JP2006039334A - Optical receptacle and optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an optical fiber from being deviated and increased in loss due to widening of an insertion end side of a sleeve when a lateral load is applied to a plug ferrule, and also, to prevent a connection loss from increasing due to floating of the sleeve by internal clearance and insufficient holding of a fiber stub. <P>SOLUTION: In the optical receptacle comprising a holder with a through-hole formed therein, the fiber stub which fixes the optical fiber at the center of the ferrule and of which the rear end part is fixedly inserted into the through-hole of the above holder, and the sleeve which allows the tip part of the fiber stub to be inserted thereinto from one open end part and also makes the plug ferrule inserted from the other open end part abut on the tip face and hold the plug ferrule, an elastic member is made to abut on the outer circumferential surface corresponding to the area where the plug ferrule of the above sleeve is inserted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical receptacle and an optical module used for optical communication.

  An optical module for converting an optical signal into an electric signal has a structure in which an optical element such as a semiconductor laser or a photodiode is housed in a case, and the optical signal is introduced into or derived from an optical fiber via a lens or the like. It has become. FIG. 3 shows an example of such an optical module in which a connector is connected. The receptacle-type optical module shown in FIG. 3 has an optical element unit 12 connected to the rear end face of the optical receptacle 10 and a front end face of the plug ferrule 11 connected from the front end of the optical receptacle.

  The optical receptacle 10 has a through hole 5a formed at the center of the bottom surface of a bottomed cup-shaped holder 5 formed by cutting or injection molding a stainless steel base material, and an optical fiber 2a is bonded and held at the center of the through hole 5a. The rear end of the ceramic fiber stub 1 is press-fitted and held. Then, the distal end side of the fiber stub 1 is fitted from the opening on one side of the sleeve 4, and the cylindrical sleeve case 6 covering the sleeve 4 by the recessed opening of the holder 5 is attached to the holder 5 side to prevent the sleeve 4 from coming off. It is structured to press fit against the wall surface.

  Here, in the optical receptacle 10 that requires high-efficiency optical coupling to a single-mode optical fiber, even if the plug ferrule 11 having the optical fiber 3 bonded and held at the center is repeatedly attached to and detached from the sleeve 4, high accuracy is achieved. Since precise positioning is required, a high-precision machining is possible as the material of the sleeve 4 and a ceramic having excellent wear resistance is often used.

  By the way, in recent years, with the spread of the Internet and the like, optical transmission has become common in data communication, and the optical communication transceiver that is the key device can simultaneously realize high speed, downsizing, and low cost. It has been demanded.

  However, if the size is reduced as it is, the insertion length of the plug ferrule 11 and the insertion length of the fiber stub 1 are shortened, so that the holding force of the sleeve 4 in the optical receptacle is reduced, and the plug ferrule 11 A displacement occurs in the position of the optical fiber 3 in the plug ferrule 11 due to a lateral load due to its own weight or tension of the cord of the fixed optical fiber 3, so that the light output is reduced or the reproducibility of attachment / detachment cannot be obtained. There was a problem.

Therefore, in order to reinforce the holding power of the optical receptacle, the entire length of the fiber stub 1 is fitted into the sleeve 4 as shown in FIG. 4, and is press-fitted into the through hole 5 a of the holder 5 at the position of the fitted sleeve 4. The holder 5 is press-fitted into an opening that is opened to a step larger on the rear end side of the sleeve case 6, so that the opening on the rear end side of the shell 4 holds the sleeve 4 and the fiber stub 1 via the holder 5. A technique for reducing the size of the receptacle by holding the stub 1 at a common position of the sleeve 4 and the holder 5 (see Patent Document 1), and the holder 5 has a distal end side from one opening of the sleeve 4 as shown in FIG. The rear end side of the inserted fiber stub 1 is configured to be held in the through hole 5a, and a step portion having a slightly wider opening area on the inlet side of the through hole 5 is formed. Three 4 of one side is pressed fiber stub 1 is held in the through hole 5a of the holder 5 together with the sleeve 4 compact in the gripping is was or suggest those stable structure (see Patent Document 2).
Japanese Patent Laid-Open No. 10-332988 Japanese Unexamined Patent Publication No. 2002-350693

  However, in the case of the optical receptacle 10 having the conventional structure as shown in FIG. 4, when a lateral load is applied to the plug ferrule 11, the insertion end side of the sleeve 4 may spread, and the holding side of the fiber stub 1 is at the same position. Since the optical fiber is held, the optical fiber is likely to be displaced, and in this case, there is a problem that the loss is increased.

  Also, in the structure in which the holder 5 side holds the end portion of the sleeve 4 as shown in FIG. 5, the insertion end side of the sleeve 4 spreads due to the lateral load on the plug ferrule 11, and the optical fiber is liable to be displaced and lost. There was a problem that would increase.

  In the case of the optical receptacle 10 having a structure in which the fiber stub 1 is held at a common position between the sleeve 4 and the holder 5 as in the conventional optical receptacle of FIG. 4, the plug ferrule 11 is optically coupled to the fiber stub 1. In order to connect without loss, it is necessary to make a pressure input that can withstand a continuous load or a momentary load during attachment / detachment. Therefore, it is necessary to process the diameter of the opening on the rear end side of the sleeve 4, the holder 5, and the sleeve case 6 holding the fiber stub 1 with high accuracy.

  That is, when the sleeve 4 is made to be in close contact with the inner diameter of the sleeve case 6 by limiting the inner diameter of the sleeve case 6 to be equal to or smaller than that of the sleeve 4 and the inclination is restricted, the through hole into which the fiber stub 1 of the holder 5 is inserted. 5a and the outer shape into which the sleeve case 6 is fitted, or the coaxiality of the through-hole 5a, the coaxiality of the inner diameter and the outer shape of the sleeve 4, the inner diameter of the sleeve case 6 and the outer coaxiality, and the inner diameter to fit the holder 5 of the inner diameter of the sleeve case 6 It is necessary not only to process the eccentric amount of the inner diameter of the sleeve case 6 to fit the sleeve 4 with high accuracy, but also to align the outer center of the fiber stub 1 and the inner diameter center of the sleeve case 6 with high accuracy and without tilting. There is a problem that not only the cost of parts increases but also the yield is poor.

  In order to obtain good characteristics in the optical receptacle 10, it is ideal that the center of the plug ferrule 11 and the fiber stub 1 coincide with each other. For this reason, an optical fiber in which the center of the sleeve is fixed to the fiber stub 1. 3 is required to be placed on the extended line at the center of the core.

  In the case of the optical receptacle having the conventional structure shown in FIG. 4, the entire length of the fiber stub 1 is fitted into the sleeve 4, and is press-fitted into the through-hole 5 a of the holder 5 at the position of the fitted sleeve 4. Since the holder 5 is press-fitted into the opening, the center of the sleeve 4 is shifted from the center of the optical fiber core of the fiber stub 1 due to the stacking of the tolerances of the components, and good characteristics cannot be obtained. have.

  In view of the above, the optical receptacle of the present invention includes a holder in which a through hole is formed, a fiber stub formed by fixing an optical fiber at the center of the ferrule, and inserting and fixing a rear end portion into the through hole of the holder, A light comprising a sleeve for inserting the tip end of the fiber stub from one open end and abutting and holding the plug ferrule inserted from the other open end to the tip end surface of the fiber stub The receptacle is characterized in that an elastic member is brought into contact with an outer peripheral surface corresponding to a region where the plug ferrule of the sleeve is inserted.

  The elastic member is formed in a ring shape, and is arranged so that the center of the opening and the center of the sleeve are on the extension line of the center of the optical fiber core of the fiber stub fixed to the holder. It is characterized by that.

  Furthermore, the elastic member is arranged on the other opening side.

  The optical module of the present invention is characterized in that a case having an optical element is attached to the optical receptacle.

  According to the present invention, the insertion of inserting the sleeve plug ferrule when a lateral load is applied to the plug ferrule by contacting the elastic member with the outer peripheral surface corresponding to the region where the plug ferrule of the sleeve is inserted. Since the elastic member can suppress the end side from spreading, it is possible to prevent the loss from increasing without causing the optical fiber shift.

  This elastic member is formed in a ring shape, and the center of the ring opening and the center of the sleeve are arranged so as to be on the extension line of the center of the core of the optical fiber fixed to the fiber stub. Even when a lateral load is applied, the plug ferrule and the fiber stub can always be repaired so that the centers thereof coincide with each other, and an optical receptacle having good characteristics can be realized at low cost.

  Furthermore, since the elastic member is arranged on one opening side, when a lateral load is applied to the plug ferrule, the sleeve insertion end side is prevented from spreading on the sleeve inlet side, so that the optical fiber is less likely to be displaced. It is possible to prevent the loss from becoming large.

  As described above, when an optical module is produced using the optical receptacle of the present invention, the effect of the elastic member suppressing the insertion end side of the sleeve from spreading when a lateral load is applied to the plug ferrule easily and reliably can be obtained. In addition, a highly accurate optical module can be realized at low cost.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of an optical receptacle of the present invention.

  FIG. 2 is a cross-sectional view showing an optical module using the optical receptacle of the present invention.

  As shown in FIG. 1 (a), an optical receptacle 10 of the present invention fixes an optical fiber to the center of a holder 5 in which a through hole 5a is formed and a ferrule 2, and the rear end portion is a through hole of the holder 5. A fiber stub 1 inserted and fixed to 5a, and a tip end portion of the fiber stub 1 are inserted from one open end portion, and a plug ferrule 11 inserted from the other open end portion is attached to the tip end surface 1a of the fiber stub 1 A sleeve 4 for contacting and gripping and a sleeve case 6 for housing the sleeve 4 are formed, and a through hole 100a through which the elastic member 100 can be inserted is formed in a part of the sleeve case 6, and the through hole 100a is formed in the through hole 100a. By pressing and fixing the elastic member 100, the outer peripheral surface of the sleeve 4 corresponding to the region into which the plug ferrule 11 is inserted can be contacted. .

  As described above, since the elastic member 100 is in contact with the outer periphery of the sleeve 4, when a lateral load is applied to the plug ferrule 11, the elastic member 100 absorbs the deformation on the insertion end side of the sleeve 4, and the sleeve 4 The position can be pushed back to the proper position to prevent spreading.

  For the elastic member 100, a method of arranging one or more of the members formed in a rectangular shape, a cylindrical shape, or a method of arranging a ring-shaped part is conceivable. In either case, a lateral load is applied to the plug ferrule 11. The elastic member 100 absorbs the deformation of the sleeve 4, preferably the deformation on the insertion side, and the effect of suppressing the expansion is obtained. However, in order to withstand lateral loads from various directions and to keep the position of the sleeve 4 at an appropriate position, it is desirable that the sleeve is formed in a ring shape as shown in FIG. It is best to arrange the center of the ring opening and the center of the sleeve 4 on the extension line of the center of the core of the optical fiber 3 fixed to the fiber stub 1. By arranging the elastic member 100 at the above position, when a lateral load is applied to the plug ferrule 11, the elastic member absorbs the deformation on the insertion end side of the sleeve 4 and pushes the position of the sleeve 4 back to an appropriate position. The plug ferrule 11 can be inserted by constantly correcting the position of the sleeve 4 at the other end where the plug ferrule 11 is inserted by applying an equal load to the sleeve 4 at all times. As a result, the center of the core portion of the optical fiber 3 of the fiber stub 1 coincides with the plug ferrule 11, and it is possible to continue to obtain good characteristics.

  Further, the elastic member 100 can be arranged at an arbitrary position in the region where the plug ferrule 11 of the sleeve 4 is inserted, but is preferably arranged on the other opening side of the sleeve 4. When a lateral load is applied to the plug ferrule, the amount of deformation on the sleeve insertion end side on the one opening side becomes the largest due to the moment. Therefore, the elastic member absorbs the deformation more when the elastic member is arranged on the one opening side, and the sleeve This is because it is possible to obtain a great effect of pushing the position back to an appropriate position and suppressing the spread.

  In order to arrange the center of the ring opening and the center of the sleeve so as to be on the extension line of the center of the core of the optical fiber fixed to the fiber stub, the through hole 100a as described above is formed on the side surface of the sleeve case 6. The elastic member 100 can be arranged by forming a groove (not shown). When it is arranged in the through hole 100a or groove provided on the side surface of the sleeve case 6, it is simply inserted, so that it does not require complicated work and can be arranged easily and inexpensively.

  The elastic member 100 can be fixed by press-fitting using the through-hole 100a, silver solder, solder, spot welding, adhesive fixing, or the like. For cost and ease of work, press-fitting using the through-hole 100a is possible. Fixing is most desirable.

  The elastic member 100 is made of a molded product of a metal material such as a plunger, stainless steel, phosphor bronze or the like, or a plastic material such as rubber, PBT or PPS, and is preferably a metal spring such as stainless steel or phosphor bronze. When it consists of metal springs, such as stainless steel and phosphor bronze, the elastic member 100 can be manufactured at low cost, and durability and long-term reliability are also excellent.

The ferrule 2 constituting the fiber stub 1 is made of a metal such as stainless steel or phosphor bronze, a plastic such as an epoxy or a liquid crystal polymer, or a ceramic such as alumina or zirconia, and is particularly preferably formed of zirconia ceramic. Specifically, partial stabilization mainly comprising tetragonal crystals, containing ZrO ₂ as a main component, at least one of Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like as a stabilizer. Zirconia ceramics are preferably used, and such partially stabilized zirconia ceramics have excellent wear resistance and are elastically deformed moderately, which is advantageous when fixing the fiber stub 1 to the holder 5 by press-fitting. is there.

  As a processing method of the ferrule 2, first, when the ferrule 2 is formed from, for example, zirconia ceramics, a cylindrical or rectangular parallelepiped shaped body that becomes the ferrule 2 by a predetermined forming method such as injection molding, press molding, extrusion molding or the like is prepared in advance. After that, the molded body is fired at 1300 to 1500 ° C. and subjected to cutting or polishing to a predetermined dimension.

  Note that a predetermined shape may be formed in advance on the formed body by cutting or the like, and then fired.

  The front end surface 1a of the fiber stub 1 is processed into a curved surface having a curvature radius of about 5 to 30 mm in order to reduce the connection loss with the optical connector, and the end surface of the rear end is emitted from an optical element 12 such as an LD (laser diode). In order to prevent the reflected light from being reflected by the end face of the optical fiber 3 and returning to the optical element 12, the optical signal is mirror-polished to an inclined surface of about 4 to 10 °.

  The holder 5 is a cylindrical storage portion 5b that is fitted and stored in the outer periphery of the sleeve case 6 in a state where the distal end portion of the fiber stub 1 is inserted and fixed to the sleeve 4 stored in the sleeve case 6. The storage portion It consists of a through hole 5a formed at substantially the center of 5b to which the rear end of the fiber stub 1 is fixed.

  Since the holder 5 is often welded to the case 14 that houses the optical element 12 of FIG. 2 as an optical module, a material that can be welded such as stainless steel, copper, iron, nickel, etc. is used. Stainless steel is used in consideration of the properties and weldability.

  In consideration of adhesion to solder, gold plating or the like may be applied to the outer surface.

  The entire sleeve 4 is completely accommodated in the sleeve case 6, and a material such as zirconia, alumina, or copper is used as the material, but a zirconia ceramic material is mainly used in consideration of wear resistance.

  In addition, the surface roughness of the inner diameter of the sleeve 4 is preferably Ra 0.2 μm or less in consideration of the insertability. The outer diameter of the fiber stub 1 and the inner diameter tolerance of the sleeve 4 are preferably ± 1 μm or less in order to obtain a low connection loss. The inner diameter of the sleeve 4 is desirably designed to be 0.98 N or more in order to hold the fiber stub 1 securely.

  As the material of the sleeve case 6, a wide range of materials such as stainless steel, copper, brass and other copper alloys, iron, nickel, and aluminum can be used. In order to increase the reliability, it is preferable to use stainless steel like the holder 5.

  Next, when the optical module 15 is configured using the optical receptacle 10 of the present invention shown in FIG. 1, the optical element 12 and the lens are provided on one side of the optical receptacle 10 provided with the fiber stub 1 as shown in FIG. The case 14 provided with 13 is joined by welding or the like.

  In the embodiment shown in FIG. 2, the optical module 15 constituted by the optical receptacle 10 using the fiber stub 1 is taken up. However, in the optical module 15 constituted by the optical receptacle 10 when the fiber stub 1 is not used. However, the present invention is effective.

  Examples of the present invention will be described.

  FIG. 1 shows an optical receptacle 10 as an embodiment of the present invention, and FIG. 3 shows an optical receptacle 20 as a comparative example. The ferrule used for each fiber stub was made of zirconia ceramics, a cylindrical ceramic molded body was obtained by extrusion molding, baked and hardened in a firing process, and cut to obtain a ferrule sample having a predetermined shape.

  An optical fiber is inserted and fixed in the through hole of each ferrule obtained in this way, the tip end surface is mirror-polished to a curved surface with a curvature radius of about 20 mm, and the rear end on the opposite side is light emitted from an optical element such as an LD. In order to prevent the reflected light from being reflected at the tip of the optical fiber and returning to the optical element, the rear end surface of the optical fiber was cut into a 6 ° inclined surface to form a fiber stub.

  Next, the rear end portion of the obtained fiber stub was inserted and fixed in the holder, and the sleeve 4 was inserted and fixed in the tip portion of the fiber stub 1.

  In the case of the sample of the present invention shown in FIG. 1, a ring-shaped elastic member made of stainless steel? Was pressed into a groove of a sleeve case 6 produced by cutting stainless steel, and the sleeve case 6 was press-fitted into the holder 5 to produce ten optical receptacles 10.

  On the other hand, in the case of the optical receptacle 20 of the comparative example of FIG. 6, 10 optical receptacles 10 were produced by press-fitting the sleeve case 6 produced by cutting stainless steel into the holder 5.

  Then, as a comparative measurement of the lateral load, the receptacles of the present invention and the conventional structure were respectively made into modules in which an optical case having an LD element was aligned and fixed to the optical receptacle as shown in FIG. After a constant light is output from the power source and the plug ferrule 11 is inserted and connected to the connector, the light output is measured by a light output measuring instrument. And the test was implemented by the method of measuring the light output with respect to a lateral load on the basis of the light output before applying a lateral load.

  The result is shown in FIG.

  As is apparent from FIG. 6, it was found that the optical receptacle 10 of the present invention does not significantly decrease the light output even when a lateral load is applied.

  On the other hand, in the conventional optical receptacle 20, the light output is reduced by about 30% when a lateral load is applied, and it has been found that the characteristics are not stable when the lateral load is applied.

  The present invention is applicable not only to optical communication modules and the like, but also to optical modules for sensor applications.

(A) is sectional drawing which shows one Embodiment of the optical receptacle of this invention, (b) is a side view of the elastic member of this invention. It is sectional drawing which shows one Embodiment of the optical module using the optical receptacle of this invention. It is sectional drawing which shows one Embodiment of the conventional optical receptacle module. It is sectional drawing which shows the conventional optical receptacle. It is sectional drawing which shows the conventional optical receptacle. It is a graph which shows the connection loss with respect to the lateral load of this invention and a prior art example.

Explanation of symbols

1: Fiber stub 1a: Tip surface 2: Ferrule 2a: Through hole 3: Optical fiber 4: Sleeve 5: Holder 5a: Through hole
6: Sleeve case

Claims (4)

A holder in which a through hole is formed, a fiber stub in which an optical fiber is fixed to the center of the ferrule and a rear end portion is inserted and fixed in the through hole of the holder, and a tip end portion of the fiber stub is connected to one open end The plug ferrule of the sleeve is inserted into the optical receptacle comprising a sleeve for inserting and gripping the plug ferrule inserted from the other open end portion to the front end surface of the fiber stub and holding the plug ferrule. An optical receptacle characterized in that an elastic member is brought into contact with the outer peripheral surface corresponding to the region. The elastic member is formed in a ring shape, and the center of the opening and the center of the sleeve are arranged so as to be on an extension line of the center of the optical fiber core of the fiber stub fixed to the holder. An optical receptacle characterized by The optical receptacle is characterized in that the elastic member is disposed on the other opening side. An optical module comprising a case having an optical element attached to the optical receptacle according to claim 1.

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