JP2007163548A - Optical receptacle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce variation in optical transfer power even when a strong lateral load acts on a plug ferrule fitted to an optical receptacle from any direction. <P>SOLUTION: The optical receptacle is structured so that the plug ferrule does not incline not less than a fixed inclination, by preparing a precise sleeve on the periphery of an elastic sleeve for holding a built-in ferrule and the plug ferrule, and is also structured to have an opening form that prevents the opening of the sleeve case from contacting the plug ferrule even if the plug ferrule inclines, and thereby, even when the strong lateral load acts on the plug ferrule from any direction, the periphery in the neighborhood of the connection part of the built-in ferrule and the plug ferrule is pressed against the cylindrical surface in the elastic sleeve in the same direction and aligns, and axial misalignment of an optical fiber is constrained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a connector mechanism for optically connecting an optical fiber and an optical semiconductor, and particularly suitable for a small optical module having a short axial length, when a strong lateral load acts on the mounted plug ferrule in any direction. However, the present invention relates to an optical receptacle with little variation in the transmitted optical power.

The conventional optical receptacle is composed of a built-in ferrule 8, an elastic sleeve 9, a ferrule holding member 10 and a sleeve case 11. The built-in ferrule is held by the ferrule holding member at a strength that does not separate under normal use conditions, and elastically expands and deforms freely. The sleeve grips the built-in ferrule and the plug ferrule with such a force that allows the plug ferrule to be freely inserted and removed, and the optical connection with less loss is made possible by aligning them coaxially. (For example, refer to Patent Document 1.)
In such a case, as shown in FIG. 6, when a strong lateral load is applied to the plug ferrule with the plug ferrule 12 attached, the elastic sleeve expands, the plug ferrule is inclined, and the side surface of the plug ferrule is the opening of the sleeve case. Contact with the contact 13. Then, the contact 13 serves as a fulcrum and the tip of the plug ferrule is pressed against the cylindrical surface of the elastic sleeve by the contact 14-a. The built-in ferrule is pressed against the cylindrical surface of the elastic sleeve by the contact 15-a and the contact 15-b. Since the built-in ferrule and plug ferrule are pressed against the opposite sides of the expanded cylindrical surface in the elastic sleeve in the vicinity of the connection between the optical fibers, there is a problem in that an optical axis shift occurs between the optical fibers and a large optical loss occurs. there were.
In particular, when the elastic sleeve is a split sleeve with a slit, if a strong lateral load is applied to the plug ferrule in a direction in which the contact 14-a or the contact 15-a overlaps the slit of the elastic sleeve, the elastic sleeve further expands at the slit portion. There is a problem in that a larger optical loss occurs because the axes are shifted between the optical fibers.
To prevent the plug ferrule from tilting even when a strong lateral load is applied to the plug ferrule, it is effective to increase the axial length in which the elastic sleeve holds the built-in ferrule and the plug ferrule, There is a problem in that the axial length L1 at which the elastic sleeve grips the outer cylindrical surface of the built-in ferrule is as short as possible, for example, 3.5 mm or less, which is incompatible with the request for downsizing the optical receptacle.

JP-A-2-33114 (Page 5-7, Fig. 1)

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a compact optical receptacle with little variation in the optical power transmitted when a strong lateral load is applied to the attached plug ferrule in any direction. Is to realize.

  In order to achieve the above object, according to the present invention, an optical receptacle to which a plug ferrule 1 is attached, which has a hollow cylindrical shape, has an inner hole smaller than the outer diameter of the plug ferrule, and is easily elastically deformed in the radial direction. A sleeve 2; a precision sleeve 3 having a hollow cylindrical shape and an inner hole larger than the outer diameter of the elastic sleeve 2; a built-in ferrule 4 having a convex spherical surface into which an optical fiber is inserted and held and one end of which comes into contact with the plug ferrule 1; A ferrule holding member 5 for holding the built-in ferrule 4; and a sleeve case 7 including the elastic sleeve 2 and the precision sleeve 3 and having an opening 6 for inserting the plug ferrule 1; The built-in ferrule in which the elastic sleeve 2 holds a part of the outer cylindrical surface and the elastic sleeve 2 does not hold A part of the outer cylindrical surface and a part of the ferrule holding member 5 are fixed by press-fitting or bonding, the ferrule holding member 5 and the sleeve case 7 are fixed by press-fitting or bonding, and the precision sleeve 3 is The elastic sleeve 2 is arranged on the outer peripheral side of the elastic sleeve 2 with a gap in a coaxial manner, and a gap is also provided on the outer cylindrical surface of the precision sleeve 3 and the inner cylindrical surface of the sleeve case 7. Is also provided between the outer cylindrical surface of the elastic sleeve 2 and the inner cylindrical surface of the precision sleeve 3, and the outer cylindrical surface of the precision sleeve 3 and the inner cylindrical surface of the sleeve case 7 are mounted. There is a gap between the plug ferrule 1 and the plug ferrule to the limit where the elastic sleeve 2 is limited to the precision sleeve 3 due to a lateral load acting on the mounted plug ferrule 1. Even when 1 is inclined, the outer cylindrical surface of the plug ferrule 1 is not in contact with the opening 6 of the sleeve case 7, so that the tip of the built-in ferrule and the tip of the plug ferrule are in the same direction of the cylindrical surface of the elastic sleeve. As a result, the axial displacement on the physical contact surface of the optical fiber can be minimized.

According to the present invention, when a lateral load does not act on the installed plug ferrule, the plug ferrule and the built-in ferrule are coaxially aligned by the gripping action of the elastic sleeve, and the axial misalignment between the optical fibers is minimized.
As shown in FIG. 2, even when a strong lateral load is applied to the plug ferrule 16, the elastic sleeve does not expand beyond a certain level due to the action of the precision sleeve, and as a result, the plug ferrule does not tilt beyond a certain level. The shape of the sleeve case opening is, for example, a cone so that the outer cylindrical surface of the plug ferrule does not contact the sleeve case opening even when the plug ferrule is tilted to the maximum. The position where the built-in ferrule contacts the inner cylindrical surface of the elastic sleeve is the contact 18-a and the contact 18-b, and the portion where the plug ferrule contacts the inner cylindrical surface of the elastic sleeve is the positional relationship between the contact 17-a and the contact 17-b. Thus, the tip of the built-in ferrule and the tip of the plug ferrule are pressed in the same direction on the inner cylindrical surface of the elastic sleeve and the axes of the ferrules are aligned, so that the misalignment between the optical fibers can be minimized. As a result, there is an effect of minimizing the fluctuation of the optical power that is always transmitted regardless of the presence or absence of the lateral load on the plug ferrule and the direction of the lateral load.

  According to the present invention, it is possible to realize a small-sized optical receptacle in which fluctuation of optical power transmitted is small even when a strong lateral load acts on the attached plug ferrule in any direction.

  An embodiment of the present invention is shown in FIG.

  The elastic sleeve 2, precision sleeve 3, built-in ferrule 4, ferrule holding member 5, and sleeve case 7 are included.

  Suitable materials for the elastic sleeve include resin, metal, ceramic, etc. In this embodiment, a material made of zirconia ceramic having a slit was used.

  The inner diameter of the elastic sleeve is preferably 2 μm to 10 μm smaller than the outer diameter of the plug ferrule.

  The precision sleeve can be made of resin, metal, ceramic, glass, etc., but in this embodiment, stainless steel was used.

  The precision sleeve preferably has an inner diameter 10 μm to 30 μm larger than the outer diameter of the elastic sleeve.

  Suitable materials for the built-in ferrule include ceramic and glass. In this example, zirconia ceramic is used, and a single mode optical fiber is fixed to the center with an adhesive, and one end is polished to a convex spherical surface and the other end is polished to an oblique plane. Formed.

  Examples of suitable materials for the ferrule holding member include resin and metal. In this embodiment, stainless steel is used.

  Suitable materials for the sleeve case include resin, metal, ceramic, glass and the like. In this embodiment, stainless steel was used.

  It is preferable to provide a gap so that the difference between the inner diameter of the precision sleeve and the outer diameter of the elastic sleeve into which the built-in ferrule and the plug ferrule are inserted is 1 μm to 20 μm.

  It is preferable to provide a gap with the difference between the inner diameter of the sleeve case and the outer diameter of the precision sleeve being 0.1 mm to 0.2 mm.

  The axial length L1 at which the elastic sleeve holds the built-in ferrule outer cylindrical surface is preferably 3.5 mm or less, and in this embodiment, the axial length L1 at which the elastic sleeve holds the built-in ferrule outer cylindrical surface. Was 2.5 mm.

As an assembling procedure, first, the ferrule holding member 5 and the built-in ferrule are integrated by press-fitting at a strength of 980 N or more.
Secondly, the end of the built-in ferrule on the convex spherical surface side is inserted into the inner hole of the elastic sleeve so that the elastic sleeve grips the built-in ferrule with a force of about 2.5N.
Third, a precision sleeve is put on the outside of the elastic sleeve.
Fourth, the sleeve holding member and the sleeve case are integrated by press-fitting at a strength of 980 N or more with the sleeve case placed on the outside of the precision sleeve.

  In the configuration shown in FIG. 3, a lens and a laser diode are welded and fixed to each of the three optical receptacles of the embodiment, the laser light 20 is introduced into the single-mode optical fiber of the built-in ferrule, and the single plug ferrule attached to the optical receptacle is used. While monitoring the optical power transmitted to the mode optical fiber with the optical power meter 19, loads were applied to the flange of the plug ferrule from four different directions by 90 degrees perpendicular to the axis, and the amount of change in optical power was measured. The values are shown in Table 1. For comparison, similar measurement values using three conventional optical receptacles are also shown. Here, a force of 9.8 N was applied to the position of L2 = 14 mm.

As a result, in the conventional optical receptacle, the amount of change in optical power is −29.9 dB or less, and light is not substantially transmitted, whereas in the optical receptacle of Example 1, the amount of change in optical power is kept low. Was made.

It is a block diagram of the optical receptacle shown in the Example of this invention. In the optical receptacle shown in the Example of this invention, it is a figure which shows the alignment state of an optical receptacle component when a strong lateral load acts on the inserted plug ferrule. The figure which shows the structure which measures the variation | change_quantity of optical power by applying a strong lateral load to a plug ferrule, monitoring the optical power transmitted to a plug ferrule from the laser diode attached to the optical receptacle shown in the Example of this invention. It is. While monitoring the optical power transmitted from the laser diode attached to the optical receptacle shown in the embodiment of the present invention to the plug ferrule, a strong lateral load is applied to the plug ferrule to measure the optical power change amount. It is a figure which shows the relative relationship between the slit position of the elastic sleeve inside a receptacle, and a lateral load direction. It is a block diagram of the optical receptacle shown in the conventional Example. In the optical receptacle shown in the conventional example, it is a figure which shows the alignment state of an optical receptacle component when a strong lateral load acts on the inserted plug ferrule.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Plug ferrule 2 ... Elastic sleeve 3 ... Precision sleeve 4 ... Built-in ferrule 5 ... Sleeve holding member 6 ... Opening 7 ... Sleeve case 8 ... Built-in ferrule 9 ... Elastic sleeve 10 ... Sleeve holding member 11 ... Sleeve case 12 ... Plug ferrule 13 ... Contact 14-a ... Contact 14-b ... Contact 15-a ... Contact 15-b ... Contact 16 ... Plug ferrule 17-a ... Contact 17-b ... Contact 18-a ... Contact 18-b ... Contact 19 ... Optical power Meter 20 ... Laser light 21 ... Slit

Claims (1)

An optical receptacle to which the plug ferrule 1 is attached, which is a hollow cylindrical shape having an inner hole smaller than the outer diameter of the plug ferrule and elastically deforming in the radial direction, and a hollow cylindrical shape outside the elastic sleeve 2 A precision sleeve 3 having an inner hole larger than the diameter, a built-in ferrule 4 having a convex spherical surface for inserting and holding an optical fiber and contacting one end of the plug ferrule 1, and a ferrule holding member 5 holding the built-in ferrule 4; A sleeve case 7 including the elastic sleeve 2 and the precision sleeve 3 and having an opening 6 for inserting the plug ferrule 1 is included, and the elastic sleeve 2 grips a part of the outer cylindrical surface of the built-in ferrule 4. A part of the outer cylindrical surface of the built-in ferrule 4 which is not gripped by the elastic sleeve 2 and the ferrule holding member Is fixed by press-fitting or bonding, the ferrule holding member 5 and the sleeve case 7 are fixed by press-fitting or bonding, and the precision sleeve 3 is coaxially spaced on the outer peripheral side of the elastic sleeve 2. And a clearance is also provided between the outer cylindrical surface of the precision sleeve 3 and the inner cylindrical surface of the sleeve case 7, and the outer cylindrical surface of the elastic sleeve 2 when the plug ferrule 1 is mounted. And a gap between the cylindrical surface of the precision sleeve 3 and a gap between the outer cylindrical surface of the precision sleeve 3 and the cylindrical surface of the sleeve case 7, and the plug ferrule mounted. Even when the plug ferrule 1 is tilted to the limit where the elastic sleeve 2 is expanded and restricted by the precision sleeve 3 due to a lateral load acting on the plug sleeve, the plug ferrule Optical receptacle 1 outer cylindrical surface, characterized in that a structure which does not contact the opening 6 of the sleeve casing 7.

Images