JP2005148180A - Optical power monitor, method of manufacturing same and analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical power monitor having small number of components, comparatively easily manufactured and to obtain an analyzer using the monitor. <P>SOLUTION: The cores of an input side optical fiber 204 and an output side optical fiber are fused by being dislocated in the optical power monitor 201, and the whole optical fibers are fixed on a base 203 forming a curve. A lens 207 composed of an adhesive is arranged at a position which is slightly separated from a fused position 206 toward the output side and a light receiving element 208 is arranged at the focal point of the lens. The light receiving element 208 detects light leaked from the fused position 206. The lens 207 can be dispensed of. Further, the analyzing device can be manufactured by using the light detected with the optical power monitor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical power monitor for monitoring the power of light transmitted through an optical fiber, a method for manufacturing the same, and an analyzer using the same.

  With the development of communication networks such as the Internet, relatively large-capacity data communication using optical fibers has been actively performed. In a communication network using an optical fiber, light transmitted through the optical fiber is attenuated with a transmission distance. Therefore, it is necessary for the relay device or the like to detect the power and adjust the signal level.

  Conventionally, several types of optical power monitors have been proposed. Among these, the 1st proposal uses a collimator lens and a filter (for example, refer patent document 1).

  FIG. 15 shows an outline of the configuration of the optical power monitor according to the first proposal. A first collimator lens 102 is disposed at the end of the first optical fiber 101 on which light for monitoring optical power is incident, and parallel light 103 is emitted therefrom. The parallel light 103 is incident on a thin film optical filter 104 that transmits a part of the incident light and reflects the rest, and most of the light is reflected by the filter surface. The reflected light 105 enters the second collimator lens 106 and is optically coupled to the second optical fiber 107. The light 108 that has passed through the optical filter 104 enters a light receiving element 109 such as a photodiode, and the optical power is monitored.

  FIG. 16 shows an outline of an optical power monitor as a second proposal in which a part of the core of the optical fiber is exposed and light leaking from the core is received as monitor light. In the second proposal, an extinction wave leaking from the stripped portion of the clad 112 present in the peripheral portion of the optical fiber 111 and a slight surface portion of the core 113 present in the central portion is locally stripped off. The (evanescent wave) 114 is directly guided to the light receiving element 115.

  FIG. 17 shows a third proposal (see, for example, Patent Document 2) for monitoring an optical signal by inserting a filter into a waveguide. In the third proposal, a single waveguide 124 is formed on a silicon substrate 123 in which an input side optical fiber 121 and an output side optical fiber 122 are connected to both ends, and this is cut in the middle. A groove is cut. In this groove, an optical filter 125 such as a thin film filter is inserted. The optical filter 125 has a characteristic of partially reflecting incident light and transmitting the remaining light. A waveguide 126 is also formed in the direction in which the light is reflected by the optical filter 125, and the reflected light is received by the light receiving element 127 disposed on the side of the silicon substrate 123. In addition to using the waveguides 124 and 126 as described above, there is also a method of inserting an optical filter such as a thin film filter by directly cutting the middle of a fixed optical fiber or fiber array.

JP 08-248275 A (paragraph 0012, FIG. 1) JP 2003-255167 A (paragraph 0036, FIG. 1)

  Among these, in the case of the optical power monitor according to the first proposal shown in FIG. 15, two collimator lenses 102 and 106 and an optical filter 104 are required in addition to the light receiving element 109. Therefore, the number of parts of the device increases. Further, it is necessary to set the incident angle and the reflection angle of the first and second collimator lenses 102 and 106 with respect to the optical filter 104 with high accuracy and to accurately maintain the positional relationship between these components. For this reason, there is a problem that it is difficult to reduce the size of the device as the optical power monitor, and alignment on the order of submicron is required, which makes it difficult to reduce the manufacturing cost. Furthermore, in this first proposal, all the light is once extracted from the first optical fiber 101, a part of it passes through the optical filter 104, and the rest passes through the second collimator lens 106 again. It is configured to be returned to the optical fiber 107. For this reason, the uncertainty that the main signal passes through the optical filter 104 and is not returned to the second optical fiber 107 cannot be eliminated. That is, there is a concern about the reliability of signal transmission that the main signal is reliably transmitted to the target location. Furthermore, there is a problem that the optical filter 104 must be prepared for each branching ratio of light passing through the optical filter 104 and reflected light.

  On the other hand, the second proposal shown in FIG. 16 does not require the collimator lenses 102 and 106 as compared with the first proposal. Further, by arranging the light receiving element 115 in the vicinity of a portion where a part of the optical fiber 111 is peeled off, a condensing lens can be omitted. For this reason, compared with the 1st proposal shown in FIG. 15, the number of parts can be reduced significantly. However, in order to obtain a product with uniform characteristics as an optical power monitor, accuracy and labor are required for the process of stripping part of the cladding 112 and the core 113. That is, while checking the light receiving state in a state where the light receiving element 115 is actually attached to the optical fiber 111, adjustment is performed so that desired leaked light can be detected by repeating the work of scraping the fiber little by little on the order of submicrons. There is a need. When the polishing is small, light hardly leaks out, and when the core is polished even a little, most of the light leaks out. For this reason, the yield of the product is poor due to the difficulty of adjustment, and time is required for the work, so the manufacturing cost of the optical power monitor itself cannot be reduced. Further, since a part of the optical fiber 111 is cut, there is a problem that it is difficult to maintain mechanical strength at this part and it is difficult to manufacture a product that is resistant to impact. Further, since light leaking from the stripped portion diffuses, a light receiving element 115 for receiving the light is required to have a large light receiving diameter, and the dark current increases accordingly. Therefore, a sufficient dynamic range as a monitor output cannot be taken.

  In the last third proposal shown in FIG. 17, the connection loss between the fiber arrays becomes large, and a low loss power monitor with a low branching ratio cannot be realized. In addition, when adopting a method of directly cutting an optical fiber and inserting an optical filter, if the number of optical fibers to be processed at the same time is small and the multi-channel is not supported, the manufacturing unit price per optical fiber is There is a problem of becoming higher. On the other hand, the variation in insertion loss due to misalignment increases as the number of optical fibers constituting the fiber array increases as the number of channels increases. Also in this third proposal, it is necessary to prepare an optical filter for each light branching ratio.

  In addition to the above proposals, a fourth proposal for bending an optical fiber and condensing an optical signal leaking from this portion has also been made. However, the optical fiber is designed for the core and the clad so that the proportion of light leaking from the core is essentially reduced. For this reason, it is difficult to secure the amount of light necessary for the monitor even if the optical fiber is bent and a condensing lens is arranged at that portion to collect the leaked light.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical power monitor having a small number of parts and relatively easy to manufacture, a method for manufacturing the same, and an analyzer using the same.

  According to the first aspect of the present invention, (a) an off-axis fused fiber obtained by fusing light-transmitting cores in an off-axis state, and (b) a fiber as leakage light from the fusion position of the off-axis fused fiber. The optical power monitor is provided with a light-receiving element for monitoring that receives light emitted outside.

  That is, in the first aspect of the present invention, the cores of the optical fibers are fused in an off-axis state, and light leaking out of the optical fiber from the fused portion through the clad is received by the light receiving element. The optical power propagating through the core is monitored. When connecting optical fibers, it is normal to prevent misalignment between the cores, but a method opposite to this is used to cause misalignment, and the light receiving element receives the leaked light. With the idea of reversal, optical power monitoring is realized.

  In the invention described in claim 2, (a) an off-axis fused fiber obtained by fusing light-transmitting cores in an off-axis state, and (b) a predetermined curved shape, and the off-axis fused fiber. By arranging along the curved shape, a fused part holding member that holds the fused position of the fused fiber and its periphery bent, and (c) leakage light from the fused position of the off-axis fused fiber. An optical power monitor is provided with a light receiving element for monitoring that receives light emitted from the fiber.

  That is, in the invention described in claim 2, the cores of the optical fibers are fused in an off-axis state, and light leaking out of the optical fiber from the fused portion through the cladding is received by the light receiving element. The optical power propagating through the core is monitored. According to the second aspect of the present invention, the leakage light is increased and the collection is facilitated by holding the fused portion and the periphery thereof in a bent state.

  In the invention according to claim 3, by disposing a condensing lens between the fused position of the fused fiber and the light receiving element, even when the aperture of the light receiving element is small, leaked light is efficiently received. I am doing so.

  According to the fourth aspect of the present invention, the optical power in the selected wavelength range can be monitored by disposing a wavelength selection filter between the light receiving element and the lens.

  In the invention described in claim 5, the condensing lens is formed by hanging a predetermined amount of adhesive on the surface of the off-axis fused fiber. The condensing lens may be obtained by processing ordinary glass. However, if the lens has a small size, it can be easily and inexpensively manufactured with an adhesive.

  In the invention of claim 6, it is indicated that the light receiving surface of the light receiving element may be disposed opposite to the fiber surface without using a lens. At this time, by filling a material having a refractive index higher than that of the clad of the off-axis fused fiber between the light receiving surface and the fiber surface, leaked light can be efficiently collected on the light receiving surface.

  In the invention of claim 7, a glass plate is disposed opposite to the off-axis fused fiber, and a glass having a higher refractive index than that of the clad of the off-axis fused fiber is filled between the fiber surface and the glass plate. Leakage light can be efficiently collected on the light receiving element via the plate. It is free to arrange a lens between the glass plate and the light receiving element as necessary.

  In the invention described in claim 8, since the optical fiber can propagate light in both directions, when monitoring the light propagating in both directions, the light receiving element and the condensing lens are symmetrically positioned around the fusion position. It can be arranged.

  In the invention according to claim 9, (a) a first step of melting and fusing the ends of the two optical fibers by discharge heating in a state where the cores at the ends of the two optical fibers are shifted from each other; (B) a second step of bending and fixing the periphery of the fused portion of the optical fiber fused in the first step; and (c) the vicinity of the fused portion of the optical fiber bent in the second step. In step (3), a lens is formed by solidifying an adhesive at a predetermined part where light emitted from the fiber as leakage light from the fused portion travels, and (d) light reception for monitoring at the condensing position of the lens. And a fourth step of arranging the elements in the optical power monitor manufacturing method.

  That is, in the invention according to claim 9, in the first step, the ends of the two optical fibers are melted and fused by discharge heating in a state where the cores of the ends of the two optical fibers are shifted from each other. In step 2, leakage light is easily emitted by bending and fixing the periphery of the fused portion. Then, in the third step, a lens is made with an adhesive at a position where leakage light proceeds, and in the fourth step, a light receiving element is arranged at the condensing position of the lens. Thus, the monitor of the optical power propagating through the optical fiber can be manufactured by a simple process.

  In the invention described in claim 10, (a) an off-axis fused fiber in which the cores through which light propagates are fused in an off-axis state, and (b) a predetermined off-axis fused fiber, By arranging along the curved shape, the fused position holding member that holds the fused position of the fused fiber and its periphery in a bent state, and (c) placed on the surface portion near the fused position of the fused fiber And (d) a lens that enters light that has exited from the fiber as leakage light and transmitted through the sample arrangement area, and (e) a monitor that is disposed at the condensing position of the lens. And an analysis means for analyzing the sample using the light receiving output of the light receiving element.

  That is, in the invention described in claim 10, the sample placed in the sample placement region can be analyzed by analyzing the output of the optical power monitor by the analyzing means. Thereby, an inexpensive and small-sized analyzer can be manufactured.

  As described above, according to the present invention, leakage light is emitted from the fused portion by a simple technique of fusing the core at the connection location of the optical fiber, and the optical power is monitored using the optical lens. Therefore, a very inexpensive and small optical power monitor can be manufactured, and an analysis apparatus using this can be reduced in size and cost. Further, by placing the fused portion and the periphery thereof in a bent state, the amount of light leakage can be increased and the S / N ratio can be improved. Furthermore, since the amount of leaked light can be adjusted only by adjusting the amount of axial deviation, no special parts for taking an arbitrary branching ratio are required. Further, if the condensing lens is made of an adhesive, not only will the cost be reduced, but the manufacturing process will be simplified, and no lens ordering or inventory management will be required. Furthermore, in the present invention, only the main signal does not branch and become monitor light. Therefore, the monitor light can be detected with high reliability. Further, since the optical power monitor itself can be made very small, a light receiving element can be used in a small size, the light receiving tolerance is increased, and the yield in manufacturing the optical power monitor is improved.

  Hereinafter, the present invention will be described in detail with reference to examples.

  FIG. 1 shows a sectional structure of an optical power monitor in the first embodiment of the present invention. In the optical power monitor 201, a plastic base 203 having a convex center and raised at a predetermined bending radius is fitted into the bottom of a rectangular parallelepiped or cylindrical case 202. Further, UV (ultra violet) -coated single-mode optical fibers (hereinafter simply referred to as optical fibers) 204 and 205 are attached to the left and right side wall portions 202A and 202B in the figure. 206 is inserted through the center of the case 202. The fusion positions 206 of the optical fibers 204 and 205 and the vicinity thereof are bare optical fibers 204A and 205A from which the UV coating has been removed, and are fixed in a curved state along the bending radius of the pedestal 203. A lens 207 obtained by dropping a predetermined amount of a transparent adhesive is attached to the bare optical fiber 205A immediately adjacent to the fusion position 206. A light receiving element 208 made of a photodiode is fixed between the lens 207 and the side wall 202B. The light leaking from the fusion position 206 is collected by the lens 207, enters the light receiving element 208, and is photoelectrically converted. Lead wires 211 and 212 of the light receiving element 208 are drawn out from the side wall portion 202B. From these lead wires 211 and 212, monitoring results of the optical power propagating through the optical fibers 204 and 205 are output.

  In this embodiment, the distances from the side wall portions 202A and 202B of the case to the fusion positions 206 of the optical fibers 204 and 205 are about 5 mm (millimeters), respectively. The lens 207 is a sphere having a diameter of 1 mm or slightly smaller than this. In this embodiment, the lens 207 is formed by directly hanging the adhesive on the bare optical fiber 205A. The light receiving element 208 is an element having a light receiving area of 0.3 mm in diameter. The bending radius around the fusion position 206 in the pedestal 203 was 30 mm to 15 mm.

  FIG. 2 is an enlarged view of the periphery of the fusion position. The two bare optical fibers 204A and 205A are connected at the fusion position 206 by melting the optical fiber surfaces by heat generated by air discharge in a state where the axes of the cores 204C and 205C are shifted. When fusion is performed in a state where the axes of the bare optical fibers 204A and 205A are shifted by the gap ΔG, the end surfaces of the cores 204C and 205C are melted so as to be attracted to each other, and this portion becomes an inclined connection portion 221. Unlike the present embodiment, when the cores 204C and 205C are fused without intentionally generating the gap ΔG, the cores 204C and 205C are aligned with each other on the submicron order, and no connection loss occurs.

  However, if the inclined connecting portion 221 is formed by the gap ΔG by shifting the central axes of the cores 204C and 205C by about 2.5 μm (microns) as in the present embodiment, the light path rapidly changes in this portion. Then, a connection loss occurs, and leaked light 222 corresponding to the gap ΔG is generated. The amount of leakage light 222 is generally proportional to the square of the gap ΔG. The gap ΔG is adjusted by adjusting the shift amount of these V grooves when the two bare optical fibers 204A and 205A are fixed by fixing means such as a V groove (not shown) and their end faces are opposed to each other. Can be adjusted easily. The leaked light 222 spreads in the clad 205D and is emitted out of the bare optical fiber 205A.

  In this figure, light is propagated from the core 204C to the core 205C. Contrary to this, even when light propagates from the core 205C to the core 204C, if the light receiving element is disposed above the bare optical fiber 204A, the light receiving element in FIG. 1 propagates from the core 204C to the core 205C. The monitor light can be detected with the same efficiency as the 208 arrangement. However, the polarization dependency of the light receiving sensitivity is better in the case of the arrangement configuration of the light receiving elements 208 shown in FIG. 1 when light is propagated from the core 204C to the core 205C.

  FIG. 3 shows the relationship between the light leaking from the bare optical fiber and the lens. The two bare optical fibers 204 </ b> A and 205 </ b> A are bent along the curve of the pedestal 203. For this reason, the leaked light 222 emitted from the inclined coupling portion 221 of the bare optical fibers 204A and 205A is incident on the transparent lens 207 that is dropped onto the neighboring bare optical fiber 205A and solidified into a spherical shape. As a result, the leaked light 222 to be diffused enters the light receiving element 208 shown in FIG. 1 as convergent light. The light receiving element 208 shown in FIG. 1 has a configuration in which a condensing lens 207 is disposed in front of the light receiving element 208, but the light receiving element in which the lens 207 is omitted and only a photodiode is disposed may be used. .

  FIG. 4 shows an outline of a manufacturing method of the optical power monitor of this embodiment. First, two optical fibers 204 and 205 having a predetermined length are prepared, one end of each is connected to an optical fiber fusion splicer (not shown), and these ends are connected by discharge fusion (step S301). . Various types of optical fiber fusion splicers are commercially available, but in order to manufacture the optical power monitor of this embodiment, as described above, the positions of the optical fibers 204 and 205 are not fixed. A V-groove with a slightly shifted position according to the amount of leakage light is used.

  When the two optical fibers 204 and 205 are fused in this way, they are set in the case 202 shown in FIG. A pedestal 203 is fitted into the bottom of the case 202. Therefore, it arrange | positions so that the fusion | fusion position 206 may be located in the center of the protrusion, and bear optical fiber 204A, 205A is fixed along the surface of the base 203 (step S302). Next, from the upper side of the case 202, a predetermined amount of a predetermined adhesive that maintains a transparent state when solidified is determined by a predetermined amount on the bare optical fiber 205A separated from the fusion position 206 by 1.5 to 2.5 mm. Hang in position. Thereby, the lens 207 is created on the bare optical fiber 205A (step S303).

  Next, the light receiving element 208 is positioned and fixed on the side wall 202B and the pedestal 203 of the case 202 while confirming the monitor output in a state where the test light is propagated to the two optical fibers 204 and 205 ( Step S304). Of course, when the direction of light reception is not particularly problematic, the light receiving element 208 may be attached at a predetermined position without optical adjustment. In this case, the light receiving element 208 may be attached before the time in step S303.

  When the above operation is completed, the cover 202C of the case 202 shown in FIG. 1 is attached and sealed (step S305). Finally, a connector (not shown) is connected to the input or output end (not shown) of the two optical fibers 204 and 205 (step S306), and the manufacture of the optical power monitor 201 is completed. The connection of the connector can also be performed in a previous work process. The optical power monitor 201 manufactured in this way is monitored by being connected to an optical fiber (not shown) at a location to be monitored by a connector.

  In the optical power monitor 201 of the present embodiment described above, when the two optical fibers 204 and 205 are fused, the gap ΔG shown in FIG. 2 is 2.5 μm and the insertion loss is 0.9 dB (decibel). Further, 100 μA / mW was obtained as the light receiving sensitivity of the light receiving element 208. Thereby, the optical power propagating through the optical fibers 204 and 205 can be monitored at a sufficient level. It should be noted that the same effect can be obtained even if the lens 207 made of an adhesive is replaced with an optical lens such as glass.

  <First Modification of First Embodiment>

  FIG. 5 shows the main part of a first modification of the optical power monitor of the first embodiment. In the optical power monitor 201A of the first modified example, when the light 223 transmitted from the one core 204C side toward the other core 205C is output as the leaked light 222 at the inclined connection portion 221, the light receiving element 208 directly receives this. Are arranged to be. If the light receiving element 208 can be arranged in the direction of the leaked light 222 in this way, the arrangement of the lens 207 in the previous embodiment can be omitted.

  A specific example is given. Two optical fibers 204 and 205 were fused to obtain a gap ΔG shown in FIG. 2 of 2.5 μm and an insertion loss of 0.8 dB. A light receiving element 208 made of a photodiode chip was fixed on the upper side of the bare optical fiber 205A so that its light receiving surface was substantially perpendicular to the axial direction. In this example, a light receiving sensitivity of 5 μA / mW could be obtained as the maximum light receiving level when the light receiving element 208 was 2 to 3 mm away from the fusion position 206. Although the light reception level is lower than in the previous embodiment, it is possible to monitor the optical power in the optical fibers 204 and 205.

  <Second Modification of First Embodiment>

  FIG. 6 shows the main part of a second modification of the optical power monitor of the first embodiment. In FIG. 6, the same parts as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the optical power monitor 201B of the second modified example, the leakage light 222 leaking from the inclined connection portion 221 to the clad 205D is diffused and emitted from the wide range of the outer surface of the clad 205D to the outside of the bare optical fiber 205A. It is assumed that there is. A transparent adhesive 231 having a refractive index higher than that of the clad 205D is used over almost the entire area where the leaked light 222 is output on the surface of the bare optical fiber 205A that is a predetermined distance away from the inclined connection portion 221. A bottom portion 232A of a rectangular parallelepiped glass substrate 232 having an equal or higher refractive index is bonded. Thereby, the leaked light 222 leaking from the upper part in the figure of the clad 205D is guided into the adhesive 231 and the glass substrate 232 having a higher refractive index.

  As an example, an optical fiber having a gap ΔG as an axis deviation amount of 2.5 μm and an insertion loss of 0.8 dB as in the first modification is prepared, and an adhesive 231 is formed. Using a UV curable adhesive having a refractive index of 1.52, light was guided to a glass substrate 232 having a width and height of 0.5 mm, a length of 1 mm and a refractive index of 1.57. When the light emitted from the glass substrate 232 was received by a light receiving element 208 made of a photodiode having a light receiving surface with a diameter of 0.3 mm, a light receiving sensitivity of 10 μA / mW could be obtained. Although the light receiving sensitivity is not large, the optical power propagating in the optical fiber can be monitored as an optical power monitor.

  In this modification, the glass substrate 232 has a rectangular parallelepiped shape, but the surface facing the light receiving element may be curved into a convex lens shape to provide a light collecting effect. By making the end surface convex in this way, it is possible to improve the light receiving sensitivity, for example, 30 μA / mW, which is several times that of the planar shape. In addition, the aperture of the light receiving element can be reduced.

  <Third Modification of First Embodiment>

  FIG. 7 shows the main part of a third modification of the optical power monitor of the first embodiment. In FIG. 7, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the optical power monitor 201C of the third modified example, light of the bare optical fibers 204A and 205A arranged along the curve on the plastic base 203 shown in FIG. 1 is emitted from the upper side. The light receiving element 208 is bonded onto the bare optical fiber 205 </ b> A with an adhesive 231 with the light receiving surface facing down. The adhesive 231 is a UV curable adhesive having a refractive index larger than that of a clad (not shown), and the light receiving element 208 has a light receiving surface for efficiently receiving light emitted from the clad (not shown) into the adhesive 231. Is fixed in a slightly inclined state.

  A specific example is given. Two optical fibers 204 and 205 were fused to obtain a gap ΔG shown in FIG. 2 of 2.5 μm and an insertion loss of 0.8 dB. It was possible to obtain a light receiving sensitivity of 80 μA / mW as the maximum light receiving level at a place where the light receiving element 208 made of a photodiode chip having a diameter of 0.3 mm was 2 to 3 mm away from the fusion position 206. Similar to the previous embodiment, the optical power in the optical fibers 204 and 205 can be monitored at a sufficient level.

  <Fourth Modification of First Embodiment>

  FIG. 8 shows the main part of a fourth modification of the optical power monitor of the present embodiment. In FIG. 8, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the optical power monitor 201D of the fourth modified example, the optical power monitor 201 shown in FIG. 1 has a lens 207 and a light receiving element 208 corresponding to the lens 207 arranged on the right side in the figure of the fusion position 206. On the other hand, the lens 247 and the light receiving element 248 corresponding to the lens 247 are similarly arranged on the left side. This is because two sets of light receiving elements 208 and 248 are provided so that the light propagating in both directions in the optical fibers 204 and 205 can be monitored. Light propagating from the optical fiber 204 toward the optical fiber 205 is received by the light receiving element 208.

  <Fifth Modification of First Embodiment>

  FIG. 9 shows an outline of a fifth modification of the optical power monitor of the first embodiment. 9, the same parts as those in FIGS. 1 and 8 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In the optical power monitor 201E of the fifth modified example, two side guides 251 and 252 are used in place of the convex base 203 of the previous embodiment shown in FIG. 1, and the UV coating is removed. The bare optical fibers 204A and 205A are shaped into an S shape along these side surfaces. If the two side guides 251 and 252 are materials that do not transmit light, they can also serve to prevent light propagating in other directions from being mixed as monitor light.

  According to the optical power monitor 201E of the fifth modification example, two sets of light receiving elements as shown in FIG. 8 in relation to the polarization dependence of the light receiving sensitivity of the leaked light with respect to the light traveling direction at the fusion position 206. If it is preferable not to place 208 and 248 together on the same side (the upper side of the optical fibers 204 and 205 in FIG. 8), these are arranged at positions symmetrical with respect to the fusion position 206. There is an advantage that you can.

  <Sixth Modification of First Embodiment>

  FIG. 10 shows an outline of a sixth modification of the optical power monitor of the first embodiment. In FIG. 10, the same parts as those in FIGS. 1 and 8 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In the optical power monitor 201F of the sixth modification, a filter 261 for selecting a wavelength is disposed between the lens 207 and the light receiving element 208. For this reason, the light receiving element 208 can detect leakage light for a specific wavelength component in light output from a light source (not shown).

  FIG. 11 shows an outline of the configuration of the gas analyzer according to the second embodiment of the present invention. The gas analyzer 400 of the second embodiment includes a light source 401, an optical power monitor 403 that inputs light output from the light source 401 through an optical fiber 402, a monitor output 404 and an optical power monitor 403 of the optical power monitor 403. The detection result display unit 406 is configured to input light transmitted from the optical fiber 205 through the optical fiber 205. A control signal line 407 is connected between the light source 401 and the detection result display unit 406 to turn on / off the light source 401 and to instruct an output wavelength.

  FIG. 12 shows an outline of the configuration of the optical power monitor. The structure of the optical power monitor 403 is basically the same as that of the optical power monitor 201 of the first embodiment shown in FIG. Therefore, in FIG. 12, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  FIG. 1 shows a state where the case 202 is cut in the vertical direction, but FIG. 12 shows a state where the case 411 is cut in the horizontal direction. The only difference between the optical power monitor 403 of the second embodiment and the optical power monitor 201 of the first embodiment is that the first tube 412 that feeds a sample gas into the case 411 of the optical power monitor 403 only. The second tube 413 is provided only for discharging the fed sample to the outside. The degree of attenuation of light reaching the light receiving element 208 is determined by sending a sample to be measured from the first tube 412 and changing the wavelength of light output from the light source 401 shown in FIG. Analysis of various components contained in the sample and measurement of concentration are performed. Examples of applications include the detection of the concentration of city gas at a location where gas leakage is detected and the measurement of gas components with respect to biological discharges incorporated in the toilet seat.

  FIG. 13 shows an outline of the detection result display unit. The detection result display unit 406 includes an optical fiber light receiving unit 421 that receives the optical power transmitted by the optical fiber 205, and inputs the detected light reception level 422 to the attenuation factor calculation unit 423. The monitor output 404 is also input to the attenuation factor calculation unit 423, and the optical power attenuation factor is calculated with respect to the current monitor output 404 with reference to the light reception level 422. That is, in the optical power monitor 403 shown in FIG. 12, the ratio of the light receiving level of the light receiving element 208 to the optical power input by the optical fiber 204 when the case 411 is in a vacuum state is measured in advance. Is remembered. Then, the actual level of the optical power output from the light source 401 (FIG. 11) is measured as the received light level 422, and the signal level to be detected by the light receiving element 208 in the corresponding vacuum state is compared with the actual measured level. Thus, the attenuation rate is calculated.

  Of course, in order to prevent measurement errors due to aging of the light receiving element 208, dirt on the lens 207, etc., the ratio of the light receiving level of the light receiving element 208 to the light power described above needs to be measured again. Further, when the ratio of the light receiving level of the light receiving element 208 to the light power is different depending on the wavelength of the light source 401, it is necessary to store the value for each wavelength in the attenuation factor calculation unit 423.

  The attenuation rate 424 measured by the attenuation rate calculation unit 423 is stored in the measurement result storage unit 425. The analysis unit 426 reads out the measurement result 427 stored in the measurement result storage unit 425 by specifying various wavelengths output from the light source 401 as required by the control signal line 407. Then, the sample existing in the case 411 shown in FIG. 12 is analyzed with reference to the data such as the attenuation rate with respect to the wavelength for each sample stored in the database 428 as the reference data 429. The analysis result 430 representing the name and concentration of the sample is sent to the display unit 431 and displayed. The display is displayed on a monitor such as a liquid crystal display (not shown) or printed out by a printer.

  In the case of measuring the gas leak of the city gas described above, the concentration of the leaked gas is displayed. When the gas concentration is higher than a predetermined value, an alarm device (not shown) can be activated based on the analysis result 430 of the analysis unit 426.

  Moreover, in the case of measuring the gas component with respect to the biological discharge incorporated in the toilet seat, various components contained in the gas emitted from the stool of the user who uses the toilet and their relative concentrations are displayed. Furthermore, by comparing these measurement results with the database 428, it is possible to simply display the health condition and advice on health on a display (not shown) in the toilet. Furthermore, after completion of the measurement by the stool examiner, the change in the odor in the toilet can be measured to control the ventilation and the operation of the deodorizing device.

  The gas analyzer 400 of the second embodiment can not only measure gas components but also detect dust and dust floating in the air. In addition, the light source 401 and the detection result display unit 406 can be variously selected from simple ones to those performing complex control equipped with a CPU (central processing unit), and can be used for many purposes. In this embodiment, since the optical power monitor 403 housed in the case 411 can be manufactured at low cost, the optical power monitor 403 is replaced for each sample, and the first tube 412 and the second tube 413 are sealed. Thus, the actual sample can be stored in units of the optical power monitor 403.

  <Modification of Second Embodiment>

  FIG. 14 shows a main part of an analyzer according to a modification of the second embodiment. While gas is detected in the second embodiment, the analysis apparatus 400A of this modification analyzes liquid or solid components and states. A substance 442 to be sensed is disposed in a region 441 between the inclined connection portion 221 and the lens 207. As a result, various liquids and solid compositions can be measured. For example, by measuring a specific wavelength component by pressing a finger of this hand on this location, it is possible to measure and analyze the ratio of hemoglobin in the blood. For example, when isopropanol having a refractive index of “1.3” is dropped into the region 441 with respect to air having a refractive index of “1”, the amount of light received by the light receiving element 208 can be reduced by 20 to 30 percent.

  In addition, although the lens was produced using the adhesive agent in Examples and Modifications, a similar lens can be produced using a resin other than the adhesive agent. Of course, the present invention can be applied to these lenses.

It is sectional drawing of the optical power monitor in the 1st Example of this invention. It is sectional drawing of the fusion position periphery of the optical power monitor of a present Example. It is explanatory drawing which showed the relationship between the light which leaks from a bare optical fiber, and a lens in a present Example. It is explanatory drawing showing the outline | summary of the manufacturing method of the optical power monitor of a present Example. It is sectional drawing which showed the principal part of the 1st modification of the optical power monitor of a present Example. It is sectional drawing which showed the principal part of the 2nd modification of the optical power monitor of a present Example. It is sectional drawing which showed the principal part of the 3rd modification of the optical power monitor of a present Example. It is sectional drawing which showed the principal part of the 4th modification of the optical power monitor of a present Example. It is sectional drawing showing the outline | summary of the 5th modification of the optical power monitor of a present Example. It is sectional drawing showing the outline | summary of the 6th modification of the optical power monitor of a present Example. It is a block diagram of the gas analyzer in the 2nd example of the present invention. It is sectional drawing showing the outline | summary of the structure of the optical power monitor in a 2nd Example. It is the block diagram which showed the outline | summary of the detection result display part in a 2nd Example. It is sectional drawing which showed the principal part of the analyzer of the modification of a 2nd Example. It is a principle figure showing the outline | summary of the structure of the optical power monitor by the conventional 1st proposal. It is a principle figure showing the outline of the composition of the optical power monitor by the conventional 2nd proposal. It is a principle figure showing the outline | summary of the structure of the optical power monitor by the conventional 3rd proposal.

Explanation of symbols

201, 201A, 201B, 201C, 201D, 201E, 201F, 403 Optical power monitor 202 Case 203 Base 204, 205 Optical fiber 204A, 205A Bare optical fiber 204C, 205C Core 204D, 205D Clad 206 Fusion position 207, 247 Lens 208 248 Light receiving element 221 Inclined connection part 222 Leakage light 231 Adhesive 251 252 Side guide 261 Filter 400 Gas analyzer 400A Analyzer 401 Light source 406 Detection result display part 423 Attenuation rate calculation part 426 Analysis part 431 Display part 442 material

Claims (10)

An off-axis fused fiber obtained by fusing the cores through which light propagates in an off-axis state;
An optical power monitor comprising: a light-receiving element for monitoring that receives light emitted out of the fiber as leakage light from the fusion position of the off-axis fused fiber. An off-axis fused fiber obtained by fusing the cores through which light propagates in an off-axis state;
A fusion part holding member that has a predetermined curved shape and holds the fusion-bonded fiber and its periphery in a bent state by disposing the off-axis fused fiber along the curved shape; ,
An optical power monitor comprising: a light receiving element for monitoring that receives light emitted from the fusion position of the off-axis fused fiber as leakage light to the outside of the fiber.   3. The optical power monitor according to claim 1, wherein a condensing lens is disposed between a fusion position of the fusion fiber and the light receiving element.   4. The optical power monitor according to claim 3, wherein a filter for wavelength selection is disposed between the light receiving element and the lens.   5. The optical power monitor according to claim 3, wherein the lens is formed by dropping a predetermined amount of adhesive on the surface of the off-axis fused fiber.   The light receiving element is disposed in the vicinity of the fusion position of the fused fiber of the off-axis fused fiber with the light receiving surface facing the fiber surface, and the off-axis fused fiber is disposed between the light-receiving surface and the fiber surface. 3. The optical power monitor according to claim 1, wherein a material having a refractive index higher than that of the cladding is filled.   A glass plate is disposed on the light receiving element side in the vicinity of the fusion position of the fusion fiber so that the light receiving element faces one end face, and the other end face of the glass plate is offset from the axis. 3. A material having a higher refractive index than that of the clad is filled between the glass plate and the off-axis fused fiber. Optical power monitor.   The off-axis fused fiber is configured such that light is propagated in both directions, and the light receiving element and the condensing lens are arranged at symmetrical positions around the fused position of the fused fiber. The optical power monitor according to claim 3. A first step of melting and fusing the ends of the two optical fibers by discharge heating in a state where the cores at the ends of the two optical fibers are shifted;
A second step of bending and fixing the periphery of the fused portion of the optical fiber fused in the first step;
In the third optical fiber bent in the second step, the adhesive is solidified at a predetermined portion where the light emitted from the fusion portion as light leaking from the fusion portion in the vicinity of the fusion portion is used as a lens. Steps,
And a fourth step of arranging a light-receiving element for monitoring at the condensing position of the lens. An off-axis fused fiber obtained by fusing the cores through which light propagates in an off-axis state;
A fusion part holding member that has a predetermined curved shape and holds the fusion-bonded fiber and its periphery in a bent state by disposing the off-axis fused fiber along the curved shape; ,
A sample arrangement region arranged in a surface portion near the fusion position of the fusion fiber;
A lens that enters light that has exited the fiber as leakage light from the fusion position and transmitted through the sample placement region; and
A light-receiving element for monitoring arranged at the condensing position of this lens;
And an analyzing means for analyzing the sample using the light receiving output of the light receiving element.

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