JP2005351918A - Optical splicing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a splicing method with which the splicing work is simplified without damaging optical fibers, the amount of bending of the optical fibers during splicing is controlled and the space on an optical module substrate is effectively used. <P>SOLUTION: The optical splicing method obtains the contacting force of the end faces of the optical fibers from the stress being generated by the bending of the optical fibers. The method has an optical fiber fixing step in which an optical fiber is inserted into a plug and fixed, a bending step in which the optical fiber is bent, a positioning step in which two optical fibers are positioned and the relative position between the plugs is fixed and a butting step in which bending of the optical fiber is released to butt the optical fibers together. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique related to an optical connection method suitable for connecting single-core and multi-core optical fibers.

  When connecting optical fibers widely used for optical communication or the like with an optical connector, or when connecting optical components on an optical module substrate with optical fibers, the end surfaces of the optical fibers or the end surfaces of the optical fiber and the optical components There is a type in which the contact force between each other is obtained from the stress generated by the bending of the optical fiber. As this type of optical connection method, the method of FIG. 7 is known (see, for example, Patent Document 1). That is, in FIG. 7, the first optical fiber 1 is attached to the first plug 3 so as to be slidable in the axial direction of the optical fiber, while the second optical fiber 2 is the second plug 4. It is being fixed to the fixed part 5 (FIG. 7 (a)). The first plug 3 and the second plug 4 are fixed to face each other at a position where the first and second optical fibers are aligned (FIG. 7B). Thereafter, when a stress is applied to move the first optical fiber in the right direction in the figure, the first optical fiber 1 is abutted against the second optical fiber 2 and further bent (FIG. 7 (c). )). In this state, when the first optical fiber 1 is fixed to the first plug 3 by the fixing portion 5, the state in which stress due to bending is applied to the end face of the optical fiber is maintained, and the optical connection is completed. However, in this method, it is necessary to apply a stress to move the first optical fiber in the right direction. However, it is not easy to give a certain amount of stress and a moving amount, and an excessive stress or moving amount. Causes problems such as damaging the optical fiber. In addition, it is necessary to secure a space behind the plug to give stress and movement in the optical fiber axis direction, and the degree of freedom of arrangement of optical components connected to the optical fiber is limited, and the space on the optical module substrate There is also a problem that cannot be used effectively.

On the other hand, the method of FIG. 8 is also known (for example, refer patent document 2). In the method of FIG. 8, the first optical fiber 1 is fixed to the first plug 3 and the second optical fiber 2 is fixed to the second plug 4 by the fixing portions 5. At that time, the first optical fiber 1 is slightly protruded from the tip of the plug 3, and the tip of the second optical fiber is located at the tip of the plug 4 (FIG. 8A). In this state, stress is applied so that the tips of the first plug 3 and the second plug 4 are in close contact with each other at a position where the first and second optical fibers are aligned. As a result, the optical fiber is bent, and the relative positions of the plug 3 and the plug 4 are fixed in this state (FIG. 8B). This method has the feature that the amount of bending can be controlled, that is, the stress due to bending can be controlled by the length of the optical fiber protruding from the tip of the plug. Since the optical fibers are aligned with each other in a state protruding from the optical fiber, there is a problem that the tip of the optical fiber is easily damaged.
JP-A-8-15567 JP 2000-235132 A

  As described above, in the optical connection method in which the contact force between the end faces of the optical fiber is obtained from the stress generated by the bending of the optical fiber, the amount of bending, that is, the amount of pressure applied to the end face of the optical fiber is simply controlled. In addition, there is no simple connection method that does not damage the tip of the optical fiber when aligning the optical fibers and does not require a space behind the plug to move the optical fiber after aligning the optical fibers. It was. The present invention proposes an optical connection method that solves these problems.

  According to a first optical connection method (claim 1) of the present invention for solving the above problems, at least one of the first and second optical fibers fixed to the first and second plugs is bent. An optical connection method in which the tips are optically connected to each other in the state, and has the following four steps as shown in FIG. The four steps are to insert the first optical fiber 1 and the second optical fiber 2 into the first plug 3 and the second plug 4 respectively, and fix each optical fiber to each plug with the fixing portion 5. An optical fiber fixing step (FIG. 1 (a)), a bending step (FIG. 1 (b)) for bending the first optical fiber 1 ahead of the fixing portion 5, and the first and second lights An alignment step (FIG. 1 (c)) for aligning the fibers and fixing the relative positions of the first and second plugs, partially opening the bend of the first optical fiber 1; This is a butting step (FIG. 1 (d)) in which a part is left and the first and second optical fibers are butted. In FIG. 1, only the first optical fiber is bent, but the second optical fiber may be bent or both of the two optical fibers may be bent.

  In the bending step, the first optical fiber can be bent by applying pressure to the first optical fiber from the side surface. Further, by releasing this pressing, the bending of the first optical fiber can be released in the abutting step. As described above, in order to apply pressure to the optical fiber from the side surface, a pressing member for pressing the plug above the plug can be detachably attached, thereby applying pressure or releasing the pressure.

  Moreover, in the said alignment process, an alignment process becomes easy by using an alignment member. As the alignment member, a V groove, a through hole, an alignment guide pin, or the like can be used.

  In the positioning step of the present invention, a method of fixing the relative positions of the first and second plugs by fixing the first and second plugs to the adapter may be employed. As the adapter, an adapter having an open top so that the plug can be mounted from above as shown by reference numeral 9 in FIG.

  The second optical connection method of the present invention (Claim 2) is the case where the first optical fiber and the optical component are directly connected, that is, the case where the second optical fiber is not interposed. The outline of the method is shown in FIG. Reference numeral 20 in FIG. 2 denotes an optical component such as a laser module, and other reference numerals are the same as those in FIG. This method also has four steps. In the four steps, the first optical fiber 1 is inserted into the first plug 3, and the first optical fiber 1 is fixed to the plug 3 with a fixing portion. An optical fiber fixing step (FIG. 2 (a)), a bending step (FIG. 2 (b)) for bending the first optical fiber 1 ahead of the fixing portion, and the first optical fiber 1. An alignment step (FIG. 2 (c)) for aligning the optical component 20 and fixing the relative position between the first plug 3 and the optical component 20, and partially releasing the bending of the first optical fiber 1. 2 is a butting process (FIG. 2D) in which a part of the first optical fiber 1 and the optical component 20 are butted. In addition, as an optical component, a laser module, a light receiving element, various lenses, a polarizing plate, a wavelength plate, or the like can be used.

  In the optical connection method of the present invention, the contact force between the end faces of the optical fiber is obtained from the stress generated by the bending of the optical fiber. The magnitude of this stress can be controlled, for example, by the length of the first optical fiber 1 protruding from the plug 3 in FIG. 1A, so that excessive stress can be prevented. It is possible to prevent the optical fiber from being damaged.

  Further, in the optical connection method of the present invention, when the optical fibers are aligned with each other, as shown in FIGS. 1B and 1C, the end of the optical fiber does not protrude from the plug. The optical fiber can be prevented from being damaged at the time of alignment. Further, in the present invention, it is not necessary to apply stress in the axial direction of the optical fiber from the rear part of the optical fiber when the optical fibers are butted together. Therefore, a space for this is not required behind the plug, and the space on the optical module substrate can be used effectively.

  The present invention will be specifically described with reference to FIGS. FIGS. 3A to 3E show examples in which the optical connection method of the present invention for connecting the first optical fiber 1 and the second optical fiber 2 can be best implemented. However, the present invention is not limited to this form. In addition, although the part inside the plug of the optical fiber in the figure cannot actually be seen from the front outside, it is drawn with a solid line for convenience.

  FIG. 3A shows members used in this embodiment. The first plug 3 has an alignment member 8 (a member having a through hole) and an optical fiber insertion portion 6b in the front, a bent cell portion 7 that provides a space where the optical fiber is bent in the center, and the rear. Has an optical fiber insertion portion 6a. In addition, a pressing member 12 that presses the optical fiber from the side surface is detachably attached to the upper part. The curved surface portion 13 is a portion that directly contacts and presses the optical fiber. On the other hand, the second plug 4 is composed of an alignment member 8 (a member having a through hole). Reference numeral 9 denotes an adapter, which has a structure in which an upper part is opened, and has a structure in which two plugs are installed and fixed from above. The portion 18 of the first plug and the portion 19 of the adapter are structured to be fitted to each other like a latch and a latch engaging portion. The plug 3, the adapter 9, and the pressing member 12 are made of ABS resin. The alignment member 5 is formed by cutting an 8-core MT ferrule and using only the tip portion.

  FIG. 3B is a diagram showing an optical fiber fixing step. As the first and second optical fibers, two coatings of the 250 μm diameter silica-based optical fiber are removed from the end by 15 mm, and the optical fiber (125 μm diameter) is cut at 10 mm from the coated end. An optical fiber is used. First, the distal end portion of the first optical fiber 1 is inserted from the left optical fiber insertion portion 6a of the first plug 3 to the alignment member 8 through the bent cell portion 7 and the right optical fiber insertion portion 6b. To do. Thereafter, the optical fiber 1 is fixed to the plug 3 by the fixing portion 5. The second optical fiber 3 is also inserted into the plug 4 and fixed by the fixing portion 5 (FIG. 3B). An adhesive or the like is used for fixing the optical fiber to the plug.

  FIG. 4 is an enlarged view when the optical fiber is fixed to the plug. The second optical fiber 2 is kept in a state in which the tip of the optical fiber is retracted from the tip of the plug so as not to protrude from the plug 4. The first optical fiber 1 is projected from the alignment member 8 at the tip of the first plug. The protruding length (b in FIG. 4) is longer than the distance (c in FIG. 4) from the tip of the second optical fiber 2 to the tip of the second plug 4 by a length a. That is, there is a relationship of a = bc. This length a determines the amount of bending of the optical fiber at the time of optical connection, and determines the stress on the end face of the optical fiber. The length of “a” will be described later.

  FIG. 3C is a diagram showing a bending process. In the bending step, the pressing member 12 is placed on the plug 3 so that the curved surface portion 13 of the pressing member 12 enters the bending cell portion 7, and the curved surface portion 13 is below the optical fiber 1 in the bending cell portion 7. By applying a pressing force to the optical fiber 1, the optical fiber 1 is bent in the bent cell portion 7 to form a bent portion (FIG. 3C). At this time, the tip of the first optical fiber protruding from the first plug is drawn into the plug.

  FIG. 3D is a diagram showing an alignment process. In the alignment step, the first plug 3 and the second plug 4 are installed on the adapter 9 from above. After the alignment members between the plug 3 and the plug 4 are aligned, both plugs are fixed to the adapter (FIG. 3 (d)). Thereby, all members are fixed. About the 1st optical fiber 1, only the part ahead from the fixing | fixed part 5 exists in the state in which the movement to the axial direction of a fiber is possible. The plug is fixed by a fitting structure of 18, 19 or using an adhesive. FIG. 5 shows an example of a fitting structure of 18 and 19, and is a view of FIG. The fitting structure of 18 and 19 is not limited to this.

  FIG. 3E is a diagram showing a matching process. In this step, the pressing member 12 is pulled upward from the bent cell portion 7 of the plug 3 and removed. The bent optical fiber 1 extends to the distal end side due to its own elasticity and is inserted into the through hole of the plug 4, so that it contacts the end face of the second optical fiber 2 inside the plug 4. At this time, since the optical fiber 1 is not fully extended and remains bent, stress is applied to the end face of the optical fiber 2 (FIG. 3E). This completes the optical connection between the optical fibers. According to the above embodiment, since the optical fiber 1 can be bent and the tip of the optical fiber 1 can be moved with only a simple jig without providing a special device in the plug 3, the optical connection method is simplified. Can be

  The length of a described above (that is, bc in FIG. 4) will be described. The appropriate length of a depends on the type of optical fiber and the length of the bent portion. When a silica glass optical fiber core wire with a diameter of 250 μm is used and the length of the bent portion of the optical fiber is 7 mm, a is preferably 20 μm or more and 300 μm or less. By setting to this range, even if the variation in the length of the optical fiber is about ± 20 μm, the tip of the optical fiber is not separated and can be connected without damaging the optical fiber. A more preferable length of a is 40 μm or more and 150 μm or less. By setting this range, it is possible to obtain a bend in which a more appropriate stress is generated, and to suppress an increase in bend loss due to an excessive bend of the optical fiber. When the optical fiber bent portion is longer than 7 mm, the preferable length of a is long and the preferable range of a is also widened. A wider preferred range of a means that the required accuracy of the initial cut length of the fiber is loosened and means that optical connection is easier. In addition, since the fracture bending radius and bending loss characteristics of the optical fiber differ depending on the material of the optical fiber, a must be selected and set according to the specifications of the optical fiber to be used and the required insertion loss. There is.

  In the above embodiment (FIG. 3), the optical fiber is fixed to the plug, but the ferrule to which the optical fiber is fixed may be fixed to the plug. The second optical fiber 2 is fixed to the plug 4 and the plug 4 is fixed to the adapter 9 later. However, after the plug 4 is installed on the adapter 9, the optical fiber 2 may be fixed to the adapter 9. I do not care.

  Alternatively, a refractive index matching agent may be applied between both optical fibers 1 and 2 in advance, and PC (Physical Contact) connection may be performed by abutting the optical fibers together. If a refractive index matching agent is applied, the reliability of optical connection is increased. When using a refractive index matching agent, the material, form, and installation method are not particularly limited. The material may be selected and used depending on the refractive index and material of the optical fiber. For example, silicone oil, silicone grease, etc. are preferably used. The form of the refractive index matching agent may be liquid or solid, and may be, for example, oil, grease, gel, or film.

  The optical fiber used for the optical fiber connecting component of the present invention is appropriately selected and used according to the application purpose of the optical fiber connecting component. For example, a single mode optical fiber made of quartz or plastic, a multimode optical fiber, etc. Preferably used. There is no limit to the number of optical fibers connected at one time. What is necessary is just to design a plug, an adapter, etc. suitably according to the number of optical fibers.

  The material of the plug and adapter used in the optical connection method of the above-described embodiment is not limited to plastic such as ABS, but ceramic, metal, zirconia, glass metal, and the like can also be used. These shapes are not particularly limited as long as the plug can be securely fixed to the adapter.

In addition, although a through-hole member is used as an optical fiber alignment means, the present invention is not limited to this, and other methods such as a method of aligning an optical fiber within a groove, as long as the optical fiber can be easily aligned, are available. The positioning means may be used. In addition, as a material for the alignment member of the optical fiber, a material made of plastic, ceramic, metal, zirconia, glass, metal or the like is preferably used.

  Moreover, in the said embodiment, although the method of pressing the side surface of an optical fiber is used as a means to give a bending to an optical fiber, it is not limited to this method. Further, the pressing member 12 that gives the bend is not limited to the shape shown in FIG. 3A, and may be any shape as long as the optical fiber 1 can be bent without being damaged. However, it is preferable to push the side surface of the optical fiber with a curved surface having a bending radius or more at which the optical fiber 1 is broken. The material of the pressing member 12 is not limited, but is preferably hard enough not to be deformed by the repulsive force of the optical fiber 1 so that the bent shape is uniquely determined by being mounted on the plug 3. Furthermore, in order to bend the optical fiber 1 smoothly without difficulty, it is preferable that the surface is slippery.

  Another example of the embodiment of the optical connection method of the present invention will be described with reference to FIG. FIG. 6 is an example in which both the first optical fiber 1 and the second optical fiber 2 are abutted in a bent state and optically connected, and shows the completion point of the optical connection. The first optical fiber 1, the second optical fiber 2, the first plug 3, the second plug 4, and the alignment member 8 used here are the same as those used in the previous example (FIG. 3A). Is. The adapter 9 has a slightly different shape from the previous example, and the distance from the place where the second plug 4 is fixed to the end of the adapter 9 is long, so that a place where the second optical fiber 2 can be bent is secured. Has been. Further, the pressing member for bending the first optical fiber 1 is the same as the pressing member 12 in FIG. The first plug 3 and the adapter 9 have the fitting structures 18 and 19 like a latch and a latch engaging portion, as in the example of FIG.

  The process leading to FIG. 6 will be briefly described. First, the distal end portion of the first optical fiber 1 is inserted from the left optical fiber insertion portion 6a of the first plug 3 to the alignment member 8 through the bent cell portion 7 and the right optical fiber insertion portion 6b. To do. Thereafter, the optical fiber 1 is fixed to the plug 3 by the fixing portion 5. 3C, the optical fiber 1 is bent using the pressing member 12, and the first plug 3 is installed on the adapter 9 from above.

  About the 2nd optical fiber 2, after inserting in the plug 4, the plug 4 is installed in an adapter from upper direction. Next, after aligning the alignment members of the plug 3 and the plug 4, both plugs are fixed to the adapter, and the second optical fiber is fixed to the adapter by the fixing portion 5. Thereby, all members are fixed. About the 1st optical fiber 1 and the 2nd optical fiber 2, only the part ahead from the fixing | fixed part 5 exists in the state in which the movement to the axial direction of a fiber is possible.

  Finally, when the pressing member (not shown) is removed, the bent optical fiber 1 is extended to the distal end side by its own elasticity, comes into contact with the end face of the second optical fiber 2, and further bends the second optical fiber. Let At this time, the optical fiber 1 and the second optical fiber are stressed on the end faces of each other while being bent together. This completes the optical connection between the optical fibers (state shown in FIG. 6). Thus, the length of a when both optical fibers are bent is preferably twice as long as the length of a when one of the fibers is bent. According to this embodiment, it is possible to bend the optical fiber 1 and the optical fiber 2 with only a simple member without providing a special device for the plug 3, and to perform optical connection in which stress is applied to each other.

(A)-(d) is a schematic diagram explaining an example of the optical connection method of this invention. (A)-(d) is a schematic diagram explaining another example of the optical connection method of this invention. (A) is a top view (front view) explaining the member used for an example of embodiment of the optical connection method of this invention. (B)-(e) is a top view (front view) explaining an example of embodiment of the optical connection method of this invention, (b) is an optical fiber fixing process, (c) is a bending process, (D) illustrates the alignment process, and (e) illustrates the matching process. In the optical fiber fixing process of the optical connection method of this invention, it is a schematic diagram explaining the protrusion length and retracted length of the fixed optical fiber. It is a top view (side view) explaining an example of the fitting structure between the plug and adapter in the optical connection method of this invention. It is a top view (front view) explaining the other example of embodiment of the optical connection method of this invention. It is a schematic diagram explaining an example of a prior art. It is a schematic diagram explaining the other example of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st optical fiber 2 2nd optical fiber 3 1st plug 4 2nd plug 5 Fixed part 6a, 6b Optical fiber insertion part 7 Bending cell part 8 Alignment member 9 Adapter 12 Pressing member 13 Curved surface part 18, 19 Fitting structure 20 Optical component

Claims (6)

An optical connection method in which at least one optical fiber of the first and second optical fibers fixed to the first and second plugs is bent, and the tips are brought into contact with each other and optically connected.
An optical fiber fixing step of inserting the first and second optical fibers into the first and second plugs and fixing each optical fiber to each plug at a fixing portion;
A bending step of bending the first and / or second optical fiber in a portion ahead of the fixed portion;
An alignment step of aligning the first and second optical fibers and fixing the relative positions of the first and second plugs;
An optical system comprising: a butting step of partially opening the bends of the first and / or second optical fibers and leaving them partially to perform butting of the first and second optical fibers. Connection method. An optical connection method for optically connecting a first optical fiber fixed to the first plug by abutting an optical component in a bent state,
An optical fiber fixing step of inserting the first optical fiber into the first plug and fixing the first optical fiber to the first plug at a fixing portion;
A bending step of bending the first optical fiber ahead of the fixed portion;
An alignment step of aligning the first optical fiber and the optical component, and fixing a relative position of the first optical fiber and the optical component;
An optical connection method comprising: a butting step of partially opening the bend of the first optical fiber and leaving the bend partially to perform a butting between the first optical fiber and an optical component.   In the bending step, the first and / or second optical fiber is pressed from the side surface to bend the first and / or second optical fiber, and in the butting step, the pressing is performed. 3. The optical connection method according to claim 1, wherein the bending of the first and / or the second optical fiber is released by releasing.   4. The optical connection method according to claim 1, wherein an alignment member is used in the alignment step.   In the alignment step, the first and second plugs, or the first plug and the optical component are fixed to an adapter, thereby fixing the relative positions of the first and second plugs, or the first plugs. 5. The optical connection method according to claim 1, wherein a relative position between the one plug and the optical component is fixed. 6. The adapter is open at the top, and the first and second plugs, or the first plug and the optical component are attached to the adapter from above the adapter and fixed. Optical connection method.

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