JPH06174943A - Mounting for optical fiber - Google Patents

Abstract

PURPOSE:To provide the optical fiber mounting method capable of adjusting the absolute position with a mounting holder only by the mechanical assembly with high accuracy, enhancing the productivity of various kinds of modules for which optical fibers are used, reducing the cost of production and facilitating the production of an arrayed module. CONSTITUTION:This optical fiber mounting method of positioning and fixing the optical fiber 3 into a groove formed on the surface of the mounting holder consists in applying a metallic coat 4 on the peripheral surface of the optical fiber 3, then pressing the optical fiber 3 to the mounting holder 1 side and positioning the optical fiber in the state of depositing a solder material 2 in the groove of the mounting holder 1 by using a mounting jig 5 formed with a reference plane in contact with the surface of the mounting holder 1 and a groove having an optical fiber contact part at the prescribed depth from this reference plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber mounting body in which optical fibers are mechanically aligned.

[0002]

2. Description of the Related Art In an optical transmission module or an optical switch module for optical communication, it is necessary to optically couple an optical semiconductor element such as a semiconductor laser or an optical waveguide to an optical fiber, and an optical axis adjusting method therefor. And, many proposals have been made so far regarding the optical fiber fixing method.

Most of the conventional methods for adjusting the optical axis and fixing the optical fiber adjust the optical axis so that the maximum value of the optical coupling can be obtained by actually passing the light and then the respective parts are somehow adjusted. It is a method of fixing by means of. Although these methods are already used in the actual product manufacturing process, it requires a considerable amount of skill and time to adjust the optical axis because of the delicate position adjustment, and the optical axis changes due to distortion and stress when fixing parts. Therefore, there is a problem that defective products are generated even if it takes a long process time to adjust the optical axis. That is, since the manufacturing process time is long, the cost of manufacturing itself is high, and the loss when a defective product occurs is larger than the material cost, which has been a factor of further raising the cost.

As another problem of such an optical monitoring method, it is said that the manufacturing difficulty increases when the optical fibers are arrayed, and the yield is reduced to a multiple of the number of arrays in the case of a single wire. There's a problem. Therefore, not only the manufacturing cost is significantly increased, but also the manufacturing of the product may be considerably difficult depending on the number of arrays.

On the other hand, there has been proposed a method of mounting an optical fiber without using an optical monitor. For example, there is a method of attaching an optical fiber by mechanical fitting and adjusting the position with mechanical processing dimensional accuracy. With this method, mounting and assembly can be performed by mechanical component mounting. In addition, since many optical fibers can be mounted at the same time, the manufacturing process and manufacturing time can be greatly reduced compared to the method of performing optical monitoring, and the loss when a defective product occurs is almost material. It depends on the cost. This method is particularly effective for mounting the optical fibers of the array, and a conventional example thereof is shown in FIG.

In FIG. 6, 1 is a mounting holder, 3 is an optical fiber, and the mounting holder 1 is formed, for example, by subjecting a Si substrate to anisotropic chemical etching to form a V groove. At this time, if the chemical etching mask is formed by photolithography similar to the semiconductor process, the mask can be processed with an accuracy of about 1 μm, and a large number of mounting holders 1 can be created at one time. This method
In principle, it is possible to mount the optical fiber with high accuracy, and the mounting method is performed as shown in FIG. 7, for example.

In FIG. 7, reference numeral 8 is an adhesive material for mounting, for example, an ultraviolet curable resin adhesive is used.
Further, 9 is a holding plate for mounting the optical fiber 3
A flat Si plate or the like is used so as to be uniformly pressed against the holder 1. The optical fibers 3 mounted by this method are mechanically aligned, and in particular, the array accuracy (mounting pitch) of the optical fibers 3 becomes extremely accurate.

However, in the method of mounting the optical fibers by mechanical fitting, the arrangement accuracy of the optical fibers, that is, the relative positional accuracy is actually high, but the absolute positional accuracy of the optical fibers is not always secured. was there.

First, the conventional optical fiber mounting body positions the optical fiber by making contact with the groove of the mounting holder. Therefore, the conventional mounting holder must realize a very precise surface state, The processing method was also limited. Further, the conventional jig for mounting an optical fiber has a function of simply pressing it as shown in FIG. 7, and it is possible to push the optical fiber into the groove of the mounting holder. It is not possible to control whether or not it is attached to. In other words, it is passive with respect to the groove processing accuracy of the mounting holder, and the mounting jig side cannot take any correction means for the groove depth accuracy, and how to change the external pressure, the pressure application angle, etc. I was not able to correct this. Furthermore, when the fixing material of the optical fiber touches the surface of the mounting jig, the mounting jig itself may be fixed, and it is not only necessary to keep the amount of the fixing material used properly, but also the fixing material is accidentally removed. It was necessary to stop the device when they contacted each other, and it was necessary to replace and adjust the mounting jig.

On the other hand, as a manufacturing method, the optical fiber mounting conditions in the same mounting holder are almost the same by simultaneous mounting, but the mounting conditions between a plurality of mounting holders do not necessarily match, and the adhesive amount at the time of mounting There is a problem that it slightly changes depending on the curing conditions, the pressure applied to the pressing plate, and the like. Generally, an optical fiber is often provided with an extra length of several tens of cm, and the method of holding the extra length of the optical fiber and the difference in the winding tendency direction at the time of manufacturing the optical fiber also affect the variation of the mounting conditions. When fixing the optical fiber with a metal such as solder, the thickness of the solder or the like and the thickness of the metal coating on the optical fiber tend to have dispersion,
Even when the processing states of the mounting holders are almost the same and the mounting holders are mounted under the same pressurizing condition, the deviation between the mounting holders tends to be large.

[0011]

As described above, in the conventional mounting technique by mechanical fitting, the position of the optical fiber in the V groove has a relative deviation for each mounting holder.
It was difficult to control the deviation between the mounting holders to several μm or less. This relative deviation is not a serious problem for a multimode fiber having a large core diameter, but a single mode fiber has a small core diameter of about 10 μm.
Since the allowable positional deviation is as severe as 1 to 2 μm or less, it easily becomes a problem. That is, it has been difficult to perform absolute position adjustment with respect to the mounting holder with high accuracy only by mechanical assembly.

The present invention has been made in consideration of the above circumstances, and an object thereof is to perform absolute position adjustment with respect to a mounting holder with high precision by only mechanical assembly. An object of the present invention is to provide an optical fiber mounting body capable of increasing the productivity of various modules using fibers, reducing the manufacturing cost, and facilitating the manufacture of arrayed modules.

[0013]

In order to solve the above problems, the present invention adopts the following configuration. That is, according to the present invention, in an optical fiber mounting body including a mounting holder having a groove formed on a main surface thereof and an optical fiber positioned and fixed in the groove of the mounting holder, the optical fiber mounting position varies depending on the surface state of the mounting holder. The feature is that the optical fiber does not come into direct contact with the mounting holder so that it does not fluctuate significantly, and it is fixed via a plastic material (generally a metal material) that is deformable according to the surface shape and has excellent mechanical holding characteristics. There is.

Further, according to the present invention, in an optical fiber mounting jig for positioning and fixing an optical fiber in a groove formed in a main surface of a mounting holder, a reference surface in contact with the main surface of the mounting holder and a predetermined surface from the reference surface. A groove having an optical fiber contact portion is formed in the depth to enable control of the optical fiber mounting height, and to prevent the mounting jig from being fixed to the optical fiber and the mounting holder by the optical fiber fixing material, It is characterized in that the surface of the optical fiber contact portion is coated with a material having low chemical compatibility or adhesiveness to the optical fiber fixing material.

Further, according to the present invention, in an optical fiber mounting method for positioning and fixing an optical fiber in a groove formed in a main surface of a mounting holder, a reference surface in contact with the main surface of the mounting holder and a predetermined depth from the reference surface. Using the mounting jig in which the groove having the optical fiber contact portion is formed, press the optical fiber toward the mounting holder side with the optical fiber fixing material deposited in the groove of the mounting holder to define the mounting position. It is characterized by that. Here, when a metal which is a plastic material is used as the optical fiber fixing material, it is desirable to apply a metal coating to the optical fiber.

[0016]

According to the present invention, the mounting position of the optical fiber can be regulated by the mounting jig irrespective of the groove machining accuracy of the mounting holder. Can be reduced to Therefore, the optical semiconductor device or the optical waveguide and the optical fiber can be coupled with high accuracy only by adjusting the mechanical position, and the mass production of the module requiring the optical fiber coupling, such as the optical transmission module or the optical switch module for the optical communication. Significant cost reduction is possible.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. Here, a V-groove type optical fiber mounting holder will be described as an example similar to the conventional example, but the groove shape, the material of the mounting holder, the processing method, etc. are not necessarily limited to the embodiments, and the optical fiber mounting holder is not limited to the embodiment. Similarly, the fixing material and the method of forming the fixing material are not limited.

FIG. 1 is a schematic sectional view showing the construction of an optical fiber mounting holder and a mounting jig for regulating the mounting height according to the first embodiment of the present invention. 1 is a mounting holder, 2 is an optical fiber fixing material (solder), 3 is an optical fiber, 3'is an optical fiber core, 4 is an optical fiber outer coat, 5 is a height-specific mounting jig, and 6 is a mounting jig. Reference numeral 5 is a fixing prevention film that prevents the optical fiber 3 and the mounting holder 1 from being fixed.

As the mounting holder 1, for example, a Si substrate having a V groove formed by photolithography and chemical etching is used. As the mounting jig 5, as in the mounting holder 1, a Si substrate having a V groove formed by photolithography and chemical etching can be used. The fixing prevention film 6 may be a dielectric film such as SiO ₂ or Si ₃ N ₄ and may be a material that easily causes compounding or adhesion with the fixing material 2. In particular, the base material of the mounting jig 5 is Si. In this case, a SiO ₂ film obtained by thermally oxidizing the Si surface can be used.

As the metal solder used for the fixing material 2, I
Materials having a relatively low melting point such as n, PbSn and AuSn are suitable in that strain and stress on the optical fiber can be reduced. These materials can be formed by vapor deposition or plating, and can be formed on a large number of mounting holders at the same time in a wafer state as in a normal semiconductor process. Further, it is desirable that the outer coat 4 of the optical fiber 3 is coated with a metal that the solder material is easily adapted to. For example, electroless plating (normal optical fiber) or electric field plating (carbon coated optical fiber) is used to coat Ni, Cr or the like. In some cases, it can be prepared by coating Au or the like on it.

As an example, the outer diameter of the optical fiber 3 is 125 μm.
The case of m will be described. Ni on the circumference of the optical fiber 3 1μ
m, followed by Au plating by 5 μm.
Since the thickness of the metal coating is a main parameter that determines the deviation correction range when the optical fiber is mounted, it is set to a value slightly larger than the mounting position deviation amount when the conventional method is used. (100) surface Si as the mounting holder 1
Thermal oxidation SiO ₂ film 200nm and Si ₃ N ₄ 400 on the substrate
nm, and mask width 15 by photolithography
An opening of 5 μm is formed, and V groove etching using a KOH solution is performed. The fixing material 2 has a Sn composition ratio of 20.
% And Au / Sn are multi-layer vapor-deposited or multi-layer plated so that the mask width is 100 μm and the thickness is 15 μm.
To be formed.

At this time, T is used as the base metal of the fixing material 2.
By forming a metal having a high reaction temperature such as i and Cr to a thickness of about 50 nm, it is possible to prevent the solder from peeling off from Si during melting and compounding (alloying) of the solder. Further, by forming the SiO ₂ film on the portion other than the region where the solder metal is formed, it is possible to prevent the loss due to the outflow of the solder. Furthermore, the fixing material 2 does not need to be formed in the entire region of the V groove of the mounting holder 1, and may be formed intermittently in the groove direction. When the solder is intermittently formed in the groove direction, the optical fiber mounting strength is slightly lowered, but the optical fiber 3
It is possible to reduce the stress applied to and to prevent the occurrence of cracks and the like.

The mounting jig 5 is in contact with the upper side of the optical fiber outer peripheral coat 4 and has a flat area (reference surface) in a state where the lower side of the optical fiber outer peripheral coat 4 and the solder 2 are alloyed. It is set so that it contacts the flat portion of the mounting holder 1 and the core 3'of the optical fiber 3 has a predetermined height. Generally, the mounting holder 1 and the mounting jig 5 have different groove widths, but in the case of the above-mentioned numerical example, the height of the core 3'of the optical fiber 3 is almost the same as the surface of the mounting holder 1, and the required mounting Since the groove width of the jig 5 is almost the same as that of the mounting holder 1, the mounting jig 5 can be created in the same manner as the mounting holder 1. At this time, it is possible to prepare jigs whose optical fiber mounting heights are slightly different due to the progress of undercutting of chemical etching by preparing the mounting jigs 5 with different V groove etching times. .

Next, an optical fiber mounting procedure using this example is shown in FIGS. First, the mounting holder 1 is heated at a temperature of 320 ° C. in a deoxidized atmosphere (in a gas such as N ₂ , H ₂ , Ar, etc.) to melt Au and Sn of the fixing material 2 to form AuSn eutectic solder. At this time, as shown in FIG. 2A, the solder gathers at the bottom of the V groove of the mounting holder 1 due to gravity and surface tension, and forms a solder pool so as to fill the V groove. Next, as shown in FIG. 2 (b), the metal-coated optical fiber 3 is inserted into the V groove, but at this time, mechanical fine movement may be applied to the optical fiber 3 so that wetting with solder is improved. . Thereafter, mechanical pressure is applied to the optical fiber 3 to determine the position. However, when pressure is applied in order as described in the section of the prior art, the solder formation thickness and the metal coat thickness of the optical fiber 3 are dispersed. As a result, a relative positional deviation occurs between the mounting holders 1.

Therefore, in this embodiment, the mounting jig 5 whose height is defined as shown in FIG. 3 is used, and mechanical pressure is applied by the pressing jig 7 to suppress the positional deviation of the optical fiber 3. That is, the mounting jig 5 is placed on the optical fiber 3 in the state of FIG. 2B, and mechanical pressure is applied to the mounting jig 5 as shown in FIG. 3 to fix the position of the optical fiber 3. By applying this pressure, the optical fiber 3 is pushed into the molten solder, and the metal (mainly Au in this case) of the optical fiber outer coat 4 is pressure-deformed or reacts with the solder to be alloyed. However, when the flat portion of the mounting jig 5 comes into contact with the flat portion of the mounting holder 1, the pressure applied to the optical fiber 3 decreases and the pushing of the optical fiber 3 stops. Therefore, in the present embodiment, it is possible to absorb the positional deviation when the optical fiber is mounted within the range of the outer coat thickness of the optical fiber, and as long as the optical fiber 3 is mounted using the same mounting jig 5, The mounting conditions are substantially the same among the plurality of mounting holders 1.

As an example of the mounting position deviation when this method is used, the thickness of the metal coat is Ni of 1 μm, A
When u is 5 μm, it is ± 1 μm or less, which is sufficiently applicable to a single mode fiber. Since the absolute value of the mounting position is determined by the combination of the processing accuracy of the mounting jig 5 and the mounting holder 1, the mounting jig 5 having different dimensions is prepared according to the method described above, and the mounting holder 1 is processed. Mounting jig 5 according to the situation
Can be used properly.

In the optical fiber mounting body thus completed, the optical fiber 3 is located near the center of its average shape even when the surface state of the mounting holder 1 is somewhat rough, and therefore the mounting is carried out. The processing method of the holder 1 is considerably eased. For example, even if it is created by a method such as mechanical cutting or die molding, a finishing step such as polishing is not necessarily required, the cost of the mounting holder 1 can be reduced, and the shape of The reproducibility can be improved.

FIG. 4 is a sectional view of the configuration of the second embodiment of the present invention, and shows the configuration corresponding to FIG. The feature of this embodiment is that the groove of the mounting jig for defining the height of the mounting position is formed with a groove having a flat bottom instead of the V groove, and the mounting position height is higher than that of the first embodiment. It is easy to set the depth, that is, the depth from the height reference plane of the jig to the optical fiber contact portion.

The mounting jig 5 of this embodiment is produced as follows. First, the two Si substrates 5a and 5b are
The Si substrate 5b on one side of the so-called Si direct-bonded substrate, which is bonded via the O ₂ film 6 ', is polished to a thickness corresponding to the desired groove depth. Next, pattern formation is performed by the photolithography as described above, and the Si substrate 5b is selectively etched. The selective etching of Si can also be performed by the chemical etching using the above-mentioned KOH solution. Since the etching rate sharply decreases when reaching the SiO ₂ film 6 ', the selective etching can be performed relatively easily. After that, the immobilization preventing film 6 may be formed as in the first embodiment.

As described above, in this embodiment, the mounting position height can be set by carefully performing the polishing process, and the setting accuracy can be improved more easily than when the V groove is used as in the first embodiment. Further, in mounting the arrayed optical fiber, if the pitch of the V-grooves is slightly different in the first embodiment, it directly leads to a setting error or deviation of the mounting height. However, in this embodiment, as shown in FIG. Since the arrangement pitch of the optical fibers 3 is determined only on the mounting holder 1 side, it has a feature that such an error or deviation does not occur.

The present invention is not limited to the above embodiments. Although the optical fiber is metal-coated in the embodiment, the metal coat can be omitted if the optical fiber can be fixed in the groove of the mounting holder without the metal coat. Further, the optical fiber fixing material is not limited to solder, and any plastic material having excellent mechanical holding characteristics may be used.

In the second embodiment, for example, 25
When 128 optical fiber arrays with a pitch of 0 μm are mounted, the mounting jig 5 becomes a bridge extending over 32 mm, and the bending of the mounting jig becomes a problem. Therefore, when the number of optical fibers to be mounted is large, the height reference portions (5b) may be provided for each optical fiber or for every several optical fibers. Sa reference part (5
It is also possible to provide b). In addition, various modifications can be made without departing from the scope of the present invention.

[0033]

As described above, according to the present invention, it becomes possible to mount an optical fiber on a single mode fiber only by mechanical alignment, and a large number of optical fibers can be mounted at the same time. There is an advantage that the manufacturing process and the manufacturing time can be significantly shortened and the arrayed module can be easily manufactured. As a result, mass production of modules requiring optical fiber coupling, such as an optical transmission module for optical communication and an optical switch module, and significant cost reduction are possible.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configurations of an optical fiber mounting holder and a mounting jig for defining a mounting height according to a first embodiment of the present invention.

FIG. 2 is a process cross-sectional view for explaining the optical fiber mounting method in the first embodiment.

FIG. 3 is a configuration cross-sectional view for explaining a mounting state of an optical fiber in the first embodiment.

FIG. 4 is a sectional view of a structure for explaining an optical fiber mounting jig according to a second embodiment.

FIG. 5 is a structural cross-sectional view for explaining an optical fiber mounting body in a second embodiment.

FIG. 6 is a perspective view showing a configuration of a conventional optical fiber mounting body.

FIG. 7 is a sectional view of a structure for explaining a conventional optical fiber mounting jig and a conventional mounting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mounting holder 2 ... Solder (optical fiber fixing material) 3 ... Optical fiber 3 '... Optical fiber core 4 ... Optical fiber surrounding coat (metal coat) 5 ... Height regulation mounting jig 6 ... Fixing prevention film 7 ... Pressure jig

Claims (1)

[Claims] 1. A mounting holder having a groove formed on a main surface and an optical fiber positioned and fixed in the groove of the mounting holder, wherein the optical fiber is fixed to the mounting holder by a plastic material. The optical fiber mounting body, wherein the optical fiber is not in direct contact with the mounting holder.