JP2008077063A - Optical receptacle and optical receptacle module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical receptacle in which misalignment between optical axes of a fiber stub and a plug ferrule is suppressed and optical loss is suppressed, and to provide an optical receptacle module using the optical receptacle. <P>SOLUTION: The optical receptacle is provided with a split sleeve, and the fiber stub having a first optical fiber inserted and fixed in a through-hole passing through the center of the ferrule. A length of the split sleeve is determined so that a value obtained by dividing a second distance by a first distance can be in a range from 1.2 to 1.6, when the fiber stub is fitted to the split sleeve up to the first distance from a first end face of the split sleeve in a longitudinal direction of the split sleeve, and when a plug ferrule is fitted to the split sleeve up to the second distance from a second end face of the split sleeve in a longitudinal direction of the split sleeve. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure of an optical receptacle used for optical fiber communication or an optical receptacle module in which the optical receptacle and a light emitting element or a light receiving element are combined.

  In recent years, with the spread of the Internet and an increase in communication data capacity, optical communication networks have been expanded. In particular, high-speed communication using an optical fiber is not only FTTH (Fiber To The Home) to each home, but also in the data storage field, Gigabit Ethernet (registered trademark) (GbE) and 10 Gigabit Ethernet (registered trademark) (10 GbE). As it has rapidly penetrated the market. In these optical fiber communications, an optical receptacle module having a function of inserting / removing an optical connector plug is employed. For example, in a communication capacity of 2.5 Gbps (giga bits per second) or less, a GBIC module using an SC connector or an SFP (Small Form Factor Pluggable) module using a smaller LC connector is used, and a communication capacity of 10 Gbps. Then, XENPAK using an SC connector and an XFP module using an LC connector are used. The SC connector is standardized in JIS C5973 F04 and IEC 61754-4, the diameter of the plug ferrule into which the optical fiber is inserted is 2.5 mm, and the LC connector is IEC 61754-20, TIA / EIA-604-10- The diameter of the plug ferrule that is standardized by A and into which the optical fiber is inserted is 1.25 mm.

The optical receptacle module includes a semiconductor laser corresponding to a light emitting element that converts electricity into light and emits light, or a light receiving element that generates electricity by converting light into electricity and an optical receptacle. The optical receptacle serves to couple a connector containing an optical fiber with a light emitting element or a light receiving element.

  FIG. 1 is a cross-sectional view showing a conventional optical receptacle 4. The optical receptacle 4 includes a receptacle holder 10, a split sleeve 8, and a fiber stub 2. The fiber stub 2 is fitted into the split sleeve 8, and the plug ferrule 6 is inserted and removed from the opposite side of the fitting side. The receptacle holder 10 has a shape that encloses the split sleeve 8, the fiber stub 2, and the plug ferrule 6, but actually has a divided structure.

  The split sleeve 8 is made of a material such as zirconia. FIG. 3 shows an external perspective view of the split sleeve 8. The split sleeve 8 is cylindrical and has a slit portion 8a.

  The fiber stub 2 is obtained by inserting and fixing an optical fiber 2a made of quartz or the like as a core material into a through hole formed in the center of the ferrule 2b. Ferrule 2b is made of a material such as zirconia. Further, the fiber stub 2 has one end surface as an oblique polishing surface 2c and the other end surface as a PC (physical contact) polishing surface 2d.

  The plug ferrule 6 is obtained by inserting and fixing an optical fiber 6a into a through hole formed in the center of the ferrule 6b. The ferrule 6b is made of a material such as zirconia, like the ferrule 2b of the fiber stub 2. The optical fiber 6a is made of quartz or the like as a core material.

  The optical receptacle 4 is assembled as follows. First, the fiber stub 2 is press-fitted into a portion of the receptacle holders 10 that are divided. At this time, the receptacle holder 10 and the fiber stub 2 are fitted by the press-fitting surface 12, and the fitting length is L1.

  Next, the split sleeve 8 is fitted into the fiber stub 2. The fitting length is L2. Further, a part of the receptacle holder 10 fitted with the fiber stub 2 is press-fitted into the rest of the receptacle holder 10 to complete the optical receptacle 4.

FIG. 4 shows an optical receptacle module 32 in which the optical receptacle 4 and the light emitting element 18 are fixed. The holder 44 is fixed to the light emitting element 18 by resistance welding, and the optical receptacle 4 is adjusted to the optical axis position, and then fixed to the holder 44 by YAG (Yittrium, Aluminum, Garnet) welding or the like. The holder 44 may be composed of two bodies in order to have a function of adjusting in the optical axis direction.

The fitting length when the plug ferrule 6 is inserted and fitted into the split sleeve 8 is L3. The total length of the split sleeve 8 is L4, and as shown in FIG. 1, the sum of L2 and L3 is L4 or less. Note that the ratio of the lengths of L2 and L3 is 1: 1.

  In Patent Document 1, a rear end portion of a fiber stub formed by fixing an optical fiber in a through hole of a ferrule is fixed to a receptacle holder, a plug ferrule connected to a front end surface of the fiber stub is held, and the receptacle holder is attached to the receptacle holder. An optical receptacle is disclosed in which a sleeve accommodated in a fixed case holds the tip of the fiber stub. Furthermore, the optical receptacle is characterized in that the outer peripheral surface of the front end portion of the fiber stub is held by the case via the sleeve (see Patent Document 1).

JP 2004-258164 A

  As shown in FIG. 1, there is a slight clearance between the split sleeve 8 and the receptacle holder 10, and the split sleeve 8 is fitted on the fiber stub 2, the split sleeve and the fiber stub fitting surface 14. ing. Since the inner diameter of the split sleeve 8 is slightly smaller than the outer diameter d 1 of the fiber stub 2, the fiber stub 2 is fitted to the split sleeve 8 with the inner diameter of the split sleeve 8 widened. That is, the fiber stub 2 is fitted to the split sleeve 8 by the elastic holding force of the split sleeve 8.

The optical receptacle 4 has a structure in which the fiber stub 2 is press-fitted into the receptacle holder 10 and fitted into the split sleeve 8. The optical receptacle 4 is fixed to the light emitting element 18 and the holder 44, for example, and becomes an optical receptacle module 32. Here, the outer diameter d1 of the fiber stub 2 is created in accordance with the same standard as the outer diameter d2 of the plug ferrule 6 inserted when the optical receptacle module 32 is used.

  When the plug ferrule 6 is inserted into the optical receptacle module 32, the plug ferrule 6 is fitted to the split sleeve 8 on the fitting surface 16 of the split sleeve and the plug ferrule. Since the inner diameter of the split sleeve 8 is slightly smaller than the outer diameter d 2 of the plug ferrule 6, the plug ferrule 6 is fitted to the split sleeve 8 with the inner diameter of the split sleeve 8 widened. That is, the plug ferrule 6 is fitted to the split sleeve 8 by the elastic holding force of the split sleeve 8.

  When the optical receptacle module 32 is actually used, the optical receptacle-side optical connector 22 containing the plug ferrule 6 is inserted into the optical receptacle 4 and connected to various devices via the optical cable 28. At that time, a plurality of connectors are bundled together, and a load may be applied to each connector. The load is transmitted to the plug ferrule 6 and acts as a force for moving the plug ferrule 6 in a direction perpendicular to the optical axis. Therefore, when a force to move the plug ferrule 6 in the direction perpendicular to the optical axis is applied, the inner diameter of the split sleeve 8 increases when the force overcomes the elastic holding force of the split sleeve 8. And the force with which the split sleeve 8 hold | maintains the plug ferrule 6 becomes weak, the plug ferrule 6 will incline with respect to the optical axis of the fiber stub 2, and the optical axis with the fiber stub 2 will shift | deviate as a result.

  As described above, since there is a clearance between the split sleeve 8 and the receptacle holder 10, the split sleeve 8 can move in the length direction of the split sleeve 8 within the receptacle holder 10. Therefore, when the plug ferrule 6 is inserted and fitted into the split sleeve 8, the split sleeve 8 moves toward the fiber stub 2, and the length (L 2) that the split sleeve 8 is fitted to the fiber stub 2 and the split sleeve 8. The ratio of the length (L3) fitted to the plug ferrule 6 may be 1: 0.8. That is, the length (L2) at which the split sleeve 8 is fitted to the fiber stub 2 is longer than the length (L3) at which the split sleeve 8 is fitted to the plug ferrule 6. When the length (L3) at which the split sleeve 8 is fitted to the plug ferrule 6 is shortened, the fitting surface 16 between the split sleeve 8 and the plug ferrule 6 is reduced, and the elastic holding force for the split sleeve 8 to hold the plug ferrule 6 is increased. It gets smaller. As a result, when a force is applied to move the plug ferrule 6 in the direction perpendicular to the optical axis as described above, the force exceeds the elastic holding force of the split sleeve 8 and the inner diameter of the split sleeve 8 is expanded. And the force with which the split sleeve 8 hold | maintains the plug ferrule 6 becomes weak, the plug ferrule 6 moves to a direction perpendicular | vertical to an optical axis, and the optical axis with the fiber stub 2 will shift | deviate.

  Accordingly, when a light emitting element is attached to the side of the oblique polishing surface 2 c of the fiber stub 2, the light emitted from the light emitting element is coupled to the optical fiber 2 a of the fiber stub 2, but the light of the fiber stub 2 and the plug ferrule 6. When the axis is displaced, the light coupled from the optical fiber 2a of the fiber stub 2 to the optical fiber 6a of the plug ferrule 6 is lost.

  That is, when the ratio between the length (L2) at which the split sleeve 8 is fitted to the fiber stub 2 and the length (L3) at which the split sleeve 8 is fitted to the plug ferrule 6 is 1: 1, the split sleeve 8 is connected to the plug ferrule. There is a problem that the elastic holding force for holding 6 is weak, the optical axis is shifted between the fiber stub 2 and the plug ferrule 6, and light is lost. The length (L3) at which the split sleeve 8 is fitted to the plug ferrule 6 needs to be longer than the length (L2) at which the split sleeve 8 is fitted to the fiber stub 2.

    An optical receptacle according to the present invention includes a split sleeve and a fiber stub in which a first optical fiber is inserted and fixed in a through hole passing through the center of a ferrule. The split sleeve fits the fiber stub from the first end face of the split sleeve to the first distance in the length direction of the split sleeve, and the second end face of the split sleeve is inserted into the through hole passing through the center of the ferrule. When the plug ferrule to which the two optical fibers are inserted and fixed is fitted to the second distance in the longitudinal direction of the split sleeve, the value obtained by dividing the second distance by the first distance is 1.2 to 1. This is a split sleeve in which the length of the split sleeve is determined to be in the range of 6.

  An optical receptacle according to the present invention includes a split sleeve and a fiber stub in which a first optical fiber is inserted and fixed in a through hole passing through the center of the ferrule. The split sleeve is configured to fit the fiber stub from the first end surface of the split sleeve to the first distance in the length direction of the split sleeve, and the length of the split sleeve is the first distance which is the fiber stub fitting length. The length of the split sleeve is determined so that the divided value is in the range of 2.3 to 2.9.

  ADVANTAGE OF THE INVENTION According to this invention, the optical receptacle module which suppressed the shift | offset | difference of the optical axis of a fiber stub and a plug ferrule and suppressed the loss of light, and the optical receptacle module using the optical receptacle are provided.

  The best mode for carrying out an optical receptacle and an optical receptacle module using the same according to the present invention will be described below with reference to the accompanying drawings.

(Embodiment)
FIG. 2 is a cross-sectional view showing an optical receptacle of the present invention. The configuration of the optical receptacle 4 shown in FIG. 2 is not significantly different from the conventional optical receptacle, but the length of the split sleeve 8 ′ is different. Further, the ratio of the length (L6) at which the split sleeve 8 'is fitted to the fiber stub 2 and the length (L7) at which the split sleeve 8' is fitted to the plug ferrule 6 is different from that of the conventional optical receptacle. The length of the split sleeve 8 ′ is preferably 5.2 mm, for example. The diameter of the plug ferrule 6 is, for example, 1.25 mm. The fiber stub 2 is press-fitted into the receptacle holder 10, and the fiber stub 2 and the receptacle holder 10 are firmly fitted by the press-fitting surface 12. On the other hand, when the plug ferrule 6 is inserted into the optical receptacle 4, the plug ferrule 6 is only fitted into the split sleeve 8 'and is not fitted as firmly as the press-fitting. Therefore, in order to prevent the optical axis between the optical fiber 2a of the fiber stub 2 and the optical fiber 6a of the plug ferrule 6 from being displaced, the length of the split sleeve 8 'is less than the length (L6) with which the fiber stub 2 is fitted. The length (L7) at which the sleeve 8 'is fitted to the plug ferrule 6 is made longer. Specifically, the ratio of the length (L6) at which the split sleeve 8 'is fitted to the fiber stub 2 and the length (L7) at which the split sleeve 8' is fitted to the plug ferrule 6 is 1: 1.2 to The range is defined as 1.6. Alternatively, the ratio between the length (L8) of the split sleeve 8 ′ and the length (L6) at which the split sleeve 8 ′ fits into the fiber stub 2 is defined as a range of 2.3 to 2.9: 1. These ranges are obtained by conducting a test for examining the level of optical coupling loss caused by the optical axis deviation. Details of the test will be described later.

  Further, the value obtained by dividing the length (L6) at which the split sleeve 8 'is fitted to the fiber stub 2 by the diameter d3 of the fiber stub 2 is also defined as 1.3 or more. The fiber stub 2 is fitted to the split sleeve 8 ′ at the fitting surface 14 of the split sleeve 8 ′ and the fiber stub 2, but the length that the split sleeve 8 ′ is fitted to the fiber stub 2 (L 6). Is short, the force with which the split sleeve 8 ′ holds the fiber stub 2 is weak, and the length of the split sleeve 8 ′ is the specified value of 1: 1.2 to 1.6 or 2.3 to 2.9: 1. Even in the range, the balance between the diameter d3 of the fiber stub 2 and the diameter d4 of the plug ferrule 6 is poor, and the optical coupling loss between the fiber stub 2 and the plug ferrule 6 increases. Therefore, a test for examining the optical coupling loss level generated due to the optical axis deviation was performed, and the value of 1.3 was obtained. Details of the test will be described later.

  FIG. 5 is a diagram for explaining an optical wiggle characteristic test for examining the optical coupling loss level. The optical wiggle characteristic test will be described below. The light emitting element 18 is coupled to the optical receptacle 4 corresponding to the test body by YAG welding or the like. A combination of the optical receptacle 4 and the light emitting element 18 is an optical receptacle module 32. When the light emitting element 18 is replaced with a light receiving element, a light receiving optical receptacle module 32 is obtained. In the optical wiggle characteristic test, the light receptacle module 32 uses the light emitting element 18. The optical receptacle 4 is fixed to a fixing jig 20 for connection to the optical receptacle-side optical connector 22. Further, the optical receptacle-side optical connector 22 having the plug ferrule 6 is fixed from the opposite side of the optical receptacle 4 of the fixing jig 20. The optical receptacle-side optical connector 22 is connected to an optical cable 28, and an optical power meter-side optical connector 24 is similarly connected to one side thereof. The optical power meter side optical connector 24 is connected to the optical power meter 26 and measures the optical output from the optical receptacle module 32.

  The weight 30 is attached to the optical cable 28 with a position 1 m from the end of the optical receptacle-side optical connector 22 (weight position starting point 34) as a weight position 36. The weight of the weight 30 was 350 gf.

  This weight load is applied to the plug ferrule 6, and the optical axes of the fiber stub 2 and the plug ferrule 6 are displaced. When the optical axis shift occurs, an optical coupling loss from the light emitting element 18 occurs, and the optical power meter 26 can measure the loss.

  When carrying out the optical wiggle characteristic test, the fixing jig 20 is fixed with the inclination angle 42 from the horizontal being 45 degrees. Further, with the light output from the light emitting element 18, the fixing jig 20 is rotated by giving the fixing jig 20 a rotation angle 40 in the range of 360 degrees around the optical axis equivalent axis 38. First, in a state before the fixing jig 20 rotates, the optical power is measured by the optical power meter 26, and the measured value is set as an initial value. Then, a change in light power is measured by the optical power meter 26 while giving the rotation angle 40 to the fixing jig 20. The light power value that is the lowest until the fixing jig 20 rotates 360 degrees is obtained, and the light output difference from the initial value is defined as the optical wiggle loss. The unit of optical Uyghur loss is dB. The smaller the value of the optical wiggle loss, the harder the plug ferrule 6 is affected by the load of the weight 30, and the optical coupling between the optical receptacle-side optical connector 22 and the optical receptacle module 32 is more stable with respect to the load. .

  FIG. 6 shows the measurement result of optical wiggle loss when the ratio of the fiber stub fitting length (L6) to the split sleeve 8 ′ and the plug ferrule fitting length (L7) to the split sleeve 8 ′ is changed in the optical wiggle characteristic test. Indicates. As described above, the smaller the optical wiggle loss, the more stable optical coupling characteristics with respect to the mechanical load on the optical cable 28. Therefore, the optical wiggle loss threshold is set to 0.3 dB or less, and further considering the safety factor, the fiber stub fitting length (L6) for the split sleeve 8 ′ and the plug ferrule fitting length (L7) for the split sleeve 8 ′ are set. The lower limit of the ratio R is preferably 1: 1.2. On the other hand, if L6 becomes too large, when a load is applied to the plug ferrule 6, bending at the portion where the plug ferrule 6 is fitted becomes large. From the results of this test, the upper limit of R is preferably 1: 1.6. The optical receptacle module 32 is required to suppress the optical wiggle loss to about 0.3 dB or less. However, in order to satisfy a more stable optical coupling characteristic, the lowest possible optical wiggle loss is preferable, and the safety factor is taken into consideration.

  The measurement result of FIG. 6 can also be expressed as a ratio between the length (L8) of the split sleeve 8 'for optical wiggle loss and the fiber stub fitting length (L6) for the split sleeve 8'. FIG. 7 shows the measurement results of the optical wiggle loss when the ratio of the length (L8) of the split sleeve 8 ′ and the fiber stub fitting length (L6) to the split sleeve 8 ′ is changed in the optical wiggle characteristic test. . Although optical wiggle loss is required to be suppressed to about 0.3 dB or less, it is necessary to satisfy more stable optical coupling characteristics. Since the optical wiggle loss as low as possible is preferable, considering the safety factor, the ratio between the length of the split sleeve 8 '(L8) and the fiber stub fitting length (L6) with respect to the split sleeve 8' is 2.3 to 2.9. : 1 is desirable.

  FIG. 8 shows measurement results of optical wiggle loss when the ratio of the fitting length (L6) of the fiber stub 2 to the length of the split sleeve 8 ′ and the diameter d4 of the fiber stub 2 is changed in the optical wiggle characteristic test. . As the ratio of the fitting length (L6) of the fiber stub 2 to the split sleeve 8 'and the diameter d3 of the fiber stub 2 increases, the optical wiggle loss decreases. As described above, the smaller the optical wiggle loss, the more stable optical coupling characteristics with respect to the mechanical load on the optical cable 28. Therefore, the threshold of the optical wiggle loss is set to 0.3 dB or less, and the ratio of the fitting length (L6) of the fiber stub 2 to the split sleeve 8 ′ and the diameter d3 of the fiber stub 2 is 1. It is desirable to set it to 3 or more. The optical receptacle module 32 is required to suppress the optical wiggle loss to about 0.3 dB or less. However, in order to satisfy more stable optical coupling characteristics, the optical wiggle loss is preferably as low as possible, so the safety factor is considered.

Sectional drawing which shows the conventional optical receptacle. Sectional drawing which shows the optical receptacle of this invention. The external appearance perspective view of a split sleeve. The perspective view of an optical receptacle module (an optical receptacle part is sectional drawing). The figure for demonstrating an optical Uyghur characteristic test. The figure which shows the measurement result of the optical wiggle loss at the time of changing the ratio of the fiber stub fitting length with respect to a split sleeve, and the plug ferrule fitting length with respect to a split sleeve in an optical Uyghur characteristic test. The figure which shows the measurement result of the optical wiggle loss when the value which remove | divided the length of the split sleeve by the fiber stub fitting length with respect to the split sleeve was changed in the optical wiggle characteristic test. The figure which shows the measurement result of the optical wiggle loss when the ratio of the fitting length of the fiber stub with respect to the split sleeve and the diameter of the fiber stub is changed in the optical wiggle characteristic test.

Explanation of symbols

2: Fiber stub 2a: Optical fiber 2b: Ferrule 2c: Obliquely polished surface 2d: PC polished surface 4: Optical receptacle 6: Plug ferrule 6a: Optical fiber 6b: Ferrule 8: Split sleeve 8a: Slit 8 ': Split Sleeve 10: Receptacle holder 12: Press-fit surface 14: Fitting surface 16 of split sleeve and fiber stub 16: Fitting surface of split sleeve and plug ferrule 17: Tapered portion 18: Light emitting element 20: Fixing jig 22: Light on the optical receptacle side Connector 24: Optical power meter side optical connector 26: Optical power meter 28: Optical cable 30: Weight 32: Optical receptacle module 34: Weight position starting point 36: Weight position 38: Optical axis equivalent axis 40: Rotation angle 42: Inclination angle 44: holder

Claims (9)

A split sleeve, and a fiber stub in which a first optical fiber is inserted and fixed in a through-hole passing through the center of the ferrule,
The split sleeve fits the fiber stub from the first end surface of the split sleeve to a first distance in the length direction of the split sleeve, and the center of the ferrule from the second end surface of the split sleeve. A value obtained by dividing the second distance by the first distance when the plug ferrule inserted and fixed in the through hole passing therethrough is fitted to the second sleeve in the length direction of the split sleeve. Is an optical receptacle which is the split sleeve in which the length of the split sleeve is determined to be in the range of 1.2 to 1.6.   2. The light according to claim 1, wherein the split sleeve is a split sleeve in which a length of the split sleeve is determined such that a value obtained by dividing the first distance by the fiber stub diameter is 1.3 or more. Receptacle.   An optical receptacle module comprising: the optical receptacle according to claim 1; and a light emitting element that emits light by converting electricity into light, and the optical receptacle and the light emitting element are coupled.   3. An optical receptacle module comprising: the optical receptacle according to claim 1; and a light receiving element that generates electricity by converting light into electricity, and the optical receptacle and the light receiving element are coupled to each other. A split sleeve, and a fiber stub in which a first optical fiber is inserted and fixed in a through-hole passing through the center of the ferrule,
The split sleeve is configured to fit the fiber stub from the first end surface of the split sleeve to the first distance in the length direction of the split sleeve, and divide the length of the split sleeve by the first distance. An optical receptacle which is the split sleeve in which the length of the split sleeve is determined so that the obtained value is in the range of 2.3 to 2.9.   6. The light according to claim 5, wherein the split sleeve is the split sleeve in which a length of the split sleeve is determined such that a value obtained by dividing the first distance by the diameter of the fiber stub is 1.3 or more. Receptacle. The optical receptacle according to claim 5 or 6, wherein the diameter of the fiber stub is 1.25 mm, and the length of the split sleeve is 5.2 mm.   8. An optical receptacle module comprising: the optical receptacle according to claim 5; and a light emitting element that emits light by converting electricity into light, and the optical receptacle and the light emitting element are coupled.   8. An optical receptacle module comprising: the optical receptacle according to claim 5; and a light receiving element that generates electricity by converting light into electricity, and the optical receptacle and the light receiving element are coupled to each other.

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