JP2007147895A - Optical fiber array and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber array capable of maintaining satisfactory characteristics because optical fibers fixed to a V-groove substrate and a cover plate with an adhesive are hardly stripped from the V-groove substrate and the cover plate even when being put under a severe environment for a long term, and optical axes of the optical fibers hardly cause positional deviation from the initial position, and to provide a manufacturing method of the optical fiber array. <P>SOLUTION: In the optical fiber array, a plurality of optical fibers of which covers on the end parts are removed are aligned on a plurality of V-grooves formed in parallel on the V-groove substrate and the respective optical fibers are fixed between the cover plate with which the optical fibers are covered and the V-groove substrate with the adhesive, wherein the minimum value of thicknesses of adhesive layers between the V-groove substrate and the cover, and the respective optical fibers is 5 nm to 1,000 nm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical fiber array and a manufacturing method thereof.

  In recent years, attention has been focused on optical fibers mainly in the communication field. In particular, in the IT (information technology) field, communication technology using optical fibers is required to develop a high-speed Internet network.

  An optical fiber has features such as low loss, high bandwidth, small diameter / light weight, non-induction, and resource saving. A communication system using such an optical fiber is a communication system using a conventional metallic cable. In comparison with the above, the number of repeaters can be greatly reduced, construction and maintenance are facilitated, and the economical efficiency and reliability of the communication system can be improved.

  In addition, since optical fibers can simultaneously multiplex and transmit not only light of one wavelength but also light of many different wavelengths using a single optical fiber, a large-capacity transmission line that can be used for a variety of applications. It has a great advantage that it can be realized and can be used for video services and the like.

  In optical communication using an optical fiber, an optical fiber ribbon in which a plurality of optical fibers are arranged in parallel and a coating resin layer is formed around the optical fibers is used. In order to connect the optical fiber ribbon to a light receiving element, a light emitting element, and various terminal devices (such as a personal computer, a mobile, and a game), a plurality of resin fibers are usually removed by removing the coating resin layer at the end of the optical fiber ribbon. The end of the optical fiber is exposed, the exposed optical fiber is placed on and fixed to the groove of the substrate having the V-groove, and a cover that covers the exposed optical fiber is attached to the substrate through an adhesive layer. Thus, an optical fiber array in which a plurality of optical fibers are arranged at a predetermined interval is used.

For example, as disclosed in Patent Document 1, such an optical fiber array includes a plurality of optical fibers on a V-groove substrate provided with a plurality of V-grooves for positioning an optical fiber in which a plurality of optical fibers are arranged in parallel. With the tips protruding from the end face of the V-groove substrate, and then covering the opening of the V-groove to hold the optical fiber between the V-groove and the lid, and then applying an adhesive to the optical fiber protrusion. Apply and let the adhesive penetrate into the clamping part by its surface tension, then cure the adhesive to fix the optical fiber to the V-groove substrate, then remove the optical fiber protrusion and match the end face of the V-groove substrate It is manufactured by forming an optical fiber end face.
JP 2005-181724 A

  However, the optical fiber array as described above is often placed in a harsh outdoor environment, and is exposed to a high temperature of 60 ° C. to a low temperature of −40 ° C., or is exposed to a desert environment or a hot and humid environment. . An optical fiber array must maintain good characteristics stably for a long period of time in such a harsh environment.

  However, when the conventional optical fiber array is exposed to the harsh environment as described above for a long period of time, the substrate and the lid on which the optical fiber is fixed are peeled off due to aging, and the optical fiber is not fixed stably. There was a phenomenon to become.

  This phenomenon is caused when the optical fiber array is manufactured, because the adhesive cannot be completely wound around the portion where the optical fiber is in contact with the groove portion and the lid portion. This is because the stress concentrates on the groove and the portion where the lid and the optical fiber are in contact with each other due to the difference in the thermal expansion coefficient between the adhesive and the substrate or between the adhesive and the lid plate.

  In addition, if the optical axis of the optical fiber is deviated from a predetermined position, the transmission loss between the optical fiber and the connected optical component increases, so extremely high positional accuracy of, for example, 0.5 μm or less is required.

  Further, in the conventional optical fiber array, only the dimensional accuracy of the V-groove substrate and the lid and the characteristics of the adhesive are mentioned, and there is no mention of the dimensions of the “optical fiber” that should be a composite material. For example, when the outer diameter of the optical fiber is “125 μm”, the numerical value of 125 μm is a nominal value, and actually, as described in JIS C6835, it is composed of optical fibers with outer diameters varying from 124 μm to 126 μm. Has been. For this reason, no matter how much the dimensional accuracy of the V-groove substrate and the lid is controlled, the desired transmission characteristics cannot be ensured without improving the dimensional accuracy of the optical fiber itself.

  The present invention has been made in order to solve the above-described problems, and the V-groove substrate and the cover plate and the optical fiber fixed thereto with an adhesive are separated even when left in a harsh environment for a long period of time. It is an object of the present invention to provide an optical fiber array capable of maintaining good characteristics and a method of manufacturing the same, because the optical axis of the optical fiber is not easily displaced from the initial position.

  Unless otherwise specified, terms used in the present specification shall conform to the definition of terms defined in JIS C6835.

  In the optical fiber array according to claim 1 of the present invention, a plurality of optical fibers from which end coating has been removed are aligned and pressed by a cover plate in a plurality of V grooves formed in parallel on a V groove substrate, In the optical fiber array in which the lid plate, the V-groove substrate, and the plurality of optical fibers are fixed with an adhesive, the minimum thickness of the adhesive layer between the V-groove substrate, the lid plate, and the plurality of optical fibers The value is 5 nm to 1000 nm.

  An optical fiber array according to a second aspect of the present invention is the optical fiber array according to the first aspect, wherein the minimum value of the thickness of the adhesive layer between each V-groove of the V-groove substrate and the plurality of optical fibers. Is 5 nm to 1000 nm, and the minimum value of the thickness of the adhesive layer between the lid plate and the plurality of optical fibers is 5 nm to 500 nm.

  An optical fiber array according to a third aspect of the present invention is the optical fiber array according to the first or second aspect, wherein a deviation Δd from an average value d of the outer diameters of the plurality of optical fibers is 0.3 μm or less. It is characterized by being.

  An optical fiber array according to a fourth aspect of the present invention is the optical fiber array according to any one of the first to third aspects, wherein the core eccentricity Δe of the plurality of optical fibers is 0.4 μm or less. It is a feature.

  An optical fiber array according to a fifth aspect of the present invention is the optical fiber array according to any one of the first to fourth aspects, wherein the deviation Δd from the average value d of the outer diameters of the coating removal portions of the plurality of optical fibers. And the core eccentricity Δe is 0.5 μm or less.

  An optical fiber array according to a sixth aspect of the present invention is the optical fiber array according to any one of the first to fifth aspects, wherein the adhesive has a viscosity before curing of 0.1 to 3.0 Pa · s ( 100-3000 cP (cps)) UV-curing or thermosetting resin.

  An optical fiber array according to a seventh aspect of the present invention is the optical fiber array according to any one of the first to sixth aspects, wherein the adhesive has a Young's modulus after curing of 500 MPa or more and a curing shrinkage of 5%. It is the following ultraviolet curable type or thermosetting type epoxy resin.

  According to an eighth aspect of the present invention, there is provided an optical fiber array manufacturing method comprising: a plurality of optical fibers having end portions removed from a plurality of V grooves formed in parallel on a V groove substrate; A step of aligning and arranging in a state of protruding from the end face of the groove substrate, and covering the plurality of optical fibers with a cover plate, and applying a first load to the plurality of optical fibers to form the V groove substrate and the cover A step of sandwiching the optical fiber with an adhesive, and applying an adhesive to the protruding tip of the optical fiber, and applying the adhesive to a space formed by the V-groove substrate and the lid plate sandwiching the plurality of optical fibers. A step of infiltrating by surface tension; and the adhesive is cured while applying a second load larger than the first load to the lid plate, and the plurality of optical fibers are made to be the V-groove substrate and the lid. A step of integrally fixing the plate, and the plurality Removing the protruding tip of the optical fiber to form end faces of the plurality of optical fibers that substantially match the end faces of the V-groove substrate and the lid plate. .

  An optical fiber array manufacturing method according to a ninth aspect of the present invention is the optical fiber array manufacturing method according to the eighth aspect, wherein the adhesive layer between the V-groove substrate and the cover plate and the plurality of optical fibers is used. The first load and the second load are selected such that the minimum value of the thickness is 5 nm to 1000 nm.

  An optical fiber array manufacturing method according to a tenth aspect of the present invention is the optical fiber array manufacturing method according to the eighth aspect, wherein an adhesive layer between the V groove of the V groove substrate and the plurality of optical fibers is formed. The first load and the first load are set such that a minimum value of the thickness is 5 nm to 1000 nm, and a minimum value of the thickness of the adhesive layer between the cover plate and the plurality of optical fibers is 5 nm to 500 nm. A load of 2 is selected.

  As described above, according to the present invention, a plurality of optical fibers from which end portions have been removed are aligned and pressed by a lid plate in a plurality of V grooves formed in parallel on a V-groove substrate, and the lid plate and the In the optical fiber array in which the V-groove substrate and the plurality of optical fibers are fixed with an adhesive, the minimum thickness of the adhesive layer between the V-groove substrate and the cover plate and the plurality of optical fibers is 5 nm to Since it is configured to have a thickness of 1000 nm, the V-groove substrate and the cover plate and the optical fiber fixed to them with an adhesive are difficult to peel off even in a harsh environment for a long period of time. Since it is difficult to cause displacement from the initial position, good characteristics can be maintained.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic end view showing an embodiment of an optical fiber array according to the present invention. The optical fiber array 10 includes, for example, an optical fiber array including four optical fibers as a plurality of optical fibers. It is.

  That is, the optical fiber array 10 includes a plurality (four) of V-grooves 21a, 21b, 21c, and 21d formed in parallel on the V-groove substrate 20 with the end portions removed. The optical fibers 1a, 1b, 1c, and 1d are aligned, and the lid plate 30 and the V-groove substrate 20 and the optical fibers 1a, 1b, 1c, and 1d that are covered with the optical fibers 1a, 1b, 1c, and 1d are fixed with an adhesive 40. It is a thing.

  The opening angle of each V groove 21a, 21b, 21c, 21d formed on the V groove substrate 20 is, for example, 60 °. Moreover, the radius of each optical fiber 1a, 1b, 1c, 1d is 62.5 micrometers, for example.

  The optical fiber array 10 has a minimum thickness tg, tc of the adhesive 40 layer between the V-groove substrate 20 and the cover plate 30 and the optical fibers 1a, 1b, 1c, 1d. It is defined as 1000 nm.

  In addition, the minimum value of the thickness tg of the layer of the adhesive 40 between each V groove 21a, 21b, 21c, 21d of each V groove substrate 20 and each optical fiber 1a, 1b, 1c, 1d is 5 nm to 1000 nm. It is desirable to be. The minimum value of the layer thickness tc of the adhesive 40 between the cover plate 30 and each of the optical fibers 1a, 1b, 1c, 1d is preferably 5 nm to 500 nm.

  Layer of adhesive 40 between each V-groove 21a, 21b, 21c, 21d and each optical fiber 1a, 1b, 1c, 1d and between the cover plate 30 and each optical fiber 1a, 1b, 1c, 1d By setting the minimum values of the thicknesses tg and tc within this range, as shown in the test results described later, the layer of the adhesive 40 is formed in the V-groove substrate 20 and the cover plate 30 and the adhesive 40 in a harsh environment. It is possible to absorb the stress generated due to the difference in thermal expansion coefficient.

  Therefore, the V-groove substrate 20 and the cover plate 30 and the optical fibers 1a, 1b, 1c, and 1d fixed thereto with an adhesive 40 are difficult to peel off even if they are left in a harsh environment for a long time. Since the optical axes of the fibers 1a, 1b, 1c, and 1d are unlikely to be displaced from the initial positions, good and stable characteristics can be maintained.

  That is, for example, it is possible to prevent an increase in transmission loss between the optical fibers 1a, 1b, 1c, and 1d due to the optical axis being shifted from a predetermined position. can do.

  Further, in this optical fiber array 10, it is desirable that the deviation Δd from the average value of the outer diameters d of the optical fibers 1a, 1b, 1c, 1d is 0.3 μm or less.

  In the optical fiber array 10, the core eccentricity Δe of each of the optical fibers 1a, 1b, 1c, 1d is desirably 0.4 μm or less.

  In the optical fiber array 10, the sum of the deviation Δd from the average value d of the outer diameters of the optical fibers 1a, 1b, 1c, and 1d and the core eccentricity Δe is preferably 0.5 μm or less. .

  By satisfying these deviation Δd and core eccentricity Δe, variations in the optical fibers 1a, 1b, 1c, 1d constituting the optical fiber array 10 can be suppressed, and the V grooves 21a, 21b, 21c, The minimum values of the layer thicknesses tg and tc of the adhesive 40 between 21d and each of the optical fibers 1a, 1b, 1c and 1d and between the cover plate 30 and each of the optical fibers 1a, 1b, 1c and 1d It is effective in restricting to a predetermined range.

  In the optical fiber array 10, the adhesive 40 is an ultraviolet curable or thermosetting resin having a viscosity before curing of 0.1 to 3.0 Pa · s (100 to 3000 cP (cps)). desirable.

  When the viscosity of the adhesive 40 before curing is less than 0.1 Pa · s (100 cP (cps)), the viscosity is too low. Therefore, the V-groove substrate 20 and the cover plate 30 and the optical fibers 1a, 1b, 1c, and 1d There is a possibility that the ultraviolet curable resin composition poured into the gap formed will flow out before curing, and when the viscosity of the adhesive 40 before curing exceeds 3.0 Pa · s (3000 cP (cps)). This is because the gap may not be filled reliably.

  Furthermore, the adhesive 40 is desirably an ultraviolet curable or thermosetting epoxy resin having a Young's modulus after curing of 500 MPa or more and a curing shrinkage of 5% or less.

  By selecting the adhesive 40 having such physical properties, the V-groove substrate 20 and the cover plate 30 and the optical fibers 1a, 1b, 1c, and 1d are fixed by the adhesive 40, and polishing and the like in the subsequent steps are performed. By handling, the tip of each optical fiber 1a, 1b, 1c, 1d can be reduced from being broken or broken.

  Here, in the optical fiber array 10 as described above, an optical fiber ribbon suitable for use as an optical fiber and a method for using the same will be described with reference to FIGS.

  The optical fiber ribbon is an optical fiber coated with an ultraviolet curable resin, arranged in a row with multiple fibers in a row, and coated in a lump. And in order to comprise the optical fiber array 10, the coating | coated of the edge part of two optical fiber ribbons 1A and 1B is removed, and each optical fiber is arrange | positioned alternately and it arranges in a horizontal line.

  For example, in the case of a four-fiber optical fiber ribbon 1A, the coating on the end is removed to form four optical fibers 1Aa, 1Ab, 1Ac, 1Ad. Similarly, in the case of the four-fiber optical fiber ribbon 1B, the coating on the end is removed to form four optical fibers 1Ba, 1Bb, 1Bc, 1Bd.

  Then, the optical fibers 1Aa, 1Ab, 1Ac, 1Ad of the optical fiber ribbon 1A and the optical fibers 1Ba, 1Bb, 1Bc, 1Bd of the optical fiber ribbon 1B are alternately arranged in a horizontal row. Eight optical fibers 1Aa, 1Ba, 1Ab, 1Bb, 1Ac, 1Bc, 1Ad, 1Bd are configured.

  In addition, the eight optical fibers 1Aa, 1Ba, 1Ab, 1Bb, 1Ac, 1Bc, 1Ad, and 1Bd are arranged one by one in at least eight V-grooves 21a to 21h formed in parallel on the V-groove substrate 20. And the optical fiber array 10 provided with the eight optical fibers 1Aa-1Bd can be comprised by covering the cover board 30 and fixing with the adhesive agent 40. FIG.

  Next, the manufacturing method of said optical fiber array 10 is demonstrated.

  (1) First, a plurality of optical fibers 1a, 1b,..., From which end coatings have been removed, are placed on a plurality of V grooves 21a, 21b,. The groove substrate 20 is aligned and protruded from the end face of the groove substrate 20.

  For example, when the optical fiber array 10 is composed of 16 optical fibers 1a to 1p, a V-groove substrate 20 having at least 16 V-grooves 21a to 21p is prepared.

  Then, the coatings of the two 8-fiber optical fiber ribbons 1A and 1B are removed, the optical fibers 1Aa to 1Ah and 1Ba to 1Bh are exposed for a predetermined length, and are superposed in two upper and lower stages.

  The optical fibers 1Aa to 1Ah and 1Ba to 1Bh of the two optical fiber tape cores 1A and 1B that are overlapped are arranged in a horizontal row alternately, and then one in each of the 16 V grooves 21a to 21p. Place one by one.

  (2) Next, the optical fibers 1 a, 1 b,... Are covered with the cover plate 30, and the first load is applied to hold the optical fibers 1 a, 1 b,. To do.

  For example, when the optical fiber array 10 is composed of 16 optical fibers 1a to 1p, each optical fiber 1Aa, 1Ba,..., 1Ah, 1Bh is sandwiched between the V grooves 21a to 21p and the cover plate 30.

  At this time, each of the optical fibers 1Aa to 1Bh is bent between the V grooves 21a to 21p and the covering portion, so that a force is generated to lift from the V groove due to the rigidity of the optical fiber itself. Therefore, the first load is selected so that the optical fibers 1Aa to 1Bh are not completely in contact with the V grooves 21a to 21p while slightly adjusting the distance between the V groove substrate 20 and the cover plate 30. To do.

  (3) Next, a space formed by the V-groove substrate 20 and the cover plate 30 that apply the adhesive 40 to the protruding tips of the optical fibers 1a, 1b,... And sandwich the optical fibers 1a, 1b,. The adhesive 40 is permeated into the (gap) by its surface tension.

  For example, when the optical fiber array 10 is configured with 16 optical fibers 1a to 1p, the adhesive 40 is applied to the protruding portions of the optical fibers 1Aa to 1Bh, and the adhesive 40 is permeated into the sandwiching portion by the surface tension. .

  (4) Next, the adhesive 40 is cured while applying a second load larger than the first load to the cover plate 30, and the optical fibers 1 a, 1 b,. And fix together.

  At this time, as the second load, a load that presses the optical fibers 1a, 1b,... To the extent that they are completely in contact with the V grooves 21a, 21b,.

  By selecting the first load and the second load, the minimum thickness tg, tc of the layer of the adhesive 40 between the V-groove substrate 20 and the cover plate 30 and each of the optical fibers 1a, 1b,. Becomes 5 nm to 1000 nm.

  Further, by selecting the first load and the second load, the thickness of the layer of the adhesive 40 between each V groove 21a, 21b,... Of the V groove substrate 20 and each optical fiber 1a, 1b,. The minimum value of the thickness tg is 5 nm to 1000 nm, and the minimum value of the thickness tc of the adhesive 40 between the lid plate 30 and each of the optical fibers 1a, 1b,... Is 5 nm to 500 nm. .

  (5) Next, the protruding tips of the optical fibers 1a, 1b,... Are removed to form end faces of the optical fibers 1a, 1b,.

  Table 1 shows an environmental test (boiling test) with 40 types of samples on an optical fiber array prepared by changing the thickness of the layer of the adhesive 40 by changing the first load and the second load. Is a table in which peeling and transmission characteristics were evaluated.

  The peel test was conducted by placing the optical fiber array in boiling water and examining the occurrence of peeling after a lapse of a predetermined time. ○ indicates a good state where no peeling occurred (passed), and x indicates peeling. Indicates a state (failed).

The transmission characteristics are ◎ (accepted) when the connection loss with a standard PLC (Planar Lightwave Circuit) is 0.1 dB or less, ◯ (accepted) when 0.3 dB or less, and 0.5 dB or less. The thing is △ (pass), and the thing exceeding 0.5 dB is set to x (failure). The measurement wavelength is 1550 nm.

  As is apparent from the test results, the optical fiber array of the present invention peels off the V-groove substrate and the cover plate from the optical fiber fixed with an adhesive even when placed in a harsh environment for a long period of time. Since the optical axis of the optical fiber is less likely to be displaced from the initial position, good characteristics can be maintained.

1 is a schematic end view showing an embodiment of an optical fiber array according to the present invention. FIG. It is a perspective view which shows two optical fiber tape core wires. It is a perspective view which shows the assembly arrangement | positioning of two optical fiber tape core wires.

Explanation of symbols

1a, 1b, 1c, 1d Optical fiber 1A, 1B Optical fiber ribbon 1Aa, 1Ab, 1Ac, 1Ad Optical fiber 1Ba, 1Bb, 1Bc, 1Bd Optical fiber 10 Optical fiber array 20 V-groove substrates 21a, 21b, 21c, 21d V groove 30 Lid 40 Adhesive

Claims (10)

A plurality of optical fibers from which end portions have been removed are arranged and arranged in a plurality of V grooves formed in parallel on the V groove substrate and pressed by a cover plate, and the cover plate, the V groove substrate, and the plurality of light beams are arranged. In an optical fiber array in which fibers are fixed with an adhesive,
An optical fiber array, wherein a minimum value of a thickness of an adhesive layer between the V-groove substrate and the cover plate and the plurality of optical fibers is 5 nm to 1000 nm.   The minimum value of the thickness of the adhesive layer between each V-groove of the V-groove substrate and the plurality of optical fibers is 5 nm to 1000 nm, and the adhesive between the lid plate and the plurality of optical fibers. 2. The optical fiber array according to claim 1, wherein the minimum value of the layer thickness is 5 nm to 500 nm.   3. The optical fiber array according to claim 1, wherein a deviation Δd from an average value d of the outer diameters of the plurality of optical fibers is 0.3 μm or less.   4. The optical fiber array according to claim 1, wherein a core eccentricity Δe of the plurality of optical fibers is 0.4 μm or less.   5. The sum of the deviation Δd from the average value d of the outer diameters and the core eccentricity Δe in the coating removal portions of the plurality of optical fibers is 0.5 μm or less. 2. An optical fiber array according to item 1.   6. The adhesive according to claim 1, wherein the adhesive is an ultraviolet curable or thermosetting resin having a viscosity before curing of 0.1 to 3.0 Pa · s (100 to 3000 cP (cps)). The optical fiber array of any one of Claims.   The adhesive is an ultraviolet curable or thermosetting epoxy resin having a Young's modulus after curing of 500 MPa or more and a curing shrinkage of 5% or less. The optical fiber array described. Arranging a plurality of optical fibers from which end coating has been removed in a plurality of V-grooves formed in parallel on the V-groove substrate, with their tips protruding from the end face of the V-groove substrate;
Covering the plurality of optical fibers with the lid plate, and applying a first load to sandwich the plurality of optical fibers between the V-groove substrate and the lid plate;
Applying an adhesive to the protruding tip of the optical fiber, and allowing the adhesive to penetrate into the space formed by the V-groove substrate and the lid plate sandwiching the plurality of optical fibers by its surface tension;
Curing the adhesive while applying a second load larger than the first load to the lid plate, and fixing the plurality of optical fibers integrally with the V-groove substrate and the lid plate; ,
Removing the protruding tips of the plurality of optical fibers to form end faces of the plurality of optical fibers substantially matching the end faces of the V-groove substrate and the lid plate;
An optical fiber array manufacturing method comprising:   The first load and the second load are selected so that the minimum value of the thickness of the adhesive layer between the V-groove substrate and the cover plate and the plurality of optical fibers is 5 nm to 1000 nm. The method of manufacturing an optical fiber array according to claim 8.   The minimum value of the thickness of the adhesive layer between the V-groove of the V-groove substrate and the plurality of optical fibers is 5 nm to 1000 nm, and the adhesive layer between the lid plate and the plurality of optical fibers 9. The method of manufacturing an optical fiber array according to claim 8, wherein the first load and the second load are selected so that a minimum thickness value is 5 nm to 500 nm.

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