JP4535985B2 - Optical receptacle and receptacle module - Google Patents

Description

  The present invention relates to an optical receptacle used as a component of an optical transceiver module, and a receptacle module including a light emitting element or a light receiving element.

  In recent years, high-speed data communication using an optical fiber is generally performed. In optical fiber communication, an optical transceiver module including a light emitting element and a light receiving element is used as a two-way communication module, and is connected to a counterpart module by an optical fiber via an optical receptacle. A structure that does not generate interference noise or a structure that is not affected by interference noise has become important for optical receptacles that connect optical fibers as the transmission signal handled increases.

  The structure of a conventional optical receptacle is shown in a longitudinal sectional view in FIG. FIG. 7 is a longitudinal sectional view showing the structure of a receptacle module in which an optical element unit is coupled to such an optical receptacle. In the present invention, the longitudinal section (figure) means a section (figure) cut along the axes of the optical fiber and the stub ferrule. On the other hand, the cross section (figure) means a cross section (figure) cut in a direction perpendicular to the axis of the optical fiber or stub ferrule.

An outline of the configuration and functions of the optical receptacle will be described below.
Reference numeral 110 denotes an optical receptacle, 109 denotes an optical element unit, and 120 denotes a receptacle module that couples them. The optical receptacle 110 is formed by combining a stub ferrule 101, a sleeve 102, a holder 103, and a shell 105.

  The stub ferrule 101 is a thick-walled cylindrical member generally made of ceramics mainly composed of zirconia or alumina, metal such as stainless steel (SUS), or plastic such as epoxy resin. Inside, a through hole is provided on the central axis, and an optical fiber having the same length is inserted. However, the optical fiber is not shown in FIGS. The tip surface 111 of the stub ferrule 101 is subjected to curved surface polishing to reduce the connection loss of the optical fiber, and is aligned so that the tip of the optical fiber inserted inside is exposed. Specifically, spherical polishing (PC polishing) processing or oblique spherical polishing (APC polishing) processing may be performed.

  The sleeve 102 is a cylindrical member in which the distal end surface 111 of the stub ferrule 101 is inserted on the proximal end side (lower side in the drawing) and the distal end portion of a plug ferrule (not shown) is inserted on the distal end side (upper side in the drawing). It is. The tip surfaces of the stub ferrule 101 and the plug ferrule are brought into contact with each other and are held by the sleeve 102, whereby the optical fibers provided on the central axes of both ferrules can be coupled in series.

  The plug ferrule is a thick cylindrical member made of ceramics or metal similar to the stub ferrule 101, and is a component part of an optical connector in which an optical fiber is inserted and fixed. The optical fiber inserted into the plug ferrule is different from the optical fiber inserted into the stub ferrule 101 in the sense that it is a long one extending to the optical communication partner module or the optical connector at the relay point. Similarly to the stub ferrule 101, the tip end surface of the plug ferrule is mirror-polished into a curved surface so that the tip end of the internal optical fiber is exposed. As a result, when the plug ferrule and the stub ferrule 101 are held by the sleeve 102 in a state where the tip surfaces thereof are in contact with each other and both are arranged in a straight line, the optical fibers provided on the respective central axes The tips are connected to each other, and an optical signal can be transmitted.

  There are a plurality of types of sleeves, and a split sleeve having a slit from one end to the other end of a cylindrical member and a precision (rigid) sleeve made of a solid cylinder without a slit are generally used.

  In the present invention, the “base end side” for the receptacle module and its components is a side where an optical element to be described later is provided, and means the lower side in FIGS. 6 and 7. On the other hand, the “tip side” is the side where the plug ferrule is inserted, and means the upper side in both figures. Further, in the stub ferrule 101, the distal end portion in the axial direction means the end surface on the distal end side and the vicinity thereof, the proximal end portion in the axial direction means the end surface on the proximal end side and the vicinity thereof, and the intermediate portion means the distal end portion. And the part except a base end part shall be meant broadly. Note that the “tip side” in the plug ferrule means the end surface side where the optical fiber inserted therein is exposed and inserted into the sleeve 102.

  The holder 103 is a cylindrical or ring-shaped hollow member that holds the outer peripheral surface of the stub ferrule 101, and is generally made of a metal material. The holder 103 uses a flange 131 provided at the periphery to couple the optical receptacle 110 to an external housing (not shown). The holder 103 also has a function of storing the proximal end portion of the sleeve 102.

An optical element unit 109 coupled to the optical receptacle 110 for receiving and transmitting an optical signal is generally composed of an alignment adapter 106, an element holder 107, an optical element 108, and the like, and an optical fiber provided in the stub ferrule 101 and an optical signal. It is an optical component that performs transmission and reception.
The optical element 108 is a light emitting element including an LD (laser diode) or a light receiving element including a photodiode, and may include other components such as a condensing lens and a wiring board.
The element holder 107 is a cover for the optical element 108 and connects the optical element 108 and the alignment adapter 106.
The alignment adapter 106 is a member for holding the holder 103 while aligning the optical fiber inserted through the stub ferrule 101 with the central axis of the light emitted from the optical element 108. Generally, a metal such as SUS is used for the element holder 107 and the alignment adapter 106.
As shown in FIG. 7, the alignment adapter 106 is generally fitted with a base end portion of the holder 103 on the distal end side and provided with an aperture through which an optical signal can pass, and on the base end side with the element holder 7. A cylindrical body provided with an inward or outward flange to be joined by welding or the like is used. The stub ferrule 101 and the center axis of the light emitted from the optical element 108 are aligned by welding the holder 103 and the alignment adapter 106, and the alignment adapter 106 and the element holder 107, respectively, by YAG welding. It is common.

  In the case of the conventional optical receptacle 110 shown in FIGS. 6 and 7, as described above, the path from the element holder 107 to the housing (not shown) through the alignment adapter 106, the holder 103 and its flange 131, and the tip In general, everything up to the shell 105 is made of conductive metal parts. For this reason, the entire optical receptacle 110 has a potential level equal to the ground or power supply of the circuit of the optical element 108. Therefore, when electrical noise occurs in the ground or power supply of the circuit of the optical element 108, the optical receptacle 110 itself acts as an antenna, and generates noise radio waves in the light transmission side unit, and also in the light reception side unit. Had the problem of electromagnetic interference (EMI), which picked up external noise. In addition, due to the high conductivity from the optical element 108 to the housing, there is a possibility that electrostatic discharge (ESD) may occur, in which the device fails due to electrostatic discharge accumulated in any of them.

  In contrast, in an optical receptacle including a ferrule inserted through an optical fiber and a holder and a sleeve for holding the ferrule, it is electrically insulated at any point on the path from the optical element to the housing to receive a noise signal. An invention that can prevent outgoing calls has been proposed. For example, Patent Document 1 below discloses an optical receptacle provided with a resin sleeve cover that covers both a sleeve and a holder. Since the sleeve cover is made of resin, a metal portion that can be a noise antenna can be reduced in size, and the amount of electromagnetic waves that enter and exit from the holder or the like can be reduced. Further, since the flange portion coupled to the housing is also made of an insulating resin, it is possible to cut off the conduction of noise signals.

JP 2001-66468 A

However, the conventional technique related to the optical receptacle described in Patent Document 1 in which an electrically insulating portion made of resin is provided on the path from the optical element to the housing has the following problems.
First, the mechanical properties of the optical receptacle are reduced and / or fluctuated by making the holder made of resin the housing that holds the optical receptacle outside the housing. That is, in the conventional optical receptacle, it is common to use a high-rigidity and high-strength metal typified by SUS for the holder coupled to the housing, but if this is replaced with a resin, the rigidity of the optical receptacle and The load resistance generally decreases, causing problems in terms of retention and resonance, and the durability decreases.
Second, by changing the holder from metal to resin, it is necessary to reduce the mounting load or torque on the housing, and the load balance at the mounting point changes. It becomes a factor to get worse. The same applies to the coupling side between the optical receptacle and the optical element unit.By changing the material of the holder from metal to resin, the optical characteristics of the optical receptacle itself are deteriorated and the interface conditions with the optical element unit are changed. This is an undesirable factor.

  Therefore, in light of these problems, in the present invention, the conventional optical receptacle, without impairing mechanical characteristics and optical signal connection loss, and without changing the coupling condition with the external interface, the optical element side, An object of the present invention is to provide an optical receptacle excellent in electromagnetic interference (EMI) characteristics and electrostatic discharge (ESD) characteristics by electrically blocking the optical connector side and the housing side at a high level.

The optical receptacle according to the present invention is
(1) A stub ferrule made of an insulating material, with a stub ferrule inserted through an optical fiber therein, and a cylindrical shape capable of holding a stub ferrule at one end and a plug ferrule connected to the stub ferrule at the other end A stub ferrule is press-fitted from the base end side, a metal first holder to be attached to an intermediate portion of the stub ferrule, and a stub ferrule is press-fitted from the base end side, and the stub ferrule base end A metal second holder to be attached to the portion, and when the first holder is attached to the stub ferrule, among the outer peripheral surfaces of the stub ferrule, the holding position of the first holder and the second holder A circular recess that does not contact the inner peripheral surface of the first holder is provided between the holding position and the first holder and the second holder are electrically insulated. Optical receptacle to be,
(2) The circular concave portion provided between the holding position of the first holder and the holding position of the second holder has a depth of 1% to 20% with respect to the thickness of the stub ferrule. The optical receptacle according to (1) above,
(3) The circumferential recess provided between the holding position of the first holder and the holding position of the second holder has an axial length of 10% to 200% with respect to the diameter of the stub ferrule. The optical receptacle according to (1) or (2), characterized in that
(4) The optical receptacle according to any one of (1) to (3), wherein the sleeve is a split sleeve provided with a slit in the axial direction.
(5) A stub ferrule having an optical fiber inserted therein, and a cylindrical sleeve made of an insulating material that holds the stub ferrule and can hold the plug ferrule connected to the stub ferrule at the other end. An optical receptacle that holds a middle portion of a sleeve, a first metal holder that can be coupled to a housing that houses the optical receptacle, a base end portion of the sleeve, and the optical fiber. A second holder made of metal that can be coupled to an optical element unit that receives and transmits an optical signal, and between the holding position of the first holder and the holding position of the second holder on the outer peripheral surface of the sleeve the circularly recess that is not in contact with the inner peripheral surface of the first holder is provided, wherein the first holder and the second holder is separated from the distal side or proximal side of said sleeve When press-fitted attachment, the first holder and the second holder and the optical receptacle, characterized by comprising electrically insulating,
Is the gist.

The receptacle module according to the present invention is
( 6 ) An optical element unit including a light emitting element or a light receiving element is coupled to the second holder of the optical receptacle according to any one of (1) to ( 5 ).

According to the optical receptacle and the receptacle module using the same according to the present invention, the first metal holder for coupling with the housing and the second metal holder for coupling with the optical element unit are electrically connected to each other. By providing the outer periphery of the stub ferrule in an electrically insulated state, it is possible to block noise signals and static electricity between the optical element circuit and the housing and improve the EMI characteristics and the ESD characteristics.
In addition, the first holder and the second holder are both made of a metal material, so that the interface conditions with the housing and the optical element unit coupled with the first optical holder can be reduced without deteriorating the mechanical characteristics as compared with the conventional optical receptacle. A good insulating state can be obtained inside the optical receptacle itself without change.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiments, for example, regarding the specific shapes of the holder and the shell and the positional relationship between these and the stub ferrule. FIG. 1 is a longitudinal sectional view of an optical receptacle according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a receptacle module in which an optical element unit is coupled to such an optical receptacle. Reference numeral 10 denotes an optical receptacle, 9 denotes an optical element unit, and 20 denotes a receptacle module. 1 represents a stub ferrule, 2 represents a sleeve, 3 represents a first holder, 4 represents a second holder, 5 represents a shell, 6 represents an alignment adapter, 7 represents an element holder, and 8 represents an optical element. An optical fiber 30 is inserted on the central axis of the stub ferrule 1.

  The configurations and functions of the optical receptacle 10 and the receptacle module 20 according to the present embodiment will be described below. However, description of points common to conventional optical receptacles and receptacle modules is omitted.

  The optical receptacle 10 and the receptacle module 20 according to the present embodiment shown in FIGS. 1 and 2 are different from the conventional optical receptacle 110 and the receptacle module 120 shown in FIGS. One feature is that the first holder 3 and the second holder 4 are separated.

The materials of the first holder 3 and the second holder 4 are not limited. In particular, when each is made of a conductive metal material, the mechanical characteristics and external interface conditions equivalent to those of the conventional optical receptacle are maintained. This is advantageous because the present invention can remarkably exhibit the effect of improving electromagnetic interference (EMI) characteristics and electrostatic discharge (ESD) characteristics according to the present invention. Specifically, SUS is preferably used from the viewpoints of rigidity, strength, corrosion resistance, durability, and availability. The metal materials constituting the first holder 3 and the second holder 4 may be the same or different from each other.
The first holder 3 is a cylindrical or annular hollow member, and the inner peripheral surface thereof fits and holds the outer periphery of the intermediate portion of the stub ferrule 1, while the flange 31 provided at the tip of the first holder 3. Thus, an external housing (not shown) and the optical receptacle 10 are coupled.

The housing is a case for housing and fixing the receptacle module 20 including a light emitting element and a light receiving element, and is generally made of a metal or a plastic material. Note that the housing is not an essential component from the viewpoint that the optical receptacle or the receptacle module according to the present invention can be used without being fixed to the housing.
The first holder 3 is coupled to the housing by the flange 31, but the coupling method is not particularly limited, such as a method of sandwiching the flange 31 in a clamping plate provided in the housing, a method of screwing, a method of latching with a fitting claw, etc. Are preferably used.

  The stub ferrule 1 is preferably joined to the first holder 3 by press-fitting from the viewpoint of high coaxiality, sufficient holding force and durability, and good assembly workability. At this time, it is preferable to press-fit the stub ferrule 1 into the first holder 3 from the base end surface 12 side so that the tip end surface 11 of the stub ferrule 1 which is mirror-polished is not damaged by burrs on the inner periphery of the holder. . Problems that may occur during the press-fitting will be described later.

  The second holder 4 is also a cylindrical or annular hollow member that fits and holds the outer periphery of the base end portion of the stub ferrule 1 and couples the optical element unit 9 and the optical receptacle 10. The second holder 4 and the stub ferrule 1 are also preferably joined by press-fitting the base end face 12 side of the stub ferrule 1 in the same manner as the first holder 3. Therefore, the mounting order of the first and second holders with respect to the stub ferrule 1 is as follows. First, the first holder 3 is first mounted deeply to the middle portion with respect to the stub ferrule 1, and then the second holder 4 is placed at the base end. It should be worn shallowly.

The stub ferrule 1 is made of an insulating material such as a ceramic material typified by zirconia ceramics or alumina ceramics, or a plastic material typified by epoxy resin. Of these, ceramic materials, particularly zirconia ceramics, are preferably used from the viewpoints of dimensional stability, moderate elasticity and wear resistance. The “insulating material” in the present invention means to exclude a metal represented by copper or SUS, or a conductive material such as a so-called conductive ceramic, and a noise signal through the first and second holders. As long as the material has a specific resistance that can satisfactorily inhibit the transmission of the above, it is a concept widely including a defective conductor from a semiconductor. Specifically, the volume resistivity is 10 ⁸ [Ωm] or more, preferably 10 ¹² [Ωm] or more.
Such an insulating material can be obtained by mixing one type or a plurality of types of materials. In particular, it is sufficient if the material of the outer peripheral surface of the stub ferrule 1 is an insulating material. Also, the plug ferrule that abuts the stub ferrule 1 is preferably made of the same material as that of the stub ferrule 1 so that the connection loss of the optical signal due to thermal strain can be reduced even when the temperature changes.
In the present invention, the fact that certain parts are insulated from each other means a state in which the parts are not connected by a conductive material.

  In the optical receptacle 10 and the receptacle module 20 using the same shown in FIGS. 1 and 2, the first holder 3 and the second holder 4 are mounted on the outer peripheral surface of the stub ferrule 1 while being separated from each other. Since 1 is made of an insulating material as described above, the first holder 3 and the second holder 4 can be electrically insulated while maintaining the rigidity of the optical receptacle as a whole high. As a result, a holder or shell made of a conductive metal material acts as an antenna or conductor to receive and transmit a noise signal with respect to an optical signal received and transmitted from the optical element 8, or an optical receptacle, an optical connector, a housing, etc. The object of the present invention can be achieved because there is no risk that static electricity stored in the battery will suddenly flow in or out and damage the equipment.

  However, the method of insulating the first holder 3 and the second holder 4 is not limited to the method of providing a predetermined gap at the holding position of the insulating stub ferrule 1 as described above. It is also possible to insulate both holders by attaching them to the stub ferrule 1 via an insulating adhesive layer. Even when the first holder 3 and the second holder 4 come into contact with each other, it is possible to insulate them by applying an insulating adhesive to the contact surfaces of both.

A ceramic material, a metal material, or a plastic material is generally used for the sleeve 2. By using zirconia ceramics in the same manner as the stub ferrule 1, the sleeve 2 is excellent in dimensional stability and wear resistance, and the stub ferrule 1 and the plug ferrule are used. The material can be prevented from being worn at the time of insertion, and the influence of the optical signal connection loss due to thermal strain can be reduced even when the temperature changes.
In the optical receptacle 10 and the receptacle module 20 according to the present embodiment, any of a split sleeve, a precision sleeve, and a half sleeve can be used as the sleeve. The precision sleeve has the advantage of being strong against lateral force applied to the plug ferrule from the outside, and the split sleeve is pushed in by urging the stub ferrule 1 and the plug ferrule with an elastic force based on radial expansion and contraction deformation. There is a function of assisting the axis alignment of the ferrules. The slit may be provided parallel to the axis of the split sleeve or may be provided obliquely.
When the sleeve 2 is a split sleeve, the inner diameter is preferably slightly smaller than the outer diameter of the stub ferrule 1 and the plug ferrule to be inserted, and the diameter is preferably expanded when these are inserted. Further, when the sleeve 2 is a precision sleeve, the inner diameter thereof is preferably about the outer diameter of the inserted stub ferrule 1 or plug ferrule +0.1 to 10 μm. However, it is not excluded that the inner diameter of the precision sleeve is slightly smaller than the outer shape of the stub ferrule 1 or the plug ferrule and is press-fitted.

  For the purpose of accommodating the sleeve 2 inside, a hollow cylindrical shell 5 may be provided at the tip of the optical receptacle 10 as necessary. The shell 5 is a cylindrical cover that houses the distal end portion of the sleeve 2 and fits with the first holder 3. A through hole having a diameter slightly larger than the inner diameter of the sleeve 2 is provided at the tip of the shell 5 so that a plug ferrule can be inserted. The shell 5 is excellent in strength and corrosion resistance by using a metal material such as SUS like the first holder 3. Even if such a conductive metal material is used, the effects of the present invention can be exhibited without the shell 5 acting as an antenna on the optical signal. The first holder 3 and the shell 5 can be joined by press-fitting, adhesion, or a combination thereof.

The optical element unit 9 is an optical component that is coupled to the optical receptacle 10 via the second holder 4 to form the receptacle module 20, and can generally be constituted by the alignment adapter 6, the element holder 7, and the optical element 8.
The optical element 8 is an optical signal receiver / oscillator. The alignment adapter 6 and the element holder 7 are made of a material such as metal or plastic, and the material is not particularly limited. However, by using a conductive metal material such as SUS, the optical receptacle 10 and the optical element 8 can be connected. It can be held with a predetermined rigidity and strength. Further, even if such a conductive metal material is used, the optical element 8 and the first holder 3 and the shell 5 are preferably insulated, and the effect of improving the EMI characteristics and ESD characteristics according to the present invention can be exhibited remarkably. it can.

  Here, in the present invention characterized in that the first holder and the second holder are insulated, the stub ferrule is press-fitted into the first holder or the second holder, and the holder is attached to the stub ferrule (hereinafter referred to as the first holder). A problem that may occur when the first (second) holder is referred to as “press-fit” is described. In the present invention, the metal first holder 3 and the second holder 4 are separated and mounted on the outer peripheral surface of the insulating stub ferrule 1 to electrically insulate them from each other, thereby preventing electromagnetic interference and electrostatic discharge characteristics. Is to improve. However, when the ceramic stub ferrule 1 is press-fitted into a metal holder, there may be a problem that a press-fitted metal mark is generated on the outer peripheral surface of the stub ferrule 1 and a complete insulation state cannot be obtained. In other words, zirconia ceramics and alumina ceramics are widely used for the stub ferrule 1 from the viewpoint of dimensional stability, wear resistance, etc., and these are extremely hard with a Mohs hardness of about 8.5 and a Vickers hardness of about 1200 or more, In the case of a metal material, even in the case of SUS having a relatively high hardness, the Mohs hardness is 6 to 7 and the Vickers hardness is about 500. Therefore, when the stub ferrule 1 made of a ceramic material with higher hardness is press-fitted into a holder made of a metal material with lower hardness, the metal material constituting the inner peripheral surface of the holder is scraped off, and the stub ferrule 1 made of ceramic material is removed. This is thinly extended on the outer peripheral surface to form a metal-plated conductive film.

A stub ferrule with such press-fitted metal marks attached is shown in a side view in FIG. In the figure, the upper side is the base end side of the stub ferrule.
This figure shows that when a stub ferrule 101 made of zirconia ceramics is press-fitted and attached to a cylindrical first holder (not shown in the figure) from a base end face 112 so as not to damage the spherically polished front end face 111, the first holder A state is shown in which a SUS base material scraped off from the inner peripheral surface is rolled and attached from the base end to the intermediate portion of the stub ferrule 101, and conductive press-fitted metal marks 116 are generated. When the second holder 4 is attached to the base end portion of the stub ferrule 101, the second holder 4 comes into contact with the press-fit metal mark 116 and is electrically connected.

  Thus, when the press-fit metal trace 116 is generated on the outer peripheral surface of the stub ferrule 1, even if the metal first holder and the second holder are separated from each other and attached to the outer peripheral surface of the insulating stub ferrule 1, It becomes possible to energize through the press-fitted metal mark 116, which causes EMI and ESD problems.

  In order to protect the base end surface 112, contrary to FIG. 3 (a), even if two holders are mounted from the front end surface 111 side of the stub ferrule, the second holder that holds the base end portion is put first. The stub ferrule 1 is mounted deeply from the distal end surface 111 to the proximal end, and then the first holder is mounted shallowly from the distal end surface 111 to the middle portion of the stub ferrule 1. Therefore, when the second holder 4 is press-fitted to the stub ferrule 1, a press-fitted metal mark is widely generated from the distal end surface 111 to the base end portion of the stub ferrule 1, and the first holder 3 is provided thereon. Similar to the above, there arises a problem that the first and second holders are electrically connected. Hereinafter, in the present invention, the case where both the first and second holders are press-fitted and installed from the base end side of the stub ferrule will be described as an example.

For example, the following three methods can be used to attach the first and second holders to the outer peripheral surface of the stub ferrule and insulate them.
(I) A method in which the first holder is loosely fitted to the stub ferrule so that no metal traces are formed in the first place, and is bonded and fixed with an adhesive.
(Ii) A method in which the second holder is joined via an insulating adhesive layer on the press-fitted metal trace generated by press-fitting the first holder.
(Iii) A method of etching and removing an exposed portion of a metal trace generated between the first holder and the second holder with an acid or the like.
(Iv) A method of mounting the first holder from the distal end side of the stub ferrule and mounting the second holder from the proximal end side.

  However, (i) requires much time for application and curing of the adhesive, and is inferior in terms of holding force and coaxiality between the stub ferrule and the second holder as compared to a method in which both are joined by press fitting. In (ii), it is necessary to strictly control the thickness of the adhesive layer so that the second holder and the press-fitted metal trace do not directly contact each other, and the coaxiality is inferior to that by the press-fitting method. In (iii), the number of etching work steps is required, and the base material of the first or second holder may be eroded. In (iv), there is a possibility that both the front end surface and the base end surface of the mirror polished surface of the stub ferrule are damaged by burrs on the inner peripheral surface when the holder is press-fitted. On the other hand, the stub ferrule is generally subjected to slant plane polishing in advance on an inclined surface of about 4 to 10 ° so that light emitted from the optical element is irregularly reflected and does not cause optical signal noise. In order to press-fit the ferrule from the distal end surface to the holder, the obliquely polished base end surface needs to be pressed with a special jig, resulting in poor press-fit workability.

  The present inventors diligently studied to solve this problem, and when the first holder is press-fitted and attached to the intermediate portion from the base end side of the stub ferrule, the mounting position of the first holder on the outer peripheral surface of the stub ferrule. By providing a circular region that does not contact the inner peripheral surface of the first holder at an intermediate position between the mounting position of the first holder and the second holder, no press-fit metal marks are generated in the circular region, and the first holder The inventors have come up with the knowledge that it is possible to electrically insulate the second holder from the second holder.

  Securing the above-mentioned circular region where no press-fitted metal marks are generated on the outer peripheral surface of the stub ferrule is realized when the cross-sectional shapes of the stub ferrule and the first holder satisfy a predetermined relationship. That is, in any axial position between the position where the first holder is mounted and held on the outer peripheral surface of the stub ferrule and the position where the second holder is mounted and held on this, The cross-sectional shape at this position is included in a non-contact manner with respect to the cross-sectional shape at any location in the axial direction on the inner peripheral surface of the first holder. By satisfying this condition, a region where no press-fit metal trace is generated is formed at such a position.

  In the present invention, among the outer peripheral surfaces of the stub ferrule, the mounting position (that is, the holding position) of the first (second) holder is the contact surface (footprint) between the outer peripheral surface and the first (second) holder. For example, when the first (second) holder has a hook-shaped extension part above the outer peripheral surface of the stub ferrule, the outer periphery of the stub ferrule corresponding to the position immediately below the extension part It is assumed that the surface portion does not constitute a mounting (holding) position (see FIG. 1).

  That is, when the stub ferrule is viewed in the axial direction, a gap of a predetermined length exists between the mounting position of the first holder and the mounting position of the second holder. At least one of these lengths is present. If there is a non-contact area that does not physically contact the inner peripheral surface of the first holder when the first holder is press-fitted to the stub ferrule, there will be no press-fit metal marks in that part. It will be.

The non-contact region may be any shape as long as the cross-sectional shape is included without contacting the inner peripheral surface of the first holder, and the shape is not limited.
As an example for forming such a non-contact region, in the stub ferrule 1 according to the present embodiment, a circular recess is provided on the outer peripheral surface. A side view of the stub ferrule 1 is shown in FIG. The upper side in the figure corresponds to the base end side of the stub ferrule 1. Generally, the stub ferrule 1 that is formed into a thick cylindrical shape by extrusion molding or injection molding can be provided with a recess 14 by grinding the outer peripheral surface. The depth of the upper limit or the lower limit of the concave portion 14 is not particularly limited, and the rigidity and strength of the stub ferrule 1 are sufficiently maintained, and the press-fitted metal trace is not generated in the concave portion 14, that is, does not contact the inner peripheral surface of the first holder. From the viewpoint of providing a sufficient level difference, it is preferable that the depth of the stub ferrule 1 is about 1% to 20%. Moreover, even if the press-fitted metal marks 16a and 16b are generated around the stub ferrule 1 at portions other than the ring groove by forming the concave portion 14 as a circular ring groove, the intermediate portion and the base end portion of the stub ferrule 1 are formed. Thus, the first holder 3 and the second holder 4 provided in each are surely insulated.

The width (length in the axial direction) of the recess 14 is not particularly limited, and can be determined from the balance between the specifications of the high frequency circuit and the miniaturization of the entire optical receptacle. Specifically, the diameter of the stub ferrule 1 is preferably about 10% to 200%.
Moreover, although the base metal scraps scraped from the holder may accumulate in the recess 14, this can be easily removed by an air shower or the like unlike the press-fit metal trace 16 a (b).

  In addition, if the generation | occurrence | production of a press-fit metal trace is suppressed locally and the 1st holder 3 and the 2nd holder 4 can be electrically interrupted | blocked, the specific shape of the recessed part 14 is shown in FIG.3 (b). It is not limited to a single ring groove. For example, a groove having a branch may be provided, or a plurality of grooves may be provided side by side. Further, regardless of the so-called groove shape, surface roughening is applied in a band shape from the middle portion to the base end portion of the stub ferrule 1 to form a concave region that does not contact the first holder 3 around the stub ferrule 1. Also good.

  Further, as shown in FIG. 4A, when a circumferential recess 14 is provided on the outer peripheral surface of the stub ferrule 1, for example, by shaving, the first holder is attached to the stub ferrule 1 so that it can be easily press-fitted and attached. The guide 15 may be left uncut. In this case, press-fitted metal marks 16a and 16b may be generated on the surface of the guide 15, but guides extending from the proximal end side and guides extending from the distal end side are provided alternately and do not contact each other. The press-fitted metal marks 16a and 16b are not electrically connected to each other, and the first holder and the second holder (not shown in the figure) that are press-fitted and mounted on both sides of the recess 14 are well insulated. The

  Furthermore, even when the concave portion 14 provided on the outer peripheral surface of the stub ferrule 1 is not a complete circular shape but a non-recessed portion remains in part, a notch groove is provided on the inner peripheral surface of the first holder 3 to escape it. Thus, in any part between the holding positions of the first holder 3 and the second holder 4, an area that does not contact the inner peripheral surface of the first holder 3 can be formed on the stub ferrule 1 in a circular shape. . A specific example is shown in FIG. The stub ferrule 1 is provided with a concave portion 14 on the outer peripheral surface. However, the concave portion 14 is not circular but a guide 15 is left in a part. However, since the notch groove 32 is provided in a penetrating manner at a position corresponding to the inner peripheral surface of the first holder 3, the guide 15 does not contact the inner peripheral surface even when the first holder 3 is press-fitted. . Therefore, even if the first holder 3 is press-fitted to the stub ferrule 1, an insulating region is formed in a circular shape at the axial position of the recess 14.

  As a specific example of the optical receptacle according to the present embodiment, a ring-shaped recess 14 is provided in an intermediate portion of a stub ferrule 1 made of zirconia ceramics, and the first holder 3 and the second holder 4 are respectively connected to the base end surface of the stub ferrule 1. The optical receptacle 10 according to the present embodiment shown in FIG. 1 was obtained by press fitting to the intermediate portion and the base end portion. Note that SUS304 was used as the material for the first and second holders. On the other hand, the conventional optical receptacle 110 shown in FIG. 6 is composed of the same material and substantially the same dimensions. When the optical signal loss rate (BER) was measured and compared for these optical receptacles, an improvement in light receiving sensitivity of two orders or more was recognized with respect to an optical input power of −27 [dBm].

FIG. 5 is a cross-sectional view of the optical receptacle 10 according to the second embodiment of the present invention. In the present embodiment, the first holder 3 and the second holder 4 are attached to the outer peripheral surface of the sleeve 2, and the concave portion 14 is provided in a circular shape between the holding positions.
In this case, electrical insulation between the first holder 3 and the second holder 4 is performed by the insulating property of the sleeve 2, and the stub ferrule 1 does not require insulating property. For this reason, an insulating material such as zirconia ceramics is used for the sleeve 2.
The sleeve 2 may be a precision sleeve and may be a system in which the stub ferrule 1 and the plug ferrule are press-fitted and held.

  According to the optical receptacle 10 according to the present embodiment, when two holders are separated and press-fitted from the distal end side or the proximal end side of the sleeve 2, the inconvenience of conducting both due to the press-fitted metal marks is avoided, and the metal receptacle is made. Since good insulation is obtained between the first holder 3 and the second holder 4 without changing the mechanical characteristics of the optical receptacle 10 and the interface conditions with the external housing and the optical element unit, ESD characteristics can be improved.

It is sectional drawing of the optical receptacle concerning 1st embodiment of this invention. It is sectional drawing of the receptacle module concerning 1st embodiment of this invention. (A) is a side view showing a stub ferrule in which a press-fit metal mark is generated, and (b) is a side view showing a stub ferrule provided with a circular recess. (A) is a perspective view showing the stub ferrule which left the guide in the recessed part, (b) is the perspective view showing the stub ferrule which press-fits the 1st holder which provided the notch groove, respectively. It is sectional drawing of the optical receptacle concerning 2nd embodiment of this invention. It is sectional drawing of the conventional optical receptacle. It is sectional drawing of the conventional receptacle module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Stub ferrule 11, 111 Front end surface 12, 112 Base end surface 13 Optical fiber insertion hole 14 Recess 15 Guide 16a, 16b, 116 Press-in metal trace 2,102 Sleeve 3 First holder 4 Second holder 5, 105 Shell 6, 106 Alignment adapter 7, 107 Element holder 8, 108 Optical element 9, 109 Optical element unit 10, 110 Optical receptacle 20, 120 Receptacle module 30 Optical fiber 31, 131 Flange 32 Notch groove 103 Holder

Claims (6)

  A stub ferrule made of an insulating material, with an optical fiber inserted inside,
  A cylindrical sleeve that holds the tip of the stub ferrule at one end and can hold the plug ferrule connected to the stub ferrule at the other end;
  A stub ferrule is press-fitted from the base end side, and a metal first holder to be attached to an intermediate portion of the stub ferrule;
  A stub ferrule is press-fitted from the base end side, and a metal second holder attached to the base end of the stub ferrule;
And having
  When attaching the first holder to the stub ferrule,
  Of the outer peripheral surface of the stub ferrule, a circular recess that does not contact the inner peripheral surface of the first holder is provided between the holding position of the first holder and the holding position of the second holder. An optical receptacle characterized in that the two holders are electrically insulated.   The circumferential concave portion provided between the holding position of the first holder and the holding position of the second holder has a depth of 1% to 20% with respect to the thickness of the stub ferrule. The optical receptacle according to 1.   The circumferential recess provided between the holding position of the first holder and the holding position of the second holder has an axial length of 10% to 200% with respect to the diameter of the stub ferrule. The optical receptacle according to claim 1 or 2. 4. The optical receptacle according to claim 1, wherein the sleeve is a split sleeve provided with a slit in the axial direction. A stub ferrule with an optical fiber inserted inside,
An optical receptacle comprising a cylindrical sleeve made of an insulating material, holding a stub ferrule and holding a plug ferrule connected to the stub ferrule at the other end,
A first holder made of metal that holds the middle portion of the sleeve and can be coupled to a housing that houses the optical receptacle;
A second holder made of metal that can be coupled to an optical element unit that holds and transmits an optical signal to and from the optical fiber while holding a base end portion of the sleeve;
And having
Among the outer peripheral surfaces of the sleeve, a circular recess that does not contact the inner peripheral surface of the first holder is provided between the holding position of the first holder and the holding position of the second holder, and the first holder and the second holder The optical receptacle , wherein the first holder and the second holder are electrically insulated when the holder is separated from the distal end side or the proximal end side of the sleeve and press-fitted and mounted .   A receptacle module formed by coupling an optical element unit including a light emitting element or a light receiving element to the second holder of the optical receptacle according to claim 1.

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