JP2011102866A - Method and device for inspecting optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect each optical fiber in a multicore optical fiber without using a complex mechanism or control. <P>SOLUTION: Openings (12, 12A-12D) of M×N optical fibers 11 are formed on a connection end face 20e having a matrix of an inter-column pitch a and an inter-row pitch b. M holes (2a-2f) of a plate are arranged one by one to each row and each column with the inter-column pitch a and an inter-row pitch N×b or larger. The extension directions of the holes and the openings are made identical. The light receiving surface 5 of a light receiving part is arranged to receive light emitted from all the optical fibers in a lump. The optical fiber inspecting method includes steps of: emitting light from a light source to the optical fibers; moving the plate in the column direction while facing the plate to the connection end face; and opposing one of the openings to one of the holes to overlap in the plate moving process and making the receiving part receive a light intensity signal from the light receiving part when the other opening is shielded. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for inspecting individual optical fibers in a multi-core optical fiber. It also relates to optical fiber inspection equipment.

  Optical fibers need to be inspected (such as measuring optical loss) prior to actual operation. As a method for inspecting an optical fiber, a light source and a light receiving element composed of a light receiving element are disposed at both ends of the optical fiber, an optical signal having a predetermined light intensity is incident on the optical fiber, and the light intensity of the emitted light is well known. Basically, the optical loss is determined by measurement using an optical power meter or the like. And if this basic inspection method is applied, the loss accompanying the connection of optical fibers can also be measured. For example, by connecting another optical fiber to be inspected through an optical connector to an optical fiber with known optical loss, and measuring the optical loss over the entire length of the optical fiber including this connection point, The optical loss of the optical fiber to be inspected including the optical loss (connection loss) is required. Non-Patent Document 1 below describes a method and apparatus for measuring optical signal loss and connection loss in an optical fiber.

  By the way, optical fibers include multi-core optical fibers that are a set of a plurality of optical fibers. In order to inspect such a multi-core optical fiber, each of the plurality of optical fibers is individually inspected. Need to do. As an inspection method for multi-fiber optical fibers, for example, for each optical fiber, an optical switch is inserted in the middle of the optical path from the light source to the light receiving unit, and each optical switch is individually opened and closed to sequentially connect the optical paths. . And optical loss etc. are measured individually about each optical fiber. Therefore, the inspection of the multi-core optical fiber takes a long time and a high inspection cost due to the long inspection time.

  In the inspection apparatus for a multi-fiber optical fiber with an optical connector described in Patent Document 1 below, a slit having the width of one optical fiber is provided on the opening end face on the light signal output side of the multi-fiber optical fiber. By moving the position of the slit, it is possible to inspect a multi-fiber optical fiber without connecting or blocking the optical path for each optical fiber.

Japanese Patent No. 3009426

Takuo Kikuchi and Junichi Nishizawa, “FTTH Construction Technology Supporting the Optical Communication Age”, Optronics Co., Ltd., December 22, 2008, 3rd edition, first printing, P161-P189

  In the inspection apparatus described in Patent Document 1, a tape core wire or the like in which a plurality of optical fibers are arranged one-dimensionally is an inspection object. That is, the inspection target is a multi-core optical fiber arranged such that the open ends of a plurality of optical fibers are in one row. And the slit extended in the column direction orthogonal to the row direction of an opening end is provided, and the slit is moved to the extension direction of a row. Thereby, only the light from one optical fiber in the multi-core optical fiber is sequentially transmitted, and only the transmitted light from the one optical fiber is input to the optical power meter.

  However, some multi-fiber optical fibers are not only one-dimensionally arranged such that the openings of the optical fibers are arranged in one row, but some fibers are arranged two-dimensionally so as to form a plurality of rows. And, when trying to inspect such a two-dimensionally arranged multi-core optical fiber by the inspection method employed by the inspection apparatus of Patent Document 1, since the slits open in the direction perpendicular to the columns, the multi-core light It is impossible to receive and inspect only the transmitted light from one optical fiber in the fiber.

The present invention has been made in view of the above problems, and in a multi-core optical fiber in which openings of a plurality of optical fibers are two-dimensionally arranged, each optical fiber is precisely inspected without using a complicated mechanism or control. It is an object of the present invention to provide a method for inspecting a multi-core optical fiber based on the method and the method. The main invention of the present invention is a method for inspecting individual optical fibers in a multi-core optical fiber composed of M × N optical fibers,
At least one end portion of the multi-core optical fiber is formed with a connection end face that is two-dimensionally arranged such that the openings of the optical fiber form a matrix of M rows and N columns with an inter-column pitch a and an inter-row pitch b. ,
Using a plate having M through holes, a light source, a light receiving unit that receives light emitted from an optical fiber and outputs a light intensity signal, and a receiving unit that receives the light intensity signal,
The through-holes of the plate are arranged one by one in each row and each column so that the pitch between columns is a and the pitch between rows is N × b or more, and the extending direction of the columns of the through-holes is , Corresponding to the extension direction of the row of openings in the connection end face,
A light incident step for allowing light from the light source to enter the optical fiber;
A plate moving step for bringing the plate close to the connection end face and facing the plate, and moving the plate in one direction parallel to the row;
In the course of the plate moving step, the light intensity signal from the light receiving unit is detected when the opening of a certain optical fiber is opposed so as to overlap one hole in the plate and the opening of another optical fiber is shielded. A light intensity signal receiving step to be received by the receiving unit;
The optical fiber inspection method is characterized by including: The features, objects, effects, etc. of the invention other than the main invention will be clarified in the following description.

  According to the multi-core optical fiber inspection method of the present invention, for a multi-core optical fiber in which the openings of a plurality of optical fibers are two-dimensionally arranged, the individual optical fibers can be precisely separated without using complicated mechanisms and controls. Can be inspected.

It is a figure which shows an example of an optical connector. It is a figure which shows the state by which the opening of the several optical fiber was arrange | positioned two-dimensionally in the optical fiber test | inspection method which concerns on the Example of this invention. In the optical fiber inspection method of the said Example, it is a figure which shows the arrangement | positioning relationship between a multi-core optical fiber and the plate used for the said inspection method. It is a figure which shows the arrangement | positioning relationship of each component in the optical fiber inspection method of the said Example. It is a figure which shows the procedure of the optical fiber test | inspection method of the said Example. It is a schematic explanatory drawing of the optical fiber inspection method which concerns on the application example of this invention. It is a figure showing composition of an optical fiber inspection device concerning one embodiment of the present invention. It is a figure which shows an example of the structure of the said optical fiber test | inspection apparatus.

=== Features of Embodiments Corresponding to the Present Invention ==
In the optical fiber inspection method according to the embodiment of the present invention, an inspection target is a multi-core optical fiber in which the opening end face of each optical fiber is two-dimensionally arranged, and only light emitted from one optical fiber is received. Individual optical fibers in a multi-core optical fiber can be individually inspected. However, if the procedure and work related to the inspection are complicated, or the configuration and control necessary for the inspection are complicated, the cost for the inspection increases. In an embodiment of the present invention, in order to solve the problems related to the inspection cost, the following features are provided in addition to the features in the embodiment corresponding to the main invention.

The pitch between rows of the through holes of the plate is an integral multiple of b.
The plate is interposed between the connection end surface and the light receiving unit, and in the light incident step, light is incident on the openings of all the optical fibers opposite to the connection end surface in a lump. Alternatively, the plate is interposed between the connection end surface and the light source.

The M × N optical fibers form the connection end face in which the openings at both ends are the matrix of M rows and N columns, and the plate is interposed between the light receiving portion at one connection end face. The plate is interposed between the light source at the other connection end surface,
In the plate moving step, the two plates are moved synchronously,
In the light incident step, light is incident on an opening of one optical fiber at the other connection end surface;
In the light receiving step, when the openings of the M × N optical fibers are normally arranged, light emitted from the one connection end surface is received by the light receiving unit.
The connection end face side of the M × N optical fibers is an optical connector that collectively accommodates the M × N optical fibers. Alternatively, the connection end face is formed by stacking N sets of optical connectors in which M optical fibers are stored in a straight line with a pitch of a in a direction perpendicular to the straight line. .

The present invention also extends to an optical fiber inspection apparatus. An embodiment of an optical fiber inspection apparatus is an apparatus for inspecting individual optical fibers in a multi-core optical fiber composed of M × N optical fibers. And
An optical fiber placement portion, a plate having M through holes, a light source, a light receiving portion, a plate moving mechanism, and a receiving portion;
The optical fiber placement section is a state in which at least one end of the multi-core optical fiber is a two-dimensional arrangement in which the openings of the optical fiber are arranged in a matrix of M rows and N columns with an inter-column pitch a and an inter-row pitch b Fixed so that it becomes the connection end face of
The M through holes of the plate are arranged one by one in each row and each column so that the inter-column pitch is a and the inter-row pitch is N × b, and the columns of the through holes are extended. The direction coincides with the extension direction of the row of openings in the connection end surface,
The light source makes light incident on the optical fiber,
The light receiving unit is arranged so that a light receiving surface can collectively receive light emitted from the M × N optical fibers, and outputs a light intensity signal of light emitted from any one of the optical fibers,
The plate moving mechanism moves the plate in one direction parallel to the row,
In the process of moving the plate by the plate moving mechanism, the receiving unit overlaps with one hole in the plate and the other optical fiber is shielded from the light receiving unit. Receiving the light intensity signal of
It is characterized by that.

=== Multi-core optical fiber ===
In the optical fiber inspection method according to the present embodiment, individual optical fibers are sequentially arranged from a multi-core optical fiber including a plurality of optical fibers (for example, an optical fiber strand, an optical fiber core wire, or an optical fiber cord). It has a feature in the configuration and procedure for selecting as an inspection object. Before explaining this feature, first, the structure of a general multi-core optical fiber will be described. Here, as an example of the multi-core optical fiber, a multi-core optical fiber having an optical connector at the end is shown. As is well known, an optical connector is a member for connection in a state in which end faces of optical fibers serving as an entrance or an exit of an optical signal are attached to each other. FIG. 1 shows an MPO type optical connector (hereinafter referred to as an optical connector) 110 as an example of the optical connector 110. In the illustrated optical connector 110, a known MT ferrule 111 in which optical fiber openings are two-dimensionally arranged is mounted in a hollow cylindrical housing 112, and the end face of the MT ferrule 111 is exposed from one end of the housing 112. is doing. In this example, when the longitudinal direction of the rectangular ferrule end face 113 is the row direction, the end faces of the optical fibers (hereinafter referred to as openings) are arranged in 2 rows and 12 columns. Hereinafter, the surface 20 on which the openings of the plurality of optical fibers are two-dimensionally arranged is referred to as a “connection end surface”.

  The optical connector 110 has a structure for connecting each optical fiber of the optical connector to be connected to its own optical fiber in a state of being coaxially opposed to each other. For example, the optical connector shown in FIG. The connector 110 includes a male connector 110M shown in (A) and a female connector 110F shown in (B). The male connector 110M includes two guide pins 114M on the ferrule end surface 113, and the previous connection end surface 20 is formed between the two guide pins 114M. On the other hand, the ferrule end face 113 of the female connector 110F is formed with an insertion hole 114F into which the guide pin 114M of the male connector 110M is inserted. Then, by inserting the guide pin 114M of the male connector 110M into the insertion hole 114F of the female connector 110F, both optical connectors (110M, 110F) are connected, and the openings of the optical fibers on the connection end face 20 are accurately positioned. Dating. Of course, the optical connector also connects to an optical adapter that engages its own shape, so that the aperture of the optical fiber is placed in a positioned state.

=== Example ===
In the optical fiber inspection method of the present embodiment, only light from one of the openings of the plurality of optical fibers included in the connection end face 20 is selectively selected by a simple procedure without using a complicated mechanism. It receives light and can measure optical loss and the like for each optical fiber. Then, as an embodiment according to the optical fiber inspection method of the present invention, a basic procedure and configuration for selectively receiving light from one opening will be given. FIG. 2 shows a plan view of the connection end face 20. The openings 12 of the optical fibers 11 in the multi-core optical fiber are two-dimensionally arranged so as to have M rows and N columns. In the following, for ease of explanation, it is assumed that M = 6 and N = 4 as shown in FIG. Further, regarding the arrangement of the openings 12 of the respective optical fibers 11 on the connection end face 20, the row direction and the column direction are defined as shown in the figure, and the pitch between the columns, that is, the pitch between the openings 12 adjacent in the row direction is a. Let b be the pitch, that is, the pitch between the openings 12 adjacent in the row direction. Then, as shown in FIG. 2, in the state where the openings 12 of the total of 24 optical fibers 11 are two-dimensionally arranged in 6 rows and 4 columns, any one optical fiber 11 is selected as an inspection target, A procedure for causing the light receiving surface of the light receiving element to receive the light emitted from the opening 12 of the selected optical fiber 11 will be described as an embodiment of the present invention.

  FIGS. 3A and 3B show a configuration for selecting the optical fiber 11s to be inspected. (A) is a structure when the multi-core optical fiber 10 is viewed from the side surface, and (B) is a plan view when the connection end surface 20 is viewed from the direction of the arrow 100 in (A). As shown here, a rectangular plate 1 with the column direction as the longitudinal direction is in close proximity to the connection end surface 20 and faces it. In this embodiment, in order to select a certain optical fiber 11 as the optical fiber 11s to be inspected, a substantially rectangular plate 1 with the column direction as the longitudinal direction is used. A plurality of holes 2 penetrating the front and back are formed in the plate 1. And the hole 2 is formed in the position based on a predetermined rule by the number based on a predetermined rule.

  In the present embodiment, the number of holes 2 is equal to the number M of the openings 12 in the row direction on the connection end face 20. One hole 2 is formed in each row and each column, and only one hole 2 is formed in the same row and the same column. That is, in this example, a total of six holes 2 are formed, one for each matrix. The inter-column pitch of each hole 2 is the same as the inter-column pitch of the openings 12 of the optical fiber 11 in the connection end face 20, and the inter-row pitch is N × b, that is, 4b. In the illustrated example, the holes 2 are arranged stepwise with a width 4b.

  The row direction of the holes 2 coincides with the row direction formed by the openings 12 of the optical fibers 11 in the connection end face 20. That is, the extending direction of the rows of the holes 2 and the extending direction of the rows by the openings 12 of the optical fiber 11 are on the same straight line. The shape of the hole 2 is the same circle as the shape of the opening 12 of the optical fiber 11, and therefore, when the plate 1 is moved in the column direction, the opening 12 s of any one optical fiber 11 s and any one of the openings 12 s. The holes 2s overlap with each other concentrically. Then, when the plate 1 is moved in the column direction by the distance b from this state, the opening 12 of the other optical fiber 11 overlaps with any one of the holes 2 concentrically.

  The area of the hole 2 can be set according to the distance between the plate 1 and the connection end face 20, the numerical aperture (NA) of the optical fiber 11, and the like. Specifically, when the opening 12 of an optical fiber 11 is concentrically overlapped with the hole 2, the light emitted from the opening 12 of the optical fiber 11 adjacent to the optical fiber 11 passes through the same hole 2 to the front of the plate 1. Set so as not to leak. For example, when an opening 12 of a certain optical fiber 11 is concentrically overlapped with the hole 2, when light enters the optical fiber 11 through the hole 2, the light is incident on the optical fiber 11 adjacent to the optical fiber 11. Is set so as not to enter through the same hole 2. Since the end face of the optical fiber 11 is exposed as the opening 12 on the connection end face 20, the plate 1 and the connection end face 20 do not come into contact with each other after satisfying the setting condition relating to the area of the hole 2 described above. Will be placed.

  Next, an outline of the inspection method for the multi-fiber optical fiber 10 will be described based on the positional relationship between the openings 12 of the optical fibers 11 in the connection end face 20 and the holes 2 in the plate 1. FIG. 4 exemplifies the arrangement relationship of each component of the light source 3, the multi-core optical fiber 10, the plate 1, and the light receiving element 4 used in the inspection method of this embodiment. Here, an example is shown in which both ends (10t, 10e) of the multi-fiber optical fiber 10 are optical connectors (110t, 110e). The light source 3 is disposed on one optical connector 110t side, and the light receiving element 4 is disposed on the other optical connector 110e side. Here, assuming that the end on the light source 3 side in the multi-core optical fiber 10 is the tip 10t and the end on the light receiving element 4 side is the end 10e, in the basic embodiment, the arrangement relationship of the above components is shown in FIG. ), The plate 1 may be disposed on the end 10e side, and the plate 1 may be disposed on the tip 10t side as illustrated in FIG. The illustrated multi-core optical fiber 10 extends linearly, but may be bent in a U shape or a loop shape. In addition, in order to measure the connection loss, there may be a connection point via another optical connector 110 on the extension of the multi-core optical fiber 10. In any case, it is only necessary that the light source 3 is disposed at one end of the optical path composed of the multi-core optical fiber 10 and the light receiving element 4 is disposed at the other end.

  Here, the optical fiber inspection method of this embodiment will be described based on the arrangement relationship shown in FIG. In addition, in the arrangement relationship of each component (1, 3, 4, 10) shown in FIG. 4 (A), the light source 3 emits all light at the connection end surface 20t on the tip 10t side of the multi-core optical fiber 10. It faces the opening 12 of the fiber 11 and the light is incident on all the optical fibers 11 at once. Of course, if the light can be incident on all the optical fibers 11, the openings 12 of the optical fiber 11 are regularly arranged in a two-dimensional manner on the distal end 10t side, like the connection end face 20 shown in FIG. There is no need to be.

  On the other hand, in the light receiving element 4 arranged on the terminal end 10e side, the light receiving surface 5 faces the connection end surface 20e, and the plate 1 is interposed between the light receiving surface 5 of the light receiving element 4 and the connection end surface 20e. The light receiving element 4 is arranged so as to receive light emitted from the optical fiber 11 at any position on the connection end surface 20e, with the formation region of the connection end surface 20e as a light reception region.

  5A to 5D show the procedure of the inspection method according to this example. In the following, as shown in FIG. 5A, the direction of rows and columns and the vertical and horizontal directions are defined. Further, the six holes are distinguished by reference numerals 2a to 2f, and the openings 12 when overlapping with the positions of the holes (2a to 2f) are distinguished by reference numerals 12A to 12D.

  First, as shown in FIG. 5A, the hole 2a in the uppermost row in the plate 1 is overlapped with the lowermost row 13 in the connection end face 20e. Since the row direction of the holes (2a to 2f) of the plate 1 and the row direction of the openings 12 in the connection end face 20e coincide with each other, the upper left hole 2a of the plate 1 and the leftmost row 14 in the connection end face 20e The opening 12A in the lower row 13 overlaps concentrically. Light from the light source 3 is emitted from the openings (12, 12A) of all the optical fibers 11 at the connection end face 20e, but only light emitted from the openings 12A concentrically with the holes 2a is received by the light receiving element 4. Received light. In this way, only one optical fiber 11 in the multi-core optical fiber 10 can be selected as an inspection target.

  Next, when the plate 1 is moved upward by a distance b, as shown in FIG. 5B, the same hole 2a is moved to the position of the second row 15 from the bottom in the connection end face 20e. And the opening 12B corresponding to the intersection of the leftmost row 14 and the hole 2a overlap in a concentric manner. At this time, the light emitted from the opening 12B is received by the light receiving element 4. Similarly, the plate is sequentially moved upward by the distance b, and as shown in FIG. 5C, when the plate 1 is moved upward by the distance 4b from the state of FIG. The hole 2b in the second row (second column) overlaps the opening 12C corresponding to the intersection of the lowermost row 13 and the second column 16 from the left in the connection end surface 20e.

  Subsequently, each time the plate 1 is moved upward in parallel with the column direction by the distance b, the opening 12 of the second column 16 from the left in the connection end surface 20e is sequentially selected, and the second row (second column) of the plate 1 is selected. It overlaps with the hole 2b. In this way, a series of operations are repeated in which the plate 1 is moved, the openings 12 of the optical fibers 11 to be inspected are sequentially selected, and light is received by the light receiving element 4. Finally, as shown in FIG. 5D, the hole 2f in the lowermost row (rightmost column) in the plate 1 corresponds to the intersection of the rightmost column 18 and the uppermost row 17 in the connection end face 20e. When light emitted from the opening 12D is received by the light receiving element 4, the inspection for all the optical fibers 11 is completed.

  Thus, according to the exemplified inspection method, the light source 3, the light receiving element 4, the plate 1 having a simple structure, and the plate 1 are merely moved in one direction with respect to the connection end surface 20. The optical fibers 11 constituting the multi-core optical fiber 10 can be accurately inspected one by one with only a simple configuration based on the mechanism. Therefore, if an apparatus for inspecting the multi-core optical fiber 10 is configured based on this inspection method, the apparatus can be provided at low cost. Further, the inspection can be completed only by operating the plate 1 in one direction, the inspection time can be saved, and the cost for the inspection can be reduced.

  By the way, the pitch in the column direction of the holes 2 may not be N × b, but may be N × b or more. Then, when one opening 12 is selected by a certain hole 2 and the other opening 12 is shielded from light, the emitted light from the opening 12 may be received. Further, if the pitch of the holes 2 in the row direction is an integral multiple of b, the plate 1 only needs to move in the row direction by a distance b at a single movement opportunity, and thus a mechanism for moving the plate 1 And control can be simplified.

  In addition, what is necessary is just to analyze the output signal of the light receiving element 4 using a suitable measuring apparatus. For example, the optical loss is measured based on the light intensity obtained from the output signal from the light receiving element 4 and the predetermined light intensity from the light source 3, or the disconnection of the optical fiber 11 is detected based on the presence or absence of the output signal. What is necessary is just to use as information for doing.

  In this example, the holes 2 are arranged in a staircase pattern. However, if only one hole 2 is formed in the same row and the same column in the plate 1, it is not necessary to arrange in a staircase pattern. Of course, the shape of the hole 2 is not limited to a circle. When the opening 12 of one optical fiber 11 and a certain hole 2 are overlapped, the opening 12 of another optical fiber 11 is shielded by the plate 1 and the plate 1 is moved in the column direction by a distance b. Light emitted from only the single optical fiber 11 may be received by the light receiving element 4.

  When the plate 1 is disposed on the tip 10t side of the multi-core optical fiber 10, light enters from the front of the plate 1 toward the connection end surface 20t. Thereby, light is incident only on the opening 12 concentrically overlapping the hole 2. The light receiving element 4 should just be arrange | positioned so that the emitted light from the opening 12 of all the optical fibers 11 can be received in the termination | terminus 10e side of the multi-core optical fiber 10. FIG. That is, it is not always necessary to regularly arrange the openings 12 two-dimensionally on the end 10e side.

=== Application Examples ===
By the way, as shown in FIG. 4, in the multi-core optical fiber 10 provided with the optical connectors (110t, 110e) at both ends (10t, 10e), the positions of the optical fibers 11 cross each other while the optical fiber 11 is being extended. In some cases, the arrangement of the 11 openings 12 is replaced by the optical connectors at both ends (10t, 10e). Therefore, as an application example of the present invention, a method (arrangement inspection method) for inspecting the presence or absence of such a placement defect in the multi-fiber optical fiber 10 will be described.

  FIG. 6 shows an outline of the above arrangement inspection method. 6 also employs the vertical relationship shown in FIG. As shown in FIG. 6A, the plates (1t, 1e) face the connection end faces (20t, 20e) on the front end 10t side and the end 10e side of the multi-core optical fiber 10, respectively. FIG. 6B is a plan view of the connection end face 20t on the tip 10t side of the multi-fiber optical fiber 10, and the hole 2xt (x: a to f) of the plate 1t when viewed from the arrow 101 direction in FIG. And the positional relationship between the opening 12 t of the optical fiber 11. Similarly, FIG. 6C is a plan view of the connection end face 20e on the terminal end 10e side of the multi-core optical fiber 10, and the hole 2ye (y: a: a of the plate 1e when viewed from the arrow 102 direction in FIG. 6A. -F) and the positional relationship between the opening 12e of the optical fiber 11 are shown. The positional relationship between the holes (2xt, 2ye) and the openings (12t, 12e) in the connection end faces (20t, 20e) on both ends (10t, 10e) shown in FIGS. This is for inspecting a cable arrangement failure. That is, in the case of the normal multi-core optical fiber 10, the openings (12t, 12e) of the optical fiber 11 at the connection end faces (20t, 20e) on both ends (10t, 10e) side are arranged in the same manner. Therefore, holes (2xt, 2ye) are formed at the same positions on the plates (1t, 1e) arranged close to the connection end faces (20t, 20e) on both ends (10t, 10e) of the multi-core optical fiber 10. Has been.

  Next, a specific procedure of the arrangement inspection method will be described with reference to FIGS. 6A to 6C. First, it is confirmed that there is no disconnection in all the optical fibers 11. For this purpose, light is incident on all the optical fibers 11 at the tip 10t side of the multi-core optical fiber 10 and the openings 12e of all the optical fibers 11 are collectively checked on the end 10e side by visual observation or the like. inspect. If there is no disconnection, light is emitted from all the openings 12e on the end 10e side. Then, if it is confirmed that there is no disconnection, then the plate (1t, 1e) is made to face the connection end face (20t, 20e) on both ends (10t, 10e) side of the multi-core optical fiber 10 and the same position is set. The two plates (1t, 1e) are moved synchronously so that the holes (2t, 2e) of the plate (1t, 1e) overlap with a certain opening (12t, 12e). On both ends (10t, 10e), the light intensity is measured when the holes (2xt, 2ye) overlap the openings (12t, 12e) at the same position. If the arrangement of the openings (12t, 12e) is normal, light incident from the tip 10t side through the hole 2t of the plate 1t is emitted through the hole 2t of the plate 1e on the terminal end 10e side, and the emitted light is received by the light receiving element 4 The light is received at. If the arrangement is wrong, the emitted light is blocked by the plate 1e, and the emitted light is not received by the light receiving element 4. In this way, all the optical fibers 11 can be inspected to determine whether there is a placement defect. Of course, in order to confirm the presence or absence of disconnection of the optical fiber 11 prior to the inspection of the defective arrangement, as shown in FIG. 6D, the size of the end of the connection end face (20t, 20e) can be seen at the upper end of the plate 1. The opening 6 is formed, and the opening 6 and the region of the connection end face (20t, 20e) are overlapped on both ends (10t, 10e) of the multi-core optical fiber 10. Then, the light is made incident on the connection end surface 20t on the tip 10t side, and the emitted light is visually confirmed on the terminal 10e side by removing the light receiving element 4 or the like. Alternatively, the light intensity is measured, and if the intensity is equal to or greater than a predetermined value, it may be determined that light is emitted from the entire opening 12e and there is no disconnection. Thus, by providing the opening 6 corresponding to the region of the connection end face (20t, 20e) in the plate (1t, 1e), the disconnection inspection and the placement inspection can be performed continuously, and the inspection time can be saved. .

  In addition, as a comparative example for this application example, for example, the optical fiber 11 in which light is incident on one optical fiber 11 from the tip 10t side of the multi-core optical fiber 10 and light is emitted on the terminal end 10e side is used. There is an arrangement inspection method in which a person visually confirms the position of the opening 12e. Alternatively, an image inspection technique using an optical sensor and a computer is used to determine whether or not the position of the opening 12t of the optical fiber 11 that receives light and the position of the opening 12e that emits light are in a correct relationship. There is a way. However, in the arrangement inspection method in this comparative example, when visually confirming, the pitch between the rows and the columns of the openings 12e forming the connection end face 20e is narrow, there is a possibility of misidentification, and the reliability of the inspection is lowered. . In the case of using the image recognition technology, the configuration required for the inspection becomes complicated and the inspection cost increases.

  Furthermore, in the arrangement inspection method in the comparative example, an optical switch is individually interposed on the optical path of all the optical fibers 11 of the multi-core optical fiber 10 in order to make light incident on one specific optical fiber 11. . Then, light is incident on the entire optical fiber 11 from the tip 10t side, and an optical switch interposed on the extension of one optical fiber 11 is connected and the other optical switches are cut off. The light is emitted from one specific optical fiber 11. Therefore, the basic configuration itself is complicated, and it is difficult in principle to reduce the inspection cost.

  Further, in the arrangement inspection method of the comparative example, it is necessary to individually perform the optical loss measurement and the arrangement inspection for each optical fiber 11. Therefore, in the comparative example, when both the placement inspection and the optical loss measurement are performed on the multi-core optical fiber 10, it takes a long time. On the other hand, in the application example of the present invention, the placement inspection can be performed with a very simple configuration and a very simple procedure, and the placement inspection and the optical loss measurement can be performed at the same time, so that the inspection cost can be drastically reduced. .

=== Embodiment ===
As an embodiment of the present invention, a configuration example of an apparatus (inspection apparatus) that inspects the multi-core optical fiber 10 using the inspection method described above will be given. FIG. 7 illustrates a functional block configuration of the inspection apparatus 200. In this figure, both ends (10t, 10e) of the multi-core optical fiber 10 are optical connectors (110t, 110e), and the embodiment in which the plate 1 is disposed only on the end 10e side is shown. The light source 3 and the light receiving element 4 are fixed so as to have a predetermined positional relationship with respect to each connection end face (20t, 20e) at the tip 10t and the end 10e of the multi-core optical fiber 10.

  In the configuration shown in FIG. 7, the control unit 201 can be configured by, for example, a computer including a CPU and a storage unit such as a RAM, a ROM, or a flash memory. And each component of the inspection apparatus 200 is controlled. The light intensity signal output unit 202 samples the signal output from the light receiving element 4 to generate data corresponding to the light intensity (light intensity data), and transmits the light intensity data to the control unit 201. The plate 1 moves linearly in the vertical direction by the driving force of the motor 203. The motor 203 is, for example, a stepping motor, and the motor driving unit 204 generates a predetermined pulse signal in accordance with a control signal from the control unit 201. Upon receiving the pulse signal, the motor 203 rotates the output shaft 205 by a predetermined angle.

  The gear box 206 includes a plurality of gears for converting the rotational motion of the output shaft 205 of the motor 203 into a linear motion in the vertical direction, and the linear motion is transmitted to the plate 1. The gear box 206 is set to move the plate 1 upward by a distance b each time the motor 203 rotates the output shaft 205 by a predetermined angle by a pulse signal. The gear box 206 includes a rotary encoder and the like, and outputs a signal (angle signal) corresponding to the rotation angle of the output shaft 205 of the motor 203. When the inspection apparatus 200 is also compatible with the above-described arrangement inspection, a configuration including the motor 203, the motor drive unit 204, the gear box 206, and the plate 1 is provided also on the distal end 10t side of the multi-core optical fiber 10. Just do it.

  Next, the operation of the inspection apparatus 200 will be described. In the storage unit of the control unit 201, for example, the identifier of each optical fiber 11, the coordinates of the reference position on the plate 1 in the initial state, the relative coordinates of the hole 2 with respect to the reference position, the rotation angle of the motor 203 and the plate 1 The relationship between the vertical movement amount, the relationship between the angle signal output by the rotary encoder and the hole 2 and the reference position of the plate 1, the relationship between the vertical movement amount of the plate 1 and the optical fiber 11 selected as the inspection target, etc. It is assumed that information necessary for controlling the inspection apparatus 200 is stored in advance.

  The control unit 201 transmits a predetermined control signal to the motor driving unit 204 to rotate the motor 203 by a predetermined angle to move the plate 1. At this time, the position of the hole 2 of the plate 1 is specified based on the angle signal from the rotary encoder, or the motor driving unit 204 is feedback-controlled, so that the plate 1 is accurately moved, and the optical fiber to be inspected 11 are sequentially selected. Further, light intensity data is received during a period in which a certain optical fiber 11 is selected as an inspection target, and the received light intensity data is stored in association with the optical fiber 11. Further, in the case where the inspection apparatus 200 supports the arrangement inspection, if the optical intensity data cannot be received during a period in which a certain optical fiber 11 is selected as an inspection target, the optical fiber 11 causes an arrangement failure. The determination result is associated with the optical fiber 11 and stored. The correspondence relationship between the optical fiber 11 and the light intensity data is processed by the control unit 201 or another information processing apparatus as data for obtaining the optical loss of each optical fiber 11 in the multi-core optical fiber 10. You can do that.

=== About Structure of Inspection Apparatus ===
The basic configuration and operation of the inspection apparatus 200 according to the embodiment of the present invention have been described above. Hereinafter, as a detailed structure of the inspection apparatus 200, a housing structure, a positioning structure of the plate 1 and the like will be described.

  FIG. 8 illustrates a detailed structure of the inspection apparatus 200 illustrated in FIG. FIG. 8A shows an example of a housing structure. In this example, the plate 1, the light receiving element 4, the motor 203, the motor driving unit 204, and the gear box 206 are housed in a light-shielded housing 210. Yes. On the surface of the housing 210, an optical adapter 211 having the same standard as the optical connector 110e is disposed, and connectors (212 to 214) conforming to an appropriate communication interface are also disposed. The control unit 201 and the light intensity signal output unit 202 outside the housing 210 and predetermined components inside the housing 210 are the connectors (212 to 214) and the internal wiring of the housing 210. 215 to be electrically connected. Of course, the control unit 201 and the light intensity signal output unit 202 may be in the housing 210 as an integrated device. The light source 3 may be housed in the housing 210 as long as it can shield the light receiving element 4.

  FIG. 8B is an example of a structure for positioning the plate 1 and the hole 2 with respect to the opening 12 of the optical fiber 11 in the connection end face 20e. In the drawing, the inner and outer boundaries of the housing 210 are indicated by dotted lines, and the vertical and horizontal directions are indicated by arrows. In this example, the optical connector 110e is connected to the optical adapter 211 disposed on the surface of the housing 210, so that each opening 12 in the connection end surface 20e is first fixed in a state of being positioned with respect to the housing 210. Is done.

  Further, in the optical adapter 211, a surface (back surface) opposite to the optical connector 110e is formed with a rectangular hole 216 that opens in a shape that borders the region of the connection end surface 20e. It is assumed that a rectangular hole is formed on the surface of the housing 210 corresponding to the hole 216 on the back surface of the optical adapter 211. The holes 216 on the back surface of the optical adapter 211 may be a plurality of holes arranged in the same manner so as to individually correspond to the openings 12 of the optical fibers 11 arranged in a matrix on the connection end surface 20e. Similarly, the holes 216 on the surface of the housing may be arranged in a matrix.

  On the other hand, the plate 1 is sandwiched between a pair of left and right guide rails 217 so as to extend vertically on the inner surface of the housing 210. Accordingly, the plate 1 slides in the vertical direction while contacting the inner surface of the casing 210 in a state where the left and right positions are determined. Of course, the configuration for sandwiching the plate 1 slidably from the left and right is not limited to the guide rail, and a guide pin, a guide roller, and the like are also conceivable.

=== Other Embodiments ===
<About the arrangement of light receiving elements>
In the inspection apparatus 200 of the above embodiment, the plate 1 is disposed close to the light receiving surface 5 of the light receiving element 4. Not limited to this example, the light from the connection end face 20e is guided to one opening of one optical fiber via an optical system using a lens or the like, and the other opening of the one optical fiber is guided to the light receiving element 4. You may make it face the light-receiving surface 5 of this. Thereby, the arrangement location of the light receiving element 4 can be set flexibly. Also, if an optical connector is provided in the other opening of one optical fiber, the optical connector can be connected to a general-purpose optical power meter, and there is no need to provide a dedicated light receiving element or light intensity signal output unit. Therefore, it can be expected to provide an inspection apparatus at a lower cost.

<About the plate moving mechanism>
The motor 203 may not be a stepping motor as long as the plate 1 can be moved upward at a predetermined speed accurately. For example, for each optical fiber 11, the order selected as the inspection target is stored in the storage unit of the control unit 201. In addition, the correspondence relationship between the elapsed time from the inspection start time and the time when each optical fiber 11 is selected is stored. The control unit 201 measures the elapsed time from the inspection start time and receives the light intensity data at the timing based on the correspondence relationship. Then, it identifies which optical fiber 11 the received light intensity data is based on the above order.

<About the structure of multi-core optical fiber>
In the above embodiment, the multi-fiber optical fiber 10 is provided with the optical connectors (110t, 110e) on both ends (10t, 10e), and the opening 12 of the optical fiber 11 is formed by the structure of the optical connector (110t, 110e) itself. It was regularly arranged in two dimensions. Not limited to this example, N sets of a set of multi-core optical fibers in which M optical fibers are arranged in a line in the row direction at a pitch a are used, and the ferrule end faces of the N sets of multi-core optical fibers are arranged in the column direction. The connection end face 20 in which the openings 12 are two-dimensionally arranged may be formed by laminating them. Accordingly, a plurality of sets of multi-core optical fibers in which the openings 12 are arranged one-dimensionally in the row direction can be inspected simultaneously.

<About connection end face>
In the above-described examples, application examples, and embodiments, the multi-core optical fiber includes ferrules at both ends, and the connection end face is included in the structure of the ferrule itself. Needless to say, the connection end face only needs to have a plurality of optical fiber openings arranged in a matrix, and the cause thereof may be any. For example, a plurality of tubes are fixed in a state where the openings are arranged in a matrix, an optical fiber is inserted from one opening of each tube, and the opening of the optical fiber is exposed to the other opening. The connection end face can be formed by an appropriate structure.

1, 1t, 1e plate,
2, 2a-2f, 2at-2ft, 2ae-2fe Plate holes,
3 light source, 4 light receiving element, 5 light receiving surface, 10 multi-core optical fiber,
11, 11s optical fiber,
12, 12s, 12A-12D optical fiber aperture,
20, 20t, 20e end face of connection, pitch between rows a, pitch between rows b,
110, 110M, 110F, 110t, 110e optical connectors,
200 optical fiber inspection device, 201 control unit, 202 light intensity signal output unit,
203 motor, 204 motor drive unit, 206 gear box, 210 housing,
211 optical adapter, 212-214 connector, 215 internal wiring,
216 Hole in the housing, 217 Guide rail

Claims (8)

A method for inspecting individual optical fibers in a multi-core optical fiber composed of M × N optical fibers,
At least one end of the multi-core optical fiber is formed with a connection end face that is two-dimensionally arranged so that the openings of the optical fiber are in a matrix of M rows and N columns with an inter-column pitch a and an inter-row pitch b. And
Using a plate having M through holes, a light source, a light receiving unit that receives light emitted from an optical fiber and outputs a light intensity signal, and a receiving unit that receives the light intensity signal,
The through holes of the plate are arranged one by one in each row and each column so that the pitch between columns is a and the pitch between rows is N × b or more, and the extending direction of the columns of the through holes is Match the extension direction of the row of openings at the connecting end face;
The light receiving surface of the light receiving unit is disposed so as to be able to collectively receive light emitted from the M × N optical fibers,
A light incident step for allowing light from the light source to enter the optical fiber;
A plate moving step for bringing the plate close to the connection end face and facing the plate, and moving the plate in one direction parallel to the row;
In the course of the plate moving step, the light intensity signal from the light receiving unit is detected when the opening of a certain optical fiber is opposed so as to overlap one hole in the plate and the opening of another optical fiber is shielded. A light intensity signal receiving step to be received by the receiving unit;
An optical fiber inspection method comprising:   2. The optical fiber inspection method according to claim 1, wherein a pitch between rows of the through holes of the plate is an integral multiple of b.   3. The plate according to claim 1, wherein the plate is interposed between the connection end surface and the light receiving surface of the light receiving unit, and in the light incident step, the opening is formed on the side opposite to the connection end surface of all the optical fibers. An optical fiber inspection method, wherein light is incident in a lump.   3. The optical fiber inspection method according to claim 1, wherein the plate is interposed between the connection end surface and the light source. In Claim 1 or 2, the said connection end surface used as the matrix of the above-mentioned M row and N column is formed in the both ends of the above-mentioned multi-core optical fiber, and the plate is used as the light-receiving surface of the above-mentioned photo acceptance unit in one connection end surface And interposing between the plate and the light source at the other connection end surface,
In the plate moving step, the two plates are moved synchronously,
In the light incident step, light is incident on an opening of one optical fiber at the other connection end surface;
In the light receiving step, when the openings of the M × N optical fibers are normally arranged, the light emitted from the one connection end surface is received by the light receiving unit. Optical fiber inspection method.   The optical fiber inspection method according to claim 1, wherein the connection end face is formed by collectively storing the M × N optical fibers in an optical connector.   In any one of Claims 1-5, 1 set of optical connectors in which the M optical fibers were accommodated in the state where the pitch is arranged in a straight line with the pitch N are stacked in a direction perpendicular to the straight line. An optical fiber inspection method, wherein the connection end face is formed. An apparatus for inspecting individual optical fibers in a multi-core optical fiber composed of M × N optical fibers,
An optical fiber placement portion, a plate having M through holes, a light source, a light receiving portion, a plate moving mechanism, and a receiving portion;
The optical fiber placement section is a state in which at least one end of the multi-core optical fiber is a two-dimensional arrangement in which the openings of the optical fiber are arranged in a matrix of M rows and N columns with an inter-column pitch a and an inter-row pitch b Fixed so that it becomes the connection end face of
The M through-holes of the plate are arranged one by one in each row and each column so that the inter-column pitch is a and the inter-row pitch is N × b or more. The extension direction coincides with the extension direction of the row of openings in the connection end surface,
The light source makes light incident on the optical fiber,
The light receiving unit is arranged so that a light receiving surface can collectively receive light emitted from the M × N optical fibers, and receives light emitted from any one of the optical fibers and outputs a light intensity signal. Output,
The plate moving mechanism moves the plate in one direction parallel to the row,
In the process of moving the plate by the plate moving mechanism, the receiving unit overlaps with one hole in the plate and the other optical fiber is shielded from the light receiving unit. Receiving the light intensity signal of
An optical fiber inspection device.

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