JPH08114723A - Sleeve member for introducing optical fiber and structure for connecting and sealing optical fiber/ optical element - Google Patents

Abstract

PURPOSE: To provide a sleeve member which seals an optical fiber introducing part with high reliability and a structure for connecting and sealing the optical fiber/optical element. CONSTITUTION: This structure has a first columnar hollow part 7 which houses the root part 2 of a secondary coated optical fiber in the through-hole of a cylindrical sleeve member 6, a second columnar hollow part 8 which houses a part of the exposed intermediate part 3 of the primary coating layer and a third columnar hollow part 9 which is bolder than this part and houses the remaining part of the intermediate part 3 and the exposed front end part 4 of the bare optical fiber. The gap of the first columnar hollow part 7 is sealed by packing of an adhesive 12 and the gap of the third columnar hollow part 9 is sealed by packing of solder 13. This sleeve member 6 is inserted into a through-hole 18 having, for example, a cylindrical body 19 of an optical element housing case 15 and is fixed and sealed by solder 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sleeve member for introducing an optical fiber, which is useful for improving the humidity resistance property of an optical fiber / optical element connecting / sealing structure and improving the reliability, and using the same. The present invention relates to an optical fiber / optical element connecting / sealing structure in which an optical fiber introducing portion is hermetically sealed and which is useful as a part of an optical communication system and an optoelectronic device.

[0002]

2. Description of the Related Art Many means have already been proposed as means for introducing airtightness into an optical fiber used for optical parts.
For example, a means for forming a notch in the middle of a metal pipe, inserting an optical fiber, and then injecting a brazing material from the notch to seal the gap in the pipe (Japanese Patent Publication No.
No. 3-43827) is known.

In Japanese Patent Publication No. 54-13995, an optical fiber is introduced into a case through a hollow portion of a tube-shaped joining material and an introduction hole provided in an optical element storage case, and this adhesive material is applied to the case. A method is disclosed in which it is inserted into an introduction hole, the joining material is heated and melted, and the introduction port of the case is sealed.

Further, in Japanese Patent Laid-Open No. 57-66405,
A sleeve for introducing an optical fiber into a two-stage hole diameter tube having a hollow portion having a pore diameter capable of inserting an exposed bare optical fiber portion of an optical fiber and a hollow portion having a large hole diameter capable of inserting an optical fiber with a secondary coating layer Used as, the exposed surface of the bare optical fiber, subjected to a metallizing treatment, the hollow portion of the sleeve, through the optical fiber while filling the adhesive, to fill the void in the hollow portion, the end of the pore diameter hollow portion A method of injecting a brazing material from the formed cutout portion and filling and sealing the void portion is disclosed.

However, in the above-mentioned conventional means, the reliability of sealing the optical fiber introducing portion is not sufficiently high. When using a sleeve member for sealing an optical fiber, the bare optical fiber exposed surface at the tip of the optical fiber is subjected to metallizing treatment, and this portion is fixed to the inner surface of the sleeve member hollow portion by soldering, and continuously. The coating layer surface of the optical fiber is fixed to the inner surface of the hollow part in the sleeve with an adhesive, the optical fiber is hermetically sealed by the soldering, and the adhesive fixing strength of the optical fiber is maintained by the adhesive bonding. It was In this case, since a part of the bare optical fiber is exposed, there is a problem that the optical fiber is easily broken at this part.

[0006]

DISCLOSURE OF THE INVENTION The present invention has a highly reliable optical fiber introducing sleeve member which hermetically seals an optical fiber introducing portion and has no or little breakage of the optical fiber, and the use thereof. The present invention is intended to provide a structured optical fiber / optical element connection sealing structure.

[0007]

The sleeve member for introducing an optical fiber according to the present invention is for inserting an optical fiber having a bare optical fiber, a primary coating layer coating the bare optical fiber, and a secondary coating layer further coating the bare optical fiber. A tubular body having a hollow through hole, wherein the hollow through hole opens at one end of the tubular body, and the optical fiber with the secondary coating layer can be inserted thereinto.
The columnar hollow portion and the optical fiber with the primary coating layer can be inserted into the columnar hollow portion and communicated therewith, but the second columnar hollow portion thinner than the first columnar hollow portion and the second hollow column portion communicated with the hollow portion A third opening which is open at the end and which is thicker than the second columnar hollow portion.
A columnar hollow portion, a first collapsible hollow portion that converges from the end of the first columnar hollow portion toward the second columnar hollow portion that faces the columnar hollow portion, and connects both of them; It is characterized in that it has a second stack-like hollow portion that expands from the end of the column-shaped hollow portion toward the end of the third column-shaped hollow portion that faces the hollow portion and connects both of them.

Further, in the optical fiber / optical element connection sealing structure of the present invention, the optical fiber is connected to the optical element in the optical element housing case through the optical fiber introducing sleeve member and hermetically sealed. In the structure being stopped, one end of the optical fiber has a root portion having the secondary coating layer, and an intermediate portion where the secondary coating layer is removed and the primary coating layer is exposed. A bare optical fiber is exposed by removing a tip portion of the exposed primary coating layer, the optical fiber end portion is inserted into a hollow through hole of the sleeve member, and the optical fiber end portion is inserted. Of the root portion with the secondary coating layer is housed in the first columnar hollow portion, and the intermediate portion of the exposed primary coating layer is the first hollow hollow portion, the second hollow pillar portion, the second hollow hollow portion, and the third hollow portion. It is housed in a part of the hollow column and Bare optical fiber exposed tip portion,
The third column-shaped hollow portion is formed by passing through the remaining portion of the third column-shaped hollow portion and projecting to the outside thereof, and filling the voids of the first column-shaped hollow portion and the first stack-shaped hollow portion with an adhesive. At least a portion of the void adjacent to the second stack-like hollow portion is filled and sealed with solder, and is inserted into the insertion hole provided in the optical element storage case, on the side of the third columnar hollow portion of the sleeve member. The end portion is inserted, the front end surface of the bare fiber is connected to the optical element in the case, the insertion hole of the optical element storage case, and the inserted sleeve member end portion, by soldering. Adhesive sealed,
It is characterized by that.

In the structure of the present invention, the exposed surfaces of the intermediate portion of the exposed primary coating layer and the exposed tip portion of the bare optical fiber of the optical fiber housed in the third columnar hollow portion are metal-plated. It is preferable.

In the structure of the present invention, the solder filled in the third columnar hollow portion may be bonded only to the exposed intermediate portion of the primary coating layer of the optical fiber.

Further, in the structure of the present invention, the third
The remaining void portion of the columnar hollow portion may be filled and sealed with an adhesive.

Further, the structure of the present invention has a cylindrical body extending outward from the sleeve member insertion opening of the optical element housing case, and the insertion end of the sleeve member is provided in the hollow portion of the cylindrical body. It is preferable that the part is inserted and held.

Further, in the structure of the present invention, it is preferable that a support member for supporting the insertion end portion of the sleeve member is provided in the optical element housing case. Further, in the structure of the present invention, the optical fiber does not have a secondary coating layer, and thus the primary coating layer exposed optical fiber may be housed in the first columnar hollow portion.

[0014]

The following are causes of breakage of the optical fiber in the optical component. (1) As a pretreatment for soldering, the exposed surface of the bare optical fiber is subjected to a metallizing treatment, and therefore the bare optical fiber surface is damaged when the coating layer is removed from the optical fiber. (2) Metallizing Damage or corrode the bare optical fiber surface during treatment, eg electroless plating,
(3) In order to locally heat the bare optical fiber for soldering, strain is applied to the bare optical fiber, (4)
In addition, give the naked optical fiber buckling or bending deformation.

For example, when a bare optical fiber held at two points separated by an interval of 5 mm is pushed by 1.5 to 1.7 mm along the optical fiber axial direction to buckle, the holding 2
Fracture occurs at the center of the point. Further, when the surface of the bare optical fiber is plated with Au / Ni alloy having a thickness of 2 to 3 μm, buckling fracture occurs by inserting 0.7 mm. That is, the metallization treatment on the bare fiber surface does not reinforce the buckling deformation strength of the bare fiber. Further, the above-mentioned degree of indentation (buckling deformation) in the optical axis often occurs due to thermal contraction of the coating layer adjacent to the exposed portion of the bare optical fiber.

Therefore, in order to prevent the breakage of the bare optical fiber exposed portion as described above, an intermediate portion between the solder fixing portion of the bare optical fiber exposed portion of the optical fiber and the adhesive fixing portion of the coating layer-attached portion is provided. In the part, (1) keep this intermediate part straight and do not bend it; and (2)
It has been found by the inventors of the present application that it is effective to keep this intermediate portion with the coating layer and not expose the bare fiber.

The present invention is based on the above findings. In FIG. 1, one end portion 1 of the optical fiber is composed of a root portion 2 having a secondary coating layer, an intermediate portion 3 where the primary coating layer is exposed, and a tip portion 4 where the bare optical fiber is exposed. . The bare optical fiber exposed surface of the optical fiber tip portion 4 (a portion other than the connection end portion) and a part of the surface of the primary coating layer that is continuous with the plated bare optical fiber portion have a plating layer 5 made of a conductive metal (for example, Au). Are formed.

As shown in FIG. 1, the optical fiber introducing sleeve member 6 is formed with a hollow through hole for inserting an optical fiber, and the hollow through hole is the first columnar hollow portion. 7, second columnar hollow portion 8, third columnar hollow portion 9, first
It is composed of a stack-like hollow portion 10 and a second stack-like hollow portion 11.

Each of the hollow portions 7 to 11 has the following conditions, and the cross-sectional shape thereof may be set so as to fit the cross section of the optical fiber to be used. It is preferably cylindrical, and it is generally preferable that the hollow hollow portion has a circular hollow shape (top notch).

The first columnar hollow portion 7 is open at the end portion of the sleeve, and its cross-sectional shape and dimensions are only required to accommodate the optical fiber 2 with the secondary coating layer in a straight line (for example, an inner diameter of 0.9 to 1). 0.2 mm), the second hollow portion 8 is thinner than the first columnar hollow portion 7, and the first coating layer exposed intermediate portion 3 of the optical fiber may be linearly accommodated (for example, inner diameter 0.4 to 0). 0.6 mm), and communicates with the first columnar hollow portion through the first stack-shaped hollow portion 10.

The third hollow portion 9 is thicker than the second columnar hollow portion 8 and has an inner diameter of 0.5 to 1.0 mm), and is open at the other end surface of the sleeve member. It communicates with the second columnar hollow portion 8 via the portion 11. The first bank-like hollow part 10 converges from the end part of the first columnar hollow part 7 toward the end part of the second columnar hollow part 8 facing it, and the second bank-like hollow part 11 is It expands from the location of the second columnar hollow portion 8 toward the end of the third columnar hollow portion 9 facing it. The first and second stack-like hollow portions having such inclined surfaces are effective for smooth insertion of the optical fiber without damaging the surface thereof, especially the exposed surface of the bare optical fiber when the optical fiber is inserted. Is.

In FIG. 1, the root portion 2 of the optical fiber with the secondary coating layer is inserted into the first columnar hollow portion 7, and the first stack-like hollow portion 10, the second columnar hollow portion 8 and the second hollow portion 8 are formed.
The primary coating layer exposed intermediate portion 3 of the optical fiber is inserted into the bank-like hollow portion, and the tip portion of the optical fiber primary coating layer exposed intermediate portion 3 extends into the third columnar hollow portion. . An adhesive 12 is filled in the space between the inner surfaces of the first column-shaped hollow portion 7 and the first stack-shaped hollow portion 10 and the optical fiber to fix the optical fiber root portion. The adhesive 12 may further penetrate into the void of the second columnar hollow portion 8 and fix the optical fiber intermediate portion therein.

As shown in FIG. 1, the third columnar hollow portion is filled with solder 13, and the solder 12
Is joined to the metal-plated surface of a part of the exposed middle part of the secondary coating layer of the optical fiber and the part of the exposed front end of the bare optical fiber which has entered the third columnar hollow part 9, and this is fixed in the sleeve. ing. As shown in FIG. 1, on the end face 14 of the sleeve member 6, the adhesive 12 is raised so as to surround the root portion of the optical fiber with the secondary coating layer and seal the void of the first columnar hollow portion. There is. The inlet of the first columnar hollow portion is preferably chamfered as shown in FIG. 1 so as not to damage the surface of the optical fiber.

As shown in FIG. 2, the sleeve member shown in FIG. 1 is bonded and sealed to the optical element housing case. In FIG. 2, an optical element 16 is fixed to a pedestal 17 in an optical element storage case 15. A through-hole 18 for inserting the sleeve member 6 is formed on one wall surface of the case 15, and a tubular body 19 is extended to surround the through-hole 18 and extends to the front end of the sleeve member 6. The portion passes through the tubular body 19, passes through the through hole 18, and is inserted into the case 15.

In FIG. 2, the tip surface of the bare optical fiber exposed tip portion 4 of the optical fiber 1 fixed by the sleeve member 6 is connected to the tip surface of the optical element 16. At the inlet of the tubular body 19, the sleeve member 6 is surrounded and soldered 20
And the sleeve member 6 is held by the tubular body 19 together with the optical fiber end fixed therein.
It is fixed to the case 15.

The sleeve member 6 shown in FIG. 3 has the same structure as that shown in FIG. 1, but at the end of the optical fiber inserted into the hollow through hole, the third columnar hollow portion is formed. The exposed end portion of the bare optical fiber, which extends further than the solder layer 13 filled therein and is further covered and sealed by the adhesive 21 filled in the third columnar hollow portion. By adding such an adhesive layer 21, the exposed portion of the bare optical fiber becomes smaller and the exposed surface is less damaged. In addition, the adhesive layer 21 is the solder layer 1
3 to protect the exposed surface and to fix the root portion of the bare optical fiber exposed portion extending outward from the solder layer 13 to prevent it from being bent, damaged or broken by an external force. it can.

The sleeve member 6 shown in FIG. 4 has the same structure as that shown in FIG. 1, but at the end of the optical fiber inserted into the hollow through hole, the primary coating layer is exposed. The metal 5 is accommodated in the third columnar hollow portion of the portion 3.
Solder 13 is applied to the portion plated with the solder layer 13 so that the solder layer 13 does not come into contact with the bare optical fiber exposed tip portion. As shown in FIG. 4, the exposed surface side of the solder layer 13 is filled with an adhesive layer 21, and in this adhesive layer 21, the remainder of the primary coating exposed intermediate portion 3 of the optical fiber and the bare optical fiber exposed tip end are filled. Part of the part is buried. By doing this, the exposed portion of the exposed optical fiber exposed tip becomes short, and since the bare optical fiber does not come into direct contact with the solder, the effect of volume contraction when the molten solder solidifies during soldering Does not directly reach the bare optical fiber, and its damage can be prevented.

The present invention can also be applied to an optical fiber having no secondary coating layer. The secondary coating layer of the optical fiber is formed of nylon, Hytrel (polyester-based), PVC resin, or the like. The coating form is such that the secondary coating layer is directly adhered on the primary coating layer, and between them. There are those that do not form voids, that is, "tight jackets", and those that may be covered with a tubular secondary coating on the primary coating layer to form voids therebetween, that is, "loose jackets". The outer diameter of each of these secondary coating layers is about 0.9 mm. The sleeve member of the present invention can also be used for an optical fiber having no secondary coating. In this case, the outer diameter of the optical fiber (with the primary coating layer) is about 0.4 or 0.25 mm. Therefore,
When such an optical fiber is inserted into the hollow through hole of the sleeve member of the present invention, as shown in FIG. 5, the gap between the inner surface of the first columnar hollow portion 7 and the peripheral surface of the optical fiber becomes large. Become. In this case, the gap 12 can be filled with the adhesive 12 to hold and fix the optical fiber linearly.

When the sleeve member of the present invention is joined to the optical element case, the fixation is not sufficient, and the connection between the optical element and the optical fiber is deformed due to vibration, shock, etc., and the optical axis is displaced. It is preferable to provide a sleeve member support member inside the optical element case. For example, as shown in FIG. 6, the support member 22 is projected from the bottom of the optical element case 15, and the upper end surface of the support member 22 and the sleeve member 6 are fixed to each other with solder or adhesive 23. The support member is not limited to the above example, and may be a hanging member extending from the lower surface of the case lid, or a supporting arm member extending from the side wall surface of the case, and a combination thereof. May be.

[0030]

The sleeve member for introducing an optical fiber of the present invention is capable of fixing and holding the optical fiber connected to the optical element with high reliability, and the optical fiber of the present invention constructed by using this sleeve member. / The optical element connection sealing structure stabilizes the connection between the optical fiber and the optical element, and hermetically seals the optical fiber introduction portion, the sleeve member and the optical element housing case. it can.

[Brief description of drawings]

FIG. 1 is a front cross-sectional explanatory view showing a configuration of an example of a sleeve member of the present invention, and an arrangement and a fixing state of an optical fiber inserted therein.

FIG. 2 is a front cross-sectional explanatory view showing the configuration of an example of the optical fiber / optical element connection sealing structure of the present invention.

FIG. 3 is a configuration of an example of a sleeve member of the present invention,
FIG. 3 is a front cross-sectional explanatory view showing the arrangement and fixing state of the optical fiber inserted therein.

FIG. 4 is a constitution of an example of a sleeve member of the present invention,
FIG. 3 is a front cross-sectional explanatory view showing the arrangement and fixing state of the optical fiber inserted therein.

FIG. 5 is a constitution of an example of a sleeve member of the present invention,
FIG. 5 is a front cross-sectional explanatory view showing the arrangement and fixing state of the optical fiber having only the primary coating inserted therein.

FIG. 6 is a front cross-sectional explanatory view showing the configuration of another example of the optical fiber / optical element connection sealing structure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical fiber end part 1a ... Optical fiber only with a primary coating 2 ... Root part with a secondary coating layer 3 ... Primary coating exposed intermediate part 4 ... Bare optical fiber exposed tip part 5 ... Plating layer 6 ... Sleeve member 7 ... 1st Columnar hollow part 8 ... Second columnar hollow part 9 ... Third columnar hollow part 10 ... First stack hollow part 11 ... Second stack hollow part 12 ... Adhesive agent 13 ... Solder 14 ... Sleeve member end surface 15 ... Optical element storage Case 16 ... Optical element 17 ... Optical element mount 18 ... Through hole 19 ... Cylindrical body 20 ... Solder 21 ... Adhesive agent 22 ... Support member 23 ... Solder or adhesive agent

Claims (8)

[Claims] 1. A cylindrical body having a hollow through hole for inserting an optical fiber having a bare optical fiber, a primary coating layer for coating the bare optical fiber, and a secondary coating layer for coating the bare optical fiber, wherein the hollow transparent fiber is used. The hole is opened at one end of the tubular body, and the first columnar hollow portion into which the optical fiber with secondary coating layer can be inserted and the columnar hollow portion are communicated with this, and the optical fiber with primary coating layer can be inserted, A second columnar hollow portion thinner than the first columnar hollow portion, a third columnar hollow portion communicating with the second columnar hollow portion, opened at the other end of the tubular body, and thicker than the second columnar hollow portion; From the end of the first pillar-shaped hollow portion, toward the second pillar-shaped hollow portion facing the first pillar-shaped hollow portion, and from the end of the second pillar-shaped hollow portion, Expand toward the end of the third columnar hollow part facing it, Second Uzutakajo and a hollow portion, and wherein the optical fiber introducing sleeve member linking the person. 2. A structure in which an optical fiber is connected to an optical element in an optical element housing case via the optical fiber introducing sleeve member according to claim 1 and hermetically sealed, One end of the fiber has a root portion having the secondary coating layer, an intermediate portion where the secondary coating layer is removed to expose the primary coating layer, and a tip portion of the exposed primary coating layer is removed. A bare optical fiber and an exposed tip portion, the optical fiber end portion is inserted into a hollow through hole of the sleeve member, the root portion with a secondary coating layer of the optical fiber end portion, It is housed in the first pillar-shaped hollow portion, and the primary coating layer exposed intermediate portion is housed in part of the first stack-shaped hollow portion, the second pillar-shaped hollow portion, the second stack-shaped hollow portion, and the third pillar-shaped hollow portion. And the bare optical fiber exposed tip portion,
The third columnar hollow portion is passed through the remaining portion of the third columnar hollow portion and protrudes to the outside thereof, and the voids of the first columnar hollow portion and the first stack-like hollow portion are filled and sealed with an adhesive. Of at least a portion adjacent to the second stack-shaped hollow portion is filled and sealed with solder, and the insertion hole provided in the optical element storage case is inserted into the insertion hole provided in the optical element storage case to the third columnar hollow portion side of the sleeve member. The end portion is inserted, the front end surface of the bare fiber is connected to the optical element in the case, the insertion hole of the optical element storage case, and the inserted sleeve member end portion, by soldering. An optical fiber / optical element connection sealing structure, which is adhesively sealed. 3. The exposed surfaces of the primary coating layer exposed intermediate portion and the bare optical fiber exposed tip portion of the optical fiber housed in the third columnar hollow portion are metal-plated. The structure described in. 4. The structure according to claim 2, wherein the solder filled in the third columnar hollow portion is bonded only to the exposed intermediate portion of the primary coating layer of the optical fiber. 5. The structure according to claim 4, wherein the remaining void portion of the third columnar hollow portion is filled and sealed with an adhesive. 6. A cylindrical body extending outward from a sleeve member insertion opening of the optical element housing case, and an insertion end portion of the sleeve member is inserted and held in a hollow portion of the cylindrical body. The structure according to claim 2, wherein 7. The structure according to claim 2, wherein a support member that supports the insertion end portion of the sleeve member is provided inside the optical element storage case. 8. The structure according to claim 2, wherein the optical fiber does not have a secondary coating layer, and the primary coating layer exposed optical fiber is accommodated in the first columnar hollow portion.