JP4128508B2 - Protective cap - Google Patents

Description

  The present invention relates to a protective cap that is used by being attached to an unused end of an optical connector or ferrule that emits high-power light such as an optical fiber laser and functions as an optical fiber terminator.

Conventionally, at an unused end face where an optical fiber is not connected to another fiber or the like and is open, if the light is reflected at the end face and propagates in the direction of returning through the optical fiber, the transmission characteristics deteriorate due to the return light. There is a problem that noise and distortion increase. However, if light is transmitted and radiated to the outside, it will be harmful to surrounding items and the human body. Therefore, in order to prevent reflection and transmission of laser light at the unused end face of the optical fiber, (1) a method using a resin cap, (2) a method using a metal cap, (3) a method using a metal shutter, and (4) Non-reflective termination of the optical fiber was performed by a method using a terminator.
As a method for terminating an unused end face of an optical fiber, there is a method of terminating an optical fiber with an optical connector and attaching a resin cap to the optical connector (see, for example, Patent Documents 1 to 3).
JP-A-11-231146 JP-A-11-281845 JP 2001-290046 A

However, the conventional methods (1) to (4) have the following problems.
(1) For resin caps (resin shutters), the resin cap is often black in order to suppress leakage light, but the part irradiated with high output light for a long time becomes hot and melts and deforms. There is a possibility of waking up.

  The metal cap (2) is difficult to manufacture and has a problem of high cost. For the metal cap material, it is desirable to use stainless steel with excellent oxidation resistance and heat resistance so that it can withstand high-power light irradiation for a long time, but in the case of a stainless steel metal cap, There is a problem of high price because it is manufactured by a mold forming method.

  (3) As a metal shutter, a stainless steel thin plate shutter, etc. can be considered, but it is necessary to form a shutter thin enough to have a spring property. There is a risk. Moreover, since this metal shutter is directly attached to the adapter, the adapter may become hot and deform. Furthermore, since dust resistance is required, it is necessary to use in combination with a cap.

  (4) The terminator has a problem that it is expensive because expensive parts such as ferrules are required. In addition, the connector end face from which light is emitted is connected to a PC (PC: Physical Contact). For example, if there is dust at this connection portion, there is a possibility that heat will be generated there. In addition, after the connection point, the light is applied to the metal plate, but there are many existing products that are not sufficiently spaced, and the power density cannot be sufficiently reduced, so that the metal plate becomes high temperature. An attenuator-like structure that uses a metal-doped fiber for the ferrule of the terminator is also conceivable, but since the energy is confined, the long-term durability remains a question.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a protective cap that can be provided at low cost, functions as a terminator for performing non-reflection termination processing of an optical fiber, and has excellent durability.

In order to achieve the above object, the present invention provides a metal member having a light receiving hole for receiving emitted light from the opposite side and reflecting and dispersing the light inside the cap body made of a synthetic resin having a cylindrical shape. A protective cap , wherein a gap is provided between a rear end of the metal member and the innermost inner surface of the cap body, and a hole reaching the gap is provided in the cap body. To do.
In the protective cap of the present invention, it is preferable that a screw portion is provided on the outer peripheral surface of the metal member, and a screw portion that is screwed into the screw portion of the metal member is provided inside the cap body.
Moreover, it is preferable that the hole shape of the said light-receiving hole is made into a polygon, and the back surface was made into the taper shape .

Since the protective cap of the present invention has a simple structure in which a metal member having a light receiving hole is provided inside a cylindrical synthetic resin cap body, it can be provided at low cost. In addition, since the synthetic resin cap body can be configured in the same manner as a synthetic resin dustproof cap that has been conventionally used, sufficient dustproof performance can be obtained.
Further, the light receiving portion is a metal member such as stainless steel, which has excellent durability against oxidative deterioration and high temperature deformation, and has a long life. Further, the amount of leakage light is reduced by irradiating the light receiving hole of the metal member with the emitted light.
In addition, since the metal member other than the light receiving part is made of synthetic resin, the heat of the metal member is not easily transmitted to the optical parts such as the receptacle housing and the ferrule disposed on the opposite side, and the cap body has excellent heat dissipation performance. Since the structure and the material can be used, it is possible to prevent deformation and oxidation deterioration due to heating of the protective cap and the housing to which the protective cap is attached.
In addition, since the cap body other than the metal member that is the light receiving part does not directly receive light, the cap body can be bright colors such as white, red, yellow, orange, green, blue, etc., thereby improving heat dissipation. it can. In addition, since the degree of freedom of color selection is expanded, it becomes easy to classify ferrule types and groups by color.

Hereinafter, an embodiment of a protective cap of the present invention will be described with reference to the drawings.
1 to 4 are views showing a first embodiment of a protective cap according to the present invention. FIG. 1 is a front view of the protective cap 1A in partial cross section, FIG. 2 is a plan view, and FIG. 3 is a left side view. FIG. 4 is a right side view.

  The protective cap 1A is provided with a metal member 3 having a light receiving hole 4 that receives outgoing light from the opposite side, reflects the light, and disperses the light inside the cylindrical cap body 2 made of synthetic resin. It is configured. The cap body 2 only needs to have a cylindrical portion capable of fixing the metal member 3 therein, and the shape and size are not particularly limited. In the illustration of FIGS. 1-4, what was shape | molded in the cap shape which can be arrange | positioned facing the ferrule 13 incorporated in the housing 11 of the receptacle 10 as shown in FIGS.

  On the inner peripheral surface of the cylinder portion of the cap body 2, a screw portion 7 that is screwed with a screw portion 8 formed on the outer surface of the metal member 3 is formed. Further, at the rear end side of the cap body 2, a handle portion 5 is provided for holding and attaching with a hand or a tool when the receptacle 10 is attached to or detached from the receptacle 10, and a flange portion is provided at the rear end of the handle portion 5. A shaped knob 6 is provided. The outer surface of the cap body 2 is provided with unevenness for fixing the mounting in accordance with the mounting structure such as the housing 11 to which the cap body 2 is mounted. Further, fins and grooves for improving the heat dissipation efficiency can be provided on the outer surface of the cap body 2.

  The material of the cap body 2 can be selected from various synthetic resin materials. Examples thereof include olefin resins such as polypropylene resins, polyester resins such as polybutylene terephthalate, and polymethacrylate esters. Acrylic (or methacrylic) resin such as resin, fluorine-containing resin such as polytetrafluoroethylene resin, chlorine-containing resin such as polyvinylidene chloride, copolymer such as ABS resin, polyamide resin such as nylon, polyimide resin, polyamide Examples include imide resins, polystyrene resins, polysulfone resins, and the like, preferably polybutylene terephthalate (PBT) resins, polypropylene resins (PP), and the like.

  In this protective cap 1A, since the cap body 2 is not directly irradiated with the emitted light, it is not necessary to make the cap main body 2 black which easily absorbs light, and can be a bright color such as white, red, yellow, orange, green, and blue. . As described above, in the present invention, the cap body 2 can have a bright color such as white, red, yellow, orange, green, and blue, thereby improving heat dissipation. Further, since the degree of freedom of color selection is expanded, it becomes easy to classify ferrule types and groups by color.

  The metal member 3 has a substantially cylindrical shape, and a light receiving hole 4 is provided on one end side thereof. Further, on the outer peripheral surface of the metal member 3, a screw portion 8 that is screwed with the screw portion 7 provided on the inner peripheral surface of the cap body 2 is formed. Although the hole shape and size of the light receiving hole 4 are not particularly limited, the light receiving hole 4 is irradiated with emitted light from the opposite side and received at the back of the light receiving hole 4, and then the light passes through the inner peripheral surface of the light receiving hole 4. It is preferable to use a polygonal hole such as a round hole or a hexagon so that it can be reflected and dispersed while being reflected a number of times. Further, it is desirable that a deep taper is formed at the back of the light receiving hole 4 and light is reflected on the taper so that the reflected light is easily reflected many times within the light receiving hole 4.

  In the illustration of FIG. 1, the light receiving hole 4 is a hexagonal hole, and the back surface thereof has a tapered shape. A tool such as a hexagon wrench can be inserted into the light receiving hole 4 to rotate the metal member 3. When the metal member 3 is attached to the cap body 2, the metal member 3 is placed in the cylinder of the cap body 2, a tool is inserted into the light receiving hole 4 and rotated in the screwing direction, and the screw portion 8 on the outer peripheral surface of the metal member 3. Can be easily attached by screwing with the screw portion 7 of the cap body 2.

  The material of the metal member 3 is not particularly limited, but it is preferable to use a metal material excellent in oxidation resistance in a high temperature atmosphere. For example, carbon steel, stainless steel, nickel alloy, copper alloy, aluminum alloy, titanium alloy, It is possible to use an integrated product made of an alloy such as a magnesium alloy or Si-Mg alloy, or a workpiece obtained by applying high reflectivity metal plating such as chromium plating, nickel plating, silver plating, or gold plating on the surface of a material such as carbon steel. it can. Among these metal materials, stainless steel such as SUS304 is preferable because it is excellent in oxidation resistance and can be provided at a low price.

  5 to 10 are views for explaining an example of mounting the protective cap 1A on a predetermined ferrule 13 of a receptacle 10 in which a plurality of ferrules 13 are attached to a housing 11 in an aligned state. FIG. 6 is a front view, FIG. 6 is a side view, FIG. 7 is a partially sectional plan view showing a state in which the protective cap 1A is attached to a ferrule 13 attached to the housing 11, and FIG. 8 is a partially sectional view. 9 is a partially sectional plan view showing a state in which the optical connector 14 is connected to the ferrule 13, and FIG. 10 is a partially sectional side view.

  The housing 11 of the receptacle 10 is provided with a ferrule mounting portion 12 for arranging a plurality of ferrules 13 in a tandem state. The ferrule 13 attached to this is not particularly limited, and either single-core or multi-core can be used. The end surfaces of the optical fibers are exposed at the tip surfaces of these ferrules 13, and a high-power laser is emitted from the end surfaces.

  Of these ferrules 13, those to be connected to other optical fibers are connected to an optical connector 14 as shown in FIGS. Here, as the optical connector 14, an SC type optical connector (SC: Single fiber Coupling) defined in JIS C 5973 or the like is adopted. In addition, the combination of the optical connector 14 and the ferrule 13 should just implement | achieve the connector connection of optical fibers, and there is no limitation in particular. As the optical connector 14, various types such as an MPO type optical connector (MPO: Multifiber Push-On; F13 type optical connector established in JIS C 5982) can be adopted, and as a ferrule on the receptacle side, an optical connector can be used. Any device that can realize connector connection corresponding to the type may be used.

  Among these ferrules 13, ferrules 13 that are not connected to other optical fibers are attached with the protective cap 1A as shown in FIGS. 7 to 8 and terminated so that the emitted light does not leak. The protective cap 1A is configured so that the handle portion 5 can be grasped with a hand or a tool, the tip side is placed at a predetermined position of the housing 11, and can be fixed at a predetermined position facing the corresponding ferrule 13 by a fixing member of the housing 11. .

  When light is emitted from the optical fiber held by the ferrule 13 in the state in which the protective cap 1A is attached, the emitted light enters the light receiving holes 4 of the metal member 3 arranged at a predetermined interval. This light is applied to the tapered back surface of the light receiving hole 4 and is dispersed while being reflected (preferably reflected many times) in the light receiving hole 4. Since this light receiving portion is made of a metal such as stainless steel, it has excellent heat resistance and oxidation resistance. Therefore, even when irradiated with high power light, the metal member 3 is not easily melted, deformed, or oxidized and deteriorated. . Furthermore, since the metal member 3 is provided at a predetermined distance from the tip of the ferrule 13, the light density of the light receiving portion is a considerably small value and the temperature rise of the metal member 3 is also small. Further, since the light is received at the inner surface of the light receiving hole 4 and reflected by the inner surface of the light receiving hole 4 to disperse the light, a local temperature rise can be suppressed. The amount of reflected light is so small that the metal member 3 is provided at a predetermined distance from the tip of the ferrule 13 and does not cause a problem by being reflected and dispersed in the middle.

Since this protective cap 1A has a simple structure in which a metal member 3 having a light receiving hole 4 is provided in a cylindrical synthetic resin cap body 2, it can be provided at low cost. Moreover, since the synthetic resin cap main body 2 can be configured in the same manner as a conventionally used synthetic resin dustproof cap, sufficient dustproof performance can be obtained.
The light receiving portion is a metal member 3 such as stainless steel, which has excellent durability against oxidative deterioration and high temperature deformation, and has a long life. Moreover, the amount of leakage light is reduced by irradiating the light receiving hole 4 of the metal member 3 with the emitted light.
Further, since the metal member 3 other than the light receiving portion 3 is formed of synthetic resin, the heat of the metal member 3 is not easily transmitted to the housing 11 of the receptacle 10 or the optical parts such as the ferrule 13 disposed on the opposite side, and the cap body 2 Can be made of a structure or material having excellent heat dissipation performance, so that it is possible to prevent deformation and oxidation deterioration due to heating of the protective cap 1A and the housing 11 to which the protective cap 1A is attached.
In addition, since the cap body other than the metal member 3 that is the light receiving portion does not directly receive light, the cap body 2 can be a bright color such as white, red, yellow, orange, green, and blue, thereby improving heat dissipation. be able to. In addition, since the degree of freedom of color selection is expanded, it becomes easy to classify ferrule types and groups by color.

FIG. 11 is a partially sectional front view showing a second embodiment of the protective cap of the present invention.
The protective cap 1B according to this embodiment is configured to include the same components as the protective cap 1A of the previous embodiment, and the metal member 3 provided inside the cap body 2 extends to the deepest in-cylinder portion of the cap body 2. The gap 15 is provided at a predetermined interval between the rear end of the metal member 3 and the in-cylinder deepest portion of the cap body 2 without reaching, and the cap body 2 is further provided with a hole 16 reaching the gap 15. It has become.

  The protective cap 1B of the present embodiment provides the same effect as the protective cap 1A of the first embodiment described above, and further provides a gap 15 between the metal member 3 and the in-cylinder deepest part of the cap body 2, Since the hole 16 reaching the gap 15 is provided in the cap body 2 and the metal member 3 in the cap body 2 is in contact with the outside air through the hole 16 and the gap 15, the cooling efficiency of the metal member 3 can be improved. In addition, even when high power outgoing light is desired, the temperature rise can be kept low.

  12-15 is a figure which shows 3rd Embodiment of the protective cap of this invention, FIG. 12 is the front view which carried out partial cross section view of the protective cap 1C, FIG. 13 is a top view of the protective cap 1C, FIG. A left side view of the protective cap 1C, and FIG. 15 is a right side view of the protective cap 1C. The protective cap 1C according to this embodiment includes the same components as the protective cap 1A of the first embodiment, and the same components are denoted by the same reference numerals. In the protective cap 1A of the first embodiment, the handle portion 5 including the knob 6 is provided on the rear end side of the cap main body 2. However, in the protective cap 1C, the rear end side of the cap main body 2 is arranged in the vertical direction. A handle 17 is provided so as to bulge out in a stepped manner.

  The protective cap 1C of the present embodiment has the same effect as the protective cap 1A of the first embodiment described above, and instead of the handle portion 5 protruding to the rear end side, the rear end side of the cap body 2 is used. By adopting a configuration in which the handle 17 bulged stepwise in the vertical direction is provided, the manufacturing becomes easy and the manufacturing cost can be reduced. Further, the overall length of the protective cap is shortened, and the housing and the like can be downsized in the mounted state.

The protective cap of the present invention can be used in the same manner as conventional dustproof caps and terminators in optical connectors having optical fiber ends, receptacles incorporating ferrules, and the like.
As a more specific application example of this protective cap, when analog video communication is performed by FTTH, this protective cap can be applied to an empty line terminal of a coupler output unit near a transmission device or near an amplifier. . The optical power of the coupler output unit needs to be about +16 dBm.

1 is a partial cross-sectional front view showing a first embodiment of a protective cap of the present invention. It is a top view of the protection cap. It is a left view of the protection cap. It is a right view of the same protective cap. It is a front view of the housing of a receptacle. It is a side view of the housing. It is the top view seen from the partial cross section which shows the state which attached the protective cap to the ferrule attached to the housing. It is the side view seen from the partial cross section of the housing. It is the top view seen from the partial cross section which shows the state which connected the optical connector to the ferrule. It is the side view seen from the partial cross section of the housing. It is the front view which carried out the partial cross section which shows 2nd Embodiment of the protective cap of this invention. It is the front view which carried out the partial cross section view which shows 3rd Embodiment of the protective cap of this invention. It is a top view of the protection cap. It is a left view of the protection cap. It is a right view of the same protective cap.

Explanation of symbols

1A, 1B, 1C ... protective cap, 2 ... cap body, 3 ... metal member, 4 ... light receiving hole, 5 ... handle, 6 ... knob, 7, 8 ... screw, 10 ... receptacle, 11 ... housing, 12 ... Ferrule mounting part, 13 ... ferrule, 14 ... optical connector, 15 ... gap, 16 ... hole, 17 ... handle.

Claims (3)

A metal member (3) having a light receiving hole (4) for receiving emitted light from the opposite side and reflecting and dispersing the light is provided inside the cylindrical synthetic resin cap body (2) . A protective cap (1) , wherein a gap is provided between a rear end of the metal member and the innermost innermost surface of the cap body, and a hole reaching the gap is provided in the cap body .   The protective cap according to claim 1, wherein a screw portion is provided on an outer peripheral surface of the metal member, and a screw portion that is screwed into the screw portion of the metal member is provided inside the cap body.   The protective cap according to claim 1 or 2, wherein a hole shape of the light receiving hole is a polygonal shape and a back surface thereof is a tapered shape.

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