JP2002277688A - Fiber array substrate, fixing structure of optical fiber array using the substrate, substrate for positioning optical fiber, and fixing structure of optical fiber using the positioning substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber array substrate in which the positioning of an optical fiber in a substrate thickness direction can be done only by adjusting the aperture width of a groove without requiring the adjustment of the depth of the groove for positioning the optical fiber in the substrate thickness direction. SOLUTION: A plurality of grooves 2 for positioning and aligning a plurality of optical fibers to be formed on a substrate 1 are constituted so as to support each optical fiber 10 by corner parts 3a, 3b formed on both the ends of the aperture part of each groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a fiber array substrate, an optical fiber array fixing structure using the same, an optical fiber positioning substrate, and an optical fiber fixing structure using the same.

[0002]

2. Description of the Related Art Conventionally, in an optical fiber array connected to an optical waveguide device such as an optical waveguide switch, it is necessary to position a plurality of optical fibers with high precision. A so-called fiber array substrate provided with a plurality of grooves for positioning and aligning a plurality of optical fibers is used, between two fiber array substrates, or between one fiber array substrate and one flat substrate. A plurality of optical fibers are sandwiched and fixed.

FIG. 9 is a perspective view of a fixing structure in which a conventional optical fiber array is sandwiched and fixed between two fiber array substrates. The two array substrates 11A and 11B are made of a zirconia substrate or a glass substrate, and the surfaces of the substrates 11A and 11B on the side supporting the optical fiber 12 have V-shaped grooves (hereinafter simply referred to as V grooves). 13) are arranged side by side. Each of the plurality of optical fibers 12 has a V-shaped groove 13 on both upper and lower sides (when the thickness direction of the substrate is the vertical direction).
And a gap 14 a at the bottom of the V-groove 13 and a gap 14 b between the optical fibers 12.
Is filled with an adhesive (not shown), and the plurality of optical fibers 12 (optical fiber array) are formed of two substrates 11A and 11B.
In between, each optical fiber 12 is positioned, sandwiched and fixed.

[0004] A fixing structure in which an optical fiber array is sandwiched and fixed between one array substrate and one flat substrate is as follows.
This is a structure in which one of the two array substrates 11A and 11B in FIG. 9 is replaced by a flat substrate, and the optical fiber array (each optical fiber 12) has a surface of the flat substrate on the flat substrate side. (Flat surface).

By the way, positioning between a plurality of optical fibers in an optical fiber array means positioning between a plurality of optical fibers in a horizontal direction (a direction in which the surface of the substrate expands) and a vertical direction (in a thickness direction of the substrate). In other words, in the horizontal direction, the distance between adjacent optical fibers is equal, and in the vertical direction, a plurality of optical fibers are at the same height position, or a plurality of optical fibers are individually determined heights. Position (not all optical fibers are at the same height,
Positioning each optical fiber so as to have a constant height difference). Therefore, in the fiber array substrate, a plurality of V grooves are equally spaced (center lines are equally spaced).
In addition, the grooves are formed so that the depth of each groove is such that the optical fiber to be supported can be supported at a predetermined height position. That is, the position of the optical fiber in the substrate thickness direction is adjusted by the groove depth of the V groove. Here, the positioning accuracy (permissible error range) between a plurality of optical fibers in the optical fiber array varies depending on the use of the optical fiber array, but is generally within 1 μm.

As a method of forming the V-groove in the fiber array substrate, generally, machining such as cutting or etching is used. But cutting tools (eg blades)
And the control of the etching rate is difficult, so that the groove depth of the V-groove cannot be controlled with high precision, which causes a decrease in the production yield (high cost) of the fiber array substrate (that is, high cost). This is a cause of defective products for which the above-described alignment accuracy (allowable error range) cannot be ensured).

In order to position and fix one optical fiber, a V-groove for positioning and supporting one optical fiber is formed in at least one of the pair of substrates, and the one optical fiber is inserted between the pair of substrates. In some cases, the position of the optical fiber to be positioned in the thickness direction of the substrate is adjusted by the depth of the V-groove, so that the same problem as described above occurs.

[0008]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention does not require adjusting the groove depth for positioning the optical fiber in the thickness direction of the substrate, and adjusts the position of the optical fiber in the thickness direction of the substrate. It is an object of the present invention to provide a fiber array substrate that can be performed only by adjusting the opening width. In addition, it is easy to adjust the direction and magnitude of the stress applied to the optical fiber to be positioned, sandwiched and fixed between the pair of substrates, and to relatively easily obtain a fixed state in which the performance deterioration of the optical fiber array is suppressed. It is an object of the present invention to provide an optical fiber array fixing structure that can be used. In addition, it is not necessary to adjust the groove depth for positioning the optical fiber in the substrate thickness direction, and the position of the optical fiber in the substrate thickness direction can be adjusted only by adjusting the opening width of the groove. The purpose is to provide. It is another object of the present invention to provide an optical fiber fixing structure in which the direction and magnitude of stress applied to an optical fiber to be positioned, sandwiched and fixed can be easily adjusted between a pair of substrates, and the performance deterioration of the optical fiber can be suppressed. And

[0009]

In order to achieve the above object, the present invention has the following features. (1) A fiber array having a plurality of grooves for positioning and aligning a plurality of optical fibers, each of the plurality of grooves being a groove for supporting an optical fiber at a corner at both ends of the opening. substrate. (2) An optical fiber array fixing structure in which a plurality of optical fibers are positioned, aligned, sandwiched and fixed between at least one of the pair of substrates comprising the fiber array substrate described in (1). (3) One substrate is made of the fiber array substrate described in (1) above, and the other substrate has a convex portion having a flat surface at the tip, which faces each of the plurality of grooves of the one substrate. The optical fiber array fixing structure according to the above (2), wherein the substrate supports the optical fiber on the flat surface at the tip of the convex portion. (4) Both substrates are made of the fiber array substrate described in (1) above, and each optical fiber is supported at the corners at both ends of both openings of each of the opposing grooves between both substrates. The fixing structure of the optical fiber array according to (1). (5) A substrate for positioning an optical fiber, comprising a groove for positioning the optical fiber, wherein the groove is a groove for supporting the optical fiber at the corners at both ends of the opening. (6) An optical fiber fixing structure in which at least one substrate is positioned, sandwiched and fixed between a pair of substrates composed of the optical fiber positioning substrate according to (5).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The fiber array substrate of the present invention has a plurality of grooves formed on at least one surface of the substrate for positioning and aligning an optical fiber array (a plurality of optical fibers). The feature is that the groove is configured to be supported. Also, the optical fiber positioning substrate of the present invention is characterized in that the optical fiber positioning groove formed on at least one surface is a groove configured to support the optical fiber at the corners at both ends of the opening. It is.

The fiber array substrate and the optical fiber positioning substrate of the present invention are positioned and supported by the substrate.
The optical fiber has a jacketed optical fiber core,
Any of the optical fibers with the jacket attached is included, and is not particularly limited.

In the above and the following description of the present specification, the term “fiber array substrate” means that a plurality of optical fibers to be used as an optical fiber array are arranged at regular intervals (predetermined regular intervals in the plane extending direction of the substrate), and Means a substrate on which a plurality of grooves for positioning and supporting are formed so that each optical fiber is at a predetermined height position. The term “substrate for positioning an optical fiber” refers to a substrate in which a groove for positioning and supporting one optical fiber is formed, or a plurality of optical fibers are disposed at non-equidistant intervals (in a predetermined direction in the surface expansion direction of the substrate). (Non-equal intervals) and a plurality of grooves for positioning and supporting each optical fiber at a predetermined height position. That is, in the case of supporting a plurality of optical fibers, it differs from the fiber array substrate in that the plurality of grooves are unequally spaced from each other. "Fiber array substrate"
And in any of the "optical fiber positioning substrate", when a plurality of optical fibers are positioned so as to be all at the same height position, a predetermined height difference is formed between the plurality of optical fibers In some cases.

The "groove for supporting the optical fiber at the corners at both ends of the opening" formed on the fiber array substrate and the optical fiber positioning substrate of the present invention is, as shown in FIG. 10, the opening width W1 is smaller than the outer diameter (diameter) D1 of the substrate 1 and the surface 1a of the substrate 1 and the groove 2
The corners 3a, 3b (the sides) at both ends of the opening of the groove, which are the intersections with the both side surfaces 2a, 2b, are the grooves 2 that come into contact with the outer peripheral surface of the optical fiber 10. In the groove 2 shown in FIG. 1, the surface 1a of the substrate 1 and both side surfaces 2a and 2b of the groove 2 intersect substantially perpendicularly to form corners 3a and 3b at both ends of the opening with an angle of about 90 °. However, as shown in FIG.
The angle between the two sides 2a, 2b of the groove 2 is an acute corner 4
a, 4b, and as shown in FIG. 2 (b), the angle formed between the surface 1a of the substrate 1 and both side surfaces 2a, 2b of the groove 2 is an obtuse corner 5a, 5b. Is also good. Also,
The corner portion may be subjected to a curved surface processing to eliminate the sharp portion in order to make the optical fiber hard to damage or the like. The opening width of the groove varies depending on the outer diameter (diameter) of the optical fiber. For example, in the case of an optical fiber having an outer diameter of 125 μm,
１２４124 μm, preferably 50-120 μm.

In the fiber array substrate and the optical fiber positioning substrate of the present invention, the groove for positioning the fiber is configured to support the optical fiber at the corners at both ends of the opening, and the opening width of the groove is reduced. The vertical position (substrate thickness direction) of the optical fiber can be changed simply by changing the position. For example, FIG. 3A and FIG.
3A, the opening width W1 of a groove having a corner having an angle of about 90 ° at both ends of the opening is changed, but the groove 2-1 of FIG. In comparison, in the groove 2-2 of FIG. 3B having a smaller opening width W1 of the groove, the position of the optical fiber 10 in the thickness direction of the substrate 1 (the direction of the arrow X1 in the figure) is higher than that of FIG. Position. Therefore, it is necessary to change the groove depth to adjust the position of the optical fiber in the thickness direction of the substrate, as in the conventional fiber array substrate and the optical fiber positioning substrate in which a V-groove is formed as the optical fiber positioning groove. Instead, the position of the optical fiber in the thickness direction of the substrate can be determined only by adjusting the opening width of the groove, whose dimensional control is relatively easy. Therefore, a fiber array substrate (positioning of optical fibers) that can position an optical fiber (one or a plurality of optical fibers) at a target position by forming a groove having a predetermined opening width by cutting or etching on the substrate. Substrate) can be manufactured with high yield.

FIG. 4 is a perspective view showing an optical fiber array fixing structure using two fiber array substrates according to one embodiment of the present invention. A pair of upper and lower substrates 1A and 1B is composed of a fiber array substrate, and the surfaces of the substrates 1A and 1B on the side supporting the optical fiber 10 have upwardly U-shaped (concave) grooves (the surface of the substrate and the groove). Grooves 2 whose both sides substantially perpendicularly intersect and whose both ends have an angle of about 90 ° at both ends are arranged in parallel. Multiple optical fibers 10 (optical fiber array)
Are supported by the corners 2a and 2b at both ends of the opening of the groove 2 on the upper and lower sides thereof, and are positioned with respect to each other. Further, the adhesive is applied to the gap 3a at the bottom of the groove 2 and the gap 3b between the optical fibers 10. (Not shown), and the plurality of optical fibers 10 are positioned, sandwiched and fixed between the pair of substrates 1A and 1B. The figure shows a pair of substrates (fiber array substrates) 1A and 1B and an end face 4 of an optical fiber 10 (optical fiber array) which are polished and flattened after bonding with an adhesive.

In FIG. 4, the opening width of the groove 2 provided on the lower substrate 1A (fiber array substrate) and the opening width of the groove 2 provided on the upper substrate (fiber array substrate) 1B are the same. May have different widths. Further, the opening width of each adjacent groove may be different.

As shown in FIG. 5, one of the pair of substrates (lower substrate 1A) is used as a fiber array substrate, and the other substrate (upper substrate 1B) is used as one substrate (fiber array substrate). 1) A substrate having a configuration in which a convex portion 6 facing each of the plurality of grooves 2 of 1A is provided, and the optical fiber 10 is supported on the tip surface (flat surface) of the convex portion 6 may be used. FIG. 5 shows only an opposing portion between one groove 2 and one convex portion 6.

As shown in FIG. 6, one of the pair of substrates (lower substrate 1A) is a fiber array substrate.
The other substrate (upper substrate 1B) may be a flat substrate (a substrate having no grooves or convex portions). FIG. 6 shows only one facing portion between one groove 2 and a flat substrate (front surface).

In the structure for fixing an optical fiber array using the fiber array substrate of the present invention shown in FIGS.
By changing the opening width of the groove 2 formed in the fiber array substrate, the direction and magnitude of the stress applied to the optical fiber change significantly, and the stress applied to the optical fiber and its direction are reduced by the groove depth of the conventional V-groove. This can be greatly changed as compared with the case of changing (the case of changing the contact position of the optical fiber to the inner surface of the groove). Accordingly, for example, by adjusting the opening width of the groove, as shown in FIGS. 7A and 7B, the concentration of stress at the center of the optical fiber is reduced (avoided), thereby damaging the optical fiber material. Is prevented or reduced,
In addition, birefringence due to the photoelastic effect is reduced, and polarization dependent loss and the like can be reduced. Further, it is possible to dare to apply a stress to the core of the optical fiber to control the light propagation characteristics (polarization characteristics) and the mode size (shape) of the emitted light.

In particular, in the optical fiber array fixing structure shown in FIGS. 5 and 6, the optical fiber is supported at three points as shown in FIG. 7B (corresponding to FIG. 6). , The stress concentration on the center (core portion) can be extremely reduced. In addition, in the structure of FIG. 5, in addition to the effect of the three-point support, the surface area of the surface of the substrate 1B having the convex portion 6 facing the optical fiber is increased, so that the bonding area with the adhesive is increased and the fixing strength is increased. And the effect of improving reliability is also obtained.

As shown in FIG. 8, grooves for fixing an optical fiber array using the fiber array substrate of the present invention are formed on both sides of the substrate (grooves for supporting optical fibers at the corners at both ends of the opening). Array substrate 1C on which 2 is formed
, The optical fiber array 10A is stacked in multiple stages via the fiber array substrate 1C (the optical fiber array and the fiber array substrate are alternately stacked), and the fiber is formed by forming grooves 2 on only one surface from both upper and lower sides. A structure in which an adhesive is filled between the array substrates 1A and 1B and gaps between the structures are provided. In the case of such a multi-stage optical fiber array structure, since the stress of the entire structure is applied to the optical fiber, the structure using the fiber array substrate having the conventional V-groove is more expensive than the case of the single-stage structure. The optical fiber was more susceptible to damage,
In the multi-stage optical fiber array structure using the fiber array substrate of the present invention, such damage can be significantly reduced.

In the present invention, an optical fiber array fixing structure using the above fiber array substrate (FIGS. 4 to 6).
Similarly to at least one of the pair of substrates,
Even when the optical fiber is positioned, pinched, and fixed using the optical fiber positioning substrate of the present invention, the same effect as the above-described fixing structure using the fiber array substrate can be obtained.

As described above, the fiber array substrate and the optical fiber positioning substrate of the present invention sandwich an optical fiber array (optical fiber) between a pair of substrates and apply an adhesive to a gap between the pair of substrates. A pair of substrates that are filled and used for a fixing structure of an optical fiber array (optical fiber) in which a substrate, an optical fiber array (optical fiber), and a substrate are bonded, and that holds and fixes the optical fiber array (optical fiber). There is a case where the optical fiber is used only for positioning and supporting the optical fiber by itself, not as a part of the optical fiber. Examples of such a substrate include a positioning substrate for an optical fiber array used as a transmission path of light from a semiconductor light emitting element in an optical parallel link module, and a positioning substrate used for a connection structure between an optical waveguide component and an optical fiber. Substrates and these positioning substrates used for a butt-connecting structure between fibers are exemplified. Even in such a usage mode, the position of the optical fiber in the thickness direction of the substrate can be adjusted by controlling the opening width of the groove, so that highly accurate positioning can be performed.

As the substrate used for the fiber array substrate (optical fiber positioning substrate) of the present invention, a known substrate such as a zirconia substrate, a glass substrate, or a silicon substrate can be used. In particular, when an optical fiber array (optical fiber) is positioned between a pair of substrates to form a fixed structure in which the optical fiber array (optical fiber) is sandwiched and fixed, a silicon substrate whose end face is easily polished is preferable. In addition, since silicon has a lower hardness than zirconia or the like, breakage due to damage to the fiber hardly occurs,
The beam shape is also improved and is preferred. The thickness of the substrate is not particularly limited, but is 100 to 10000 μm, preferably 400 to 1500 μm. In addition, as an adhesive to be filled between optical fibers or between a substrate and an optical fiber,
Known adhesives used for this type of fixing structure can be used, but a photocurable resin (ultraviolet curable type, visible light curable type), a thermosetting resin (for example, epoxy resin) and a resin having both of these functions simultaneously And the like are preferred.

In the fiber array substrate and the optical fiber positioning substrate of the present invention, the grooves are formed by grooving (cutting) by a dicing device, wet etching, dry etching, ultrasonic machining, electric discharge machining, stamping ( (Die) and various other methods.

In the fiber array substrate and the optical fiber positioning substrate of the present invention, the optical fibers to be positioned and supported include, for example, various types of optical fibers such as a single mode fiber for communication and a multimode fiber. It is also possible to apply stress in an arbitrary direction in the fiber to change the polarization state, interatomic distance, etc. of the propagating light, and change the light intensity, shape, polarization direction, wavelength (frequency), etc. of the emitted light. Fibers that have a structure that applies stress to the core around the core (for example, polarization-maintaining fibers), fibers with a structure and composition in which the refractive index of the core tends to change with stress, and photonic bands Fiber having a gap structure (a structure in which a lotus root-shaped hole or the like is formed around the core) or a crystal fiber (KLN, L
Fibers having a periodic structure of refractive index and composition in the length direction (fiber grating structure), fibers having two or more cores (one that controls and switches the coupling state of mutual fibers) And the like. The material of the optical fiber is not limited to quartz, but may be an optical fiber made of crystal or plastic (organic material).

[0027]

The present invention will be more specifically described below with reference to examples and comparative examples. (Example 1) A silicon substrate (500 μm thick) was straightened with a high-precision dicing apparatus by a high-precision dicing device so that an optical fiber having a core diameter of 50 μm and a core spacing of 128 μm was supported in a total of 18 lines. A groove with an opening width of 90 μm and an upward U-shaped cross section
Eight fibers were formed to produce a fiber array substrate. further,
Another fiber array substrate was prepared. Then, after positioning the optical fibers with the jacket stripped in each groove of one of the fiber array substrates and aligning and positioning the other array substrate, a thermosetting adhesive: Ecobond (Nippon Ablestick Co., Ltd.) ), And the fiber exit end face was mirror-polished with a mechanical polishing machine (FIG. 4). When the propagation loss of each optical fiber of the optical fiber array thus positioned and fixed was measured by a cutback method, it was 0.39 d on average.
B.

(Comparative Example 1) A high-precision dicing device has a blade tapered at 45 ° so that an optical fiber having a core diameter of 50 μm can be supported in a state where a total of 18 fibers are aligned at a core interval of 128 μm. Then, an opening width of 128 μm and a groove depth of 6 were formed on a zirconia substrate (thickness: 500 μm).
Create 18 parallel V-shaped grooves with a cross section of 4 μm,
A fiber array substrate was made. Further, another one identical to the fiber array substrate was prepared. Then, using these two fiber array substrates, the optical fiber array was sandwiched and fixed between the two substrates in the same manner as in Example 1, and the fiber emission end face was mirror-polished by a mechanical polishing machine (FIG. 9). Then, the propagation loss of each optical fiber of the optical fiber array produced in this manner was measured by a cutback method and found to be 0.5 dB on average.

The effect of reducing the propagation loss according to the first embodiment is that the optical fibers are supported by the V-grooves in the comparative example 1, so that the stress concentration on the core is intense.
Then, silicon is used for the substrate and each optical fiber is supported at the corners at both ends of the opening of the groove (U-shaped V-shaped groove), so that stress concentration on the core of the fiber can be reduced. This is probably because

[0030]

As apparent from the above description, according to the fiber array substrate of the present invention, it is not necessary to adjust the groove depth for positioning the optical fiber in the thickness direction of the substrate.
Since the position of the optical fiber in the substrate thickness direction can be adjusted only by controlling the opening width of the groove, the production yield can be improved, and the cost can be reduced as compared with the conventional fiber array substrate. In addition, by using the fiber array substrate of the present invention on at least one of a pair of substrates, positioning, sandwiching and fixing the optical fiber array, the performance of the optical fiber array is not deteriorated as compared with the conventional one, and Can be fixed in between. Further, according to the optical fiber positioning substrate of the present invention, it is not necessary to adjust the groove depth for positioning the optical fiber in the substrate thickness direction, and the position of the optical fiber in the substrate thickness direction is adjusted to the opening width of the groove. Since the adjustment can be performed only by the control, the production yield can be improved, and the cost can be reduced as compared with the conventional optical fiber positioning substrate. Further, by using the positioning substrate of the optical fiber of the present invention on at least one of the pair of substrates, the optical fiber is positioned, pinched, and fixed, without deteriorating the performance of the optical fiber as compared with the related art. It can be fixed between substrates.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an essential part showing an example of a groove in a fiber array substrate of the present invention.

FIGS. 2A and 2B are cross-sectional views of a main part showing another example of the groove in the fiber array substrate of the present invention.

FIG. 3 is an explanatory view showing that a position of an optical fiber in a substrate thickness direction changes depending on a groove width of a fiber array substrate of the present invention.

FIG. 4 is a perspective view showing an example of an optical fiber array fixing structure using the fiber array substrate of the present invention.

FIG. 5 is a sectional view of a main part showing another example of an optical fiber array fixing structure using the fiber array substrate of the present invention.

FIG. 6 is a cross-sectional view of a main part showing another example of an optical fiber array fixing structure using the fiber array substrate of the present invention.

7 (a) and 7 (b) are diagrams illustrating the effect of sandwiching and fixing an optical fiber array using the fiber array substrate of the present invention.

FIG. 8 is a perspective view of a multi-stage optical fiber array structure using the fiber array substrate of the present invention.

FIG. 9 is a perspective view showing a fixing structure of an optical fiber array using a conventional fiber array substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Groove 3a, 3b Corner of groove 10 Optical fiber

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Miura 4-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Electric Cable Industry Co., Ltd. Itami Works F-term (reference) 2H036 LA02 LA08 NA08 2H037 BA24 CA06 DA04 DA06 DA12

Claims (6)

[Claims] 1. A plurality of grooves for positioning and aligning a plurality of optical fibers, wherein each of the plurality of grooves is a groove for supporting an optical fiber at a corner at both ends of the opening. Fiber array substrate. 2. An optical fiber array fixing structure in which a plurality of optical fibers are positioned, aligned, sandwiched and fixed between at least one of the pair of substrates comprising the fiber array substrate according to claim 1. 3. One of the substrates comprises the fiber array substrate according to claim 1, and the other substrate has a convex portion having a flat surface, which is opposed to each of the plurality of grooves of the one substrate. 3. The structure for fixing an optical fiber array according to claim 2, wherein the substrate has an optical fiber supported on a flat surface at the tip of the convex portion. 4. A fiber array substrate according to claim 1, wherein both substrates are formed of said fiber array substrate, and each optical fiber is supported at a corner at both ends of both openings of each opposed groove between said two substrates. 3. The fixing structure of the optical fiber array according to 2. 5. An optical fiber positioning substrate, comprising a groove for positioning an optical fiber, wherein the groove is a groove for supporting the optical fiber at corners at both ends of the opening. 6. An optical fiber positioning substrate according to claim 5, wherein at least one of the substrates comprises a pair of substrates.
An optical fiber fixing structure in which an optical fiber is positioned, pinched, and fixed.