JP2005062295A - Ferrule-less optical fiber, and its manufacturing method and connection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber that needs no ferrule, and also to provide its manufacturing method and connection method. <P>SOLUTION: A clad 11 of an optical fiber is designed to have the same shape and size as the ferrule 16 of a connector 17 to be connected with. In addition, in preparing the ferrule-less optical fiber, a bend with a required angle is preliminarily added to a required position in accordance with a mounting condition by using heating, a chemical method, or the like. As a result, mounting with an extra stress imparted is eliminated, making a long period use possible without lowering the performance. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention improves the structure of an optical fiber so that it can be connected to an SC (Single Fiber Coupling) connector, an MU (Miniature Unit Coupling) connector, or the like without using a ferrule, and a manufacturing method and connection therefor Regarding the method.

JP-A-8-94880 JP-A-8-82722

  As an optical fiber connection technique, a technique is known in which an insertion port is provided in a ferrule made of zirconia or crystallized glass, and an optical fiber is inserted therein. SPC polishing of ferrule end face and inserted optical fiber (SPC is an abbreviation of Super Physical Contact. This is a method to polish the connector end face or ferrule end face into a convex spherical shape. Prevent reflection at the connection point by bringing them into close contact with each other.In the case of Super Physical Contact, polish them so that the return loss is 40 dB or more.) Connect with. Also known are a method of connecting using an adapter and a method of connecting via a receptacle when bending occurs.

  FIG. 8 shows a receptacle according to Patent Document 1. This is composed of a housing 21, a split sleeve 22 and a ferrule 23. First, an optical fiber core wire 24 having an ultraviolet curable resin film peeled off and a fixing adhesive applied thereto is inserted into a ferrule 23 provided with an insertion opening for the optical fiber core wire. Next, the optical fiber core wire protruding from the ferrule 23 is cut at the ferrule end face and polished by SPC polishing or the like. The receptacle 25 shown in FIG. 9 is completed by combining the produced ferrule part 23, the split sleeve 22, and the housing 21.

  When the receptacles 25 are attached to both ends of the optical fiber core wire 24, the length of the core wire is required to be about 10 cm for the attachment work. The optical fiber and the ferrule must be aligned linearly. When this is to be stored in a limited space as shown in FIG. 10, bending is applied to the exposed core portion of the optical fiber. If it exceeds the limit, it will be mounted under load, and there is a problem that the performance decreases as time passes.

  Patent Document 2 proposes a method for easily connecting fibers having different diameters. For example, in order to connect two fibers having a clad diameter of 1.5 mm and 2.5 mm, an adapter that changes the diameter from 1.5 mm to 2.5 mm is created and connected.

  Also in this case, since the optical fiber and the adapter can be connected only in a straight line, there is a problem that a useless space is taken.

  An object of this invention is to provide the optical fiber which does not require a ferrule, its manufacturing method, and a connection method.

  The ferruleless optical fiber of the present invention is characterized in that the cross section of the clad is adjusted so as to have the same shape as the cross section of the ferrule of the connector to be connected.

  In the method for manufacturing a ferruleless optical fiber according to the present invention, after forming a preform from a quartz rod, the preform is processed so that the cross section of the ferrule and the clad of the connector to be connected have the same shape. Features.

  The ferruleless optical fiber connecting method of the present invention uses two aligning means to align the core portions of the two ferruleless optical fibers or the core portion of the ferruleless optical fiber and the core portion of the optical connector using an aligning means. It is characterized by connecting while.

  In addition, VAD (Vapor-Phase Axial Deposition) method, MCVD (Modified Chemical Vapor Deposition) method, OVD (Outside Vapor Deposition: outside) (Adhesion welding) method can be considered, but in this specification, the VAD method will be described.

  According to the first aspect, the clad portion of the ferruleless optical fiber has the same shape and size as the ferrule of the optical connector to be connected. This eliminates the need for conventional procedures such as the above, and enables connection to an SC connector or MU connector as it is.

  According to the second aspect, by adding a step of bending in advance when producing the ferruleless optical fiber, it is not mounted with extra stress applied. Therefore, it can be used for a long time without degrading performance. Also, it can be easily mounted on modules with limited space.

  According to the third and fourth aspects, the ferrule for the optical fiber becomes unnecessary, and the work after the drawing for creating the optical fiber from the preform becomes easy.

  According to the fifth aspect, since the manufactured ferruleless optical fiber can be mounted without applying extra stress, it can be used for a long time without degrading performance.

  According to the sixth aspect, the ferruleless optical fiber can be easily connected to various optical connectors while aligning.

  According to the seventh aspect, the ferruleless optical fiber can be easily connected with the SC connector or the MU connector in particular while aligning.

According to the eighth aspect, the ferruleless optical fiber can be easily connected with the MT connector (Multi Fiber Connector) in particular while aligning.
(Example)

  The ferruleless optical fiber of the present invention will be described below. The following examples are merely illustrative of the invention and do not limit the scope of the invention.

FIG. 1 shows a method of manufacturing a linear ferruleless optical fiber using the VAD method.

First, as shown in FIG. 1 (a), silicon tetrachloride, germanium tetrachloride or the like, which is a raw material of an optical fiber, is sprayed on a rotating quartz rod 1 together with hydrogen gas and oxygen gas from a cladding burner 2 and a core burner 3. The porous base material 4 is created. The porous mother material 4 is rotated upward while being rotated and heated with a ring heater to form a transparent glass, thereby producing a preform 5 shown in FIG.

As shown in FIG. 1 (c), the preform 5 is heated and pulled at an end portion and cut into an arbitrary length, for example, a core having a diameter of 10 μm and a cladding having a diameter of 2.5 mm. Get the ferruleless optical fiber.

  Although the core and clad of the ferruleless optical fiber have been described as being formed into a cylindrical shape, the present invention is not limited to this. Any device that matches the cross section of the connector to be connected may be used. For example, when it is desired to make a ferruleless optical fiber whose outer periphery is a polygonal column, a die whose inside is punched into a polygonal column is prepared. In step (c), a ferruleless optical fiber is made so as to pass through this mold while the preform 5 is heated.

FIG. 2 shows a linear ferruleless optical fiber 9 manufactured by the above method. For example, the core 10 has a diameter of 10 μm and the cladding 11 has a diameter of 2.5 mm, and can be connected to an SC connector without covering the optical fiber with a ferrule.

  FIG. 3 shows a method for connecting the ferruleless optical fiber. FIG. 3 (a) shows a cross-sectional view of a ferruleless optical fiber, FIG. 3 (b) shows a cross-sectional view of an SC connector, and FIG. 3 (c) shows these connection methods. In the SC connector, an optical fiber core wire having a core portion 14 having a diameter of 10 μm and a cladding portion 15 having a diameter of 125 μm is inserted into a ferrule 16 having a diameter of 2.5 mm. The ferruleless optical fiber 9 and the ferrule 16 of the SC connector 17 are connected from both ends of the sleeve 19 by insertion.

  In FIG. 3, the sleeve 19 is used as the aligning means for aligning the core portion 10 of the ferruleless optical fiber and the core portion 14 of the connector, but the present invention is not limited to this. For example, a convex guide rail may be provided at the outer periphery of the ferruleless optical fiber, and a concave guide rail may be provided at a portion where the ferruleless optical fiber of the connector is inserted, and the two guide rails may be joined together. . In this way, a ferruleless optical fiber can be connected to the MT connector.

  FIG. 4 shows a method of connecting two ferruleless optical fibers 31 while matching the core portions. A guide rail recess 32 is provided in the ferruleless optical fiber, and the guide rail 33 is used for connection. By bringing the two ferruleless optical fibers 32 into contact and then pushing the guide rails 33 from both sides along the guide rail portion 32, the optical fibers can be connected without using a ferrule.

  Two ferruleless optical fibers may be connected using a sleeve.

  As described above, according to this example, it is possible to connect to an SC connector, an MU connector, or the like without preparing a ferrule for an optical fiber. This eliminates the need for conventional procedures such as fixing and polishing by inserting an optical fiber into the ferrule insertion port as in the prior art, and enables connection in a short time.

  In this embodiment, after manufacturing a straight ferruleless optical fiber by the method shown in FIG. 1, for example, as shown in FIGS. 5 (a) and 5 (b), a burner 7 is placed at an arbitrary position of the ferruleless optical fiber. The ferruleless optical fiber is bent into an L shape while being heated by heating.

  Thereafter, as shown in FIG. 5C, both end surfaces of the ferruleless optical fiber 8 formed in an L shape are polished by SPC polishing or the like.

  In FIG. 5, the ferruleless optical fiber is formed in an L shape by adding a bend while being heated after being formed, but is not limited thereto. For example, the bending method is not limited as long as the properties as an optical fiber are not impaired, such as bending during drawing from a preform, fitting into a mold, or using a chemical method. Also, the shape is not limited as long as the characteristics as an optical fiber are not impaired, such as S-shape and U-shape.

  FIG. 6 shows a ferruleless optical fiber to which a bending process is added. 6A shows an L-shaped ferruleless optical fiber 12 that is bent at one location, and FIG. 6B shows an S-shaped ferruleless optical fiber 13 that is bent. Both optical fibers have a core 10 diameter of 10 μm and a cladding 11 diameter of 2.5 mm, for example, similar to the linear ferruleless optical fiber of FIG. 2, and the SC is not covered with a ferrule. Connectable with connector.

  FIG. 7 shows a state where the SC connectors 17 are connected to both sides of the ferruleless optical fiber 20 bent into an S shape. Since the ferrule-less optical fiber 20 and the SC connector 17 have the same ferrule diameter, the receptacle portion 25 shown in FIG. 9 is not necessary, and simple connection is possible. In addition, since bending is applied in advance, no load is applied to the bent portion after mounting. Therefore, even if it is mounted in a limited space, it can be used for a long period of time without degrading performance, and it can be made compact.

It is the schematic which shows the manufacturing method of the linear ferruleless optical fiber which concerns on Example 1 of this invention. It is a perspective view of the linear ferrule-less optical fiber manufactured according to Example 1 of the present invention. The figure which shows the connection method of the ferruleless optical fiber which concerns on Example 1 of this invention, and SC collector, FIG.3 (a) is sectional drawing of a ferruleless optical fiber, FIG.3 (b) sectional drawing of SC connector, FIG. c) is a side view showing a method of connecting a ferruleless optical fiber and an SC connector. It is a perspective view which shows the method of connecting two ferruleless optical fibers manufactured according to this invention using a guide rail. It is the schematic which shows the manufacturing method of the L-shaped ferruleless optical fiber which concerns on Example 2 of this invention. FIG. 6A is an L-shaped ferruleless optical fiber, and FIG. 6B is an S-shaped ferruleless optical fiber manufactured according to the second embodiment of the present invention. It is a top view which shows the state which connected the SC connector to the both sides of the S-shaped ferruleless optical fiber which concerns on Example 2 of this invention. It is a side view which shows the method of attaching a ferrule to the optical fiber core wire which concerns on a prior art example. It is a side view of the receptacle completed by the method of FIG. 8 of a prior art example. It is a top view which shows the state which attached and accommodated the receptacle in the both ends of the optical fiber core wire which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Quartz stick 2 Clad burner 3 Core burner 4 Porous base material 5 Preform 6 Ferruleless optical fiber 7 Burner 8 L-shaped ferruleless optical fiber 9 Linear ferruleless optical fiber 10 Ferruleless optical fiber core 11 Ferruleless light Fiber Clad 12 Ferruleless Optical Fiber 13 with One Bend S-shaped Ferruleless Optical Fiber 14 SC Connector Core 15 SC Connector Clad 16 Ferrule 17 SC Connector 19 Sleeve 20 S-shaped Ferruleless Optical Fiber 21 Housing 22 Split sleeve 23 Ferrule 24 Optical fiber core wire 25 Receptacle 31 Ferruleless optical fiber 32 Guide rail recess 33 Guide rail

Claims (8)

  A ferruleless optical fiber, characterized in that a clad cross section is adjusted to have the same shape as a ferrule cross section of a connector to be connected.   2. The ferruleless optical fiber according to claim 1, wherein a bend is added to one or more locations in advance according to the mounting condition.   A method for manufacturing a ferruleless optical fiber, comprising: forming a preform from a quartz rod; and processing the preform so that a cross section of a ferrule of a connector to be connected and a cross section of a clad have the same shape.   4. The method for producing a ferruleless optical fiber according to claim 3, wherein a preform is produced while spraying a raw material gas from a clad burner and a core burner onto a quartz rod and heating.   The method for manufacturing a ferruleless optical fiber according to claim 3 or 4, wherein bending is added to one or more locations in advance according to the mounting condition.   The core part of two ferruleless optical fibers according to claim 1 or claim 2 or the core part of the ferruleless optical fiber and the core part of an optical connector are connected while aligning using an aligning means. A method for connecting ferruleless optical fibers.   The ferruleless optical fiber connection method according to claim 6, wherein a sleeve 19 is used as the aligning means. 7. The ferruleless optical fiber connection method according to claim 6, wherein two ferruleless optical fibers to be connected, or a ferruleless optical fiber and an optical connector are connected by providing a guide rail as a centering means.

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