JP3289752B2 - Planar lightwave circuit protection member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection member for a planar lightwave circuit which has a small fluctuation in lightwave propagation loss and excellent long-term reliability.

[0002]

2. Description of the Related Art Various types of planar lightwave circuits are known, which include a substrate made of glass, silicon, or the like, and a plate-like light propagation path provided on the substrate. Typical planar lightwave circuits include a lightwave branch circuit, a wide wavelength range coupler, and the like.

As an example of a conventional planar lightwave circuit, 1
FIG. 7 shows a planar lightwave branch circuit having eight input branches. In the figure, reference numeral 21 is a planar lightwave circuit, 22 is input light, 50 to 58 are light propagation paths, and 60 to 67 are output lights. As shown in this figure, in the planar lightwave circuit 21, the input light 22 is branched from the light propagation path 55 as it passes through the light propagation paths 51 to 58, and becomes eight lights to form the output light 60 to 67. Is emitted.

A conventional planar lightwave circuit having such a configuration is widely used in an optical information line using an optical fiber communication network, and is used under various environmental conditions inside and outside a station. In particular, since the lightwave branch circuit as described above is often used in a cable television or the like when distributing an optical video signal to each subscriber, it is strongly required that the component operate stably outdoors. One. In order to actually use such a planar lightwave circuit, it is necessary to connect an optical fiber to an input / output end.

FIG. 8 is a perspective view for explaining a schematic configuration of a component (called a module) in which an optical fiber is connected to an input / output end of a planar lightwave circuit. In this figure,
Reference numeral 1 is a planar lightwave circuit block, 2 is an optical fiber block, 4, 5a and 5b are optical fibers, and 10
And 11 are connections. This module manufacturing method is disclosed in JP-A-4-212113. That is, a planar lightwave circuit manufactured by adjusting the intervals of the light propagation paths as shown by reference numerals 51 to 58 in FIG. 7 with high precision, and a block of glass or the like precisely adjusted to the intervals of the propagation paths. After optically and uniformly polishing the input and output end faces of both using an optical fiber block in which the optical fibers are aligned and fixed, align the optical axes by abutting these end faces, and further fix with an adhesive. Is achieved by

Further, as an example of a method for fixing the connection portion, there is a method disclosed in JP-A-2-298904. In this method, a planar lightwave circuit block and an optical fiber block are made of metal, and both are fixed by YAG laser welding or an ultraviolet curing adhesive. This fixing method using an adhesive is currently most used because it is simple and economical. However, in the fixing method using an adhesive, the adhesive portion of the connection portion is exposed, so that the adhesive strength and the like are deteriorated due to moisture or the like. Such deterioration of the adhesive causes displacement of a light conducting portion between the planar lightwave circuit and the optical fiber component, thereby changing or deteriorating the optical characteristics of the planar lightwave circuit module. Therefore, in the case where the lightwave circuit module is used as a practical product, as shown in FIG. 9, conventionally, the planar lightwave circuit modules 1 to 5 are made of metal or metal from the viewpoints of easiness of handling and ensuring reliability in a humid atmosphere. Attempts have been made to protect it in a plastic case 40. In this case, a sealing material 41 such as a rubber-like sealant or silicon grease is filled, and the case is sealed with an adhesive 42. In this way, entry of moisture and the like is prevented, and the adhesive at the connection interface is not deteriorated even when left in a moist heat atmosphere for a long time.

[0007]

However, the conventional planar lightwave circuit has the following problems.

First, the sealing material to be filled in the case to protect the module is determined in consideration of moisture permeability and water absorption, and flexibility so as not to apply distortion to the connection portion of the module and the optical fiber. Thermosetting materials typified by epoxy are relatively excellent in moisture resistance, but have high hardness and large strain applied to the module when the environmental temperature fluctuates. Therefore, there is a problem that an excessive stress is applied to a connection portion of the module or the optical fiber to cause a peeling-off phenomenon of the adhesive layer, or a micro-bending loss of the optical fiber is increased, thereby affecting a light propagation loss.

Although some sealant materials are rubbery and flexible even when cured, they often contain a solvent, and if not subjected to a long drying step, react with the adhesive at the connection portion, and There is a problem that the agent is deteriorated. In addition, when the ambient temperature is low, the hardness increases and stress is generated in the small-diameter single-core fiber in addition to the connection portion, and there is a problem that the light propagation loss is affected. In addition, something very soft at room temperature, such as silicon grease, is also used,
These materials flow at a high temperature of about 60 ° C., and have a problem that they leak from a portion where sealing with an adhesive or the like is incomplete even when sealed in a case.

On the other hand, at low temperatures, there is a problem that the sealing material becomes rigid and the optical characteristics of the module change. In some cases, a jelly-shaped encapsulant is used to prevent fluidity at high temperatures, but as described above, the sealing material used in conventional planar lightwave circuit modules is The optical fiber may cause stress, and the one with low stress may take a long time in the processing process, leak with high fluidity, or have the required moisture resistance and wide environmental temperature change. There were drawbacks such as poor physical properties and deterioration of the connection in the long term.

Second, in the prior art, in order to prevent moisture from entering from the boundary between the case and the optical fiber,
It was necessary to seal the boundary between the case and the optical fiber using a thermosetting adhesive. For this reason, there has been a problem in that a stress is applied to the optical fiber due to a change in volume at the time of solidification of the adhesive or a change in environmental temperature, and an increase in loss due to microbending occurs. This becomes more noticeable as the sealing is completed. Even if an elastic material is used at the boundary between the case and the optical fiber, the above problem cannot be solved because the periphery of the optical fiber must be fixed with an adhesive. Conventional LSI
Although there is a technique of molding using a thermosetting resin for encapsulating a semiconductor component such as described above, it has been difficult to apply it to a lightwave circuit module for the reasons described above.

The planar lightwave circuit module may be placed outdoors or on a utility pole in the future, so
It is necessary to withstand an accelerated deterioration test for 5000 hours in 5% moist heat, and to have sufficiently small fluctuation in loss even by a heat cycle of 75 ° C to -40 ° C. However, conventional components have not always had sufficient properties when subjected to a long-term wet heat test or a heat cycle test for the reasons described above. For example, using a metal case as shown in FIG. 9, a 1 × 8 splitter-type planar lightwave circuit component having a boundary with an optical fiber component fixed with an epoxy-based thermosetting resin at 75 ° C. to −40 ° C. As a result of the heat cycle test, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB within this temperature range, but it was 9.6 dB at 75 ° C. and -40 dB at −40 ° C. To 9.9 dB. Since this value is almost the same regardless of the number of heat cycles, it is considered that the loss is increased due to the micro-bending of the fixed portion of the optical fiber.

[0013]

According to a first aspect of the present invention, there is provided a planar lightwave circuit comprising: a planar lightwave circuit; an input / output optical fiber; Used in a planar lightwave circuit module consisting of a connection portion for an optical fiber,
A planar lightwave circuit protection member comprising an encapsulant covering the periphery of the connection part, wherein the encapsulant is a silica filler-containing polymer resin, a silica filler-free silicon-based heating addition type gel type adhesive and a silica filler-free. Silicon based
It is characterized by comprising a composition selected from the group consisting of a heat-adding type flexible adhesive, which does not dissolve an adhesive component used in a bonding portion between a planar optical circuit and an input / output optical fiber.

The protection member for the planar lightwave circuit based on the second invention comprises a planar lightwave circuit, an input / output optical fiber,
And a planar lightwave circuit protection member used in a planar lightwave circuit module comprising a connection portion between the planar lightwave circuit and the input / output optical fiber, and at least a metal case surrounding the planar lightwave circuit and the connection portion, A protective body made of a sealing material covering a portion including a boundary between the optical fiber and the metal case is provided, and the sealing material is a raw material that becomes an elastomer after curing. Preferably, a silica filler-containing polymer resin, a silica filler-free silicon-based heat-addable gel type adhesive and a silica filler-free
The metal case is an encapsulant made of a composition that does not dissolve the adhesive component used in the bonding portion between the planar optical circuit and the input / output optical fiber, which is selected from the group consisting of a silicon-based heating-adding flexible type adhesive. Is filled in.

[0015] The protection member for the planar lightwave circuit based on the third invention is a planar lightwave circuit, an input / output optical fiber,
And a planar lightwave circuit comprising an enclosing material covering the periphery of the connection portion, which is used in a planar lightwave circuit group in which a plurality of planar lightwave circuit modules each including a connection portion between the planar lightwave circuit and the input / output optical fiber are connected in series. A protective member, wherein the encapsulating material is a silica filler-containing polymer resin, a silica filler-free silicon-based heat-addable gel-type adhesive, and a silica filler-free silicon-based heater.
It is made of a composition which does not dissolve the adhesive component used for the bonding portion between the planar optical circuit and the input / output optical fiber, which is selected from the group consisting of the additive type flexible adhesive .

The protection member of the planar lightwave circuit based on the third invention is a planar lightwave circuit, an input / output optical fiber,
And a planar lightwave circuit protection member used for a planar lightwave circuit group in which a plurality of planar lightwave circuit modules each comprising a connection portion between the planar lightwave circuit and the input / output optical fiber are connected in series, wherein at least the planar lightwave circuit is provided. And a metal case surrounding the connection portion, and a protective body comprising a sealing material covering at least a portion including a boundary between the optical fiber and the metal case are provided, and the sealing material is an elastomer after curing. It is characterized by being a raw material body. Preferably, a silica filler-containing polymer resin, a silica filler-free silicon-based heat-addable gel type adhesive and a silica filler -free silicone
An encapsulant made of a composition that does not dissolve the adhesive component used in the bonding portion between the planar optical circuit and the input / output optical fiber, which is selected from the group consisting of heat-applied flexible adhesives, is contained in the metal case. Is filled.

The above-mentioned encapsulating material has a particularly low moisture permeability in order to guarantee long-term wet heat characteristics, and further has a glue having a viscosity of 4000 to 300,000 cps so that stress is not applied to the lightwave circuit module. And has a chemical property that does not affect the dissolution of the components of the adhesive. The metal case assures the mechanical strength of the entire lightwave circuit module, and is mainly made of stainless steel or aluminum. The outermost polymer is made of a material having low moisture permeability.

[0018]

The planar lightwave circuit protection member effectively prevents the adhesive of the connection portion of the planar lightwave circuit module from being deteriorated by moisture by a combination of an enclosing material or a metal case and a sealing material covering the case. The reliability of the characteristics of the planar lightwave circuit is ensured for a long period of time, and loss fluctuation due to temperature change is sufficiently reduced.

The sealing material covering the metal case flexibly holds the optical fiber protruding from the module, prevents an increase in microbending loss due to a temperature change, and exerts a mechanical reinforcing effect on the optical fiber.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 An embodiment of a planar lightwave circuit according to the present invention will be described in detail with reference to FIG. In this figure, reference numeral 1 is a planar lightwave circuit block,
2 is an optical fiber block, and 6 is an encapsulating material.

As the inner wrapping material, a material having a very low self-fluidity obtained by mixing about 20% of a silica filler with a polymer mainly composed of polypropylene glycol was used. The viscosity is
It is about 15000 cps at room temperature. The characteristics of this material are
Solvents that are glue-like over a temperature range of -50 ° C to more than 150 ° C so as to suppress the deterioration of the bonded part of the module that blocks moisture from the outside world and not to give extra stress to the module. Is not included. Therefore, a planar lightwave circuit module surrounded by such a material can be expected to operate stably for a long period of time.

The above material was carefully painted around the module with a spatula-shaped stick as it was not flowable. As another application method, it is also possible to use a syringe to apply around the module. In this case, it is necessary to prevent bubbles from being taken into the inner packaging material, but it can be easily implemented.

The planar lightwave circuit module thus manufactured was subjected to a heat cycle test at 75 ° C. to -40 ° C. As a result, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB. , 9.5 dB at 75 ° C. and 9.5 dB even at −40 ° C., and no increase in loss was observed. This value was not changed even when the number of heat cycles was increased, and it was possible to prevent an increase in loss due to micro-bending of the connection portion of the module and the fixed portion of the optical fiber.

Further, at 120 ° C.
Even after a wet heat test at 00% for 99 hours, no peeling phenomenon due to deterioration of the adhesive at the connection portion was observed.

<Embodiment 2> A second embodiment of the planar lightwave circuit according to the present invention will be described. The configuration of this lightwave circuit is the same as that of the first embodiment, as shown in FIG. 1, but the composition of the encapsulating material is different. The encapsulant used in this example was a mixture of a polymer mainly composed of a modified epoxy, a main agent obtained by mixing about 20% of a silica filler, and a curing agent in a ratio of 2: 1. This is quickly applied to the module,
After degassing in vacuo, the mixture was left standing at room temperature for 6 hours to cure.

The feature of this material is that it has a great effect of blocking the external moisture and suppresses the deterioration of the bonded portion of the module. Since the rate of change in volume is small, the change in loss due to stress applied to the module and the optical fiber must be small in the range of −40 ° C. to 100 ° C. For example, it does not contain a solvent that affects the adhesive.

Therefore, a planar lightwave circuit module surrounded by such a material can be expected to operate stably for a long period of time.

A heat cycle test at 75 ° C. to −40 ° C. was performed using the planar lightwave circuit module manufactured as described above. As a result, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB. However, it was 9.5 dB at 75 ° C. and 9.5 dB even at −40 ° C., and no increase in loss was observed. This value was not changed even when the number of heat cycles was increased, and it was possible to prevent an increase in loss due to micro-bending of the connection portion of the module and the fixed portion of the optical fiber.

Further, this module was heated at 120 ° C. for 1 hour.
Even after a wet heat test at 00% for 99 hours, no peeling phenomenon due to deterioration of the adhesive at the connection portion was observed.

<Embodiment 3> A third embodiment of the planar lightwave circuit according to the present invention will be described. The configuration of this lightwave circuit is the same as that of the first embodiment, as shown in FIG. 1, but the composition of the encapsulating material is different.

A silicone-based heat-addable gel type adhesive was used as the inner packaging material. Mixing ratio of main material and hardening material is 10
After mixing the two liquids at 0:10, the mixture was applied to the module, degassed under vacuum, and then heated at 85 ° C. for 6 hours or more to cure.
This material has a very soft property with a penetration of about 60 after curing. The characteristic of this material is that it has excellent adhesion to glass and silicon, which are the constituent materials of the module, so that the effect of moisture on the module is small, the deterioration of the adhesive at the bonded part of the module is suppressed, and extra -60 ° C to 200 ° C so as not to give excessive stress
It is flexible over the wide temperature range described above, does not contain solvents that affect the adhesive, and has electrical insulation,
Good dielectric properties. Therefore, a planar lightwave circuit module surrounded by such a material can be expected to operate stably for a long period of time, and has characteristics capable of maintaining good characteristics even for a module in which an electric circuit is mounted.

The planar lightwave circuit module manufactured in this manner was subjected to a heat cycle test at 75 ° C. to -40 ° C. As a result, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB. , 9.5 dB at 75 ° C. and 9.5 dB even at −40 ° C., and no increase in loss was observed. This value was not changed even when the number of heat cycles was increased, and it was possible to prevent an increase in loss due to cyclobending of the connection portion of the module and the fixed portion of the optical fiber.

Further, at 120 ° C.
Even after a wet heat test at 00% for 99 hours, no peeling phenomenon due to deterioration of the adhesive at the connection portion was observed.

<Fourth Embodiment> A fourth embodiment of a planar lightwave circuit according to the present invention has the same configuration as that of the first embodiment, but in this embodiment, a silicon-based heating type flexible type is used as an enclosing material. The difference is that an adhesive is used. The encapsulant of this example has a mixing ratio of the main material and the hardening material of 100:
After mixing the two liquids of No. 10 with each other, the mixture was applied to a module, deaerated in a vacuum, and then heated at 85 ° C. for 6 hours or more to cure. This material has an elongation of 140% after curing and has a soft property. The characteristic of this material is that it has excellent adhesion to glass and silicon, which are the constituent materials of the module, so that the effect of moisture on the module is small, the deterioration of the adhesive at the bonded part of the module is suppressed, and extra Flexible in a wide temperature range from -60 ° C to 200 ° C or higher so as not to give excessive stress, not containing solvents that affect the adhesive, and good electrical insulation and dielectric properties And so on. Therefore, a planar lightwave circuit module surrounded by such a material can be expected to operate stably for a long period of time, and has characteristics capable of maintaining good characteristics even for a module in which an electric circuit is mounted.

The planar lightwave circuit module thus manufactured was subjected to a heat cycle test at 75 ° C. to −40 ° C. As a result, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB. , 9.5 dB at 75 ° C. and 9.5 dB even at −40 ° C., and no increase in loss was observed. This value was not changed even when the number of heat cycles was increased, and it was possible to prevent an increase in loss due to micro-bending of the connection portion of the module and the fixed portion of the optical fiber.

Further, at 120 ° C.
Even after a wet heat test at 00% for 99 hours, no peeling phenomenon due to deterioration of the adhesive at the connection portion was observed.

Embodiment 5 FIG. 2 shows a fifth embodiment of the planar lightwave circuit according to the present invention. Reference numeral 1 is a planar lightwave circuit block, 2 is an optical fiber block, 7 is a metal case, 8 is a sealing material covering the entire case,
Used to seal the case and the fiber part.

The metal case 7 is a stainless steel case having a thickness of 0.1 mm. The module is fixed in the case from the opening of the stainless steel case, and a stainless steel plate of the same thickness is also fitted into the case opening from above, and the case is covered. Next, this is placed in a Teflon mold, and after stopping the mold, a polyurethane resin mixed with an isocyanate prepolymer and a polyol is poured while applying a slight tension to the optical fiber coming out from both ends, and curing is performed at room temperature. . The curing time is about 20 hours. Curing at 60 ° C. can reduce the time to about 2 hours. This polyurethane resin is in the form of a soft rubber,
Since it shows an elongation of about 00 to 300%, there is a feature that a stress is not applied to a portion holding the optical fiber.

A heat cycle test at 75 ° C. to -40 ° C. was performed on the planar lightwave circuit component manufactured as described above. As a result, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB. 9.5 at 75 ° C
Even at -40 ° C. at dB, the loss was 9.5 dB, and no increase in loss was observed. This value was not changed even when the number of heat cycles was increased, and an increase in loss due to microbending of the fixed portion of the optical fiber could be prevented.

Although no encapsulating material is used in the present embodiment, each of the conventionally used silicon-based grease, sealant, and ultraviolet curable resin is used as the encapsulating material, and the connecting portions of the module are connected in accordance with the present embodiment. The fluctuation of the light propagation loss due to the heat cycle was 9.5 dB at 75 ° C. and 9.7 dB at −40 ° C., and the increase in loss could be suppressed to less than half of the conventional value. .

In this embodiment, a mixture of an isocyanate prepolymer and a polyol is used as a raw material for an elastomer, but the present invention is not limited to this, and similar characteristics may be obtained with other raw materials. Furthermore, although polyurethane resin was used as the elastomer here, it was possible to use other butyl-based, silicon-based, fluorine-based, and polyolefin-based resins to achieve flexibility that does not affect the propagation characteristics of optical fibers. Add what you can do.

<Embodiment 6> A sixth embodiment of the planar lightwave circuit according to the present invention will be described in detail with reference to FIG.
Reference numeral 1 is a planar lightwave circuit block, 2 is an optical fiber block, 6 is an encapsulating material, 7 is a metal case, 8 is a sealing material covering the entire case, and is used to seal the case and the fiber portion. .

As the inner encapsulant, a self-fluidity material having a very low self-flow property obtained by mixing about 20% of a silica filler with a polymer mainly composed of polypropylene glycol was used.

This material was applied around the module using a plastic syringe. At this time, bubbles were not taken into the inner packaging material. Next, a module with an inner packaging material was fixed to a U-shaped stainless steel case 7 having a thickness of 0.1 mm, and a stainless steel plate having the same thickness was also fitted from above, and a lid was formed. . Next, this is placed in a Teflon mold, and after stopping the mold frame, a polyurethane resin mixed with an isocyanate prepolymer and a polyol is poured while applying a slight tension to the optical fiber coming out from both ends, and curing is performed at room temperature. Was. The curing time is about 20 hours. Curing at 60 ° C. can reduce the time to about 2 hours. This polyurethane resin is in the form of a soft rubber, and has a characteristic that it does not apply stress to the portion holding the optical fiber because it exhibits an elongation of about 200 to 300%.

The planar lightwave circuit component thus manufactured was subjected to a heat cycle test at 75 ° C. to −40 ° C. As a result, the loss of the original planar lightwave circuit module alone was 9.5 ± 0.1 dB. 9.5 at 75 ° C
Even at -40 ° C. at dB, the loss was 9.5 dB, and no increase in loss was observed. This value was not changed even when the number of heat cycles was increased, and an increase in loss due to microbending of the fixed portion of the optical fiber could be prevented.

The same results were obtained when the encapsulating materials shown in Examples 2 to 4 of the present invention were used.

Further, the planar lightwave circuit of the present invention is different from the single lightwave circuit module of the first to sixth embodiments in that
It is also possible to use a lightwave circuit module group consisting of a plurality of lightwave circuit modules connected in series.

Embodiment 7 An embodiment of a planar lightwave circuit according to the present invention will be described in detail with reference to FIG. In this figure, reference numeral 1 is a planar lightwave circuit block,
Reference numeral 2 denotes an optical fiber block, reference numeral 6 denotes an enclosing material, and reference numeral 1 'denotes a light wave circuit module group including a plurality of light wave circuit modules connected in series.

As the inner encapsulant, a material having a very low self-fluidity obtained by mixing about 20% of a silica filler with a polymer mainly composed of polypropylene glycol was used. The viscosity is
It is about 15000 cps at room temperature.

<Eighth Embodiment> An eighth embodiment of the planar lightwave circuit according to the present invention will be described. The configuration of this lightwave circuit is the same as that of the seventh embodiment, as shown in FIG. 4, but the composition of the encapsulating material is different.

The encapsulant used in this example is a polymer containing a modified epoxy as a main component and a silica filler of about 20%.
% And a 2: 1 mixture of the main agent and the curing agent, respectively. This was quickly applied to the module, degassed under vacuum, and then left at room temperature for 6 hours to cure.

Embodiment 9 A ninth embodiment of the planar lightwave circuit according to the present invention will be described. The configuration of this lightwave circuit is the same as that of the seventh embodiment, as shown in FIG. 4, but the composition of the encapsulating material is different.

As the encapsulating material, a silicone-based heat-addable gel type adhesive was used. Mixing ratio of main material and hardening material is 10
After mixing the two liquids at 0:10, the mixture was applied to the module, degassed under vacuum, and then heated at 85 ° C. for 6 hours or more to cure.

<Embodiment 10> A tenth embodiment of a planar lightwave circuit according to the present invention has the same structure as that of the seventh embodiment, but in this embodiment, a silicon-based heating type flexible type is used as an enclosing material. The difference is that an adhesive is used. The encapsulant of this example has a mixing ratio of the main material and the hardening material of 1
After mixing the two liquids of 00:10, the mixture was applied to the module,
After defoaming under vacuum, the composition was cured by heating at 85 ° C. for 6 hours or more. This material has an elongation of 140% after curing and has a soft property.

<Embodiment 11> FIG. 5 shows an eleventh embodiment of the planar lightwave circuit according to the present invention. Reference 1
Is a planar lightwave circuit block, 1 ′ is a lightwave circuit module group including a plurality of lightwave circuit modules connected in series, 2 is an optical fiber block, 7 is a metal case,
A sealing material 8 covers the entire case, and is used to seal the case and the fiber portion.

The metal case 7 is a stainless steel case having a thickness of 0.1 mm. The module is fixed in the case from the opening of the stainless steel case, and a stainless steel plate of the same thickness is also fitted into the case opening from above, and the case is covered. Next, this is placed in a Teflon mold, and after stopping the mold, a polyurethane resin mixed with an isocyanate prepolymer and a polyol is poured while applying a slight tension to the optical fiber coming out from both ends, and curing is performed at room temperature. . The curing time is about 20 hours. Curing at 60 ° C. can reduce the time to about 2 hours. This polyurethane resin is in the form of a soft rubber,
Since it shows an elongation of about 00 to 300%, there is a feature that no stress is applied to a portion holding the optical fiber.

Embodiment 12 A twelfth embodiment of the planar lightwave circuit according to the present invention will be described with reference to FIG. Reference numeral 1 denotes a planar lightwave circuit block, 1 ′ denotes a lightwave circuit module group including a plurality of lightwave circuit modules connected in series, 2 denotes an optical fiber block, 6 denotes an encapsulating material, 7
Is a metal case, and 8 is a sealing material covering the entire case, which is used to seal the case and the fiber portion.

The inner encapsulant used was a polymer mainly composed of polypropylene glycol mixed with about 20% of a silica filler to make the self-fluidity extremely small.

This material was applied around the module using a plastic syringe. At this time, bubbles were not taken into the inner packaging material. Next, a module with an inner packaging material is fixed to a U-shaped metal case 7 having a thickness of 0.1 mm, a stainless steel plate having the same thickness is also fitted from above, and the module is covered. It is. Next, this is placed in a Teflon mold, and after stopping the mold frame, a polyurethane resin mixed with an isocyanate prepolymer and a polyol is poured while applying a slight tension to the optical fiber coming out from both ends, and curing is performed at room temperature. Was. Curing time is 2
It is about 0 hours. Curing at 60 ° C. can reduce the time to about 2 hours. This polyurethane resin is in the form of a soft rubber, and has a characteristic that it does not apply stress to the portion holding the optical fiber because it exhibits an elongation of about 200 to 300%.

[0061]

As described above, according to the present invention, the use of an encapsulating material having a proper viscosity in a wide temperature range prevents moisture from permeating and does not cause stress around the connection portion. Its properties and stability have improved dramatically.

Further, the portion for sealing the boundary of the optical fiber is made of a high-molecular elastomer and is easily manufactured by casting or the like, so that the process can be easily controlled, and the loss due to micro-bending caused by holding the optical fiber. In addition, the reliability and stability of the planar lightwave circuit module have been dramatically improved because the metal case is responsible for the mechanical strength, preventing fluctuations.

The sealing material, the encapsulating material, the metal case, and the like used here are relatively inexpensive, and furthermore, since the present invention does not require special bullet equipment, the economic effect can be said to be extremely large. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a planar lightwave circuit module protection member according to the present invention.

FIG. 2 is a cross-sectional view for explaining an example of a planar lightwave circuit module protection member according to the present invention.

FIG. 3 is a sectional view illustrating an example of a planar lightwave circuit module protection member according to the present invention.

FIG. 4 is a cross-sectional view illustrating an example of a planar lightwave circuit module protection member according to the present invention.

FIG. 5 is a cross-sectional view for explaining an example of a planar lightwave circuit module protection member based on the present invention.

FIG. 6 is a sectional view illustrating an example of a planar lightwave circuit module protection member according to the present invention.

FIG. 7 is a schematic front view for explaining an example (1 × 8 splitter) of a conventional planar lightwave circuit.

FIG. 8 is a perspective view illustrating an example of a conventional planar lightwave circuit module.

FIG. 9 is a cross-sectional view illustrating a conventional planar lightwave circuit component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Planar lightwave circuit block 1 'Planar lightwave circuit group 2 Optical fiber block 4 Optical fiber 5 Optical fiber 6 Enclosure material 7 Metal case 8 Sealing material

Continuation of front page (72) Inventor Motohiro Nakahara 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-7-198990 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/30 G02B 6/12

Claims (6)

(57) [Claims] 1. An inner covering material for a planar lightwave circuit, an input / output optical fiber, and a planar lightwave circuit module including a connection portion between the planar lightwave circuit and the input / output optical fiber. Oyo made a planar lightwave circuit protection member, wherein the inner material is silica filler-containing polymeric resin, silica filler-free silicon heated addition type gel type adhesive
Silicon-free heating-type flexible
A planar lightwave circuit protection member comprising a composition selected from the group consisting of a glue-type adhesive and a composition that does not dissolve an adhesive component used in a bonding portion between a planar optical circuit and an input / output optical fiber. 2. A planar lightwave circuit protection member used in a planar lightwave circuit module comprising a planar lightwave circuit, an input / output optical fiber, and a connection portion between the planar lightwave circuit and the input / output optical fiber, wherein at least the A metal case surrounding the planar lightwave circuit and the connecting portion, and a sealing material covering at least a portion including a boundary between the optical fiber and the metal case; and further, the sealing material is an elastomer after curing. A planar lightwave circuit protection member, characterized by being a raw material body. 3. The planar lightwave circuit protection member according to claim 2, wherein the silica filler-containing polymer resin, the silica filler-free silicon-based heat-addable gel-type adhesive, and the silica filler.
Silicone-free, heat-adding flexible type adhesive
Selected from the group consisting of an agent , a composition that does not dissolve the adhesive component used for the bonding portion between the planar optical circuit and the input / output optical fiber, and that has an enclosing material filled in the metallic case. A planar lightwave circuit protection member, characterized in that: 4. A planar lightwave circuit group comprising a plurality of planar lightwave circuit modules each comprising a planar lightwave circuit, an input / output optical fiber, and a connection portion between the planar lightwave circuit and the input / output optical fiber. Can be
A planar lightwave circuit protection member consisting of inner material covering the periphery the connecting portion, the inner material is silica filler-containing polymeric resin, silica charge
Filler-free silicone-based heat -addable gel-type adhesive and
Silicon-free heating-type flexible
A planar lightwave circuit protection member comprising a composition selected from the group consisting of a glue-type adhesive and a composition that does not dissolve an adhesive component used in a bonding portion between a planar optical circuit and an input / output optical fiber. 5. A planar lightwave circuit group in which a plurality of planar lightwave circuit modules each including a planar lightwave circuit, an input / output optical fiber, and a connection portion between the planar lightwave circuit and the input / output optical fiber are connected in series. A planar lightwave circuit protection member, comprising: a metal case surrounding at least the planar lightwave circuit and the connection portion; and a sealing material covering at least a portion including a boundary between the optical fiber and the metal case. A planar lightwave circuit protection member, wherein the sealing material is a raw material that becomes an elastomer after curing. 6. The planar lightwave circuit protection member according to claim 5, wherein a silica filler-containing polymer resin, a silica filler-free silicon-based heat-addable gel-type adhesive, and silica-filling are provided.
Silicone-free, heat-adding flexible type adhesive
Selected from the group consisting of an agent , a composition that does not dissolve the adhesive component used for the bonding portion between the planar optical circuit and the input / output optical fiber, and that has an enclosing material filled in the metallic case. A planar lightwave circuit protection member, characterized in that: