JPH09197157A - Optical fiber connector and method for connecting optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber connector in which the butting connection of optical fibers and the switching of connection can be simply executed and the butting connection state of the optical fibers can be easily confirmed. SOLUTION: The operator can know the butting connection state of optical fibers 7 in a working field by observing visible test light leaked from the connection point of optical fibers 7 and transmitted through a transparent press cover 3 from an observing window 18 and only checking a discrimination signal constituted of the test light. Consequently, the working efficiency of butting connection of optical fibers 7 can dratically be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connector used for butt connection of optical fibers such as mechanical splice.

[0002]

2. Description of the Related Art Conventionally, an optical fiber connector has a structure in which two butted optical fibers are fixed in the same housing. The positioning and aligning structure of the optical fiber connector includes (1) a structure in which an optical fiber is inserted from both ends and abutted in a precision thin tube (hereinafter, "microcapillary"), and (2) optical fibers in positioning grooves And (3) a structure in which an optical fiber is carried at the center of three precision rods or three precision balls and positioned. In this optical fiber connector, a pair of optical fibers are aligned and abutted with each other in the aligning mechanism to be bonded or mechanically sandwiched and fixed to the aligning mechanism.

[0003]

By the way, in the case of the optical fiber connector as described above, the connected optical fiber cannot be reused, so that the optical fiber cannot be attached or detached, which is effective for connection switching. There was a problem that it could not be used. That is, when the optical fiber is bonded to the aligning mechanism, it is difficult to remove it from the aligning mechanism, and the abutting end is soiled with the adhesive, which makes reuse difficult. Further, when the optical fiber is mechanically clamped, it is difficult to evenly apply the clamping force to the abutting end portions of the optical fiber. Therefore, the clamping force is unevenly distributed, and as a result, the abutting state is released. At this time, there arises a problem that the refraction index of the abutting end portion is changed and the reuse becomes difficult.

In addition, the above-mentioned optical fiber connector has a structure in which the abutting state of the optical fibers in the housing cannot be visually inspected from the outside, so that the workability of the abutting connection is deteriorated. It was happening.
Moreover, in order to confirm the connection state of the optical fiber for which the connection work has been completed, OTDR (Optical Time)
Domain Refrctometory. An optical test is performed using an optical test device. Especially, when the optical line is branched into a large number, there is a limit to the detection accuracy of the disconnection position by the OTDR, and the operator is required to correctly connect the optical fibers. Is OTDR
There is a problem that the work efficiency is poor because it has to repeatedly make a round trip between the optical fiber connector and the optical fiber connector.

The present invention has been made in view of the above-mentioned problems, and it is possible to easily perform the butt connection and connection switching of the optical fibers, and it is possible to easily confirm the butt connection state of the optical fibers. An object is to provide an optical fiber connector.

[0006]

An optical fiber connector according to claim 1, which is an optical fiber connector for butt-connecting optical fibers to each other, wherein at least a part of a housing of the optical fiber connector is an optical fiber connector. The means for solving the above-mentioned problems is to form the transmitting portion that transmits the test light emitted from the butt joint portion.

In the optical fiber connector according to the second aspect of the present invention, the base and the pressing lid, which constitute a substantially rod-shaped split structure when integrated, and the pressing force for inserting the base and the pressing lid into contact with each other are applied. A C-shaped spring and a centering mechanism for positioning and aligning an optical fiber arranged between the base and the pressing lid so that they can be abutted and connected to each other, are provided at a position corresponding to at least one of the base and the pressing lid. A light-transmitting portion is formed which guides the test light, which is incident from one end portion of the fiber and is emitted from the abutting end portion of the optical fiber arranged in the centering mechanism, to the outside. At the position corresponding to the light transmission direction,
The means for solving the above-mentioned problems was to form a visual observation window for visually observing the test light transmitted through the transparent portion from the outside.

According to a third aspect of the present invention, there is provided an optical fiber connecting method, wherein a butt end portion is connected to one end portion of an optical fiber butt-connected by the optical fiber connector according to the first or second aspect, and a visible light test is conducted from an optical test device. Light is incident, and the test light emitted from the abutting end portion of the optical fiber arranged in the aligning mechanism is connected while visually observing the test light through the visual window of the optical fiber connector. did.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical fiber connector according to the present invention will be described below with reference to FIGS. Reference numeral 1 in the figure is an optical fiber connector of the present invention. As shown in FIGS. 1 and 2, the optical fiber connector 1 includes a base 2 and a pressing lid 3 that form a two-divided structure having a square cross section when integrated, and an integrated base 2.
And a C-shaped spring 4 that inserts the pressing lid 3 and applies a pressing force to press the pressing lid 3 against each other.

As shown in FIG. 4, the base 2 and the pressing lid 3 have substantially the same cross-sectional shape in which a rod having a square cross section is divided in half by a diagonal line of the square, and the abutting surfaces 5 and 6 thereof are arranged. It is designed to be integrated by overlapping. The base 2 and the pressing lid 3 of the present embodiment are
The whole is made of transparent resin such as plastic. Therefore, the base 2 and the pressing lid 3 as a whole form the light transmitting portion according to claim 1.

As shown in FIG. 2, a centering mechanism that is formed separately from the base 2 at the center of the contact surface 5 of the base 2 in the longitudinal direction to position and align the optical fiber 7 so that the optical fiber 7 can be butted and connected. 11b having a positioning groove 11a as a
Is installed. The positioning groove 11a is provided in the optical fiber 7
The coating 9 is removed to expose the bare fiber, and a pair of butt ends 10 are butt-connected to each other to form a V-groove shape. As the connection base 11b, one formed of aluminum, ceramics or the like is applied.

A V-groove 8 which is continuous with the positioning groove 11a is formed on the base contact surface 5 around the installation position of the connection base 11b. As shown in FIG. 4, the V groove 8 is formed at the center of the contact surface 5 in the width direction. A coating support groove 12 that supports and aligns the coating 9 portion of the optical fiber 7 is formed at the end of the contact surface 5 in the longitudinal direction (see FIGS. 2 and 5).
The coating support groove 12 is adapted to support the bare fiber in the coating 9 on the same straight line as the butt end 10 which is aligned and supported by the positioning groove 11a. Further, the coating support groove 12 is opened at the longitudinal end portion of the contact surface 5, and the optical fiber 7 inserted from the longitudinal end portion of the optical fiber connector 1 is positioned through the V groove 8 to the positioning groove 11 a. It is supposed to lead to.

In a region of the contact surface 6 of the pressing lid 3 which faces the coating support groove 12 of the base 2 when the base 2 and the pressing lid 3 are integrated, as shown in FIG. A fiber holding groove 13 is formed which can be pushed inward in the depth direction of the coating support groove 12 while holding the fiber at a predetermined position.

As shown in FIGS. 1, 3 and 4, a tool insertion groove for inserting a tool 14 for separating the integrated base 2 and the pressing lid 3 is formed on the side surface of the base 2 and the pressing lid 3. 15, 16 are drilled. The tool insertion groove 1
Reference numerals 5 and 16 are formed inwardly from the side surfaces of the base 2 and the pressing lid 3 along the contact surfaces 5 and 6 inside the base 2 and the pressing lid 3, respectively. Also, the tool insertion grooves 15, 1
6 are formed in each of the base 2 and the pressing lid 3 at four positions in the longitudinal direction, and if the contact surfaces 5, 6 of the base 2 and the pressing lid 3 are overlapped with each other, an integrated rectangular opening hole is formed. It is like this. In addition, the tool insertion grooves 15 and 16
May be formed on only one of the base 2 and the pressing lid 3. Further, as shown in FIG. 1, taper holes 2a and 3a for inserting the optical fiber 7 into the V groove 8 are formed on both end surfaces of the base 2 and the pressing lid 3 in the axial direction. These tapered holes 2a, 3a are designed to be integrated when the base 2 and the pressing lid 3 are integrated.

As shown in FIGS. 1 and 3, the C-shaped spring 4 is formed in a substantially cylindrical shape in external view having a minute slit-shaped opening 4a parallel to the central axis. C-shaped spring 4
As a material of, for example, beryllium copper or the like is applied. In the case of beryllium copper, it may be a target shape that has been subjected to age-hardening treatment after molding, or one that has been heat-treated and then coated with a fluororesin or the like. Longitudinal direction 4 of C-shaped spring 4
A jig insertion hole 17 for inserting the tool 14 into the tool insertion grooves 15 and 16 is opened at the location. These jig insertion holes 17 are continuously provided on the opening 4a at equal intervals so that all tool insertion grooves 15 and 16 can be exposed at the same time. Further, in the cross-sectional diametrical direction of the C-shaped spring 4, the elastic deformation amount of the C-shaped spring 4 near the jig insertion hole 17 and the base 2 and the pressing lid 3 are provided at the positions corresponding to the jig insertion holes 17. An adjustment hole 17a for adjusting the pressure contact force for pressure contact is opened (see FIG. 4).

As shown in FIGS. 1 to 3, the C-shaped spring 4 is radiated from the abutting end 10 of the optical fiber 7 arranged in the positioning groove 11a to the central portion in the longitudinal direction of the portion corresponding to the pressing lid 3. A viewing window 18 for viewing the light transmitted through the pressing lid 3 is opened. Visual window 18
Is opened at a position corresponding to the positioning groove 11a, and the optical fiber 7 is abutted and connected in the positioning groove 11a.
When there is a misalignment between the optical fibers 7, the light diffusely reflected from the connection point between the optical fibers 7 and leaking out in a direction substantially perpendicular to the centering axis of the optical fiber 7 can be seen from the outside of the C-shaped spring 4. Has become. In addition, as the viewing window 18,
It is also possible to form in a shape other than the elongated hole shape shown. Also,

The C-shaped spring 4 is divided into three clamp regions 4b by dividing grooves 18a formed in the circumferential direction at two locations in the longitudinal direction. Each clamp area 4b
Although the maximum pressure contact force that can be applied is the same, they can be opened and closed individually by inserting and removing the tool 14. In addition, by adjusting the shape of the adjustment hole 17a in each clamp region 4b, the elastic deformation amount of the C-shaped spring 4 near the jig insertion hole 17 and the pressure contact force for pressing the base 2 and the pressing lid 3 into contact with each other. It can be adjusted individually. Therefore, for example, a clamp region 4b corresponding to the positioning groove 11a,
It is also possible to adjust so that the amount of elastic deformation and the pressure contact force of the C-shaped spring 4 are different between the clamp region 4b corresponding to the covering support groove 12.

The pressing force of the C-shaped spring 4 for pressing the internally mounted base 2 and pressing lid 3 in the direction in which they are pressed against each other is
It is set according to the material and shape of the C-shaped spring 4. That is, for example, as shown in FIG. 6, in the case of the U-shaped thin leaf spring 20, the load acting between both ends is P, the bending radius is R, the plate thickness of the spring is t, and the length of the spring is b. Then, the deflection δ between both ends is expressed by the mathematical expression (1).

[0019]

[Equation 1]

Here, λ1 = L1 / R and λ2 = L2 / R. Further, the bending stress σ of the thin leaf spring 20 is expressed by the equation (2).

[0021]

[Equation 2]

When the thin leaf spring 20 is applied to the C-shaped spring 4 shown in FIG. 7, L1 = 0 and L2 = 0, and the flexure δ and the bending stress σ of the C-shaped spring 4 are expressed by Equations (3) and (3), respectively. 4)
Indicated by

[0023]

(Equation 3)

[0024]

(Equation 4)

When a spring material of JIS C1720H / 2 is used as the material of the C-shaped spring 4, the proof stress (maximum bending stress) σ ≧ 90 kg / mm ² , the bending elastic modulus E
= 1200 kg / mm ² . Further, when the dimensions of the C-shaped spring 4 are such that the inner diameter d = 4.5 mm, the plate thickness t = 0.23 mm, and the axial length b = 9 mm, the load acting in the diametrical direction of the C-shaped spring 4 is P = 3.02 kg (however, maximum value @b
= 9 mm), and the deflection is δ = 0.573 mm (maximum value).

As shown in FIG. 4, the tool 14 is formed in a wedge shape that can be easily inserted into the integrated tool insertion grooves 15 and 16, and is press-fitted to the inner side of the tool insertion grooves 15 and 16, Mutual contact surface 5 of the base 2 and the pressing lid 3,
6 are separated from each other. The tool 14 may be a ready-made hand tool such as a screwdriver, as long as it can be inserted into the tool insertion grooves 15 and 16 and can separate the contact surfaces 5 and 6.

The operation and effect of this embodiment will be described below. In order to butt-connect a pair of optical fibers 7 with each other by the optical fiber connector 1, first, the C-shaped spring 4 and the integrated base 2 and pressing lid 3 are relatively rotated about their axes. The insertion grooves 15 and 16 are exposed to the outer surface through the jig insertion holes 17 (states shown in FIGS. 1, 3, and 4). At this time, the friction between the inner surface of the C-shaped spring 4 and the abutting portions of the base 2 and the pressing lid 3 is reduced only at each vertex of the square of the integrated base 2 and the pressing lid 3 in a sectional view. The relative rotation of the C-shaped spring 4 with respect to the pressing lid 3 can be manually performed. Next, by inserting the tool 14 into the tool insertion grooves 15 and 16 and pushing it into the back side of the tool insertion grooves 15 and 16,
The base 2 and the pressing lid 3 are displaced to separate the contact surfaces 5 and 6.

Next, with the distance between the contact surfaces 5 and 6 maintained, the optical fibers 7 from the tapered holes 2a and 3a at both axial ends.
Is inserted into the covering support groove 12 from the butted end 10.
Then, the optical fiber 7 having the butt end 10 inserted into the coating support groove 12 is pushed further into the back side to bring the butt end 10 to the positioning groove 11a through the V groove 8 and to the positioning groove 11a at both ends thereof. The butt ends 10 of the optical fibers 7 inserted from above are brought into contact with each other. By doing so, the positioning groove 1 of the butt end 10 is formed.
Insertion into 1a and butting can be done smoothly.
At this time, the optical fiber 7 is formed in advance with the abutting end 10 exposing the bare fiber by removing the coating 9.
The butt end 10 is sized to allow the coating 9 to be placed in the coating support groove 12 at the time of butting. Further, in the abutting work, since the base 2 and the pressing lid 3 are formed of a transparent material, the adjustment holes 17a and the viewing window 18 are used to reach the coating support groove 12, the V groove 8, and the positioning groove 11a of the optical fiber 7. Can be performed while observing the insertion state of.

When the optical fibers 7 are brought into abutment with each other, the tool 14 is pulled out from the tool insertion grooves 15 and 16.
By doing so, the elasticity of the C-shaped spring 4 applies the clamping force of the optical fiber 7 between the base 2 and the pressing lid 3, and the pair of optical fibers 7 are fixed while maintaining the abutted state. At this time, by sequentially pulling out the tool 14 while applying abutting force to both the optical fibers 7, the abutting force between the optical fibers 7 inside the optical fiber connector 1 can be maintained even after the clamping is completed.

In order to confirm that the optical fibers 7 are properly abutted with each other, a test light of visible light is made incident on one of the optical fibers 7 to be butt-connected, and the vicinity of the positioning groove 11a is passed through the viewing window 18. It is judged by observing and visually observing the test light leaking (radiated) from between the butt ends 10 (butting points) abutting each other.

Specifically, for example, as shown in FIG.
In the closure 22 installed in the overhead optical cable 21, a drop line 23 (optical fiber 7) that is pulled out from the closure 22 and an optical fiber 24 led out from the overhead optical cable 21.
When (7) and (7) are connected by the optical fiber connector 1, the OTDR 28 that makes the optical pulse test light incident on the drop line 23 is connected to the drop tip 26 of the drop line 23 with respect to the connection end 25. In addition to the laser diode light source, an oscillating device 27 that oscillates visible light is also installed in the OTDR 28. The test light oscillated by the oscillating device 27 is communication light (laser diode wavelength 1.31 μm or 1.5
Visible light having a wavelength different from 5 μm) is preferable, and for example, helium-neon laser light (red light) or the like is applied.

A computer 29 that can be remotely operated is connected to the OTDR 28. When the computer 29 receives an operation signal from a remote controller 30 carried by an operator, the OTDR 28 draws the optical pulse test light through the drop line 23. The optical fiber 24 of the overhead cable 21 and the drop line 23 are connected to each other to determine the connection state (the size of the connection loss), and a signal corresponding to the determination result (hereinafter, “discrimination signal”) is sent to the drop line 23. Make it incident. As the determination signal, for example, when the connection loss of the connection portion based on the scattered light received by the OTDR 28 is 0.3 dB or less, it is determined that the butt connection is properly performed, and the light source is set to the oscillation device 27. Switch to and test light (visible light)
Incident on the falling line 23 without interruption, and 0.
In the case of 3 dB or more, it is determined that the connection state is not appropriate, and the test light is applied by intermittently blinking at regular intervals. In this case, the leaked light diffusely reflected from the connection point of the optical fibers 23 and 24 observed through the viewing window 18 is continuously lit when the connection is proper, and blinks when the connection is inappropriate. Looks like Therefore, when the worker determines the connection state between the outgoing optical fiber 24 and the drop line 23,
It is no longer necessary to move to the subscriber's home to directly check the TDR28 or to keep in touch with another worker who operates the OTDR28 by telephone or wireless, etc. Can be easily known. When the connection state is inappropriate, the tool 14 is inserted into the tool insertion grooves 15 and 16 again to release the clamping force of the optical fibers 23 and 24 between the base 2 and the pressing lid 3 and perform a butt joint operation. Start over.

The test light as the discrimination signal can be used, for example, for collation of the drop line 23 connected to the lead-out optical fiber 24 (core fiber comparison). For the discrimination signal, it is possible to apply a means such as changing the color (wavelength) of the test light by changing the light source, in addition to using the incident interval of the test light. The discrimination signal can also be used for transmitting information other than the connection state between the optical fibers 23 and 24.

After the connection is completed, the optical fiber connector 1 is housed in the closure 22 so that the communication light can be easily prevented from being influenced by sunlight or the like.
In the optical fiber connector 1, the tool 14 is inserted into the tool insertion groove 1
Alternatively, the optical fibers 23 and 24 may be inserted into the positioning grooves 11a and inserted into the positioning grooves 11a. In this case, by simply pulling out the tool 14 after the optical fibers 23 and 24 are butted to each other,
It is possible to clamp 3, 24 while keeping the butted state.

In the optical fiber connector 1, in order to switch connection between the pair of butt-connected optical fibers 23 and 24, the tool 14 is inserted into the tool insertion grooves 15 and 16,
An optical fiber 23 between the base 2 and the pressing lid 3,
The clamping force of 24 is released, and the optical fibers 23 and 24 are pulled out from the positioning groove 11a. Pulled out optical fiber 2
It is possible to butt-connect the other optical fibers 23 and 24 by inserting them into the optical fiber connector 1 again.

When only one of the optical fibers 23 and 24 connected by butt connection in the optical fiber connector 1 is pulled out, the tool is inserted only in the tool insertion grooves 15 and 16 in the portion for clamping the pulled out optical fibers 23 and 24. 14 is inserted, the clamping force is released, and the drawing operation is performed.
At this time, the optical fiber 2 left in the optical fiber connector 1
The optical fibers 3 and 24 are stably clamped between the base 2 and the pressing lid 3 by the action of the clamping force, so that the optical fibers 23 and 24 are inserted into the positioning groove 11a that has been pulled out and abutted. Just put it in a state,
Can be butt-connected again.

In the connection switching work, if the test light is incident from the OTDR 28 to the drop line 23 involved in the connection switching work, the test light is confirmed from the end of the drop line 23 or the visual window 18 of the optical fiber connector 1. Only by doing so, the target drop line 23 and the optical fiber connector 1 can be easily found.

Therefore, the optical fiber connector 1 of the present invention
According to the method of connecting the optical fibers, the optical fibers 23 and 24 can be freely inserted and removed between the base 2 and the pressing lid 3 only by adjusting the clamping force of the C-shaped spring 4, so that butt connection or The workability of connection switching is improved, and the operator can operate the optical fiber 2 through the viewing window 18.
Only by visually observing the test light of visible light leaking from the connection points of 3 and 24 and visually recognizing the determination signal formed by the test light, the determination result of the butt connection state of the optical fibers 23 and 24 by the OTDR 28 can be obtained. Since the worker can know it while he is at the work site, the optical fiber 23, 2
The work efficiency of the butt connection of 4 is greatly improved.

It should be noted that the base and the pressing lid may be constructed such that only a portion corresponding to the viewing window is a light transmitting portion through which the test light of visible light can be transmitted. The translucent part need not be transparent as long as it can pass the test light, and
The test light may be configured to pass only a specific wavelength. As the centering mechanism, it is also possible to apply a V-groove in which a microcapillary having translucency is installed or a positioning groove other than the V-groove, a centering structure using a precision rod or a precision ball. There are various types of optical fiber connector to which the present invention is applied, and the type is not limited to the type in which the whole is molded into a cylindrical shape as described in the above embodiment, and the optical fiber connection It shall include all fiber optic connectors whose parts are covered by some form of housing.

[0040]

According to the optical fiber connector of the first aspect of the present invention, an optical fiber connector for butt-connecting optical fibers to each other, wherein the optical fibers are butted to at least a part of the housing of the optical fiber connector. By forming the transmissive part that transmits the test light emitted from the splicing part, it is possible to connect the optical fibers while visually observing the test light transmitted through the translucent part from the outside. It is possible to surely proceed with the connection work while checking the state, and there is an excellent effect that the connection work efficiency is improved.

According to the optical fiber connector of the second aspect of the present invention, the base and the pressing lid, which constitute a substantially rod-shaped split structure when integrated, and the pressing force for inserting the base and the pressing lid into pressure contact with each other. C-shaped spring to give,
An optical fiber arranged between the base and the pressing lid is provided with a centering mechanism for positioning and aligning so that they can be abutted and connected to each other. From one end of the optical fiber to a position corresponding to at least one of the base and the pressing lid. A transparent portion that guides the test light emitted from the abutting end portion of the optical fiber that is incident and arranged in the centering mechanism to the outside is formed, and the transparent portion of the C-shaped spring transmits the test light in the transmission direction. By forming a viewing window at the corresponding position for viewing the test light transmitted through the light transmitting part from the outside, it is possible to perform connection work based on the information transmitted by the test light. It has an excellent effect that the work efficiency of connection can be improved.

According to the optical fiber connecting method of the third aspect, the visible light is emitted from the optical test device to the one end of the optical fiber whose butt end is butt-connected by the optical fiber connector of the first or second aspect. By injecting the test light of, the test light emitted from the butt end of the optical fiber arranged in the aligning mechanism, while performing the connection work while visually observing through the visual window of the optical fiber connector, By performing the connection work based on the information transmitted by the test light, it becomes possible to know the connection status of the optical fibers from the work site just by operating the optical test equipment. It has an excellent effect that it can improve.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing an embodiment of an optical fiber connector of the present invention.

FIG. 2 is a view showing an embodiment of the optical fiber connector of the present invention and is a cross-sectional view taken along the line AA in FIG.

FIG. 3 is a front view showing an embodiment of the optical fiber connector of the present invention.

FIG. 4 is a view showing an embodiment of the optical fiber connector of the present invention and is a sectional view taken along the line BB in FIG.

FIG. 5 is a view showing an embodiment of the optical fiber connector of the present invention, and is an enlarged cross-sectional view showing the vicinity of the coating support groove of the V groove.

FIG. 6 is a model diagram showing bending and bending stress with respect to a load in a thin leaf spring.

FIG. 7 is a diagram showing an embodiment of the optical fiber connector of the present invention, and is a model diagram showing deflection and bending stress with respect to a load in a C-shaped spring.

FIG. 8 is a diagram showing an embodiment of a method for connecting optical fibers of the present invention, and is an overall view showing the connection of optical fibers in a closure of an overhead optical cable.

[Explanation of symbols]

1 ... Optical fiber connector, 2 ... Base, 3 ... Holding lid, 4
... C-shaped spring, 7 ... Optical fiber, 11a ... Aligning mechanism (positioning groove), 18 ... Visual window, 23 ... Optical fiber (drop line), 24 ... Optical fiber (outgoing optical fiber), 26 ... One end ( 28. Optical test device (OTDR).

Claims (3)

[Claims] 1. An optical fiber connector for butt-connecting optical fibers to each other, wherein at least a part of a housing of the optical fiber connector transmits the test light emitted from the butt-connecting part of the optical fibers. An optical fiber connector characterized by being formed. 2. An optical fiber connector (1) for butt-connecting optical fibers (7, 23, 24) to each other, the base (2) constituting a substantially rod-shaped split structure when integrated, and A holding lid (3), a C-shaped spring (4) for inserting a base and the holding lid into a pressure contacting force to press each other, and an optical fiber arranged between the base and the holding lid are positionally adjusted so that they can be butt-connected to each other. A centering mechanism (11a) for centering, and at least one of the base and the pressing lid is positioned at a position corresponding to the centering mechanism, and the optical fiber is incident from one end (26) of the optical fiber and arranged in the centering mechanism. A transparent portion (3) for guiding the test light emitted from the abutting end portion to the outside is formed, and the transparent portion is provided at a position corresponding to the transmission direction of the emitted test light in the transparent portion of the C-shaped spring. Transparent trial Optical fiber connector, characterized in that the formation of the viewing window for viewing the light from the outside (18). 3. A test light of visible light is made incident from an optical test device (28) to one end of an optical fiber whose abutting end is abutted and connected by the optical fiber connector according to claim 1 or 2. A method for connecting optical fibers, characterized in that the test light emitted from the abutting end portions of the optical fibers arranged in the mechanism is visually observed through a visual window of the optical fiber connector to perform the connection work.