JPH10268166A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain and prevent the occurrence of the dislocation of an optical fiber, and improve the positional accuracy thereof for an optical element. SOLUTION: This module is formed out of a substrate 2 having an optical element 5 laid thereon as well as a groove for laying an optical fiber 1 optically coupled to the optical element 5, and an optical fiber pressing lid body 3 mounted on the substrate 2. In addition, the lid body 3 has through-holes 4 reaching the optical fiber 1 across an optical fiber abutting surface and the opposite surface thereof, and is mounted on the substrate 2. A jointing material is fed from the through-holes 4 for fixing the optical fiber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module as an optical transceiver in optical fiber communication.

[0002]

2. Description of the Related Art A conventional optical module is shown in FIG.
1995 IEICE General Conference C-184).
In FIG. (A) is a plan view of the optical module M _1, (b) is a side view. As shown in the figure, a groove 7 such as a V-groove for installing an optical fiber 1 is provided on a substrate 2 made of silicon or the like, and glass, silicon or the like is provided on the surface of the substrate 2 on which the optical fiber 1 is installed. And a cover 3 provided with a groove 9 such as a V-shaped groove for pressing the optical fiber 1 and the optical fiber 1 is fixed to the two grooves 7 and 9 with an adhesive. One end of the optical fiber 1 is optically coupled to an optical element 5 mounted on an optical element mounting portion 2a on the substrate 2, and the optical element 5 is an LED or an LD (Laser Diode: semiconductor laser element). ) And a light receiving / emitting element such as a photoelectric conversion light receiving element such as a PD (Photo Diode: photodiode) and an APD (Avalanche Photo Diode: Avalanche photodiode). The drive of the optical element 5 or the extraction of the output is performed through the electrode 6.

FIGS. 8A to 8D are diagrams for explaining a conventional method of installing and fixing the optical fiber 1.
It is process drawing in the cross section of the BB line of FIG.5 (a).
(A) is a step of installing the optical fiber 1 in a first V-groove 7a formed on one main surface of the substrate 2, and (b) is made of an adhesive or a foil-like solder so as to cover the optical fiber 1. A step of supplying the bonding material 8; (c) is a second step corresponding to the first V groove 7a;
(D) is a step of covering the lid 3 (pressing plate) provided with the V groove 9a from above the optical fiber 1, and (d) pressing the lid 3 from above the substrate 2 using a pressing jig or the like. . At this time, the bonding material 8 is cured in (d). When the bonding material 8 is an adhesive, it is cured by heating, or when the bonding material 8 is solder, the solder is once heated and melted to be cured. Further, by pressing the lid 3 in (d), the bonding material 8 enters the first V-groove 7a, the second V-groove 9a and the gap between the substrate 2 and the lid 3, thereby improving the adhesiveness. I am trying to do.

[0006] FIG. 6 is a plan view showing a configuration in which four optical fibers 1 can be juxtaposed, and four optical elements 5 are provided corresponding to the optical fibers 1.

Further, as another conventional example, alignment grooves (a plurality of V-shaped grooves) for installing an optical fiber array on the surface of a mounting board are disclosed.
Groove), a part of the alignment groove is provided with a deeper part than the others, and the optical fiber array is fixed at that part with solder,
An optical array module of a type that directly supports an optical fiber array at another portion is known (see C-355 Spring Meeting of the Institute of Electronics, Information and Communication Engineers, 1994).

[0006]

However, in the conventional installation-fixing method shown in FIG. 8, the optical fiber 1 can be installed on the substrate 2 along the first V-groove 7a with high accuracy. For 3, the bonding material 8 easily intervenes in the gap between the second V structure 9 and the optical fiber 1, and the optical fiber 1 is hard to be directly supported by the second V groove 9 a of the lid 3. As a result, the bonding material 8
Of the optical fiber 1 due to deformation and flow at the time of heat curing, or the bonding material 8 expands and contracts due to ambient temperature fluctuation after assembling the optical module, and the optical fiber 1 is displaced. There was a problem.

Further, as in the above-mentioned other conventional example, when a part of the alignment groove is formed as a deeper groove and bonding is performed only there, and the optical fiber is directly supported by the other part of the alignment groove,
Although the positional accuracy of the optical fiber is improved, it is necessary to form two large and small grooves for each alignment groove. Therefore, it takes time and effort to manufacture the mounting board or the holding plate, and there is a problem that the manufacturing process is complicated and the manufacturing cost is increased.

Further, as shown in FIG. 8, in the method of supplying the bonding material 8 before holding the optical fiber 1 with the lid 3, the optical fiber 1, the substrate 2, the lid 3 and the like are formed when the bonding material 8 is cured by heating. It is necessary to put all components to be mounted in the heating device. In this case, thermal stress such as tensile stress, compressive stress, composition fluctuation, heat shock, etc. is applied to the optical element 1, the substrate 2, and the optical element 5 which is mounted on the optical axis of the optical fiber 1 and is generally composed of a semiconductor element. Gives stress. This means that substrate 2
Causes a warp, and causes a decrease in reliability of the optical element 5.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to provide an optical module which can be manufactured at low cost and has improved positional accuracy of an optical fiber.

[0010]

An optical module according to the present invention comprises a substrate having an optical element mounted on a substrate, a groove for installing an optical fiber to be optically coupled to the optical element, and a substrate mounted on the substrate. A lid for pressing the optical fiber to be placed, wherein the substrate and / or the lid are provided with a through-hole penetrating between the optical fiber abutting surface and the opposite surface. A bonding material is supplied from the hole to fix the optical fiber.

An optical module according to the present invention has a substrate having an optical element mounted on a substrate, a groove for installing an optical fiber to be optically coupled to the optical element, and an optical module mounted on the substrate. A cover for pressing the fiber, wherein a groove crossing the groove for setting the optical fiber is provided from one side to the opposite side on the substrate, and a bonding material is inserted through the groove crossing the groove for setting the optical fiber. To fix the optical fiber.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
This will be described with reference to FIGS. 1A and 1B show a basic configuration of an optical module M according to the present invention. FIG. 1A is a plan view of the optical module M, and FIG. 1B is a side view of the optical module M when the lid 3 has a V-groove for pressing an optical fiber. FIG. 3A is a partially broken cross-sectional view taken along a wavy line in FIG. 4A, and FIG. 4C is a side view of the optical module M when the lid 3 has no groove for pressing an optical fiber.

In FIG. 1, 1 is an optical fiber, 2 is a substrate made of silicon or the like, 3 is a cover made of glass, silicon or the like, 4 is an optical fiber contact surface of the cover 3 and its back surface (opposite surface), That is, a through hole penetrating between the lower surface and the upper surface of the lid 3 and reaching the second V-groove 9a and the optical fiber 1 is denoted by L
An optical element including a semiconductor light receiving / emitting element such as a light emitting element such as an ED and an LD and a photoelectric conversion light receiving element such as a PD and an APD.
Is an optical element mounting portion, 6 is an electrode for supplying drive power to the optical element 5 or obtaining an output from the optical element 5, 7a is a first V-groove provided in the substrate 2, 9a is a lid 3 The second provided
V-groove. In FIG. 1, the same parts as those in FIG. 5 are denoted by the same reference numerals.

FIG. 2 shows another embodiment, in which (a) shows four optical fibers 1 juxtaposed to cover the entire optical fiber 1.
FIG. 2B is a plan view of an optical module M having two through holes 4a, 4a, and FIG. 2B is an optical module M having two through holes 4b, 4b in which four optical fibers 1 are juxtaposed and two optical fibers 1 are covered. FIG. In (a), the through holes 4a, 4a are
Although one is provided, one may be provided. Also, three or more may be provided. In (b), the through holes 4b, 4b are substantially 1
It is provided at a position of 80 ° rotational symmetry, a so-called oblique position.

FIG. 3 shows still another embodiment, in which (a) shows a type in which four optical fibers 1 are juxtaposed, and a V-groove 1 extending across all the optical fibers 1 so as to cross all the four optical fibers 1.
0 is provided on the substrate 2 (the lid 3 is not shown), and (b) is a mortar-shaped through hole 4 on the substrate 2 of (a).
c, a plan view of a state where the lid 3 provided with 4c is mounted,
(C) is a side view of the optical module of (b). In the figure, through holes 4c, 4c are provided at positions corresponding to the V-groove 10, and a bonding material is supplied through the through-holes 4c, 4c, and the bonding material travels through the V-groove 10 to transmit all the optical fibers. 1 can be glued.

In the embodiment shown in FIG. 3, the size of the through holes 4c, 4c can be made smaller than that of the type shown in FIG. It has the effect of maintaining strength. Such through holes 4c, 4c can be easily formed by drilling or etching with a drill or the like.
The cross-sectional shapes of c and 4c may be cylindrical, and the planar shape may be elliptical or elliptical. Further, the V groove 10 has a U-shaped section.
The groove may be a mold, a concave shape, an inverted trapezoidal shape, or the like.

FIG. 7 is a view for explaining the manufacturing process of the optical module M according to the present invention, and is a process drawing in a section taken along the line AA in FIG. FIG. 2A shows a process of installing the optical fiber 1 in a first V-groove 7a as a groove formed on the substrate 2, and FIG. 2B shows a process in which a first V-groove 7a is formed so as to correspond to the first V-groove 7a. The cover 3 provided with the second V-groove 9a and the through-hole 4 is covered on the substrate 2, the optical fiber 1 is set between the first V-groove 7a and the second V-groove 9a, and the A step of pressing the fiber 1, a step (c) of supplying a bonding material 8 made of an adhesive such as an epoxy resin adhesive, solder, or the like from the through hole 4 while pressing the lid 3, and a step (d) of bonding material 8 is a step of curing by heating.

With such a configuration, the optical fiber 1 is pressed against the first V-groove 7a on the substrate 2 side and the second V-groove 9a on the cover body 3 in close contact with each other, and is held with high precision. In this state, the bonding material 8 can be supplied from the through holes 4 and cured. That is, the optical fiber 1 and the first V groove 7a
The optical fiber 1 can be fixed by positioning the optical fiber 1 in a state where the bonding material 8 does not intervene in the contact portion with the optical fiber 1 and the contact portion between the optical fiber 1 and the second V groove 9a. Therefore, there is no displacement of the optical fiber 1 due to the flow or the like during the heating and curing of the bonding material 8, and high-precision installation can be performed.

In view of the accuracy of the outer diameter of the optical fiber 1 and the processing accuracy of the V-groove, the distance between the optical fiber 1 and the V-groove is 0.1 to 0.1.
A gap is formed on the order of several μm, and as shown in FIG. 7D and FIG. 8D, the bonding material 8 can enter from the gap and fill the periphery of the optical fiber 1 with the bonding material 8. For example, some epoxy-based resin adhesives have a viscosity similar to that of water when heated, and easily enter the gap as described above. Further, even with an epoxy resin adhesive generally used for fixing the optical fiber 1 (for example, “EPOTEK353ND” manufactured by Epoxy Technology Inc.), it is possible to enter a gap of about 1 μm or less. Furthermore, in order to promote the penetration of the joining material 8, when the joining material 8 is heated and the viscosity decreases in FIG. 7D, the lid 3 may be temporarily lifted slightly upward.

When the joining material 8 is solder, a foil-shaped solder can be supplied from the through-hole 4 and heated, or solder melted by a soldering iron can be supplied from the through-hole 4. In this case, only the solder portion is locally heated, so that the influence of thermal stress on the optical element and the like caused by heating the entire substrate 2 can be suppressed or prevented. Of course, a non-heating type material such as an acrylic ultraviolet curing resin adhesive may be used as the bonding material 8.

In the present invention, the lid 3 does not necessarily need to be provided with the second V-groove 9a, but the first V-groove 7a
When the optical element mounting portion 2a is provided together with the optical element mounting portion 2a as shown in FIG.
Does not need to be formed lower than others, which is advantageous for coupling with the optical element 5. In addition, the first V groove 7a and the second V groove 9
a is not limited to the V-groove, but may be a U-shaped groove, a concave groove, an inverted trapezoidal groove, or the like.

FIG. 4 shows another embodiment, in which a groove 11 crossing the groove 7 for setting the optical fiber 1 is provided from one side to the opposite side on the substrate 2. 2A is a plan view showing four optical fibers 1 arranged side by side on a substrate 2, FIG. 2B is a plan view of an optical module having a cover 3, and FIG. 2C is a side view of FIG. FIG. Note that the same reference numerals as in FIG. 5 denote the same parts in FIG. In the present invention, a bonding material for fixing the optical fiber 1 is supplied through the groove 11. That is, the bonding material supplied from the end of the groove 11 in the state of (b) is transmitted through the groove 11 by capillary action or gravity caused by tilting the substrate 2 to fix the optical fiber 1.

In the invention shown in FIG. 4, the groove 11 is a V groove, but may be a U-shaped groove, a concave groove, an inverted trapezoidal groove, or the like. Further, a groove for installing the optical fiber 1 may be provided on the lid 3 side, and further, as shown in FIGS. 2 and 3, a through hole reaching the optical fiber 1 is provided in the lid 3 and / or the substrate 2, You may comprise so that a joining material may be supplied also from this through-hole.

The substrate 2 and the lid 3 of the present invention are made of Si single crystal (silicon), glass, ceramics, quartz, GaAs.
The first V-groove 7 a, the V-groove 10, the groove 11 of the substrate 2, and the second V-groove of the lid 3
V groove 9a and through holes 4, 4a, 4b can be easily formed by the following anisotropic wet etching.
The same applies to the case where a through hole is provided in the substrate 2. At this time, the material forming the substrate 2 and the lid 3 is preferably a material such as silicon whose etch rate greatly changes depending on the crystal orientation.

The material of the substrate 2 and the lid 3 is silicon,
V-grooves and inverted trapezoidal grooves can be formed on the substrate surface by precisely controlling the width and depth by anisotropic wet etching utilizing the fact that the etch rate of an alkaline etchant of silicon greatly depends on the crystal orientation. As the alkaline etchant, KOH, NaOH, EPW
(Ethylenediamine + pyrocatechol + water), hydrazine, TMAH (tetramethylammonium hydroxide) and the like are preferable. These alkaline etchants are such that the etch rate of the (100) or (110) plane of silicon is several tens to several hundreds of the etch rate of the (111) plane.
By selecting the crystal planes of the substrate 2 and the lid 3 so that the (111) plane, which is twice as large and has a small etch rate, becomes the side surface of the groove, fine processing with less undercut on the lower portion of the mask such as silicon oxide can be performed. It becomes possible. In particular, KOH has a large etch rate ratio of several hundred times, and is most suitable for fine processing.

The surfaces of the substrate 2 and the lid 3 to be etched are (100) planes, and V-grooves and the like are formed in the mask openings formed by straight lines parallel or perpendicular to the <011> direction by the above-described anisotropic wet etching. The side surfaces such as the V-grooves are (111) surfaces inclined by 54.74 ° with respect to the surfaces of the substrate 2 and the lid 3. Therefore, since the mask pattern is accurately reflected on the side surface such as the V-groove, if an optical device such as an optical fiber is held on this side surface, the same positional accuracy as that of the mask can be obtained, which is suitable as a substrate for passive alignment. is there. Also, V formed on the surfaces of the substrate 2 and the lid 3
The depth of the groove or the like and the difference between the V groove and the inverted trapezoidal groove are controlled by the etching time.

V-grooves and the like formed by such anisotropic wet etching can be easily formed with an alignment accuracy of ± 0.5 μm or less.

The first V groove 7a and the second V groove 9
The formation of the a, V-groove 10, the groove 11, the through holes 4, 4a, 4b, 4c is performed by a general etching method, a cutting method by drilling or dicing, a laser processing method, an injection molding method, a forging method,
A punching method or the like may be used.

Incidentally, the passive alignment means that light from an optical element is passed through an optical fiber on a trial basis, or light from the outside is received by an optical element on a trial basis through an optical fiber.
Rather than monitoring the light output and adjusting the coupling between the optical element and the optical fiber, the mounting part of the optical element and the optical fiber is designed with high precision in advance and mounted by silent gaze, pattern recognition, infrared image recognition, etc. This is an alignment method that allows a desired coupling state to be obtained just by performing the above operation.

In the present invention, an optical module may be provided in which two or more optical fibers are provided in parallel or non-parallel. In this case, a plurality of grooves corresponding to the optical fibers may be provided.

Thus, the present invention has the effect of preventing the optical fiber installed in the groove from being displaced and suppressing or preventing the occurrence of thermal stress in the optical element or the like due to the heating of the bonding material. Have.

The present invention is not limited to the above embodiment, and various changes may be made without departing from the scope of the present invention.

[0033]

According to the present invention, an optical fiber is provided in a groove of a substrate, a cover is put on the substrate, and a bonding material is supplied from a through hole of the cover and / or the substrate to fix the optical fiber. Or
A groove crossing the groove for setting the optical fiber is provided from one side to the opposite side on the substrate, and a bonding material is supplied through the groove crossing the groove for setting the optical fiber to fix the optical fiber. With the optical fiber installed in the groove pressed and held, the fixing by the bonding material is possible, and as a result, the bonding material is interposed in the contact part between the optical fiber and the groove and the contact part between the optical fiber and the lid. Without this, the displacement of the optical fiber can be suppressed and prevented, and the positional accuracy of the optical fiber with respect to the optical element is improved. In addition, the optical fiber can be directly supported in close contact with the groove, thereby suppressing displacement of the optical fiber due to expansion and contraction of the bonding material, and stabilizing the optical coupling of the optical fiber to the optical element.

Further, since the bonding material such as solder can be supplied while being locally heated from the through holes, the occurrence of thermal stress on the optical element and the like due to the heating of the entire substrate is suppressed and prevented, and Can improve the reliability of the optical module.

[Brief description of the drawings]

1A and 1B show an optical module according to the present invention, wherein FIG. 1A is a plan view of the optical module, FIG. 1B is a side view of an optical module having a V-groove in a lid, and FIG. It is a side view of a module.

FIGS. 2A and 2B show another embodiment of the present invention, wherein FIG. 2A is a plan view of an optical module in which two through holes covering all four optical fibers are provided in a lid, and FIG. Two optical fibers
It is a top view of the optical module which provided two through holes which cover one by one in the lid.

3A and 3B are other embodiments of the present invention, in which FIG. 3A is a plan view in which a V-groove is newly provided so as to cross four optical fibers and a lid is omitted, and FIG. 2 shaped grooves
FIG. 3C is a plan view showing a state in which two provided lids are covered, and FIG. 3C is a side view of FIG.

FIG. 4 shows another embodiment of the invention, wherein (a) is 4
A plan view of the one in which a groove that crosses the optical fiber of the book is provided from one side to the opposite side on the substrate and the lid is omitted,
(B) is a plan view showing a state in which a lid is mounted, and (c) is a side view of (b).

5A and 5B show a conventional optical module, FIG. 5A is a plan view of the optical module, and FIG. 5B is a side view of the optical module.

FIG. 6 is a plan view showing a conventional optical module in which four optical fibers are juxtaposed.

FIG. 7 illustrates a manufacturing process of the optical module of the present invention.
FIG. 2A is a process diagram illustrating a cross section taken along line AA of FIG.
Installing an optical fiber in the first V-groove of the substrate;
(B) a step of mounting the lid on the substrate and placing and pressing an optical fiber between the first V-groove and the second V-groove; (c) a step of supplying a bonding material from a through hole; d) is a step of heating and curing the bonding material.

FIG. 8 is a process diagram illustrating a manufacturing process of a conventional optical module in a cross section taken along line BB of FIG. 5A, wherein FIG. 8A illustrates a process of installing an optical fiber in a first V groove of a substrate. , (B)
Supplying a bonding material to cover the optical fiber,
(C) is a step of mounting the lid provided with the second V-groove from above the optical fiber, and (d) is a step of pressing the lid from above the substrate.

[Explanation of symbols]

 1: optical fiber 2: substrate 2a: optical element mounting part 3: lid 4: through hole 4a: through hole 4b: through hole 4c: through hole 5: optical element 6: electrode 7a: first V groove 8: bonding Material 9a: Second V-groove 10: V-groove 11: Groove

Claims (2)

[Claims] 1. A substrate having an optical element mounted on a substrate, a groove for installing an optical fiber to be optically coupled to the optical element, and a lid for pressing the optical fiber mounted on the substrate. Wherein the substrate and / or the lid are provided with a through hole penetrating between the optical fiber contact surface and the opposite surface. A substrate having an optical element mounted on the substrate, a groove for installing an optical fiber to be optically coupled to the optical element, and a lid for pressing the optical fiber mounted on the substrate. An optical module, wherein a groove crossing the groove for installing the optical fiber is provided from one side to the opposite side on the substrate.