JP2006039061A - Connecting device and connecting method of optical fiber, and optical fiber used in this connecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting device and a connecting method of an optical fiber safe to use, without burning or welding the core end surfaces by quickly absorbing the excitation light, and to provide an optical fiber used in this connecting device. <P>SOLUTION: The optical fiber connecting device 10 has an optical fiber 12, having an input side end surface 12a and an output side end surface 12b to input and output exciting light y emitted from the light source, a double-cladded fiber 14 provided on the same optical axis z with a necessary space in front of the output end surface 12a of the optical fiber 12, and a light guide lens 13 disposed on the optical axis z of the space. The optical fiber 12 has a cladding 17 for covering the cores 16 aligned on the optical axis z, and those cores 16 are arranged alienating from the center of the optical fiber at the output side of the optical fiber 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber joining apparatus and method, and a method for joining the signal light and the pumping light output from the light source to the other optical fiber side through the optical fiber such as one bundle fiber. The present invention relates to an optical fiber used in a bonding apparatus.

  Conventionally, in order to transmit both signal light and pumping light, this type of optical fiber bonding apparatus includes a core that transmits signal light and a cladding layer that transmits pumping light at the center of the cross section of the optical fiber. It has a configuration provided.

  Such an optical fiber bonding apparatus is disclosed in Japanese Patent Application Laid-Open No. 2001-68766 (see [Patent Document 1]).

  As schematically shown in FIG. 4, this optical fiber joining apparatus integrally joins end surfaces of one bundle fiber 1 and the other double clad fiber (illustrated line) 2.

  One bundle fiber 1 includes a core 3 that transmits signal light, and a plurality of fiber members 4 that are located at the outer periphery of the core 3 and transmit excitation light. The core 3 is located at the center of the optical fiber 1, and signal light is transmitted while being repeatedly reflected in the direction of the optical axis by a reflection layer formed on the inner surface, and a core (not shown) on the end face of the double clad fiber 2. To the side.

Each fiber member 4 has a reflection layer formed on the inner surface thereof, and excitation light is transmitted while being repeatedly reflected in the optical axis direction, and transmitted to the clad 5 side of the end surface of the double clad fiber 2. The other double clad fiber 2 includes a core (not shown) optically bonded on the same optical axis as the core 3 of the bundle fiber 1 for transmitting signal light, and a clad provided so as to surround the core. 5 and an outer clad 6 provided so as to surround the outside. As shown in FIG. 4, the clad 5 has a rectangular cross section, and an interface 7 with the outer clad 6 located outside the clad 5 acts as a reflection surface of the excitation light.
JP 2001-68766 A

  The bundle fiber 1 and the double clad fiber 2 configured as described above have a configuration in which end faces are butted and joined, and the fiber member 4 is disposed adjacent to the peripheral portion of the core 3 on the bundle fiber 1 side. ing.

  In addition, when the opening surface of the core (not shown) of the double clad fiber 2 is larger than the opening surface of the core 3 of the bundle fiber 1 at the joint end face of the double clad fiber 2 corresponding to one bundle fiber 1, for example. When pumping light is transmitted from the bundle fiber 1 side to the other double-clad fiber 2 side, the pumping light may be dispersed and input to the core side.

  In this case, the absorption rate of the pumping light is high at the core end surface portion on the pumping light input side of the double clad fiber 2, and for example, as shown in FIG. 5, the pumping light absorption at the core end surface portion s1 on the pumping light input side As shown in the change curve a, the rate shows a tendency to increase rapidly.

  Then, as it enters the optical axis direction from the core end surface portion s1, the pumping light absorptance rapidly decreases as shown by the change curve b, and thereafter changes until reaching the core end surface portion s2 side on the pumping light output side. As shown by curve c, a stable tendency is shown at a low absorption level.

  As described above, the excitation light absorption rate at the core end surface portion s1 on the excitation light input side suddenly rises, so that the temperature rapidly rises at the core end surface portion s1, and the temperature rises to about 500 ° C., for example. There was a risk that the part would burn or melt.

  The present invention has been made in view of the above circumstances, and a plurality of fiber members of an optical fiber that outputs excitation light are arranged at least on the output side end face of the optical fiber so as to be separated from the core side. It is an object of the present invention to provide an optical fiber bonding apparatus and bonding method that are safe to use without burning or melting the core end surface portion on the double clad side, and an optical fiber used in the bonding apparatus. .

  Another object of the present invention is to optically bond the end faces of an optical fiber that outputs excitation light and optical fibers on the side to which excitation light is input via a light guide lens. An object of the present invention is to provide an optical fiber bonding apparatus and bonding method that are safe to use without burning or melting the core end face portion of the optical fiber on the input side, and an optical fiber used in the bonding apparatus.

  To achieve the above object, according to the present invention, an optical fiber having an input side end face and an output side end face for inputting / outputting pumping light output from the light source side, and a required space on the output side end face of the optical fiber are provided. A double-clad fiber installed on the same optical axis and a light guide lens provided so as to be positioned on the optical axis of the space, and the optical fiber is disposed on the optical axis A plurality of cores are provided so as to cover the plurality of cores, and the plurality of cores are spaced apart from the center position of the optical fiber on the output side of the optical fiber, and are distributed radially. An optical fiber bonding apparatus is provided.

  In order to achieve the above object, according to the present invention, the input side end face of an optical fiber having a plurality of cores arranged at the center is connected to the pumping light source side, and the pumping light is spaced from the output side end face. An optical fiber joining method is provided, wherein the optical fiber is refracted through a light guiding lens and optically joined so as to enter an input side end face of a clad on a double clad fiber side.

  In order to achieve the above object, according to the present invention, an input side end face of an optical fiber in which a plurality of cores are arranged in a bundle at the center, and a ring at a position where the plurality of cores are radially spaced from the center. And an output side end face arranged in a shape.

  ADVANTAGE OF THE INVENTION According to this invention, the optical fiber used for the optical fiber used for the joining apparatus and joining method of an optical fiber safe to use without the end surface part of the excitation light input side of a double clad fiber burning or melting is obtained. be able to.

  Embodiments of an optical fiber bonding apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing an embodiment of an optical fiber bonding apparatus according to the present invention.

  The optical fiber bonding apparatus 10 is an input side end face on the same optical axis as the optical axis z of the optical output unit 11a of the excitation light output light source 11, for example, the excitation light output light source 11, which is a light source of the excitation light y. A bundle fiber (optical fiber) 12 to which the optical fiber is connected, and a light guide lens 13 disposed on the same optical axis z as the bundle fiber 12 via a space portion at an output side end surface portion of the bundle fiber 12; The double clad fiber 14 disposed on the same optical axis z as the light guide lens 13 and the signal light x from the signal light source (not shown) can be received, and the signal light x can be reflected on the optical axis of the excitation light y. The color separation mirror 23 is arranged in this manner.

  The excitation light output light source 11 is a light source that optically joins with the light input side end face 12 a of the bundle fiber 12 and outputs the excitation light y.

  As shown in FIG. 2A, the bundle fiber 12 has a shape of the input side end face 12a so as to cover a plurality of cores 16 arranged in a bundle at the center and the plurality of cores 16 as a whole. And an outer clad 18 provided so as to cover the outer side of the clad 17.

  A reflection layer 16a is formed on the outer side of the core 16, and the excitation light y is input to the core 16 from the excitation light output light source 11 side and transmitted to the double clad fiber 14 side while being repeatedly reflected along the optical axis z. Configured to be

  Further, as shown in FIG. 2B, the bundle fiber 12 is in a state in which a plurality of cores 16 are scattered and distributed in the clad 17 at the center of the cross section. Furthermore, the bundle fiber 12 has an interface 19 of the clad 17 at a position where the plurality of cores 16 of the fiber 12 are radially spaced from the center of the bundle fiber 12 as shown in FIG. Is installed in a ring shape.

  As described above, the plurality of cores 16 that are radially arranged are molded integrally with the clad 17 at the stage of manufacturing the bundle fiber 12, or are formed on the output side end face 12 b side of the clad 17. 16 can be radially arranged along the interface 19 of the clad 17 at a position away from the center of the optical fiber, and held on the wall surface of the clad 17 by a holding means such as adhesion.

  The light guide lens 13 is installed on the optical axis z through the output side end face 12b side of the bundle fiber 12 and a required space. This light guide lens 13 has a required refraction angle in consideration of the incident angle of the excitation light y output from the output side end face 12b side of the bundle fiber 12 and the radiation angle with respect to the double clad fiber 14 side in the subsequent stage. .

  On the other hand, the signal light x output from the signal light source side is reflected on the direction axis z by the color separation mirror 23.

  The refraction angle of the light guide lens 13 will be described in more detail.

  The light guide lens 13 is installed on the same optical axis z as the bundle fiber 12 and the double clad fiber 14. Moreover, when the bundle fiber 12 and the double clad fiber 14 are joined via space, the light guide lens 13 is set to a required refraction angle according to the spatial distance.

  That is, the refraction angle required for the light guide lens 13 is such that the excitation light y output from the bundle fiber 12 side is guided to the core 20 of the double clad fiber 14 through the color separation mirror 23 and the signal light x is The angle at which light is guided so as to be fitted into the core 20 of the double clad fiber 14.

  The light guide lens 13 can guide the signal light x and the excitation light y to the double clad fiber 14 by the common light guide lens 13 when guiding the signal light x and the excitation light y at a required refraction angle. The light guide lens 13 is, for example, a light guide lens having a two-layer refractive index in which the center portion can correspond to the signal light x and the peripheral portion can correspond to the excitation light y.

  The double clad fiber 14 has a core 20 facing the input-side end face 14a of the signal light x and the pumping light y, a clad 21 provided so as to coat the outside of the core 20, and a coat outside the clad 21. And an outer cladding 22 provided on the outer surface.

  The double clad fiber 14 acts to transmit the pumping light y transmitted through the clad 21 along the optical axis z while repeatedly reflecting it through the interface 19 between the clad 21 and the outer clad 22.

  Further, the core 20 of the double clad fiber 14 has a considerably larger cross-sectional area than the cross-sectional area of the core 15 of the bundle fiber 12 and enables transmission of the signal light x including a required amount of data. Is.

  Next, the operation of the optical fiber bonding apparatus 10 will be described with reference to FIGS.

  The excitation light y output from the excitation light output light source 11 side is transmitted from the light output unit 11a side to the input side end face 12a of the bundle fiber 12. The transmitted excitation light y is transmitted to the core 16 side of the bundle fiber 12 shown in FIGS. 2A to 2C, and is transmitted in the optical axis direction while being repeatedly reflected by the reflection layer 16a and the interface 19 of the core 16. Is done.

  The excitation light y transmitted into the bundle fiber 12 is output from the output side end face 12 b of the bundle fiber 12 and transmitted to the double clad fiber 14 side through the light guide lens 13. The signal light x that is coaxial with the excitation light y by the color separation mirror 23 is transmitted to the double clad fiber 14 side through the light guide lens 13.

  The transmitted signal light x is transmitted on an axis close to the optical axis z and guided to the core 20 side of the double clad fiber 14 as shown in FIG. The light guide lens 13 having a required refractive index can be selected and mounted in advance so that the signal light x is efficiently guided to the core 20 side of the double clad fiber 14. At that time, the light guide lens 13 having an appropriate refractive index is selected in advance for the distance between the output side end face 12b of the bundle fiber 12 and the input side end face 14a of the double clad fiber 14.

  Further, as shown in FIG. 1, the transmitted excitation light y is transmitted in a ring shape or a radial shape slightly separated from the optical axis z, and guided to the sleeve-like or cylindrical clad 21 side of the double-clad fiber 14. The Thus, the excitation light y output from the bundle fiber 12 side is appropriately refracted by the light guide lens 13 and guided to the core 20 and the clad 21 side, respectively.

  In particular, since the excitation light y is guided to the clad 21 side of the double clad fiber 14, the abrupt excitation light absorption action by the excitation light y does not occur on the input side end face 14 a of the core 20.

  According to the optical fiber bonding apparatus 10, as shown by the change curve h in the graph of FIG. 3, the double-clad fiber 14 has an abrupt portion at any part in the longitudinal direction from the input side end face 12a to the output side end face 12b. A stable excitation light absorptivity characteristic can be obtained at a low level without exhibiting an excitation light absorptance.

  Therefore, the portion of the input side end face 14a of the double clad fiber 14 does not generate heat and burn or melt. In addition, according to the bundle fiber 12 of the optical fiber bonding apparatus 10, the one in which the core 16 is arranged on the clad 17 is manufactured and can be handled according to the size of the core 20 on the double clad fiber 14 side. The fiber 12 is manufactured in advance as a standard product and can be used for various purposes.

  Furthermore, although the bundle fiber was illustrated as the optical fiber 12, what is necessary is just an optical fiber provided with the some core 16 which transmits the excitation light y.

  Furthermore, according to the optical fiber bonding apparatus 10, the light sources of the signal light x and the pumping light y to be handled use, for example, pumping light output from a fiber couple LD (Laser Diode), while the optical fiber bonding apparatus 10. It is also possible to employ a configuration having signal light guide means that is output from the control signal light generation means (not shown) side of the information control apparatus employing the above.

The schematic diagram which shows the outline | summary of the joining apparatus of the optical fiber which concerns on this invention. It is a figure which shows an optical fiber, (a) is an enlarged view which shows the end surface of the optical fiber seen from the AA arrow direction shown in FIG. 1, (b) is an expansion along the BB line of FIG. Sectional drawing and (c) are expanded sectional views which follow the CC line of FIG. The figure which shows the outline | summary of the change of the excitation light absorptance in the one end surface side of the double clad fiber shown in FIG. The figure for demonstrating the conventional optical fiber joining apparatus. The figure which shows the outline | summary of the change of the excitation light absorption factor in the core end surface part of one optical fiber in the conventional optical fiber joining apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical fiber bonding apparatus 11 Signal light / pumping light output light source 11a Light output part 12 Bundle fiber (optical fiber)
12a, 14a Input side end face 12b Output side end face 13 Light guiding lens 14 Double clad fiber 16, 20 Core 16a Reflective layer 17, 21 Cladding 18, 22 Outer clad 19 Interface 23 Color separation mirror x Signal light y Excitation light z Optical axis

Claims (5)

An optical fiber having an input side end face and an output side end face for inputting / outputting pumping light output from the light source side, and a double clad installed on the same optical axis through a required space on the output side end face of the optical fiber Comprising a fiber and a light guide lens provided so as to be positioned on the optical axis of the space;
The optical fiber includes a clad provided to cover a plurality of cores disposed on the optical axis,
The optical fiber bonding apparatus according to claim 1, wherein the plurality of cores are radially distributed on the output side of the optical fiber and spaced from the center position of the optical fiber. 2. The plurality of cores of the optical fiber are gradually spaced from the center position of the optical fiber and arranged in a radially distributed manner from the input side end face to the output side end face of the plurality of cores. The optical fiber bonding apparatus described. 3. The optical fiber bonding apparatus according to claim 2, wherein the plurality of cores of the optical fiber are arranged along an end surface of the clad at an output side end surface portion of the plurality of cores. Connects the input side end face of the optical fiber having a plurality of cores in the center to the pumping light source side, and refracts the pumping light through a light guide lens arranged away from the output side end face. An optical fiber bonding method comprising optically bonding so as to be incident on an input side end face of the clad. An input side end face of an optical fiber having a plurality of cores arranged in a bundle at the center, and an output end face arranged in a ring shape at a position radially spaced from the center. An optical fiber characterized by

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