JP2004264543A - Ferrule with optical fiber and optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical module provided with a ferrule which has an enlarged contact area with the optical module without forming a recessed groove on the outer periphery of the ferrule to thereby exhibit increased fixation strength to the optical module. <P>SOLUTION: The optical module 1 is provided with the ferrule 3 having an optical fiber 2, an optical fiber connector 4 in which the ferrule 3 is arranged and LD 5 and PD 6 used for optical communication. The ferrule 3 has a large diameter part 7 larger than the ferrule diameter specified by the plug grade of the optical fiber connector 4 on the outer periphery. The optical module 1 is provided with the large diameter part 7 on the outer periphery of the ferrule 3 and, thereby, the position of the ferrule 3 is not shifted in the axial direction of the ferrule 3 when the optical module 1 is assembled or is connected with another ferrule. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ferrule with an optical fiber incorporating an optical fiber and an optical module using the ferrule. In particular, the present invention relates to a ferrule with an optical fiber having excellent fixing strength to an optical module, and an optical module using the ferrule.
[0002]
[Prior art]
Conventionally, as an optical module used for optical communication, for example, the one shown in FIG. 3 is known. FIG. 3 is a perspective view showing a state where a cap is opened in a conventional optical module.
[0003]
This optical module comprises a resin-made module body 50 composed of a package 50A and a cap 50B, a cylindrical ferrule 52 having an optical fiber 51 inserted at the center, and a light used for optical communication via the optical fiber 51. An element 53 is provided. One end side of the module main body 50 is a connector portion 54 in which a part of the ferrule 52 is arranged. Semi-cylindrical grooves 55 and 56 that are fitted to the outer periphery of the ferrule 52 are provided in each of the package 50A and the cap 50B. . Further, a Si substrate 57 is arranged on a plane portion in the package 50A. The Si substrate 57 is provided with a V-groove 58 for positioning the optical fiber 51 protruding from one end of the ferrule 52, and a semiconductor laser (LD) is provided at a predetermined position in the axial direction of the optical fiber 51 disposed in the V-groove 58. And an optical element 53 such as a photodiode (PD). The package 50A is usually injection-molded integrally with the lead frame 59, and a flat portion of the lead frame 59 appears inside.
[0004]
As shown in FIG. 3, the ferrule 52 is disposed in the semi-cylindrical groove 55 of the package 50A, and the optical fiber 51 is disposed in the V groove 58, and is fixed such that the end face of the optical fiber 51 is arranged at a prescribed position near the optical element 53. Is done. In this state, the optical module is assembled by turning the cap 50B upside down from the state shown in FIG.
[0005]
FIG. 4 is a cross-sectional view near the optical fiber connector of the optical module. The outer periphery of the ferrule 52 is provided with a plurality of fixing grooves 52A extending over the entire periphery, and the semi-cylindrical groove of the cap 50B is provided with a ridge 60 in the longitudinal direction. For this reason, when the cap 50B is pressed against the package 50A, the ridge 60 is crushed and deformed as shown in FIG. 4, and bites into the fixing groove 52A of the ferrule 52, so that the ferrule 52 is fixed, and its movement in the axial direction is restricted. Is done.
[0006]
Further, as another optical module different from the above, there is one described in, for example, Patent Document 1. In this optical module, a ferrule containing an optical fiber is aligned and fixed in a groove provided on a substrate, an optical element and an end of the ferrule are sealed with a resin, and the whole is molded with a resin. Also in this document, similarly to the optical module shown in FIG. 3, a groove is formed in the ferrule, and a ferrule is firmly fixed by providing a fitting projection on a holding plate for fixing the ferrule.
[0007]
[Patent Document 1]
JP 2000-98188 A (0035, see FIG. 11)
[0008]
[Problems to be solved by the invention]
However, in the above-mentioned conventional technique, there is a limit to an increase in the contact area due to the groove provided on the outer periphery of the ferrule, and it is difficult to expect a further improvement in fixing strength.
In order to increase the fixing strength of the ferrule, it is necessary to increase the contact area with the ridge provided in the semicircular groove of the connector portion and the contact area with the holding plate. Thus, in the technique shown in FIG. 4, it is conceivable to increase the depth of the fixing groove provided on the outer periphery of the ferrule to increase the contact area with the ridge. In the technique disclosed in Patent Document 1, it is conceivable to increase the contact area with the holding plate by increasing the depth of the groove provided in the ferrule and increasing the height of the fitting protrusion provided on the holding plate. . However, in consideration of maintaining the physical strength of the ferrule, there is a limit in increasing the depth of the groove provided in the ferrule, and there is a limit in increasing the contact area by the groove provided in the ferrule. In particular, in recent ferrules having a diameter of 1.25 mmφ, the restrictions on the depth of the groove are severe.
[0009]
In addition, in order to improve the fixing strength, the molding accuracy of the cap and the holding plate of the optical module is increased, so that the manufacturing cost tends to increase.
[0010]
Therefore, a main object of the present invention is to provide a ferrule capable of improving the fixing strength by providing a concave groove on the outer periphery of the ferrule or increasing the contact area with the optical module without roughening the surface. is there.
[0011]
Another object of the present invention is to provide an optical module having a ferrule having excellent fixing strength and having excellent moisture resistance.
[0012]
[Means for Solving the Problems]
The present invention achieves the above object by providing a specific protrusion on the outer periphery of the ferrule.
That is, the present invention relates to a ferrule with an optical fiber in which an optical fiber is inserted and arranged in an optical fiber connector, wherein the ferrule having a larger diameter on the outer periphery of the ferrule than the ferrule diameter defined by the plug class of the optical fiber connector. It has a part.
[0013]
The ferrule of the present invention has a large-diameter portion having a diameter larger than the diameter specified by the plug class of the optical fiber connector on the outer periphery as a protrusion, so that the contact area with the fixing member of the optical module can be increased. It can improve fixing strength. Further, by increasing the contact area, the ferrule of the present invention disposed on the fixing member of the optical module can increase the distance between the interface and the fixing member. Is difficult to penetrate. Therefore, when the ferrule of the present invention is used for an optical module, it is possible to improve the moisture resistance. Hereinafter, the present invention will be described in more detail.
[0014]
The connector portion provided in the optical module, that is, the so-called optical fiber connector, is generally an F04 type single fiber optical connector (commonly called SC connector), an F14 type connector (commonly called MU connector), and an F01 type single fiber optical connector (commonly specified in JIS). A so-called FC connector) is used. The structure, shape, characteristics, and the like of these optical fiber connectors are specified by JIS for each plug, adapter, and receptacle. For example, the ferrule diameter is specified to be 2.499 mm ± error in the F04 type single core optical fiber connector, and the ferrule diameter is specified to be 1.249 mm ± error in the F14 type optical fiber connector. In the present invention, the ferrule diameter specified by the plug grade of the optical fiber connector is a ferrule diameter specified corresponding to the optical fiber connector specified by the JIS. Accordingly, in the present invention, the diameter of the largest portion of the large diameter portion is more than 2.499 mm, more specifically, 2.70 to 3.00 mm when disposed in the F04 type single core optical fiber connector. When it is arranged in the connector, it is more than 1.249 mm, more specifically, 1.45 to 1.75 mm. When it is arranged in the F01 type single-core optical fiber connector, it is more than 2.499 mm, more specifically, in 2.0.1 mm. 70 to 3.00 mm.
[0015]
The large diameter portion provided on the outer periphery of the ferrule of the present invention is preferably provided, for example, in a ring shape over the entire outer periphery of the ferrule. In addition, at least one large diameter portion may be provided, but a plurality of large diameter portions may be provided. In the case where a plurality of large diameter portions are provided, the size of each large diameter portion may be the same or different. And such a large diameter part is preferably formed integrally with the ferrule. As a material for forming the large diameter portion, zirconia or the like is used. In the present invention, since the concave groove is not provided on the outer periphery of the ferrule, the physical strength of the ferrule can be sufficiently maintained.
[0016]
In the ferrule of the present invention, it is preferable that the inserted optical fiber is led out at one end, and the other end is formed into a curvature shape together with the inserted optical fiber.
[0017]
On the other hand, the optical module of the present invention includes the above-described ferrule, an optical fiber connector in which the ferrule is arranged, and at least one of a light emitting element and a light receiving element used for optical communication via an optical fiber provided in the ferrule. It is characterized by. The optical fiber connector serves as a coupling portion when a ferrule having a shape similar to that of the above ferrule is opposedly connected by applying a constant pressure on the same axis.
[0018]
Since the optical module of the present invention having the above configuration has a large diameter portion on the outer periphery of the ferrule, it has excellent fixing strength between the module body and the ferrule, and the ferrule positioned at the time of assembling the optical module has its axial direction. Hardly ever move to. Further, when connecting another ferrule for use as a product, a constant pressure is applied in the axial direction of the ferrule, but even at this time, the ferrule does not shift in the axial direction. Further, by using a ferrule having a large diameter portion, the distance between the interface and the fixing member can be increased, so that moisture does not easily enter the inside of the optical module along the interface and the moisture resistance can be improved.
[0019]
In the present invention, the optical module body may be composed of a resin package and a cap, or may be formed by a resin mold. In the former case, the optical fiber connector in which a part of the ferrule is disposed has a fitting groove formed on at least one of the package and the cap, which fits the outer periphery and the large diameter portion of the ferrule, and is fitted into this groove. A ferrule may be arranged. Further, after the ferrule is arranged on the optical fiber connector on the package side, the ferrule may be fixed to the package side of the module body by resin by potting with resin. At this time, since the ferrule is firmly fixed to the package with the resin and does not displace, the fitting groove as described above need not be provided in the cap. That is, in the case of resin potting, the contact side with the ferrule in the optical fiber connector on the cap side only needs to have a shape that covers the resin potted ferrule and can be joined to the package. The ferrule can be fixed.
[0020]
In the latter case, ie, when the optical module body is a resin mold, by providing the large diameter portion, the contact area between the ferrule and the mold resin can be easily increased, and the fixing strength can be improved. Further, since the distance between the interface between the ferrule and the mold resin can be increased, it is difficult for water to enter the optical module along the interface and the moisture resistance is improved. Furthermore, when the optical module main body is made of a resin mold, the molding accuracy of the cap is not required unlike the conventional optical module. It is more preferable that the large-diameter portion has a curved cross section in the axial direction of the ferrule, for example, an arc shape, so that the molding resin can easily spread around the large-diameter portion.
[0021]
In the optical module of the present invention, the light emitting element is preferably a semiconductor laser (LD) optimal for optical communication, and the light receiving element is preferably a light receiving diode (PD). When the optical module is for reception, it is desirable to include a light emitting element and a driver IC for the light emitting element. For transmission, it is desirable to include an amplifier that amplifies the signal of the light receiving element or the signal of the light receiving element. For transmission and reception, it is desirable to have at least one set of light emitting element and driver IC, and at least one set of light receiving element and amplifier.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
(Example 1)
FIG. 1 is an optical module of the present invention in which a main body includes a package and a cap. FIG. 1A is a schematic configuration diagram schematically showing a state in which a cap is removed, and FIG. 1B is a ferrule part in a state where a cap is joined. FIG. The optical module 1 of the present invention includes a ferrule 3 having an optical fiber 2, an optical fiber connector 4 in which a part of the ferrule 3 is arranged, and an LD 5 and a PD 6 used for optical communication. The ferrule 3 includes a large-diameter portion 7 having diameters R ₁ and R ₂ larger than a ferrule diameter r defined by a plug grade of the optical fiber connector 4 on the outer periphery.
[0023]
In this example, two large diameter portions 7 are provided on the outer periphery of the ferrule 3 (large diameter portions 7a and 7b). Therefore, the ferrule 3 is provided with the large diameter portion 7 and the portion of the ferrule diameter r defined by the optical fiber connector 4 alternately, so that the contact area with the module main body can be further increased, and the fixing strength can be increased. Expected. The large-diameter portions 7a and 7b have different diameters R ₁ and R ₂ and are provided over the entire outer periphery of the ferrule 3 and are formed integrally with the ferrule 3 main body. In the package 8 in which the ferrule 3 is arranged, the fitting groove 8a, 8b that fits the outer periphery of the ferrule 3 and the large-diameter portions 7a, 7b as shown in FIG. Is provided. In this example, after the ferrule 3 is disposed in the fitting grooves 8a and 8b, the ferrule 3 is fixed to the package 8 by performing resin potting 9 as shown in FIG. The side of the cap 10 facing the ferrule 3 was shaped so as to provide a space that did not contact the resin potting 9. The large diameter portion 7 was formed of zirconia.
[0024]
The optical fiber 2 is inserted into the ferrule 3 and is led out from one end (the left end in FIG. 1) of the ferrule 3. The other end (right end) of the ferrule 3 is formed into a curvature shape together with the inserted optical fiber 2. The package 8 is injection-molded integrally with a lead frame (not shown), and a flat portion of the lead frame appears inside. An Si substrate 11 is disposed on a plane portion of the package 8. The Si substrate 11 is provided with a positioning V-groove 12 for the optical fiber 2, and the LD 5 and the PD 6 are mounted at specified positions in the axial direction of the optical fiber 2 arranged in the V-groove 12. LD5 and PD6 are fixed with a transparent resin 13. The optical fiber connector 4 is provided with a fitting portion 4a for joining with an optical fiber connector at an end of another optical fiber cord or the like.
[0025]
The optical module of the present invention has a large diameter portion on the outer periphery of the ferrule, thereby increasing the contact area between the ferrule and the module main body without impairing the physical strength of the ferrule, and the ferrule is firmly fixed to the module main body. Is done. Therefore, the position of the ferrule does not shift in the axial direction when assembling the optical module or coupling with another ferrule. Further, since the ferrule is fixed to the package 8 with excellent strength by the resin potting 9, the shape of the side of the cap facing the ferrule is not limited to the ferrule even if the ferrule is not precisely formed. There is no displacement.
[0026]
(Example 2)
In the first embodiment, the optical module main body is separated into the package and the cap. In the present embodiment, the optical module main body is integrally formed by resin molding. FIG. 2 is a schematic configuration diagram schematically showing the optical module of the present invention, in which only an upper half of a main body is removed. 1 denote the same parts. The basic configuration of the optical module 20 shown in this embodiment is the same as that of the first embodiment. That is, it includes a ferrule 3 having an optical fiber 2, an optical fiber connector 4 in which a part of the ferrule 3 is arranged, and an LD 5 and a PD 6 used for optical communication. Ferrule 3 comprises large-diameter portion 7a having a ferrule diameter larger diameter R ₁ than _r, R ₂ defined by the plug grade optical fiber connector 4 and 7b on the outer circumference.
[0027]
The optical module shown in this example has a large diameter portion on the outer periphery of the ferrule, so that the contact area between the ferrule and the mold resin can be easily increased without impairing the physical strength of the ferrule, and the optical module Improves the fixing strength of the ferrule to the main body. Further, since the ferrule is firmly fixed, the position of the ferrule does not shift when the ferrule is joined to another ferrule. Further, since the distance between the interface between the ferrule and the mold resin is increased, it is difficult for water to enter the inside of the optical module, and the moisture resistance is improved. In addition, when the optical module body is made of a resin mold, the molding accuracy of the cap is not required unlike the conventional optical module. In this example, the large-diameter portion has a rectangular cross section in the axial direction of the ferrule, but if the cross-section is provided in an arc shape, the molding resin can be easily spread around the large-diameter portion, and the molding accuracy can be improved. Can be improved.
[0028]
【The invention's effect】
As described above, according to the ferrule with an optical fiber of the present invention, by providing a large-diameter portion on the outer periphery of the ferrule, the contact area with the optical module body can be increased, so that the fixing strength is improved. Excellent effects can be achieved. Further, since the large-diameter portion protrudes from the outer periphery of the ferrule, the physical strength is not impaired unlike the prior art in which a concave groove is provided on the outer periphery unlike the ferrule.
[0029]
The optical module of the present invention using the ferrule having the large-diameter portion has excellent fixing strength between the optical module body and the ferrule, so that when the optical module is assembled or another ferrule is connected after commercialization, the ferrule is There is no displacement in the axial direction. Further, since the optical module of the present invention can increase the distance of the interface with the fixing member by using the ferrule having the large diameter portion, it is difficult for water to enter the inside of the optical module along this interface, and the moisture resistance is also improved. It is possible.
[Brief description of the drawings]
FIG. 1 is an optical module of the present invention in which a main body includes a package and a cap, (A) is a schematic configuration diagram schematically showing a state in which a cap is removed, and (B) is a ferrule part in a state in which the cap is joined. FIG.
FIG. 2 is a schematic configuration diagram schematically showing an optical module of the present invention, in which only an upper half of a main body is removed.
FIG. 3 is a perspective view showing a state where a cap is opened in a conventional optical module.
FIG. 4 is a sectional view showing the vicinity of an optical fiber connector of a conventional optical module.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 20 Optical module 2 Optical fiber 3 Ferrule 4 Optical fiber connector 4a Fitting part 5 LD 6 PD 7, 7a, 7b Large diameter part 8 Package 8a, 8b Fitting groove 9 Resin potting 10 Cap 11 Si substrate 12 Positioning V Groove 13 Transparent resin 50 Optical module main body 50A Package 50B Cap 51 Optical fiber 52 Ferrule 52A Fixing groove 53 Optical element 54 Connector part 55, 56 Cylindrical groove 57 Si substrate 58 Positioning V groove 59 Lead frame 60 Ridge

Claims (3)

An optical fiber is inserted therein, and is a ferrule with an optical fiber disposed in an optical fiber connector,
A ferrule with an optical fiber, comprising a large-diameter portion larger than a ferrule diameter defined by a plug grade of the optical fiber connector on an outer periphery of the ferrule. The ferrule with an optical fiber according to claim 1, wherein the large-diameter portion is formed integrally with the ferrule. The ferrule with an optical fiber according to claim 1 or 2,
An optical fiber connector on which the ferrule is arranged;
An optical module comprising at least one of a light emitting element and a light receiving element used for optical communication via an optical fiber.

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