The present invention relates to an apparatus for manufacturing a bent optical fiber that includes a bent portion in which bending stress has been decreased and a method for manufacturing the bent optical fiber.
In order to optically connect an electronic substrate and an internal wiring line of a device or an external transmission path to each other, an optical connecting component that includes an embedded optical fiber is used. With the reduction in the sizes of optical modules that are mounted onto electronic substrates, there has been a demand for reduction in the heights of optical fibers that are used in the vicinity of such optical modules. Thus, International Publication No. 2015/076105 discloses a technology for manufacturing a bent optical fiber by radiating an infrared laser beam.
Accordingly, it is an object of the present invention to provide an apparatus for manufacturing a bent optical fiber that includes a bent portion in which bending stress has been decreased and a method for manufacturing the bent optical fiber, the apparatus and the method being capable of reducing the temperature difference between an irradiated surface of an optical fiber that is to be irradiated with an infrared laser beam and a rear surface of the optical fiber that is opposite to the irradiated surface when causing the optical fiber to have a bent portion by using the infrared laser beam and the temperature difference between, among a plurality of optical fibers that are arranged side by side, the optical fiber positioned in the middle and the optical fibers positioned at the both sides when causing each of the plurality of optical fibers to have a bent portion.
A manufacturing apparatus according to the present invention for manufacturing a bent optical fiber that includes a bent portion in which bending stress has been decreased includes a bending formation mechanism, a fiber feeding mechanism, a light-source mechanism, and a rear reflective member. The bending formation mechanism holds an optical fiber and forms the bent portion. The fiber feeding mechanism feeds the optical fiber toward the bending formation mechanism. The light-source mechanism includes a light source and emits a laser beam to a portion of the whole periphery of the optical fiber. The rear reflective member is disposed at a position facing the light source across the optical fiber, which is fed toward the bending formation mechanism.
The manufacturing apparatus according to the present invention may further include a side reflective member that is disposed at a position facing an outer peripheral side surface of the optical fiber, which is sent out. The optical fiber, which is sent out, may be included in a plurality of the optical fibers arranged side by side, and the manufacturing apparatus according to the present invention may include the side reflective member provided between adjacent ones of the plurality of optical fibers. The light-source mechanism may include a laser-scanning unit that causes the laser beam to scan in a direction crossing a direction in which the optical fiber is sent out.
A method according to the present invention for manufacturing a bent optical fiber that includes a bent portion in which bending stress has been decreased includes forming a bent portion by causing stress to be generated in an optical fiber that has been sent out in a predetermined direction and emitting a laser beam from a light source that is disposed at a predetermined position toward a position at which the stress is generated in the optical fiber. Some of the laser beam emitted by the light source is reflected by a reflective member that is disposed in the vicinity of the optical fiber, which is sent out, and is oriented toward the optical fiber.
According to the apparatus and the method for the present invention for manufacturing a bent optical fiber that includes a bent portion in which bending stress has been decreased, the possibility of variations occurring in the quality of a bent optical fiber can be reduced.
A preferred embodiment of an apparatus according to the present invention for manufacturing a bent optical fiber and a preferred embodiment of a method according to the present invention for manufacturing a bent optical fiber will be described below with reference to the accompanying drawings.
When an optical fiber is bent by using an infrared laser beam, it is desired to make the temperature distribution between an irradiated surface of the optical fiber that is irradiated with the laser beam and a rear surface of the optical fiber that is opposite to the irradiated surface uniform. More specifically, silica glass included in an optical fiber has a transmittance of 1% or lower in the mid-infrared region (2.5 μm to 4.0 μm) and in the far-infrared region (4 μm to 1,000 μm). In other words, most of the laser beam is absorbed by the irradiated surface, and the laser beam is unlikely to reach the rear surface (the surface on the side on which shadow is generated), which is opposite to the irradiated surface. Thus, a temperature gradient occurs in which the temperature decreases from the irradiated surface toward the rear surface. Consequently, there is a case where the irradiated surface becomes softer than the rear surface and is stretched, which in turn results in a reduction in the diameter of the optical fiber. There is another case where, when the temperature of the rear surface becomes lower than the temperature of the irradiated surface, and the rear surface does not bend at a constant curvature or deformation occurs in the rear surface, this causes a bending failure and a loss increase.
In order to densely mount electronic components that are used for optical communication, there is an optical connecting component in which a plurality of bent optical fibers are arranged side by side (also called a fiber array). In this case, when an infrared laser beam is radiated onto the component, the optical fiber that is positioned in the middle receives radiant heat from the adjacent optical fibers as well as the laser beam. In contrast, the optical fibers that are positioned at the both sides are less likely to receive radiant heat from the adjacent optical fibers. Thus, a temperature gradient occurs in which the temperature decreases from the optical fiber positioned in the middle toward the optical fibers positioned at the both sides. It is desired to make the temperature distribution between the optical fiber positioned in the middle and the optical fibers positioned at the both sides uniform.
The work stage 10 includes a base 11 having a flat plate-like shape, a holder 12, and a support 13. The fiber feeding mechanism 20 is mounted on the holder 12, and the bending formation mechanism 30, the light-source mechanism 40, and the rear reflective member 50 are mounted on the support 13. The support 13 is fixed to the base 11, whereas the holder 12 is capable of moving with respect to the base 11. More specifically, the holder 12 and the support 13 are connected to each other by a rail 14 extending in the X-axis direction in
The fiber anchoring component 21 includes a V-grooved substrate 22 and a lid 24, and the V-grooved substrate 22 is placed on the holder 12 in a state where V-grooves 23 are open upward (in the positive Z-axis-direction in
The lid 24 is formed in a flat plate-like shape and covers the V-grooves 23 so as to restrict upward movement of the optical fibers F. The fiber anchoring component 21 holding the trailing ends of the optical fibers F is fixed to the holder 12 with a fixing jig 25. Each of the optical fibers F is made of silica-based glass and includes a core and a clad, and for example, four optical fibers F each extending in the X-axis direction in
Note that each of the optical fibers F may be a single-core optical fiber that includes a single core or may be a multicore optical fiber that includes a plurality of cores. In addition, in the present embodiment, although a case has been described in which the four optical fibers F are arranged in the Y-axis direction, for example, one optical fiber F may be fed toward the bending formation mechanism 30.
The rotary shaft 32 is integrally formed with a support plate 33 that has a circular shape, and a pair of bending levers 34 and 35 are fixed to the support plate 33. More specifically, the bending levers 34 and 35 are each formed in, for example, a round bar-like shape and arranged on a surface of the support plate 33 so as to extend in the Y-axis direction in
As illustrated in
In contrast, the rear reflective member 50 is disposed at a position facing the light source 41 with the optical fibers F interposed therebetween. This enables the rear reflective member 50 to reflect some of the laser beam emitted by the light source 41 and to cause the reflected laser beam to be oriented toward the rear surfaces of the optical fibers F. Note that it is preferable that the rear reflective member 50 be made of a material (e.g., gold, silver, or aluminum) that has excellent durability and high reflectivity with respect to the wavelength of a laser beam in the near-infrared region. In addition, it is preferable that a surface of the rear reflective member 50 be rough and have a shape capable of realizing diffuse reflection, or it is preferable that the surface of the rear reflective member 50 be a mirror and have a shape capable of realizing specular reflection.
The control unit 60 includes a central processing unit (CPU), memory, and so forth, and can output signals to the driving unit 15, the motor 31, and the light-source mechanism 40 by loading various programs and data stored in, for example, read only memory (ROM), which is included in the memory, into random access memory (RAM) and executing the various programs, so as to control the operation of the manufacturing apparatus 1.
Portions of the optical fibers F are sandwiched between the bending lever 34 and the bending lever 35, and the motor 31 is caused to rotate in the direction of arrow M1 in
Accordingly, when the fiber anchoring component 21 is moved by a certain distance in the direction of arrow M2 in
More specifically, as illustrated in
As described above, since the laser beam from the light-source mechanism 40 is radiated onto the optical fibers F that are sent out and is also reflected by the rear reflective member 50 so as to be radiated onto the rear surfaces of the optical fibers F (the surfaces on the side on which shadow is generated when viewed from the light source 41), when the bent portions are formed by using a laser beam in the near-infrared region, the temperature distribution between the irradiated surfaces and the rear surfaces is uniform. As a result, the possibility of variations occurring in the quality of a bent optical fiber can be reduced.
In addition, by causing the laser beam to scan in the direction in which the optical fibers F are arranged, an irradiation range of the laser beam can be expanded. In particular, even in the case where the optical fibers F are sent out in the form of a fiber array, the temperature distribution between the optical fiber F that is positioned in the middle and the optical fibers F that are positioned at the both sides can be made uniform.
In the first to fourth embodiments, a case has been described as an example in which the light-source mechanism 40 is provided at the upper portion of the support 13 and in which the rear reflective member 50 is provided below the optical fibers F. However, the light-source mechanism 40 may be provided below the optical fibers F, and the rear reflective member 50 may be provided at an upper portion of the support 13. In this case, if the optical fibers F are sandwiched between the bending levers 34 and 35, the motor 31 is caused to rotate in a direction opposite to the direction of arrow M1 in
The embodiments disclosed herein are examples in all respects, and the present invention is not to be considered limited to the embodiments. The scope of the present invention is to be determined not by the above-described meanings, but by the claims, and it is intended that meanings equal to the claims and all the modifications within the scope of the claims are included in the scope of the present invention.
Number | Date | Country | Kind |
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2017-119451 | Jun 2017 | JP | national |