JP3354337B2 - Optical module and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule type optical module connected to a connector, and more particularly to an optical module in which an optical input / output end is exposed by cutting.

[0002]

2. Description of the Related Art Conventionally, an optical module used for optical parallel communication or data parallel transmission using light using an optical fiber is a pigtail type optical module as shown in FIG. The type that was long connected behind was the mainstream. In addition, 102 is an optical element,
103 is a ferrule. However, in this type, since the optical fiber 115 that requires handling is long connected to the rear, care must be taken in handling the entire optical module, and even if the optical fiber 115 is broken due to disconnection, There was a problem that the whole had to be replaced.

Therefore, recently, as shown in FIG. 1, there is a demand for an optical module in which the end faces of the optical fiber are aligned with the end faces of the substrate and the ferrule and connected to an optical connector. In the figure, 11 is a substrate, 12 is an optical element, 14 is an optical fiber, 15 is a fiber end face, 17 is a ferrule, and these 11 to 17 constitute an optical module. Reference numeral 18 denotes a connector coupling portion, 19 denotes an optical fiber,
An optical connector is constituted by these 18 and 19.

In an ordinary optical module, after an optical fiber is passed through a ferrule and fixed with an adhesive, the end faces of a plurality of optical fibers are aligned by polishing or the like of the ferrule. Similarly, in the case of the optical module of FIG. 1, after the optical fiber 14 is bonded and fixed to the substrate 11 and the ferrule 17 with an adhesive, the end faces 15 of the optical fiber 14 are aligned by polishing or a rotating blade (for example, a polisher or a dicing saw). There is a need.

[0005] In the case of using a cutting process for finding the end face, the end face 15 of the optical fiber 14 must be optically smoothed, and under that condition, the substrate 11, the optical fiber 14, the ferrule 17, and Since the adhesive is polished or cut at the same time, cutting conditions are often limited.
In particular, since the adhesive entrains the cutting chips of the substrate 11 and the optical fiber 14 and adheres to the cutting blade and causes large scratches, it is very difficult to obtain an optical end face. For this reason,
There is also a method of cutting while performing electrolytic polishing of the blade, that is, while sharpening the blade. However, in this case, there are problems such as an increase in the size of the apparatus, a reduction in cutting speed, and a difficulty in increasing the throughput.

On the other hand, when polishing is performed, the conditions are
If it is optimized, it is possible to expose many optical modules at once, and since polishing itself is a process that is performed while sharpening, it is relatively easy to expose optical ends, and the throughput improvement of the end faces themselves is not possible. It is possible. However, there is a problem that it is difficult to increase the throughput as a whole because it is necessary to separate the substrates into individual substrates before or after polishing.

[0007]

As described above, conventionally, when exposing the optical input / output end of a ferrule type parallel optical module, the use of polishing requires a separate substrate separation step, and thus the overall throughput is increased. Is difficult to rise. Further, when cutting is used, there is a problem that the scale of the apparatus is increased, that is, the cost is increased, and the throughput is hardly increased.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to prevent cutting chips caused by an adhesive from being caught in a cutting blade even when an end face is formed by cutting. An object of the present invention is to provide an optical module and a method of manufacturing the optical module, which can prevent such a problem and can simplify the manufacturing apparatus and improve the throughput.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is to arrange an adhesive so that no adhesive is present at a cut portion when an optical input / output end is exposed by cutting.
That is, the present invention provides a substrate having a plurality of optical fibers, a plurality of grooves for positioning these optical fibers formed on one main surface, and disposing the optical fibers in the respective grooves of the substrate. A ferrule for pressing and fixing the fiber to the substrate side with at least one light input / output end of the fiber and a substrate end face aligned, and an adhesive for bonding and fixing the optical fiber to the substrate Wherein the adhesive is formed at least on a surface where the substrate and the optical fiber are in contact with each other, and is separated from an optical input / output edge of the optical fiber which is flush with a substrate end surface. It is characterized by.

According to the present invention, there is also provided a method of manufacturing an optical module having the above-described structure, wherein a plurality of grooves for positioning an optical fiber are formed on a substrate having a main surface formed thereon, except for a region where an adhesive is to be formed. Forming a resist on the substrate, depositing an adhesive made of a solder metal on a portion of the substrate not covered with the resist, and removing the resist together with an adhesive on the resist. And a step of bonding and fixing a ferrule to the substrate with the optical fiber disposed in the groove of the substrate; and cutting the substrate and the ferrule together with the optical fiber in a region where the adhesive is not provided, and forming a light input / output end. And a step of forming

Here, preferred embodiments of the present invention include the following. (1) An optical element that optically couples to the optical input / output end on the other end of the optical fiber is provided on the substrate. (2) The plurality of grooves are provided in parallel, and the light input / output end should be exposed in a direction perpendicular to the grooves or in a direction slightly inclined from the perpendicular surface. (3) The adhesive shall be solder metal or resin.

[0012]

According to the present invention, since the adhesive is arranged away from the light input / output edge of the optical fiber which is flush with the substrate end face, the light input / output end is exposed at the portion without the adhesive. For cutting can be done. Therefore, the cutting blade is not caught by the adhesive, so that sharpening at the time of cutting becomes unnecessary. For this reason, the end face can be formed with a relatively simple device, and the throughput can be improved.

Further, by employing a vapor deposition of a solder metal and a lift-off method for forming the adhesive, it is possible to easily form the adhesive only on a necessary portion on the substrate, and to selectively form the adhesive. In addition, there is no inconvenience that the manufacturing process becomes large and complicated.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an exploded perspective view showing a basic configuration of the optical module according to one embodiment of the present invention. In the figure, reference numeral 11 denotes a substrate made of Si, alumina, or the like. An optical element 12 is provided on the substrate 11 and a plurality of grooves for positioning an optical fiber 14 are provided. An adhesive 13 made of a photocurable resin, solder, or the like is applied to a portion of the upper surface of the substrate 11 that does not span the end of the substrate.

Reference numeral 17 denotes a ferrule made of Si, alumina, or the like. In order to hold and fix the optical fiber 14 between the substrate 11 and the ferrule 17 via an adhesive 13, a groove is formed in the ferrule 17 similarly to the substrate 11. Are formed. The optical element 12 is a laser diode, a photodiode, or the like, and the optical fiber 14 is a single mode fiber, a multimode fiber, or the like.

When assembling the above members, the substrate 11
When the ferrule 17 is pressed and fixed on the substrate 11 in a state where the optical fiber 14 is arranged in the groove of the optical fiber 1,
4 is automatically positioned in the groove. At this time, the optical element side end face 16 of the optical fiber 14 is optically coupled to the optical element 12. Then, the substrate 11, the optical fiber 14, and the ferrule 17 are cut using a dicing saw or the like in a surface direction perpendicular to the groove in a region where the adhesive 13 is not provided, so that the optical input / output end 15 of the optical fiber 14 is exposed. I do. The basic configuration of the optical module thus produced is the same as that of FIG. 1 described above, except that the adhesive 13 is separated from the optical input / output end 15 of the optical fiber 14.

As described above, in this embodiment, when the optical end face is cut out by cutting, the end face can be cut out while avoiding a portion where the adhesive 13 is present. Therefore, the adhesive 13 entrains cutting chips and adheres to the blade. The optical end face can be easily formed by a small-scale apparatus without any need, and the optical end face is separated from the substrate in the same process, so that the throughput is high.

As an example, a comparison of the optical loss when the optical fiber is cut with a dicing saw under the same conditions when the optical fiber is cut with an adhesive and when the optical fiber is cut without the adhesive is shown. As shown in FIG. The horizontal axis represents the dicing saw feed speed, and the vertical axis represents the optical loss. When the blade feed speed is low, no light loss is observed, but it can be seen that the light loss tends to differ as the feed speed is increased to increase the throughput.
This measurement result is a result under a certain condition, and does not represent the case of all the conditions. However, it is recognized that the tendency almost coincides even if the condition changes.

In FIG. 2, the adhesive 13 is applied to the substrate 1 in advance.
1 or may be separately supplied in the form of a preform, and in any case, the adhesive 13 is configured so as not to span the portion that is cut off when the end face is exposed. For example, when solder is used for the adhesive 13, Au is deposited on the substrate 11 by means such as vapor deposition, sputtering, or plating.
A solder metal such as Sn, PbSn or PbIn (including an adhesive metal to the substrate, for example, Ti, Cr or the like, and a barrier metal for the solder, for example, Pt, etc.) is formed leaving a portion to be cut off when forming the optical surface. Make sure to remove only the parts without solder metal.

A state in which a minimum of about 10 μm of solder metal is not bridged on the light input / output edge of the optical module formed by this method can be realized, and the positional accuracy of the optical fiber is high (for example, a single mode fiber is used). In the case of the optical coupling described above, it is possible to realize a module that requires an alignment accuracy of 1 μm or less).

FIG. 4 shows an example of a method for forming an adhesive made of a solder metal. In this method, first, FIG.
As shown in (a), a resist 42 is applied on the substrate 41 so as to cover the cut portion 43. Next, as shown in FIG. 4B, a solder metal 44 is deposited on the entire surface. Thereafter, as shown in FIG. 4C, the resist 42 is removed, so that the solder metal 44 on the resist 42 is removed. That is, the solder metal 44 is patterned by the vapor deposition / lift-off method.

In the case where the required positional accuracy is lower, there is no particular limitation on the manufacturing method as long as the adhesive is not stretched over the light input / output edge, and the method is not limited to the case where the adhesive is solder and the method other than the evaporation lift-off. It can be manufactured, for example, metallization by sputtering, plating or screen printing can be used. When the adhesive is other than solder, for example, in the case of a resin-based adhesive, a method such as screen printing or spray coating using a metal mask can be used.

In these methods, as shown in FIG. 5, when mounting an optical element 52, an optical fiber and a ferrule, a patterned adhesive 53 is formed on a bar-shaped substrate 51 which is connected in a horizontal direction, and After bonding and fixing each member to 51, the substrate 51 is cut out together with the input and output end faces,
Multiple optical modules can be created at once. In addition, a new cutting into individual substrates can be performed in the same step as the end face cutting, and the throughput can be improved, that is, it can be manufactured at low cost.

Further, in the present invention, the ferrule is adhered and fixed on the substrate by applying an adhesive also to a portion other than the groove of the substrate. However, it is sufficient that the optical fiber is positioned and fixed in the groove of the substrate. It can be omitted. That is,
The adhesive may be formed at least on the contact portion between the substrate and the optical fiber. Furthermore, an optical element installed on the substrate is not always necessary, and a configuration in which an optical fiber is only mounted in the groove of the substrate may be used. For example, if an optical module having an optical fiber installed in a groove of a substrate is embedded in a wall, optical transmission can be performed through the wall by connecting connectors to the module on both sides of the wall. In addition, various modifications can be made without departing from the scope of the present invention.

[0025]

As described in detail above, according to the present invention, when the optical input / output end is exposed by cutting, the adhesive is arranged so that no adhesive is present in the cut portion. It is possible to prevent cutting chips from being caught in the cutting blade due to the agent. Therefore, it is possible to realize a ferrule-type optical module and a method of manufacturing the same, which can easily expose the optical input / output end without causing an increase in the scale of the manufacturing apparatus and a decrease in throughput.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic configuration of a ferrule type optical module compatible with an optical connector.

FIG. 2 is an exploded perspective view showing a basic configuration of an optical module according to one embodiment of the present invention.

FIG. 3 is a view for explaining effects of the embodiment.
FIG. 4 is a characteristic diagram showing a change in light loss with respect to a blade feed speed.

FIG. 4 is a sectional view showing a step of forming an adhesive made of a solder metal in the embodiment.

FIG. 5 is a perspective view showing a configuration of a main part of an optical module according to another embodiment.

FIG. 6 is a perspective view showing a basic configuration of a conventional pigtail type optical module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Substrate 12 ... Optical element 13 ... Adhesive 14 ... Optical fiber 15 ... Optical input / output end 16 ... Optical element side end face 17 ... Ferrule 41 ... Substrate 42 ... Resist 43 ... Cutting part 44 ... Solder metal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-227107 (JP, A) JP-A-2-289803 (JP, A) JP-A-5-264841 (JP, A) JP-A Sho 52- 148140 (JP, A) JP-A-63-163413 (JP, A) JP-A-63-175809 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/42 G02B 6 / 38

Claims (3)

(57) [Claims] 1. A substrate having a plurality of optical fibers, a plurality of grooves for positioning these optical fibers on one main surface, and the optical fibers arranged in the respective grooves of the substrate. A ferrule for pressing and fixing the fiber to the substrate side with at least one light input / output end of the fiber aligned with the substrate end face, and an adhesive for bonding and fixing the optical fiber to the substrate. Wherein the adhesive is formed at least on a surface where the substrate and the optical fiber are in contact with each other, and is separated from an optical input / output edge of the optical fiber that is flush with a substrate end surface. An optical module, comprising: 2. A substrate having a plurality of optical fibers, a plurality of grooves for positioning these optical fibers on one main surface, and the optical fibers arranged in the respective grooves of the substrate. A ferrule for pressing and fixing the fiber to the substrate side with one optical input / output end of the fiber aligned with the substrate end face, and an optical fiber fixed to the substrate and connected to the other optical input / output end of the optical fiber. An optical module comprising an optical element to be coupled and an adhesive for bonding and fixing the optical fiber to the substrate, wherein the adhesive is formed on at least a surface where the substrate and the optical fiber are in contact with each other, and an end surface of the substrate. An optical module, wherein the optical module is separated from an optical input / output edge of the optical fiber which is flush with the optical fiber. 3. A step of forming a resist on a substrate on which a plurality of grooves for positioning an optical fiber are formed on one principal surface except for a region where an adhesive is to be formed, and A step of vapor-depositing an adhesive made of a solder metal on a portion not covered with the resist and the resist, a step of removing the resist together with the adhesive on the resist, and an optical fiber disposed in the groove of the substrate. A step of bonding and fixing a ferrule to the substrate in a state, and a step of cutting the substrate and the ferrule together with the optical fiber in a region without the adhesive to form a light input / output end. Module manufacturing method.