JP3688935B2 - Optical module and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical module that can be suitably used, for example, in the field of optical communication and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, in an optical communication device or the like, an optical module that introduces light emitted from a semiconductor laser into an optical fiber and transmits light from the optical fiber has been used. In order to manufacture this type of optical module, passive alignment mounting using a substrate called a so-called silicon platform is generally performed.
[0003]
In the above passive alignment mounting, an optical fiber is placed in a V-groove provided on the surface of the silicon platform, and the optical fiber is fixed with a pressing plate. At this time, the optical fiber and the pressing plate are fixed on the silicon platform using a thermosetting resin or an ultraviolet curable resin.
[0004]
That is, the optical fiber is fixed after optical coupling between the tip of the optical fiber disposed in the V-groove formed in the silicon platform and accurately positioned and the light emitting part of the semiconductor laser chip fixed on the silicon platform. However, a technique using an adhesive such as a thermosetting resin or an ultraviolet curable resin for the fixing and a technique of pressing and fixing the optical fiber to the silicon platform side with a pressing plate are employed (for example, a special technique). (See Kaihei 9-69585).
[0005]
[Problems to be solved by the invention]
However, when fixing an optical fiber with a thermosetting resin, after adjusting the optical coupling, it is necessary to hold the optical fiber against the silicon platform so that it does not move and to apply and cure the thermosetting resin in this state. However, since it takes time to cure the thermosetting resin, it is necessary to always hold down the optical fiber while the resin is cured. Furthermore, since the displacement of the optical fiber is likely to occur during movement of the silicon platform in the pressed state or during resin curing, this reduces the yield.
[0006]
In the technology of applying UV curable resin to the optical fiber and the silicon platform, and then irradiating the UV curable resin with UV light to cure it, the optical fiber is fixed to the silicon platform. Even if the fiber can be fixed in a short time, the portion that is not irradiated with ultraviolet rays is not cured, so the optical fiber is not suitably fixed and the reliability is lowered. In addition, since this fixing is performed by curing by ultraviolet irradiation, it is necessary to select a material that transmits ultraviolet rays as a material of the pressing plate for preventing warping of the optical fiber. In addition, materials that transmit ultraviolet light are very limited, and quartz glass is usually used. However, since quartz glass is hard, its processing accuracy is poor, and further, it requires a long processing time and is unusable.
[0007]
Therefore, the present invention eliminates the conventional problems and improves the optical fiber mounting structure and method for optical coupling, thereby providing an excellent optical module that can be easily manufactured with high reliability and its manufacture. The purpose is to provide the law.
[0008]
[Means for Solving the Problems]
The above-described problems are solved by the following optical module and manufacturing method thereof.
[0009]
That is, the optical module of the present invention includes an optical element, an optical fiber that is optically connected to the optical element, and a pressing plate that covers the upper surface of the optical fiber on the substrate. Or it has a notch and it is being fixed to the said board | substrate via the photocurable and thermosetting adhesive agent arrange | positioned corresponding to the said through-hole and / or a notch .
[0010]
Further, the through hole and / or the notch formed in the pressing plate is arranged at a symmetrical position with respect to the optical axis of the optical fiber.
[0011]
Further, the substrate and the pressing plate are made of a material capable of anisotropic etching.
[0012]
In addition, the optical module manufacturing method of the present invention includes a step of disposing an optical fiber on a substrate, a step of disposing a photocurable and thermosetting adhesive on both sides of the optical fiber, and an optical fiber. A pressing plate having a through hole and / or a notch on both sides of the optical fiber on the upper surface of the optical fiber and the upper surface of the adhesive so that the through hole and / or the notch coincides with the position of the adhesive. And a step of irradiating the adhesive with light from at least through holes and / or notches of the pressing plate and curing, and a step of heating and curing the adhesive.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an optical module and a method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same member and the repeated description regarding it is abbreviate | omitted.
[0014]
Embodiment 1
FIG. 1A shows an optical module before mounting a pressing plate, which will be described later (or a state where the pressing plate is not mounted). That is, for example, on the substrate 1 having the V-shaped or U-shaped groove 4 formed by anisotropic etching, the optical element 2 which is a light emitting element such as a semiconductor laser is provided at the end of the groove 4. The optical fiber 3 that is optically coupled (optically connected) to the optical element 2 with high efficiency is disposed in the groove 4, and further, on the optical axis (= core axis 3 a) of the optical fiber 3 in the substrate 1. On the other hand, a photo-curable and thermosetting adhesive 5 is provided at a substantially symmetrical position.
[0015]
Then, as shown in FIG. 1B, a pressing plate 7 that covers a part of the adhesive 5 and the upper surface of the optical fiber 3 is disposed to constitute the optical module M1. In the figure, reference numeral 6 denotes a stopper groove for abutting the distal end portion (light incident portion) of the optical fiber 3, which is formed by dicing or the like.
[0016]
Here, in order to form the groove 4 suitably, the substrate 1 can be anisotropically etched with an alkaline aqueous solution such as potassium hydroxide or sodium hydroxide. A crystal substrate is used, but a GaAs single crystal, an InP single crystal material, or the like can be used as a material that can be anisotropically etched. In particular, it is not necessary to use a material that can be anisotropically etched. In this case, a groove or the like may be formed by cutting processing such as laser processing, dicing, and polishing in various materials. Further, the groove may be formed using a molded resin material.
[0017]
As the optical element 2, for example, various semiconductor lasers such as a Fabry-Perot type or DFB type semiconductor laser having a wavelength of 1.3 μm or 1.5 μm can be used.
[0018]
The adhesive material 5, at the and thermosetting photocurable epoxy resin or an acrylic resin, for example, UV: used which cure (UV wavelength of about 365 nm) or visible light (wavelength of about 400 to 480 nm). In addition, it is good to use what hardens | cures only with the light of a specific wavelength so that it may not harden | cure easily with light, such as a fluorescent lamp, for example.
[0019]
The pressing plate 7 is preferably one that can be easily manufactured by anisotropic etching, and a silicon single crystal or the like can be suitably used. The lower surface of the pressing plate 7, groove 9 forming a V-shape or U-shape is brought into contact with the upper surface of the fiber optic 3 are formed substantially symmetrical positions with respect to the bottom of the groove 9, i.e., the light A through hole 8 and / or a notch to be described later is formed by anisotropic etching at a position substantially symmetrical with respect to the optical axis of the fiber 3 (= core axis 3a).
[0020]
Thus, since a state that has entered the contact Chakuzai 5 lacks through-holes 8 and / or cut formed in the retainer plate 7 capable of fixing, the adhesive material 5 other than the adhesive force of the adhesive 5 through holes and In other words, fixing by locking including fitting with a notch or the like is performed, and the pressing plate 7 and the optical fiber 3 can be securely and firmly fixed without causing any displacement. Moreover, since the through-hole 8 and / or the notch are formed in the pressing plate 7, light such as ultraviolet rays can be transmitted. For example, even if an ultraviolet curable resin is used, the pressing plate 7 can be irradiated with ultraviolet rays. There is no need to select a transparent material, and a metal material such as stainless steel or aluminum that can be easily processed can be preferably used. Thereby, it can be produced by machining such as cutting and bending, and the degree of freedom of the processing shape of the pressing plate can be greatly improved.
[0021]
In particular can be used as a plate holding the silicon single crystal substrate which can be anisotropic etching, can be formed easily and highly accurately by anisotropic etching a guide groove 9 of the through-hole 8 and the optical fiber It becomes. This also with the control of the depth and diameter of the through hole 8 of the groove 9 of the pressing plate 7 (size) becomes easy, be by Ri together form a groove 9 and the through hole 8 in the photo process and an etching process This makes it possible to provide an optical module with excellent mass productivity. Further, since the plurality of through holes and / or notches are formed at symmetrical positions with respect to the optical axis of the optical fiber 3 , it can be stably pressed against the optical fiber 3 by the adhesive 5. Secure and accurate fixing to 3 is realized.
[0022]
Next, an example of a method for manufacturing the optical module M1 will be described.
[0023]
First, a substrate having a groove on the surface is prepared, and an optical element such as a semiconductor laser chip is fixed to one end side of the groove, and placed along the optical fiber in the groove. Then, as shown in FIG. 2A, the optical fiber 3 for exchanging light with the optical element is accurately positioned and arranged in the groove 4 of the substrate 1 to which the optical element is fixed. Next, an ultraviolet curable adhesive 5 for fixing the presser plate 7 is applied. Here, the adhesive 5 is applied and formed at a substantially symmetrical position with respect to the optical axis (= core axis) 3 a of the optical fiber 3.
[0024]
Next, a groove 9 on the lower surface and a pressing plate 7 in which a through hole 8 is formed in a substantially symmetrical position in the groove 9 are prepared. As shown in FIG. So that the upper surface of the optical fiber 3 is covered with the groove 9 formed on the lower surface of the pressing plate 7, and the pressing plate 7 is pressed toward the optical fiber 3 side. As a result, a protruding portion 5a is formed at the opening of the through hole 8 of the adhesive material 5, and this protrudes slightly upward due to the action of surface tension, capillary action, and the like.
[0025]
Next, as shown in FIG. 2 (c), a portion 5b of the adhesive 5 is cured by irradiating the portion 5b of the adhesive material 5 from above with the ultraviolet light source K irradiating the portion where the through hole 8 formed in the holding plate 7 is located. . As a result, the pressing plate 7 is fitted (locked) to the protruding portion 5a of the adhesive material 5 and is positioned and fixed. Then, the region (outer portion) 5c covered with the pressing plate 7 of the adhesive 5 is cured by heating the adhesive 5 at a predetermined temperature and time (for example, 80 to 120 ° C., 30 minutes to 2 hours). The optical module M1 can be manufactured.
[0026]
By adopting the above-described method, the pressing plate 7 can be temporarily fixed at the ultraviolet curing portion, and the position of the optical fiber 3 does not fluctuate during handling for heat curing as in the past, and the reliability is extremely high. A high optical module M1 can be manufactured.
[0027]
[Embodiment 2]
Next, an optical module M2 according to another embodiment of the present invention will be described. As shown in FIG. 3A, first, a substrate 11 having a V groove 14 for mounting the optical fiber 3 and a mounting groove 10 for mounting the adhesive 5 is prepared. The optical fiber 3 is placed on the V-groove 14 on the substrate 11 in the same manner as described above, and the optical element 2 is placed and fixed on an electrode (not shown).
[0028]
Then, after filling the mounting groove 10 with the adhesive 5 so as to rise from the surface of the substrate 11, and after adjusting the optical coupling state between the optical element 2 and the optical fiber 3, the optical coupling efficiency is maximized. In this state, as shown in FIG. 3B, a pressing plate 17 having a V groove 19 formed on the lower surface is placed so as to cover the upper surface of the optical fiber 3, and the adhesive 5 is cured in the same manner as described above. Let According to this optical module M2, the pressing plate 17 and the adhesive material 5 can be firmly locked, so that the optical fiber 3 can be more firmly fixed, and the optical module M2 with higher reliability is provided. be able to.
[0029]
[Embodiment 3]
Further, an optical module M3 according to another embodiment will be described. As shown in FIG. 4, the notch portion 28 into which the adhesive 5 can enter is provided in a substantially symmetrical position with respect to the V groove 19, that is, the optical axis (= core axis) 3 a of the optical fiber 3, The optical fiber 3 can be firmly and accurately fixed by the engagement between the notch portion 28 of the pressing plate 27 and the adhesive material 5.
[0030]
Since the formation of such a notch 28 is easier than the formation of the through hole shown in the first and second embodiments, various materials can be used.
[0031]
[Modified Example of Pressing Plate] Further, a modified example of the pressing plate that can be used in the present invention will be described. Pressing plate 37 shown in FIG. 5, it is provided with a cutout portion 38 at its four corners.
[0032]
According to the pressing plate 37, since the cutout portions 38 are provided at the four corners, it is possible to expect reliable curing by irradiating the adhesive from four directions with a curing light source . As this lack through-hole or cut formed in the holding plate can adopt various forms, also, it may be a pressing plate comprising both notches and the through hole, without departing from the gist of the present invention It can be implemented with appropriate changes within the scope.
[0033]
【The invention's effect】
According to the optical module and the manufacturing method thereof of the present invention, the adhesive force of the adhesive is simply obtained by utilizing the engagement between the plurality of through holes and notches formed on both sides of the optical fiber of the pressing plate and the adhesive. As compared with the conventional optical fiber fixing method using only the optical fiber, it is possible to provide an excellent optical module that can be fixed more firmly and accurately.
[0034]
Further, since the through hole or notch can be used as a light transmission window for curing the light curable adhesive, a press plate that is limited to a light transmissive material as in the prior art is exclusively used. The optical module can be provided with excellent versatility and high reliability.
[Brief description of the drawings]
1A and 1B are schematic views for explaining an embodiment of an optical module according to the present invention, in which FIG. 1A is a perspective view of an optical module before mounting a pressing plate, and FIG. It is a perspective view of an optical module.
FIGS. 2A to 2C are schematic cross-sectional views for explaining a method for manufacturing an optical module of the present invention, and are cross-sectional views taken along line AA in FIG.
3A and 3B are schematic views for explaining another embodiment of the optical module according to the present invention, in which FIG. 3A is a perspective view of the optical module before mounting the pressing plate, and FIG. 3B is after mounting the pressing plate. It is a perspective view of this optical module.
FIG. 4 is a schematic perspective view for explaining another embodiment of the optical module according to the present invention.
FIG. 5 is a perspective view schematically illustrating an example of a pressing plate used in the optical module according to the present invention.
[Explanation of symbols]
1, 11, 21: Substrate 2: Optical element 3: Optical fiber 4, 9: Groove 14, 19: V groove 5: Adhesives 7, 17, 27, 37, 47: Holding plates M1, M2, M3: Optical module

Claims (4)

An optical module comprising an optical element, an optical fiber that is optically connected to the optical element, and a pressing plate that covers an upper surface of the optical fiber on a substrate, wherein the pressing plate is formed of the optical fiber. It has a through hole and / or a notch on both sides, and is fixed to the substrate via a photocurable and thermosetting adhesive disposed corresponding to the through hole and / or the notch. An optical module. The optical module according to claim 1 wherein the pressing plate the through-holes and / or cut is formed in the outs, characterized in that it is disposed at symmetrical positions with respect to the optical axis of the optical fiber.   The optical module according to claim 1, wherein the substrate and the pressing plate are made of a material capable of anisotropic etching. A step of disposing an optical fiber on a substrate; a step of disposing a photocurable and thermosetting adhesive on both sides of the optical fiber; and an upper surface of the optical fiber and an upper surface of the adhesive , A step of disposing a pressing plate having a through hole and / or a notch on both sides of the optical fiber so that the through hole and / or the notch coincides with the disposition position of the adhesive; and at least the adhesive on the adhesive A method of manufacturing an optical module, comprising: a step of irradiating and curing light from a through hole and / or a notch of a pressing plate; and a step of heating and curing the adhesive.

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