JP4127634B2 - Optical receptacle and optical module using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical receptacle structure that can be applied to an optical communication system and to which an optical connector can be attached and detached, and particularly relates to an optical receptacle that can suppress optical connection loss and can improve mounting density by downsizing.
[0002]
[Prior art]
Increasing information transmission capacity in public communication networks, LANs, and the like accompanying information sophistication and multimediaization has become a serious problem. As means for solving this, various optical communication systems applying optical transmission technology are attracting attention, and the opticalization of networks is rapidly spreading.
[0003]
In recent years, optical modules using optical receptacles that allow optical connectors to be removably fitted and propagate light emitted from optical elements to optical fibers are versatile and easy to handle. The importance has been increasing more and more, and further downsizing has been demanded in order to improve the mounting density.
[0004]
As shown in FIG. 5, the receptacle-type optical module includes an optical element 29 at one end of the optical receptacle 21 and an optical connector connected to the other end.
[0005]
The optical receptacle 21 includes a ferrule 24b made of a ceramic material such as zirconia or alumina, and a rear end portion of a fiber stub 24 obtained by inserting and fixing the optical fiber 24a into a through hole of the ferrule 24b. The sleeve case 27 is press-fitted or adhesively fixed to the holder 26 after the tip portion is inserted into the inner hole of the sleeve 23.
[0006]
Further, when an optical module is configured by using the optical receptacle 21 described above, a case 31 having an optical element 29 and a lens 28 is provided on the rear end surface side of the optical receptacle 21 having the fiber stub 24. The plug ferrule 22 is inserted into the sleeve 23 from the distal end side of the optical receptacle 21, and the end face of the optical fiber 24 a held by the fiber stub 24 and the optical fiber 22 a held by the plug ferrule 22 are inserted. An optical signal can be exchanged by contacting the end face.
[0007]
Here, regarding the insertion length of the plug ferrule 22 and the fiber stub 24 in the sleeve 23, as shown in the conventional optical receptacle module of FIG. 5, the plug ferrule 22 is inserted when a radial load (bending load) is applied. The optical fiber 22a held by the ferrule 22 and the optical fiber 24a held by the fiber stub 24 are designed to have substantially the same dimensions in order to prevent the shaft from being greatly displaced and the connection loss from increasing. Further, the fiber stub 24 and the holder 26 are designed to have a sufficient press-fitting length so as to maintain the position without being pulled out even when pressed by the plug ferrule 22.
[0008]
[Problem to be Solved by the Invention]
In the above-described conventional example, the holding force of the tip portion of the fiber stub 24 in the sleeve 23 and the holding force of the plug ferrule 22 are not substantially the same, and when the radial load (bending load) of the plug ferrule 22 is applied. In the optical fiber 22a held by the plug ferrule 22 and the optical fiber 24a held by the fiber stub 24, the axis that is weakly held by the sleeve 23 is greatly displaced, resulting in a large connection loss. For this reason, the insertion length of the fiber stub 24 and the plug ferrule 22 in the sleeve 23 must be the same size, and is sufficient to hold the plug ferrule 22 and the fiber stub 24 coaxially even under a bending load. Insertion length is required. On the other hand, since the rear end portion of the fiber stub 24 is press-fitted and fixed inside the holder 26 and a sufficient press-fitting holding strength is required to prevent the plug ferrule 22 from being pulled out, the fiber stub 24 is formed by the sleeve 23. It has a long shape having a holding part and a holding part by the holder 26. As a result, it has been very difficult to shorten and miniaturize the optical receptacle 21.
[0009]
[Means for Solving the Problems]
In view of the above problems, an optical receptacle of the present invention includes a fiber stub in which an optical fiber is held in a through hole of a ferrule, a cylindrical stub holder having a hole, and the fiber stub inserted in the hole, as the end plane of the fiber stub is located inside a sleeve which is inserted and fixed to the distal end portion of the stub holder has a through hole, and a holder holding the rear end portion of the stub holder in the through hole, the wherein the holder has an abutment portion rear end surface of the stub holder in the through hole is in contact of the holder, said stub holder, the end plane of the fiber stub into the hole has a contact portion in contact with It is characterized by that.
[0012]
Furthermore, the optical module of the present invention is characterized in that a case containing an optical element is attached to the holder of the optical receptacle.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a cross-sectional view showing an optical module using the optical receptacle of the present invention. The optical receptacle of the present invention has a fiber stub 4 in which an optical fiber 4a is held in a through hole of a ferrule 4b. 4 is fixed to the stub holder 5 by press-fitting. The front end portion of the stub holder 5 is inserted into the inner hole of the sleeve 3, and the rear end portion of the sleeve case 7 and the rear end portion of the stub holder 5 are held by the holder 6. Has been.
[0015]
Furthermore, in order to configure an optical module using the above-described optical receptacle 1, a case 11 having an optical element 9 and a lens 8 is welded to the rear end face side of the stub holder 5 in the optical receptacle 1 via an alignment ring 13. Then, an optical connector holding the optical fiber 2a is inserted into the sleeve 3 from the front end surface side of the optical receptacle 1, and the end surface of the optical fiber 4a held by the fiber stub 4 and the plug ferrule 2 are inserted. An optical signal can be exchanged by contacting the end face of the held optical fiber 2a.
[0016]
The holder 6 is provided with an abutting portion 6a of the stub holder 5 so that the stub holder 5 is not pulled out by pressing of the plug ferrule 2 when the plug ferrule 2 is inserted into the sleeve 3, and is smaller than the diameter of the fiber stub 4. A through hole having a diameter is provided, and the outgoing light 8 from the optical element 9 passes through the lens.
[0017]
In the optical receptacle 1 of the present invention, it is important that the fiber stub 4 is held by the stub holder 5 and the stub holder 4 is held by the holder 6.
[0018]
With this mechanism, the insertion depth of the plug ferrule 2 and the stub holder 5 in the sleeve 3 can be made the same regardless of the length of the fiber stub 4, and a radial load (bending load) is applied to the plug ferrule 2. In any case, a stable optical connection is maintained without shifting the axis of either the plug ferrule 2 or the fiber stub 4.
[0019]
The insertion depths of the plug ferrule 2 and the stub holder 5 in the sleeve 3 are preferably the same, and the optical fiber 2a held by the plug ferrule 2 and the optical fiber 4a held by the fiber stub 4 are sleeves. 3 abuts at the center.
[0020]
On the other hand, the rear end surface of the fiber stub 4 is preferably disposed in the hole of the stub holder 5 by shortening the fiber stub 4 and further in the hole of the sleeve 3.
[0021]
With respect to the fiber stub 4, after the fiber stub 4 is press-fitted and fixed to the stub holder 5, the stub holder 4 is inserted into the sleeve 3. 5 or in the sleeve 3.
[0022]
With this structure, the distance between the rear end face of the fiber stub 4 and the front end face of the optical connector is smaller than that of the prior art, so that the emitted light 10 from the optical element 9 can be coupled at a position closer to the optical connector. Thus, the length of the fiber stub 4 can be freely designed according to the focal length of the optical element 9 or the size limitation on the module mounting, and the actual length of the fiber stub 4 is the insertion length of the stub holder 5 into the sleeve 3. In comparison, 1/2 to 1/4 is sufficient, and as a result, the optical receptacle can be significantly shortened.
[0023]
However, it is preferable to provide the abutting portion 5a of the fiber stub 4 in the stub holder 5 so that the fiber stub 4 is not pulled out from the stub holder 5 by pressing the plug ferrule 2 when the optical connector is inserted into the sleeve 3. The light stub 4 has a structure in which light passes through a through hole smaller than the outer diameter of the fiber stub 4. Further, the depth of the press-fitting hole of the fiber stub 4 in the stub holder 5 is larger than the total length of the fiber stub 4 so as not to hinder the connection between the optical fiber 2a held by the plug ferrule 2 and the optical fiber 4a held by the fiber stub 4. It should be 0.02-0.1 mm shallow.
[0024]
The insertion length of the plug ferrule 2 and the insertion length of the stub holder 5 in the sleeve 3 are the optical fiber 2a held by the plug ferrule 2 when a radial load (bending load) is applied to the plug ferrule 2. In order to prevent the optical fiber 4a of the fiber stub 4 from being misaligned and the optical connection from being largely lost, the same dimensions are preferable.
[0025]
Further, the diameter of the stub holder 5 in the sleeve 3 is preferably the same as the diameter of the plug ferrule 2, and it is preferable to match the removal force of the plug ferrule 2 in the sleeve 3 with the removal force of the stub holder 5.
[0026]
In the optical receptacle 1 according to the present invention, the sleeve 3 is preferably an elastic sleeve that can be expanded and contracted in the radial direction. A suitable material together with the fiber stub is ceramic such as zirconia / alumina. It is preferable to use a metal such as SUS304 material. Finally, the optical receptacle 1 according to the present invention is completed by press-fitting or welding and fixing a sleeve case 7 covering the sleeve 3 to the holder 6.
[0027]
Next, another embodiment of the optical receptacle of the present invention will be described.
[0028]
2 and 3 are sectional views showing other embodiments of the optical receptacle according to the present invention.
[0029]
In FIG. 2, the integrated holder 12 which integrated the holder 6 and the stub holder 5 in FIG. 1 is employ | adopted. The advantage of this embodiment is a reduction in the number of parts and assembly man-hours. FIG. 3 shows an example in which polarizers 13 a and 13 c and an optical isolator element 13 and a magnet 14 including a rotor 13 b held by these are mounted in the stub holder 5. These are joined by an adhesive or solder. In this embodiment, a function of suppressing the light reflected on the end face of the fiber stub 4, the optical fiber front end face 2 a of the plug ferrule 2 and other optical paths from returning to the optical element 9 is provided. In manufacturing, since an optical receptacle with an isolator can be manufactured with a minimum necessary shape change without adding new fixing parts or the like, the cost performance is excellent.
[0030]
The optical receptacle 1 as described above can be suitably used as an optical module with a case 11 housing the optical element 9 on the rear end side. In this case, stable optical connection can be realized, and at the same time, miniaturization and high-density mounting can be realized. It can be.
[0031]
【Example】
Examples of the present invention will be described below.
[0032]
First, in order to obtain an optical module as shown in FIG. 1, an optical receptacle type optical module and a conventional optical receptacle type optical module as shown in FIG. Each of the characteristics was compared.
[0033]
Since the optical module of the present invention and the conventional optical module use the fiber stub 4 having the same length, the total length of both is the same.
[0034]
In the optical module according to the present invention, the length of the sleeve 3 is 8 mm, and the insertion lengths of the plug ferrule 2 and the stub holder 5 are 4 mm and 4 mm, respectively. On the other hand, in the conventional optical module, the length of the sleeve 3 is 4 mm, the insertion length is 2 mm and 2 mm, respectively, and the press-fitting length of the fiber stub 4 into the holder 6 is 1.5 mm.
[0035]
Then, each optical module was caused to emit light, and the plug ferrule 2 holding the optical fiber 2a was inserted into the sleeve 3, whereby the emitted light 10 from the optical element 9 was propagated to the optical fiber 2a. Next, a predetermined amount of radial load (bending load) was applied to the plug ferrule 2, and the amount of deterioration of the optical output from the optical fiber 2a (the amount of change in the optical fiber connection loss) was measured.
[0036]
FIG. 4 shows the result. FIG. 4 is a graph showing the applied load and the deterioration amount of the light output from the optical fiber 2a.
[0037]
As is apparent from FIG. 4, in the optical module according to the present invention, the degree of deterioration was small, indicating that a stable optical connection was made.
[0038]
On the other hand, in the conventional optical module, the light output greatly deteriorated as the load increased, and the light output deteriorated as much as 2.4 dB when the weight was 400 g.
[0039]
As described above, it has been proved that the optical module of the present invention realizes a significantly superior optical connection as compared with the conventional optical module. In the prototype optical receptacle according to the present invention, it is obvious that the length of the fiber stub can be shortened by at least 2 mm while maintaining a stable optical connection, which can sufficiently cope with downsizing.
[0040]
【The invention's effect】
As described above, an optical receptacle in which the front end portion of a fiber stub formed by holding an optical fiber in the through-hole of the ferrule is inserted into the sleeve and the rear end portion is held by the holder, the fiber stub being a stub holder The stub holder is held by the holder, and a rear end surface for coupling light emitted from the optical element in the fiber stub is disposed in the hole of the stub holder or the hole of the sleeve, and By attaching a case containing an optical element to the rear end side to form an optical module, stable optical connection, miniaturization and high-density mounting can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a receptacle-type optical module of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the receptacle-type optical module of the present invention.
FIG. 3 is a cross-sectional view showing another embodiment of the receptacle-type optical module of the present invention.
FIG. 4 is a graph showing a characteristic comparison between the present invention and a conventional optical module.
FIG. 5 is a cross-sectional view showing a conventional receptacle-type optical module.
[Explanation of symbols]
1: Optical receptacle 2: Plug ferrule 2a: Optical fiber 3 held by plug ferrule 3: Sleeve 4: Fiber stub 4a: Optical fiber 4b held by fiber stub: Ferrule 5: Stub holder 5a: Fiber stub butting portion 6: Holder 6a: Stub holder butting portion 7: Sleeve case 8: Lens 9: Optical element 10: Emission light 11: Case 12: Integrated holder 13a: Polarizer 13b: Rotor 13c: Polarizer 14: Magnet

Claims (2)

A fiber stub that holds an optical fiber in the through-hole of the ferrule;
A cylindrical stub holder having a hole and the fiber stub inserted in the hole;
As the end plane of the fiber stub is located inside a sleeve which is inserted and fixed to the front end of the stub holder,
A holder having a through hole, and holding a rear end portion of the stub holder in the through hole,
The holder has an abutting portion with which a rear end surface of the stub holder abuts in a through hole of the holder ,
The stub holder is optical receptacle end plane of the fiber stub into said hole and having an abutting portion abutting.   An optical module comprising a case containing an optical element attached to the holder of the optical receptacle according to claim 1.

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