JP2004264843A - Optical fiber with optical function element, and method and device for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber with an optical function element allowing a plurality of optical fibers to be connected thereto by fusion at the the same time irrespective of outer diameter differences by irradiating the end face of the optical function element with laser beams so that the temperature distribution of the end face is made uniform, and to provide a method and device for manufacturing the same. <P>SOLUTION: A plurality of optical fibers can be connected to the optical function element by fusion irrespective of outer diameter differences by abutting the end faces of the optical fibers on the end face of the optical function element, and irradiating the abutting parts to be abutted thereto with at least one or more laser beams at an incident angle of 25-70° for 1 to 20 sec to form a uniform temperature distribution state on the end face of the optical function element. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an optical fiber with an optical functional element, which is obtained by fusion splicing an optical fiber to an optical functional element, using a laser beam, and a method and apparatus for manufacturing the optical fiber. The present invention relates to an optical fiber with an optical functional element, a method for manufacturing an optical fiber with an optical functional element, and an apparatus for manufacturing an optical fiber with an optical functional element, which are simultaneously fused.

  As a method of connecting the end face of the optical fiber to the end face of the optical functional element, a method of connecting with an adhesive or a method of fusion splicing using a fusion device is general. Among these connection methods, typical fusion connection methods include those shown in FIG. 12, FIG. 13, and FIG.

  In the fusion splicing method shown in FIG. 12, a condensing lens mirror 103 is disposed on an end face of a rod lens 102 as an optical function element, and is formed at a central portion of the condensing lens mirror 103 at an angle to the end face. The laser beam 105 is applied to the converging lens mirror 103 by irradiating the laser beam 105 to the converging lens mirror 103 through the optical fiber 104 through the through-hole 103a, and the laser beam 105 is condensed and applied to the abutting portion of the rod lens 102 and the optical fiber 104. In this way, fusion splicing is performed.

  Further, the "laser fusion splicing apparatus and method" described in JP-A-5-346517 shown in FIG. 13 is used to connect two optical components having different diameters (the quartz-based waveguide 112 and the optical fiber 114). The end surfaces of the silica-based waveguide 112 and the optical fiber 114 are abutted so as to prevent a step from occurring, and a laser beam 105 is irradiated in parallel to the abutting surface to irradiate the outer surfaces of the two. The surfaces are simultaneously fusion-spliced.

Further, "optical fiber functional component and its manufacturing method" of JP-A-6-138342 JP shown in FIG. 14 has an outer diameter of the optical fiber 124 of the W _2, the outer diameter W ₂ or more and the outer diameter W ₂ An optical functional element 122 having an outer diameter W ₁ of 2 times or less is butted, and an electrode bar 123 is disposed opposite the electrode so as to sandwich the abutted portion, and the butted portion is melted by an arc discharge 125 generated from the two electrode rods 123. By doing so, the optical function element 122 and the optical fiber 124 are connected. At this time, a reliable connection cannot be realized unless the outer diameters of the optical function element 122 and the optical fiber 124 maintain the relationship of W ₁ <2W ₂ .
U.S. Pat. No. 6,033,515 U.S. Pat. No. 6,217,698 JP-A-5-346517 JP-A-6-138342

  The fusion splicing method described above has fine restrictions depending on the size, cross-sectional shape (area), material, and the like of the optical functional element, and fusion splicing may be difficult due to this restriction.

  For example, the fusion splicing method shown in FIG. 12 can surely irradiate the laser beam 105 to the abutting portion, so that two or more optical components (rod lens and optical fiber) having different cross-sectional areas are used. Has the advantage of being able to be fusion spliced, but on the other hand, since only one laser beam is irradiated, the temperature distribution of the irradiation spot by the laser beam formed on the end face of the optical functional component is a so-called Since the temperature becomes the Gauss type, the temperature at the center is the highest, and the temperature becomes lower toward the outer diameter direction. Therefore, the uniform temperature distribution range is narrow, and there is a problem that a plurality of optical fibers cannot be connected at the same time. Even if fusion can be performed, it is very difficult to perform fusion splicing with low loss without causing an optical fiber axis shift.

  Further, when the melting temperature of the optical function element and the melting temperature of the optical fiber are different, according to the configuration of FIG. 12, the side of the optical fiber is irradiated with a large amount of laser beam, and the rod lens is irradiated with only a small amount of laser beam. Only melt quickly and it is difficult to fuse both at the same time.

  Further, the "laser fusion splicing apparatus and method" described in JP-A-5-346517 is capable of fusion splicing the silica-based waveguide 112 and the optical fiber 114 formed on the same plane with low loss. Although it has an advantage, since the temperature distribution spread of the laser beam has a linear spread parallel to the connection boundary surface, the temperature distribution of the laser beam does not spread planarly on the end face. In addition, the connection surface cannot be melted sufficiently uniformly. For this reason, the degree of fusion bonding may be reduced and reliability may be reduced.

  Further, when the material of the optical functional component and the material of the optical fiber are different, the laser absorptivity is different, that is, since the melting rate is different, there is a problem that the fusion splicing cannot be performed with low loss.

  Further, when there is a large step between the butted optical functional element and the optical fiber, even if the laser beam is irradiated in such a state, the one near the irradiation port (optical functional element) melts quickly and the far one (optical functional element) Since the optical fiber is melted late, there is also a problem that the two are not melted uniformly and an axis shift occurs.

  On the other hand, the "optical fiber functional component and its manufacturing method" described in JP-A-6-138342 perform fusion splicing by arc discharge. The difference must be about twice or less.

  In other words, fusion by arc discharge, the spread of the discharge extends over a wide range, so it is not possible to selectively melt only the optical functional element or only the optical fiber, and even if you want to melt, as described above If the difference between the outer diameters of the two optical components is twice or more, the two components are not uniformly melted, and the reliability may be reduced.

  Also, since the converging rod lens and the optical fiber are fused concentrically by surface tension, there is a problem that two or more optical fibers cannot be connected to the end surface of the rod lens.

  In spite of these problems, in the fusion splicing of optical parts, fusion of optical parts having cross sections different from each other by two times or more, or fusion of a plurality of optical parts to one end face is performed. There is a request to make a connection.

  The present invention has been made in view of the above problems, and an object of the present invention is to irradiate a laser beam so as to make the temperature distribution of an end face of an optical functional element uniform, thereby providing a plurality of laser beams regardless of an outer diameter difference. An object of the present invention is to provide an optical fiber with an optical function element that can be fusion spliced with an optical fiber at the same time, and a method and an apparatus for manufacturing the same.

  In order to achieve the above object, according to the first aspect of the present invention, an end face of an optical fiber is abutted on an end face of an optical functional element, and at least one or more laser beams are applied to the abutted portion at a predetermined incident angle. The gist is that irradiation is performed for a certain period of time, and the end face of the optical functional element and the end face of the optical fiber are melt-connected.

  According to the second aspect of the present invention, at least one or more laser beams are irradiated to the end surface of the optical functional element at a predetermined incident angle for a certain period of time, and the end surface of the optical fiber is brought into contact with the area irradiated with the laser light. The gist of the invention is that the laser light is further irradiated at a predetermined incident angle on a portion where the end face of the optical functional element and the end face of the optical fiber are brought into contact.

  According to a third aspect of the present invention, in the first or second aspect, the incident angle is smaller than an angle formed by a radial direction of the optical function element and an axial direction of the optical fiber.

  According to the fourth aspect of the present invention, in the first or second aspect, the irradiation time of the laser beam is in the range of 1 second to 20 seconds.

  According to the fifth aspect of the present invention, in the first or second aspect of the present invention, the position where the laser light is irradiated on the end face of the optical functional element is determined with reference to the center point of the end face of the optical functional element. The laser beam is adjusted so that the center of the first laser beam is located at a position shifted by 10 to 50% from the center, and the second laser beam is shifted by −10 to −50% from the center point of the optical function element. The point is that the center is adjusted to be centered.

  According to the invention described in claim 6, in the invention according to claim 1 or 2, the position of irradiating the laser light on the end face of the optical function element is, with reference to the center point of the end face of the optical function element, the center point. The laser light is adjusted so that the center of the first laser light is shifted by 30% from the center, and the center of the second laser light is shifted by -30% from the center point of the optical function element. The gist is to make adjustments.

  According to the invention of claim 7, in the invention of claim 1 or 2, the end face area of the optical functional element has at least four times the end face area of the optical fiber, and the step of the optical fiber is smaller than the optical fiber. The gist is that it is equal to or larger than the radius of the optical fiber over the entire circumference of the fiber.

  According to an eighth aspect of the present invention, in the invention of the first or second aspect, it is the gist that, in the outer surface of the optical functional element, the outer peripheral ridge portion of the surface to which the optical fiber is connected is not chipped.

  According to the ninth aspect of the present invention, there is provided a method of manufacturing an optical fiber with an optical function element by connecting an end face of an optical fiber to an end face of an optical function element, wherein the end face of the optical function element and the optical fiber A butting step of abutting an end face, and an irradiating step of irradiating at least one or more laser beams at a predetermined incident angle for a predetermined time to a butting portion formed by abutting the end face of the optical functional element and the end face of the optical fiber. It is the gist to have.

  According to the tenth aspect of the present invention, there is provided a method of manufacturing an optical fiber with an optical function element by connecting an end face of an optical fiber to an end face of the optical function element, wherein at least one or more fibers are provided on the end face of the optical function element. A first irradiation step of irradiating a laser beam at a predetermined incident angle for a predetermined time, and after irradiating the laser light for a predetermined time, a butting step of abutting an end face of the optical fiber on an end face of the optical functional element; The present invention has a second irradiation step of irradiating at least one or more laser beams at a predetermined incident angle for a certain period of time to an abutting portion between the end face of the optical function element and the end face of the optical fiber.

  According to an eleventh aspect of the present invention, in the invention of the ninth or tenth aspect, the gist is that the incident angles in the first and second irradiation steps are not less than 25 ° and not more than 70 °.

  According to the twelfth aspect of the present invention, in the ninth or tenth aspect, the gist is that the irradiation time of the laser beam is 1 second or more and 20 seconds or less.

  According to a thirteenth aspect of the present invention, in the invention according to the ninth or tenth aspect, the position of the end face of the optical function element where the laser light is irradiated is determined by using the center of the end face of the optical function element as a reference. The laser beam is adjusted so that the center of the first laser beam is located at a position shifted by 30% from the point, and the center of the second laser beam is located at a position shifted by -30% from the center point of the optical function element. The gist is that it is adjusted to.

  According to the fourteenth aspect, in the ninth or tenth aspect, the end face area of the optical functional element has at least four times the end face area of the optical fiber, and the step of the optical fiber has the step. The point is that the radius of the optical fiber is equal to or larger than the radius of the optical fiber over the entire circumference of the optical fiber.

  According to the invention as set forth in claim 15, there is provided an apparatus for manufacturing an optical fiber with an optical function element for connecting an optical fiber end face to an end face of the optical function element, comprising: a holding section for holding the optical function element; A reflecting plate disposed to cover one end surface of the optical fiber, a movable plate movable with the optical fiber placed horizontally, and a movable plate for controlling movement of the movable plate in x, y, and z-axis directions. A control unit, a laser generator that outputs melting energy for melting the optical function element and the optical fiber, an output control unit that controls an output of the laser generator, and a laser beam output from the laser generator. An incident angle control unit that performs angle control so that light enters the end face of the optical functional element at a predetermined incident angle, and a light collecting element that collects light on the optical functional component and irradiates light. And

  According to a sixteenth aspect of the present invention, in the fifteenth aspect, the light collecting element is a convex lens.

  According to the seventeenth aspect of the present invention, the gist of the fifteenth aspect is that the light-collecting element is a concave mirror.

  Therefore, in the present invention, the end face of the optical functional element is abutted with the end face of the optical fiber, and a plurality of laser beams are simultaneously irradiated at a predetermined angle to the abutting portion to form a uniform temperature distribution state on the end face of the optical functional element. Thus, the optical functional elements having different diameters and the optical fiber are fusion-connected.

  That is, according to the present invention, since the axis of the laser beam can be intentionally shifted and more laser power can be applied to only one of the optical components, when the material and the heat capacity of the parts to be fused are different, the two components are different. Can be melted at the same time. As a result, in the past, the axis connecting the two parts to be fused and the axis of the laser beam coincided, and only the optical fiber was irradiated with the laser beam, so that the optical fiber with a low softening temperature was melted first. However, such a problem can be solved.

  In addition, the present invention provides an optical functional device that has been impossible in the prior art because a substantially uniform energy distribution can be obtained over a wide range by simultaneously irradiating the end face of the optical functional device with a plurality of laser beams at a predetermined angle. It is possible to simultaneously fuse two or more optical fibers to the end face of the optical fiber. In addition, according to this fusion, the optical fibers can be connected with low loss without causing an axial deviation.

  Further, in the present invention, in the first irradiation step, only the optical function element is irradiated with the laser beam for a predetermined time (1 second to 20 seconds), and the end face of the optical fiber is brought into contact with the end face of the optical function element. By simultaneously irradiating both the optical function element and the optical fiber in the second irradiation step, even if the optical function element and the optical fiber have different melting temperatures, fusion connection can be performed.

  Therefore, by irradiating at least one or more laser beams within a range of an irradiation angle of 25 ° to 70 ° to a butt portion formed by abutting an end face of an optical functional element with an end face of an optical functional element, the end face of the optical functional element and the optical fiber Can be simultaneously fused and fusion-spliced.

  Alternatively, the end face of the optical functional element may be irradiated with a laser beam within an irradiation angle range of 25 ° to 70 °, and the optical fibers may be joined after the end face of the optical functional element is melted. By doing so, the end faces of the optical fiber are melted at the melting temperature of the end faces, and the end faces can be connected by both surface tensions. After the connection by the surface tension, by further irradiating the laser beam, the coupling strength between the optical function element and the optical fiber can be further increased.

  Furthermore, when irradiating the laser beam to the end face of the optical functional element, the apex of each Gaussian distribution of the two laser beams is illuminated to one of the positions shifted from the center of the end face of the optical functional element by 10 to 50%, The other is irradiated at a position shifted by -10 to -50%, so that the low irradiation power overlaps, and thereby the irradiation power has a flat uniform energy distribution in the radial direction of the end face. The fibers can be fusion spliced.

  Another effect of the present invention is improvement in mechanical reliability. The rod lens, which is an optical functional component, is manufactured by cutting the original lens base material into a predetermined length. However, chipping is likely to occur on the end surface of the lens in the cutting process. If there is a chip, the damage may grow from the starting point, leading to destruction of the part. In particular, when fixing is performed using an adhesive having a high hardness after curing, the adhesive is constantly distorted due to the curing shrinkage of the adhesive, and the end face scratches grow, which easily leads to breakage.

  When a collimator lens is manufactured according to the present invention, the end face of the rod lens is melted by heating, and the ridge portion of the end face has a natural curvature due to surface tension. By adjusting the laser irradiation time, chipping at the end is eliminated, and the laser is appropriately rounded. This improves the mechanical reliability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of a manufacturing apparatus 1 for manufacturing an optical fiber with an optical function element according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of an optical fiber with an optical function element (two-core optical fiber collimator 10) of the present invention.

First, as shown in FIG. 1, the manufacturing apparatus 1 of the optical functional device with optical fibers of the present invention, a CO ₂ laser beam and CO ₂ laser oscillator 2 (hereinafter, referred to as a laser beam.) Outputs a, the laser beam two A half mirror 3 for branching, a total reflection mirror 4 for totally reflecting the laser beam, a condenser lens 5 for reducing the diameter of the laser beam, a collimating lens (optical function element) 11 for converting incident light into parallel light, and a collimator Two optical fibers (an input optical fiber 12 and an output optical fiber 14) which are vertically arranged on one end surface of the lens 11, and a movable optical fiber on which the input optical fiber 12 and the output optical fiber 14 are placed. The movable plate 7, the light source 6 that outputs the test light to be incident on the input side optical fiber 12, the power meter 8 that detects the output light power of the test light, and controls these various functional units. At least a control unit 9 is provided.

  Here, the optical fibers 12 and 14 are optical fibers made of quartz glass, but are not limited thereto, and may be of a type called fluoride glass or multi-component glass. The material of the collimating lens 11 is quartz glass, but is not limited thereto. For example, an ion exchange rod lens such as a SELFOC lens (manufactured by Nippon Sheet Glass) may be used. Further, the optical function element is not limited to a collimator lens, but may be a Faraday element used for an optical isolator.

Here, the half mirror 3 is arranged in the vicinity of the emission port of the CO ₂ laser oscillator 2 and splits the output laser beam by 50%. The total reflection mirror 4 is disposed on a previously calculated optical path to propagate the two laser beams split by the half mirror 3 while reflecting them at equal distances to the end face of the collimator lens 11. Here, the output wavelength output from the CO ₂ laser oscillator 2 is 10.6 μm.

  One end face of each of the input-side optical fiber 12 and the output-side optical fiber 14 is disposed so as to face the end face of the collimator lens 11, and both the input-side optical fiber 12 and the output-side optical fiber 14 have a diameter of 0.1 μm or less. It is mounted on a movable plate 7 that can move with high precision. The light source 6 is connected to the other end of the input side optical fiber 12, and the power meter 8 is connected to the other end of the output side optical fiber 14. The ends of the optical fibers 12 and 14 opposed to the collimator lens 11 are in a state where the coating is stripped off for a certain length and the optical fiber 13 is exposed.

  On the other hand, a reflector 16 is disposed at the other end of the collimator lens 11 so as to cover the end face, and the collimator lens 11 and the reflector 16 are fixed by being collectively set in the optical function element holder 17. ing.

Although not shown, the control unit 9 outputs a signal from the CO ₂ laser oscillator 2 to the movable plate control unit that freely moves the movable plate 7 in the x, y, and z axis directions with an accuracy of 0.1 μm or less. An output controller for controlling the output of the laser beam, an angle controller for controlling the angle so that the laser beam is incident on the end face of the optical function element 11 at a predetermined incident angle, and a laser beam for irradiating the end face of the collimating lens 11 At least a timer control unit for controlling the irradiation time.

  Next, the operation and effect of the optical fiber manufacturing apparatus 1 with an optical function element will be described.

As shown in FIG. 1, a laser beam output from a CO ₂ laser oscillator 2 is branched into two by a half mirror 3, and each of the branched laser beams is a total reflection mirror 4, a condenser lens 5, and a bundle fiber (see FIG. 1). (Not shown) and the like, and is guided to the end face of the collimator lens 11 at an equal distance.

  Here, when a control command for moving the movable plate 7 is input, the movable plate control unit controls the opposing positional relationship between the collimator lens 11 and each of the optical fibers 12 and 14. A specific adjustment method is as follows. First, test light (wavelength λ1) emitted from the light source 6 is made incident on the input side optical fiber 12, subsequently, incident on the collimating lens 11 and reflected by the end face of the collimating lens 11. By adjusting the axial direction while monitoring λ 1 ′ with the power meter 8 connected to the end of the output side optical fiber 14, accurate alignment (alignment) between the optical fiber and the collimating lens 11 is performed.

  After this alignment, the two optical fibers 12 and 14 are once separated from the collimator lens 11 in one direction (the separated distance is stored), and then the incident angle of the laser beam is adjusted. This incident angle adjustment may be performed manually or automatically. In the case of automatic adjustment, for example, an angle of incidence on the end face of the collimator lens 11 and how much the total reflection mirror 4 is inclined to realize the angle of incidence are stored in a database in advance by associating the angle with a memory (non-volatile storage medium). When a designated incident angle is input, the tilt angle of the mirror corresponding to the incident angle according to this command is read from the database and transmitted to the total reflection mirror 4 to adjust the tilt angle. Do. The predetermined angle of incidence will be described later with reference to FIG.

  Next, after the irradiation angle and the irradiation position are adjusted, the output of the laser beam whose melting temperature has been increased to start melting the collimating lens 11 is started. Then, when melting with the collimating lens starts, the end faces of the optical fibers 12 and 14 that have been separated previously are returned to their original positions, and brought into contact with the end faces of the melted collimating lens 11. Thereby, the melted collimator lens 11 and the optical fiber are fusion-connected by surface tension.

  Here, in order to sufficiently melt the collimating lens 11, it is necessary to focus the laser beam by the focusing lens 5. This is because the output power density of a laser which is usually available at a low cost is low, and thus a sufficient amount of heat cannot be obtained until the end face of the collimating lens 11 is melted. In the present embodiment, a convex lens made of zinc selenide, germanium, or the like that transmits a laser wavelength of 10.6 μm is used as the condenser lens 5, but it is made of a special material and is expensive. Therefore, except for the condensing lens 5, even if a concave mirror is used instead of the total reflection mirror 4, the same condensing effect can be obtained, and the device can be realized at low cost.

  Here, the collimating lens 11 and the optical fiber are butt-joined first, and the laser beam is irradiated later. However, regardless of this, the laser beam is first applied only to the collimating lens 11 with the optical fiber separated. Then, the optical fibers may be brought into contact with each other, and the optical fibers may be connected by surface tension depending on the melting temperature of the collimating lens 11. Further, in order to further increase the reliability, the laser beam may be further radiated after the two are connected. This can further increase the bond density.

  Finally, after confirming that the temperature of the irradiated portion of the laser beam has sufficiently decreased, the completed two-core optical fiber collimator 10 is removed from the optical function element holder 17.

FIG. 2 is a diagram showing a configuration of the two-core optical fiber collimator 10 manufactured in this manner.

  As described above, the laser beam is irradiated at a predetermined angle from the axis of the optical fiber obliquely to melt the end face of the collimating lens 11 and to circulate the thermal energy of the laser beam also to the end faces of the optical fibers 12 and 14, so that The collimating lens 11 can be connected to the optical fibers 12 and 14.

  Further, when the two optical fibers 12 and 14 are connected to the end face of the collimator lens 11 as described above, the connection portion is further irradiated with a laser beam to improve the coupling density.

On the other hand, as shown in FIG. 2, the completed two-core optical fiber collimator 10 has a configuration in which two optical fibers 12, 14 are connected in parallel to an end face of a collimator lens 11, and specifically, a collimator The diameter of the lens 11 is W ₁ , the diameter of the optical fiber 13 of the input side optical fiber 12 is W ₂ , the diameter of the optical fiber 15 of the output side optical fiber 14 is W ₃ , the fusion spliced optical fiber the shortest distance to the outer periphery of the line 13 and the collimating lens is one that has a W _2/2.

  When propagating light enters the two-core optical fiber collimator 10 from the input side optical fiber 12, the light is reflected by the end face of the collimator lens 11, and the light is emitted from the output end of the output side optical fiber 14. .

  Therefore, according to the present invention, regardless of the end area of the optical functional element, the end area of the optical fiber, and the step between the optical functional element and the optical fiber, the cross-sectional area of the optical functional element is at least four times the cross-sectional area of the optical fiber, Even if the step is equal to or larger than the radius of the optical fiber over the entire circumference of the optical fiber, the laser beam can be irradiated to a desired position by entering the laser beam at a predetermined incident angle. It becomes possible.

  Here, the optical functional element is a collimating lens, but the optical functional element is not limited to this, and may be a rod lens such as a single refractive index type lens or a graded index type lens.

  Next, the irradiation environment will be described in detail with reference to an enlarged view of the end face when the end face of the optical function element 11 is enlarged in the fusion splicing step of the optical fiber with the optical function element shown in FIG. The energy distribution state of the laser beam on the end face of the optical function element will be described with reference to FIG. Further, the absorptance of quartz glass with respect to the irradiation angle of the laser beam will be described with reference to FIG.

  First, as shown in FIG. 3, two laser beams a and b are incident on the end face of the collimator lens 11 at a predetermined angle, a predetermined interval, and a predetermined laser energy. FIG. 3 shows a state in which the optical fibers 13 and 15 are vertically inserted into a uniform heat energy distribution range formed on the end face of the collimator lens 11 in such an environment.

  In this state, assuming that the angle between the laser beam a and the axis of the optical fiber 13 is θ1 and the angle between the laser beam b and the axis of the optical fiber 15 is θ2, the angle θ1 is 25 ° to 70 °, When the angle θ2 is 25 ° to 70 °, the optical fiber strands 13 and 15 and the collimating lens 11 can be melted at the same time.

  Although not shown, ideally, the diameter of the laser beam applied to the collimating lens 11 is desirably substantially equal to the cross-sectional diameter of the collimating lens 11.

  In this state, the energy distribution within the irradiation range in the YY direction of the end face in FIG. 3 is as shown in FIG. Here, the horizontal axis of FIG. 4 indicates the end face diameter (μm) of the optical function element, and the vertical axis indicates the power (mW) of the laser beam. As shown in FIG. 4, the energy distributions of the two laser beams a and b are both Gaussian. Therefore, by adjusting the irradiation range of the laser beam by the angle control unit so as to overlap the bases of the two energy distributions, the energy of the low energy portions is increased, and a trapezoidal energy distribution having a substantially flat upper surface is obtained. .

  A specific method of superimposing the two energy distributions is to adjust the laser beam a so that the center of the laser beam a is shifted by 30% from the center 0 with respect to the center 0 of the collimator lens 11. Similarly, by adjusting the center of the laser beam b so as to be at a position shifted by −30% from the center 0 of the collimator lens, the energy distribution on the upper surface becomes substantially uniform as shown in FIG. Obtainable.

  However, the present invention is not limited to this, and by arranging the two energy distributions so as to overlap each other at a half value of the maximum energy value of each energy distribution, it is possible to obtain an energy distribution in which the upper surface is substantially uniform.

Table 1 shows whether or not two-core fusion can be performed when the position of the laser beam is changed and the average tensile strength at break. Here, the tensile strength is the strength at which the tensile force is applied to the completed collimator until it is broken, and the collimator is broken. If the fusion splicing is successful, the tensile strength increases, and the higher the numerical value, the more desirable it is. However, in practice, it can be said that 500 g weight or more is sufficient. From the results summarized in Table 1, the two cores can be fused when the position of the first laser light is 10% to 70% and the position of the second laser light is -10% to -70%. is there. However, when the position of the first laser light is 60% to 70% and the position of the second laser light is -60% to -70%, sufficient tensile strength is not obtained. Therefore, it is desirable that the position of the first laser light is 10 to 50% and the position of the second laser light is -10 to -50%.

On the other hand, the relationship between the irradiation angle and the absorptance of the quartz glass is shown in FIG. 5 when the horizontal axis is the irradiation angle θ [deg] of the CO ₂ laser and the vertical axis is the absorptivity [%] of the quartz glass. It is shown that the absorption rate decreases as the irradiation angles θ1 and θ2 increase. As a result of an experiment, it has been found that, in order to perform fusion with practically sufficient strength, the absorptance of laser power in quartz glass is preferably 60% or more. From the relationship between this result and FIG. 5, the irradiation angle is desirably 70 ° or less.

  On the other hand, the irradiation time depends on the material of the optical functional element to be connected and the power of the laser light to be irradiated, but if the time is 1 second or less, the optical functional component can be sufficiently fused when the optical fiber is fused to the optical functional component. It is not in a softened state, but in a state in which the optical fiber can be easily removed after connection. Therefore, the irradiation time needs to be 1 second or more. If the irradiation time is longer than 20 seconds, heat is transmitted to the entire optical functional component, and the optical functional component is likely to be deformed. Therefore, the performance of the optical functional component may deteriorate. Therefore, the irradiation time is desirably set to 20 seconds or less.

  For the above reasons, it is desirable that the irradiation time of the laser beam be 1 second or more and 20 seconds or less. Further, even when the irradiation time is 20 seconds or less, the components added to the optical functional component may be diffused by heating, and the performance of the component may be changed. For example, in a quartz rod lens, germanium is added to form a refractive index distribution. However, heat generated by laser irradiation may cause germanium to diffuse and change the refractive index distribution in long-term irradiation. Therefore, the irradiation time is desirably 10 seconds or less if possible.

  Specifically, when the irradiation angle θ1 of the laser beam a is reduced to, for example, about 30 °, the absorptance at the end face of the collimator lens 11 increases, and the melting efficiency at the end face increases.

Similarly, when the irradiation angle θ2 of the laser beam b is reduced to, for example, about 30 °, the absorptance of the end face of the collimator lens 11 increases, and the melting efficiency at the end face increases.

Therefore, by superposing the two laser beams at an angle of 60 ° at a reduced angle, a uniform temperature distribution can be obtained over a wider range than realized by a single laser beam. If the irradiation angle is reduced to 25 ° or less (the irradiation is made closer to the optical fiber), the outer periphery of the optical fiber is melted, so it is not preferable to reduce the irradiation angle to 25 ° or less.

  From the above, it is desirable to adjust the irradiation angle of the laser between 25 ° and 70 ° in order to sufficiently heat the optical functional component and not to melt the outer periphery of the optical fiber.

  Further, since the optical axes of the laser beams a and b of the manufacturing apparatus 1 are arranged so as not to be perpendicular to the central axis of the optical fiber, the laser beam has conventionally been two-dimensionally spread. Has a three-dimensional distribution. This makes it possible to irradiate only the collimator lens 11 with a laser beam, to irradiate the optical fiber strands 13 and 15 after abutting the end face of the collimator lens 11, or to irradiate both at the same time.

  In the present embodiment, the uniform energy distribution is obtained over a wide range using two laser beams a and b. However, the uniform energy distribution is obtained over a wider range using a plurality of laser beams. You can also

  Further, in the present embodiment, the description has been given only of the case where the material of the collimating lens 11 and the optical fiber strands 13 and 15 is a quartz material. However, the present invention is not limited to this, and the material of the collimating lens 11 and the optical fiber strands 13 and 15 is not limited thereto. Even if they are different or the connection part is not on the surface, by adjusting the irradiation angle θ, both can be melted uniformly and stable fusion can be performed.

  Further, the manufacturing apparatus 1 of the present invention further includes a time for irradiating only the collimating lens 11 and a time for simultaneously irradiating both the collimating lens 11 and the optical fiber wires 13 and 15 (the collimating lens 11 is moved to the optical fiber wires 13 and 15). It also has a timer control unit that controls the distance from the object and the speed at which it approaches the sensor. If the optical function element and the optical fiber cannot be melted uniformly using only the irradiation position and irradiation angle, these elements are included. Optimal conditions can be set.

That is, by controlling the following four elements, connection can be made with low loss. When the collimating lens 11 is used as in the present embodiment, it can be manufactured with a connection loss of 0.1 dB or less. (1) Irradiation position of CO ₂ laser, (2) Irradiation angle θ of CO ₂ laser beam, (3) Time to irradiate only optical functional element, (4) Time to irradiate both optical functional element and optical fiber simultaneously .

  Another effect of the present invention is improvement in mechanical reliability. The rod lens, which is an optical functional component, is manufactured by cutting the original lens base material into a predetermined length. However, chipping is likely to occur on the end surface of the lens in the cutting process. If there is a chip, the damage may grow from the starting point, leading to destruction of the part. In particular, when fixing is performed using an adhesive having a high hardness after curing, the adhesive is constantly distorted due to the curing shrinkage of the adhesive, and the end face scratches grow, which easily leads to breakage.

  When a collimator lens is manufactured according to the present invention, the end face of the rod lens is melted by heating, and the ridge portion of the end face has a natural curvature due to surface tension. By adjusting the laser irradiation time, chipping at the end is eliminated, and the laser is appropriately rounded. This improves the mechanical reliability.

In order to confirm this, an experiment was conducted in which a collimator having a chipped end and a chipped collimator manufactured according to the present invention were repeatedly placed in liquid nitrogen and repeatedly subjected to distortion caused by a temperature difference. As a result, Table 2 shows the number of times of repeated temperature distortion and the cumulative failure rate. The number of collimators tested was 20 each. As is clear from Table 2, no break occurs when there is no chipping, and the mechanical reliability is very good.

(Modification 1)
FIG. 6 is a diagram showing a manufacturing apparatus and a manufacturing method of an optical fiber with an optical function element according to a second modification of the present invention, and FIG. 7 is an enlarged end view showing an end surface of the optical function element. .

The present modified example is different from the first embodiment in that two laser beams are incident on the collimating lens 11 in the first embodiment, but a plurality of (four) laser beams are used. In that the light is incident. In this realization method, one laser beam emitted from one CO ₂ laser is split into four optical paths by using a half mirror 3, a total reflection mirror 4, and a condenser lens 5 (shown in FIG. 7). The light paths are made to have the same distance, and are simultaneously incident on the end face of the collimator lens 11. Then, the end faces of the four optical fibers 12 are vertically abutted on the irradiation range formed by the irradiation of the four laser beams, and are fusion-spliced.

  FIG. 7 specifically shows a state in which four laser beams are incident on the end face of the collimator lens. At this time, the irradiation of the four laser beams overlaps the bases of the energy distribution so that the energy distribution is uniform over a wide range as described with reference to FIG. The specific superposition is the same as the method described in the first embodiment, that is, the superposition is performed by setting the inclination angles of various mirrors to 25 ° to 70 °.

  By increasing the number of laser beam irradiations in this manner, a uniform irradiation energy distribution can be formed over a wider area on the end face of the collimating lens. Can be simultaneously fusion-spliced.

(Modification 2)
Next, Modification 2 of the optical fiber with an optical function element of the present invention will be described. FIG. 8 is an energy distribution diagram showing the ratio between the amount of laser beam applied to the end face of the optical function element and the amount of laser beam applied to the optical fiber in the method for manufacturing an optical fiber with an optical function element of the present invention.

  As described above, since the optical axis of the laser beam and the central axis of the optical fiber are shifted by the irradiation angle θ1, the amount of the laser beam irradiated on the end face of the optical functional element and the amount of the laser beam irradiated on the end face of the optical fiber Can be changed at an arbitrary ratio such as 2: 8 or 3: 7 as shown in FIG. In this way, it is possible to irradiate a large amount of a laser beam to a hardly meltable optical functional element and irradiate a small amount of a laser beam to an easily meltable optical fiber to melt and connect the two at the same time. .

  A specific realization method is performed by adjusting the total reflection mirror 4 and the condenser lens 5 in the configuration diagram of the manufacturing apparatus 1 shown in FIG. That is, for example, how much the inclination of the total reflection mirror 4 and the condensing lens 5 should be changed in the control unit 9 to change the irradiation angle and the irradiation amount is stored in a database, and the inclination data is read out as needed and read out as a whole. By automatically adjusting the angle change of the reflection mirror 4 and the condensing lens 5, a laser beam is irradiated to the optical function element and the optical fiber at a desired ratio.

  Thus, even if the heat capacity difference (diffusion difference) between the optical function element and the optical fiber is large, the optical function element is irradiated with a laser beam of 80% and the optical fiber is irradiated with a laser beam of 20%. Thereby, both can be melted simultaneously and fusion-spliced.

(Example of use)
FIG. 9 is a diagram showing an example of use of the optical fiber with an optical function element of the present invention. FIG. 10 is a diagram showing another example of use of the optical fiber with an optical function element of the present invention. FIG. 11 is a diagram showing a configuration of an optical fiber with an optical function element when a three-dimensional medium is used as the optical function element.

  First, as shown in FIG. 9, this optical fiber with an optical function element is a so-called optical fiber obtained by fusion-splicing an optical fiber 13 to a gradient index lens 21 as an optical function element by the manufacturing method of the present invention. It is a fiber collimator.

  When light is input from one end of the optical fiber 13 of such an optical fiber collimator, the light spreads in the gradient index lens 21 and finally becomes parallel light and is output from the end of the lens 21. This operation is a general operation, but by using the manufacturing method and the manufacturing apparatus of the present invention, the difference between the outer diameter of the optical fiber 13 and the outer diameter of the gradient index lens 21 is twice or more. Even if there is an opening, there is an effect that both can be reliably fused and connected at a high melting density.

  Similarly, a so-called two-core fiber collimator in which two optical fiber strands 13 and 15 are fusion-spliced to one collimating lens 11 as shown in FIG. 10 via a dielectric multilayer filter. By disposing an optical fiber collimator, two different lights can be split.

  In this case, the propagation action is common as described above, but in the manufacturing method, conventionally, it has not been possible to fusion splice optical components having a difference of 2 times or more in outer diameter and 4 times or more in end area. However, according to the present invention, the two can be reliably fused and connected at a high melting density.

  FIG. 11 shows an example in which a prism is used as a three-dimensional medium. In this case, the input optical fiber 13 is fused to one surface of the prism by the manufacturing method of the present invention, and the output optical fiber 15 is placed at a position where the branched light is output in the prism. Light can be three-dimensionally propagated by laser fusion using the manufacturing method of the present invention.

  Also in the case of this use example, similarly to the above, there is an effect that the fusion splicing can be performed regardless of the outer diameter of the optical fiber and the size of the end area to be fused (here, prism).

It is a figure showing the example of composition of manufacturing device 1 of the optical fiber with an optical functional element concerning a first embodiment of the present invention. It is a schematic structure figure of the optical fiber with an optical functional element of the present invention. It is the end surface enlarged view which expanded the end surface of the optical function element 11 in the fusion | fusion process of the optical fiber with an optical function element. FIG. 3 is a diagram illustrating an energy distribution state of a laser beam on an end face of an optical function element. 5 is a graph showing the relationship between the laser beam irradiation angle and the absorptance of quartz glass. It is a figure which shows the manufacturing apparatus and manufacturing method of the optical fiber with an optical function element concerning the modification 1 of this invention. FIG. 9 is an enlarged end view of the optical function element according to Modification Example 1 when the end face is enlarged. FIG. 11 is an energy distribution diagram showing a ratio of an amount of a laser beam applied to an optical functional element and an optical fiber in a method for manufacturing an optical fiber with an optical functional element according to Modification 2 of the present invention. It is a figure showing the example of use of the optical fiber with an optical functional element of the present invention. It is a figure which shows the other usage example of the optical fiber with an optical function element of this invention. FIG. 3 is a diagram illustrating a configuration of an optical fiber with an optical function element when a three-dimensional medium is used as the optical function element. It is a figure showing the conventional fusion splicing method. It is a figure showing the conventional fusion splicing method. It is a figure showing the conventional fusion splicing method.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Optical fiber manufacturing apparatus 2 ... Laser oscillator 3 ... Half mirror 4 ... Total reflection mirror 5 ... Condensing lens 6 ... Light source 7 ... Movable plate 8 ... Power meter 9 ... Control part 10 ... 2-core optical fiber collimator 11 ... Collimating lens 12, 14 optical fibers 13, 15 optical fiber wires 16 reflector 17 optical function element holder 21 refractive index distribution type lens 101 optical fiber with optical function element 102 rod lens 103 light collecting lens mirror 103a … Through-hole 104… optical fiber 105… laser beam 112… silica-based optical waveguide 114… optical fiber 122… optical functional element 123… electrode rod 124… optical fiber 125… arc discharge

Claims (17)

  The end face of the optical functional element is abutted with the end face of the optical fiber, and at least one or more laser beams are irradiated at a predetermined incident angle to the abutted portion at a predetermined incident angle for a predetermined time to melt the end face of the optical functional element and the end face of the optical fiber. An optical fiber with an optical function element, characterized by being connected.   The end face of the optical functional element is irradiated with at least one or more laser lights at a predetermined incident angle for a predetermined time, and the end face of the optical functional element is further contacted with the end face of the optical fiber after the end face of the optical fiber is brought into contact with the area irradiated with the laser light. An optical fiber with an optical function element, wherein a laser beam is irradiated at a predetermined incident angle on a portion where the end face of the optical fiber is in contact. The incident angle is
The optical fiber with an optical function element according to claim 1, wherein the optical fiber is at least 25 ° and at most 70 °. The irradiation time of the laser light,
The optical fiber with an optical functional element according to claim 1, wherein the optical fiber has a duration of 1 second to 20 seconds.   The position where the laser light is irradiated on the end face of the optical functional element is such that the center of the first laser light is shifted by 10 to 50% from this center point with respect to the center point of the end face of the optical functional element. The laser beam is adjusted so that the center of the second laser beam is located at a position shifted from -10% to -50% from the center point of the optical functional element. 3. The optical fiber with an optical function element according to 1 or 2.   The position where the laser light is irradiated on the end face of the optical function element is such that the center of the first laser light is located at a position shifted by 30% from the center point with respect to the center point of the end face of the optical function element. 3. The light according to claim 1, wherein the laser beam is adjusted so that the center of the second laser beam is located at a position shifted by -30% from the center point of the optical function element. Optical fiber with functional element. The end surface area of the optical functional element,
3. The light according to claim 1, wherein the optical fiber has at least four times the end face area of the optical fiber, and a step of the optical fiber is at least a radius of the optical fiber over the entire circumference of the optical fiber. 4. Optical fiber with functional element.   The optical fiber with an optical function element according to claim 1, wherein, in an outer surface of the optical function element, an outer peripheral ridge of a surface to which the optical fiber is connected is not chipped. A method for manufacturing an optical fiber with an optical functional element by connecting an end face of an optical fiber to an end face of the optical functional element,
A butting step of abutting the end face of the optical functional element and the end face of the optical fiber,
An irradiation step of irradiating at least one or more laser beams at a predetermined incident angle for a predetermined time to a butted portion formed by abutting an end face of the optical functional element and an end face of the optical fiber,
A method for producing an optical fiber with an optical function element, comprising: A method for manufacturing an optical fiber with an optical functional element by connecting an optical fiber end face to an end face of the optical functional element,
A first irradiation step of irradiating at least one or more laser beams to the end face of the optical functional element at a predetermined incident angle for a predetermined time,
After irradiating the laser light for a certain period of time, a butting step of abutting the end face of the optical fiber on the end face of the optical functional element,
After the butting step, a second irradiation step of irradiating at least one or more laser beams at a predetermined incident angle for a certain time to a butted portion of the end face of the optical functional element and the end face of the optical fiber,
A method for producing an optical fiber with an optical function element, comprising: The incident angle in the first and second irradiation steps,
The method for producing an optical fiber with an optical function element according to claim 9, wherein the optical fiber has an angle of 25 ° or more and 70 ° or less. The irradiation time of the laser light,
The method for producing an optical fiber with an optical function element according to claim 9, wherein the time is from 1 second to 20 seconds.   The position where the laser light is irradiated on the end face of the optical function element is such that the center of the first laser light is located at a position shifted by 30% from the center point with respect to the center point of the end face of the optical function element. 11. The light according to claim 9, wherein the laser light is adjusted and the center of the second laser light is adjusted to a position shifted by -30% from the center point of the optical function element. Manufacturing method of optical fiber with functional element. The end surface area of the optical functional element,
The light according to claim 9, wherein the optical fiber has four times or more the end surface area of the optical fiber, and a step of the optical fiber is equal to or more than a radius of the optical fiber over the entire circumference of the optical fiber. Manufacturing method of optical fiber with functional element. An optical fiber-equipped optical fiber manufacturing apparatus for connecting an optical fiber end face to an end face of an optical functional element,
Holding means for holding the optical functional element,
A reflecting plate arranged to cover one end face of the optical function element,
A movable plate movable with the optical fiber placed horizontally,
Movable plate control means for controlling the movement of the movable plate in x, y, and z axis directions;
Laser generating means for outputting melting energy for melting the optical function element and the optical fiber,
Output control means for controlling the output of the laser generation means,
Incident angle control means for performing angle control so that the laser light output from the laser generating means is incident on the end face of the optical functional element at a predetermined incident angle,
A method for manufacturing an optical fiber with an optical function element, comprising: a light condensing element for condensing light onto an optical function part and irradiating light.   16. The method according to claim 15, wherein the light-collecting element is a convex lens.   The method according to claim 15, wherein the light-collecting element is a concave mirror.

Images