguide 8 and the end face of the optical lens array 14 face each other so as to maintain a gap having a constant width (w) (FIG. 9A). Next, the refractive index matching sheet 3 is inserted into the gap, and then the optical waveguide and the optical lens array are pressed against the refractive index matching sheet, and the optical waveguide, the refractive index matching sheet, and the optical lens array are fixed with the adhesive 12. Then, a connection structure between the optical waveguide and the optical lens is formed (FIG. 9B). According to the above method, it is possible to easily form a connection structure in which the optical waveguide and the optical lens maintain a constant connection distance, and the optical fiber may be broken during the connection work. It is possible to easily connect the optical fiber to the optical lens.
[0022]
In the present invention, the gap between the optical transmission parts of the pair of optical transmission parts facing each other needs to be in the range of 1 to 100 μm from the viewpoint of forming and holding the gap. When the gap width is larger than 100 μm, the connection loss between the optical transmission components increases. On the other hand, when the gap width is smaller than 1 μm, it is difficult to insert the refractive index matching sheet, and the gap between the optical transmission components is maintained. It is difficult to do this, and the optical transmission component is damaged due to a collision in the connection of the optical transmission component. Therefore, it is necessary to be within the above range.
[0023]
The optical transmission component having the optical transmission unit used in the present invention is not particularly limited as long as it is used for transmitting light, and may be appropriately selected according to the purpose of use. Examples thereof include a single mode or multimode optical fiber made of quartz or plastic, an optical waveguide made of quartz or polymer resin, and a lens.
[0024]
  In the present invention, the refractive index matching sheet is inserted into a gap between optical transmission components that are mechanically optically connected, and the gap is maintained to avoid direct contact in the optical transmission portion of the optical transmission component. It is a sheet-like material having a refractive index almost equal to that of the transmission part of the optical transmission component so that the refractive index matching between them can be achieved.TheIn addition, the refractive index of the refractive index matching sheet is preferably in the range of about ± 0.1 with respect to the refractive index of the optical transmission part of the optical transmission component from the aspect of transmission loss due to avoidance of Fresnel reflection. It is preferably in the range of ± 0.05, more preferably in the range of ± 0.02.
[0025]
Further, the thickness of the refractive index matching sheet inserted into the gap is not particularly limited as long as it can be inserted into the gap, and is specifically in the range of about 1 to 100 μm. More preferably, it is 1-50 micrometers, More preferably, it is the range of 1-20 micrometers. When the thickness of the refractive index matching sheet is greater than 100 μm, as described above, the connection loss between transmission components increases, which is not preferable. On the other hand, if the refractive index matching sheet is thinner than 1 μm, it becomes difficult to handle the refractive index matching sheet, and the gap between the optical transmission parts cannot be maintained even in the connection of the optical transmission parts. The possibility of causing damage to the optical transmission component is increased. Further, if the thickness of the refractive index matching sheet is too thick with respect to the gap, it is difficult to insert the refractive index matching sheet into the gap. Conversely, if the thickness is too thin, it is difficult to hold the refractive index matching sheet and the optical transmission part of the optical transmission component. Therefore, it is preferable that the thickness of the refractive index matching sheet has substantially the same thickness as the gap between the optical transmission parts facing each other.
[0026]
  The refractive index matching sheet in the present invention satisfies the aforementioned thickness and refractive index.TheIts constituent materialsIsPolyethylene, polypropyleneandPolyvinylidene fluorideChosen fromA porous substrate with a refractive index matching agent applied or impregnated to form a sheet.It is.
[0027]
In addition, the shape of the refractive index matching sheet in the present invention is not particularly limited, and may be appropriately selected and used depending on the optical transmission component to be used. In consideration of maintainability such as the above, it is preferable that the refractive index matching sheet has a cartridge structure.
[0028]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.
[0029]
Reference example 1
  As a refractive index matching sheet, a fluorinated epoxy resin adjusted to a refractive index of 1.46 was made into a sheet, and a sheet having a thickness of 12 μm and a size of 2 mm × 2 mm was produced. Next, optical connection was made using this refractive index matching sheet to form a connection structure shown in FIG. That is, the coating of the optical fiber 1 (Furukawa Electric Co., Ltd., 250 μm diameter) was removed 20 mm from the end, the optical fiber (125 μm diameter) was exposed, and the optical fiber was cut at 10 mm from the end. This optical fiber was inserted into the through holes of the two alignment members 10 having the engaging grooves 10a. Thereafter, the end surfaces of the two alignment members 10 were faced to maintain a gap of about 12 μm (FIG. 5A). Next, a refractive index matching sheet cartridge having a structure in which the refractive index matching sheet 3 is fitted to the support frame 11 provided with the latch portion 11a shown in FIG. 6 is inserted into the gap, and the latch portion 11a is engaged with the engaging groove 10a. Together, each alignment member 10 and the cartridge were fixed. Thereafter, the end face of the optical fiber 1 was pressed against the refractive index matching sheet 3, and the optical fiber was fixed to the alignment member 10 with the adhesive 12 to form an optical fiber connection structure (FIG. 5B).
[0030]
The formed optical fiber connection structure is formed by inserting a 12 μm thick refractive index matching sheet into a 12 μm gap between facing optical fibers. Damage to the optical fiber could be prevented. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0031]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 0.4 dB or less. Further, this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of 500 times from −40 ° C. to 75 ° C. It was found that it was 7 dB or less, showed a very stable optical transmission property, and was sufficiently usable as an optical connection structure.
[0032]
Reference example 2
  Reference example 1In order to maintain the thickness of the sheet, 1 part by weight of silicone rubber powder (manufactured by Toray Dow Corning Silicone Co., Ltd.) is added, and the refractive index is 15 μm made of polyfluoroalkyl methacrylate adjusted to a refractive index of 1.46. A matching sheet was prepared and used, and the gap between the facing optical fiber strands was changed to 15 μm.Reference example 1In the same manner, an optical fiber connection structure was formed.
[0033]
The formed optical fiber connection structure is formed by inserting a refractive index matching sheet having a thickness of 15 μm into a 15 μm gap between facing optical fiber strands. It was possible to prevent damage to the connecting optical fiber. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0034]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 0.4 dB or less. Further, this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of 500 times from −40 ° C. to 75 ° C. It was found to be 8 dB or less, exhibit very stable light transmission properties, and be sufficiently usable as an optical connection structure.
[0035]
Example 1
  In Example 1, as a refractive index matching sheet, a fluorinated epoxy resin adjusted to a refractive index of 1.46 is supported on a porous base material of polyvinylidene fluoride by impregnation, and formed into a sheet, thickness 20 μm, size 2 mm × 2 mm. Except for using the sheet made of the above, and changing the gap between the facing optical fiber strands to 20 μm,Reference example 1In the same manner, an optical fiber connection structure was formed.
[0036]
The formed optical fiber connection structure is formed by inserting a refractive index matching sheet having a thickness of 20 μm into a 20 μm gap between facing optical fiber strands. It was possible to prevent damage to the connecting optical fiber. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0037]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 0.8 dB or less. In addition, when this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of 500 times from −40 ° C. to 75 ° C. It was found that it was 0 dB or less, showed a very stable optical transmission property, and was sufficiently usable as an optical connection structure.
[0038]
Reference example 3
  Reference example 1In the above, except that a refractive index matching sheet having a thickness of 3 μm was prepared and the gap between the facing optical fiber strands was changed to 3 μm,Reference example 1In the same manner, an optical fiber connection structure was formed.
[0039]
The formed optical fiber connection structure is formed by inserting a 3 μm thick refractive index matching sheet into a 3 μm gap between facing optical fiber strands. It was possible to prevent damage to the connecting optical fiber. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0040]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 0.3 dB or less. Further, this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of -40 ° C. to 75 ° C., 500 times. It was found to be 5 dB or less, very stable optical transmission property, and sufficiently usable as an optical connection structure.
[0041]
Reference example 4
  Reference example 1In the above, except that a refractive index matching sheet having a thickness of 95 μm is manufactured and the gap between the facing optical fiber strands is changed to 95 μm,Reference example 1In the same manner, an optical fiber connection structure was formed.
[0042]
The formed optical fiber connection structure is formed by inserting a 95 μm thick refractive index matching sheet into the 95 μm gap between the facing optical fiber strands, so that it is not necessary to apply a pressing force to the optical fiber. It was possible to prevent damage to the connecting optical fiber. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0043]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 2.0 dB or less. In addition, when this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of 500 times from −40 ° C. to 75 ° C. It was found that it was 0 dB or less, showed a very stable optical transmission property, and was sufficiently usable as an optical connection structure.
[0044]
Reference Example 5
  Reference example 2A refractive index matching sheet having a thickness of 12 μm and a size of 1 × 5 mm was produced using the same material as that used in the above. Next, an optical connection structure shown in FIG. 2 was formed using this refractive index matching sheet. That is, the coating of each of the four optical fibers 1a to 1d, 2a to 2d (Furukawa Electric Co., Ltd., 250 μm diameter) is removed 20 mm from the end to expose the optical fiber (125 μm diameter), and 10 mm from the end. By the way, the optical fiber was cut. Each of these four optical fibers was inserted into the through holes of the two alignment members 4 and 5. The two alignment members 4 and 5 were then abutted against each other. Thereafter, the refractive index matching sheet is inserted into the slit formed by the recess 6 provided in the alignment member 5, and the end faces of the optical fibers 1 a to 1 d and 2 a to 2 d are formed on the refractive index matching sheet 3. The optical fibers 1a to 1d and 2a to 2d are fixed to the alignment members 4 and 5 with an adhesive, and the alignment members 4 and 5 are fixed with a clip 13 to connect a large number of optical fibers. The connection structure of the structure was formed.
[0045]
Since the formed optical fiber connection structure is formed by inserting a 12 μm thick refractive index matching sheet into a 12 μm gap between the facing optical fiber strands, it is not necessary to apply a pressing force to the optical fiber. It was possible to prevent damage to the connecting optical fiber. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0046]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 0.6 dB or less. Further, this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of 500 times from −40 ° C. to 75 ° C. It was found to be 8 dB or less, exhibit very stable light transmission properties, and be sufficiently usable as an optical connection structure.
[0047]
Reference Example 6
  Reference Example 5In the above, except that a refractive index matching sheet having a thickness of 50 μm is manufactured and the gap between the optical fiber strands facing each other is changed to 50 μm,Reference Example 5In the same manner, an optical fiber connection structure was formed.
[0048]
The formed optical fiber connection structure is formed by inserting a refractive index matching sheet having a thickness of 50 μm into a 50 μm gap between the facing optical fiber strands. It was possible to prevent damage to the connecting optical fiber. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent occurs around the connection portion, and no dust or the like is attached.
[0049]
In addition, when the connection loss of the optical fiber in the formed connection structure was measured, it was 1.5 dB or less. Further, this connection structure was subjected to a high temperature and high humidity test that was allowed to stand at 85 ° C. and 85% RH for 5000 hours and a temperature cycle test of 500 times from −40 ° C. to 75 ° C. It was found that it was 0 dB or less, showed a very stable optical transmission property, and was sufficiently usable as an optical connection structure.
[0050]
Reference Example 7
  Reference Example 5In the same manner as described above, the alignment member 4 in which the refractive index matching sheet 3 and the four optical fibers 1a to 1d were inserted was produced. Next, as shown in FIG. 8, the gap between the alignment member 4 and the optical lens array 14 is maintained at about 12 μm, and the refractive index matching sheet 3 is inserted into the gap, and then the optical fiber and the optical lens array are refracted. The optical fiber and the alignment member, and the alignment member, the refractive index matching sheet, and the optical lens array were each fixed with an adhesive 12 to form the connection structure of the present invention.
[0051]
The connection structure between the formed optical fiber and the optical lens is formed by inserting a refractive index matching sheet having a thickness of 12 μm into the gap between the facing optical fiber and the optical lens. Therefore, it was not necessary to apply it, and therefore damage to the connected optical fiber could be prevented. Further, it is not necessary to perform a polishing operation, the connection operation is simple, and a connection structure having a simple structure can be formed. Furthermore, since the refractive index matching sheet is formed into a sheet, there is no work of applying a refractive index matching agent, and therefore no contamination by the refractive index matching agent in the vicinity of the connection portion occurs, and no dust or the like is attached.
[0052]
Comparative Example 1
In Example 1, an optical fiber connection structure was prepared in the same manner as in Example 1 except that a refractive index matching sheet having a thickness of 0.5 μm was prepared and the gap between the facing optical fibers was changed to 0.5 μm. Formed.
[0053]
The formed optical fiber connection structure is such that the optical fiber is connected via the refractive index matching sheet, but the thickness of the refractive index matching sheet is thin, so that the optical fiber end portion is formed by mechanical optical connection of the optical fiber. Was damaged. Moreover, it was very difficult to handle and it was not easy to mount the refractive index matching sheet.
[0054]
Comparative Example 2
In Example 1, an optical fiber connection structure was formed in the same manner as in Example 1 except that a refractive index matching sheet having a thickness of 150 μm was prepared and the gap between the facing optical fibers was changed to 150 μm.
[0055]
In the formed optical fiber connection structure, the optical fiber was able to keep the connection distance constant by the refractive index matching sheet, and it was possible to prevent damage in the optical connection of the optical fiber. As a result of measurement, it was found that the connection loss is 10 dB, and an excessive loss occurs, so that it is not suitable for use as a connection structure of an optical transmission component.
[0056]
【The invention's effect】
The connection structure of the optical transmission component of the present invention is a structure in which a gap is provided between the optical transmission components and a refractive index matching sheet is inserted into the gap, and the structure is very simple. Further, since the refractive index matching sheet formed into a sheet is used, in the connection between the same or different optical transmission components, the optical transmission components are not in direct contact with each other, and therefore, the optical transmission components to be connected are not damaged, and In addition, since it is not necessary to apply a polishing operation or a pressing force, the connection operation is simple, and a connection structure is obtained in which a stable light output can be obtained. Furthermore, when the refractive index matching sheet is formed into a cartridge, the operation at the time of connection is further simplified, and it is possible to repeatedly connect using the cartridge.
[Brief description of the drawings]
FIG. 1 is a plan view for explaining an example of a connection structure of the present invention when an optical fiber is used as an optical transmission component.
FIG. 2 is a drawing for explaining another example of the connection structure of the present invention when an optical fiber is used as an optical transmission component.
FIG. 3 is a drawing for explaining an example of a connection structure when optical connection of the present invention is performed using an optical waveguide and an optical fiber as an optical transmission component.
4 is a plan view of various refractive index matching sheet cartridges used in FIG. 3. FIG.
FIG. 5 is a diagram illustrating an example of an optical connection method for forming the connection structure of the present invention.
6 is a plan view and a partially broken side view of the refractive index matching sheet cartridge used in FIG.
FIG. 7 is a diagram illustrating another example of the optical connection method for forming the connection structure of the present invention.
FIG. 8 is a diagram for explaining an optical connection method of the present invention when an optical fiber and an optical lens are used as an optical transmission component.
FIG. 9 is a diagram for explaining an optical connection method of the present invention when an optical waveguide and an optical lens are used as an optical transmission component.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a-1d, 2, 2a-2d ... Optical fiber, 3 ... Refractive index matching sheet, 4, 5, 7, 10 ... Alignment member, 7a, 10a ... Engaging groove, 6 ... Recessed part, 8 ... Optical waveguide, 9, 11 ... support frame, 11a ... latch part, 12 ... adhesive, 13 ... clip, 14 ... optical lens (array), w ... width of gap.

Claims (6)

Light composed of a pair of optical transmission parts in which the optical transmission parts face each other with a gap of 1 to 100 μm in width, and a refractive index matching sheet inserted in the gap and having almost the same refractive index as the optical transmission part A connection structure for transmission parts,
The connection structure for an optical transmission component, wherein the refractive index matching sheet is a porous substrate selected from polyethylene, polypropylene, and polyvinylidene fluoride, and a refractive index matching agent is supported.   The connection structure for an optical transmission component according to claim 1, wherein the pair of optical transmission components includes optical fibers.   2. The connection structure for an optical transmission component according to claim 1, wherein the pair of optical transmission components includes an optical fiber and an optical waveguide.   2. The connection structure for an optical transmission component according to claim 1, wherein the pair of optical transmission components includes an optical fiber or an optical waveguide and an optical lens. 2. The connection structure for an optical transmission component according to claim 1, wherein the refractive index matching sheet has a cartridge type structure. The optical transmission part of a pair of optical transmission parts faces each other with a gap of 1 to 100 μm in width, and a refractive index matching sheet having substantially the same refractive index as the optical transmission part is inserted into the gap. A connection method,
The method for optical connection of an optical transmission component, wherein the refractive index matching sheet is obtained by supporting a refractive index matching agent on a porous substrate selected from polyethylene, polypropylene, and polyvinylidene fluoride.

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