JPH0961657A - Optical component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dampproofing and waterproofing technology for the optical component constituted by connecting a non-quartz-based optical fiber to a quartz-based optical fiber by installing the whole non-quartz-based optical fiber and a connection part in jelly put in a container and extending part of the quartz-based optical fiber out of the container. SOLUTION: After the entire surfaces of the circular hollow 15, rectangular hollow 16, and fiber guide groove 17 of a container main body 5 are coated thinnly with jelly, the optical fiber consisting of the non-quartz-based optical fiber 20 and quartz-based fibers 3 and 4 is put in the circular hollow 15, rectangular hollow 16, and fiber guide groove 17. At this time, the tips of the quartz- based fibers 3 and 4 are projected onto the prolongation of the fiber guide groove 17. After jelly 22 is made to flow onto the non-quartz-based optical fiber 20, connection part 21, and quartz-based optical fibers 3 and 4, the surface is leveled and a lid is put over it and screwed. Consequently, water is stopped by the high-viscosity jelly from reaching the non-quartz-based optical fiber 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component (optical fiber module) in which a silica optical fiber is connected to a non-silica optical fiber, and for example, an amplification optical fiber portion (optical component) of an optical fiber amplifier is provided. The present invention relates to a technique effectively applied to a technique for maintaining a waterproof property for a long period of time.

[0002]

2. Description of the Related Art A non-quartz optical fiber, as represented by a fluoride optical fiber, is used as an amplifying optical fiber portion of an optical fiber amplifier by taking advantage of its characteristics such as high optical transparency in the infrared wavelength region. Its application area is expanding.

However, in many non-quartz optical fibers, when water drops adhere to the surface of the fiber, the glass surface is corroded by a chemical reaction with the glass, resulting in a significant deterioration in strength. In particular, in a fluoride optical fiber, water droplets adhering to the glass surface may cause the crystallization of the glass and breakage of the optical fiber.

On the other hand, as a conventional method for ensuring the waterproofness of an optical fiber cable, there is a jelly-filled type cable. The main component of this structure is a loose tube in which an optical fiber element wire or a tape core wire is loosely accommodated, and a grease-like compound called jelly is filled in the gap. As this jelly, generally, a polymer having silica dispersed therein, or a petroleum-based polymer having a mixture of silica and sodium salt dispersed therein is used. In both cases, the jelly prevents water from entering the surface of the optical fiber and ensures the reliability of the optical fiber.

[0005]

In an optical fiber amplifier, a non-silica optical fiber of a predetermined length is connected in the middle of a silica optical fiber that guides light such as pumping light and signal light. Make up part.

However, so far, no effective moisture-proof technology has been developed in consideration of the peculiarities of the non-quartz optical fiber and the connecting portion of the non-quartz optical fiber and the quartz optical fiber.

In addition, since the connection loss between the silica-based optical fiber and the non-silica-based optical fiber easily changes due to mechanical deformation, an effective fixing method has not been developed.

An object of the present invention is to provide a moisture-proof and water-proof technology for an optical component, which is formed by connecting a non-silica optical fiber to a silica optical fiber.

Another object of the present invention is to provide a technique for protecting a connecting portion in an optical component formed by connecting a non-silica optical fiber to a silica optical fiber.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0011]

The following is a brief description of an outline of typical inventions disclosed in the present application.

(1) An optical component having a non-silica optical fiber and a silica optical fiber connected to at least one end of the non-silica optical fiber, at least the whole non-silica optical fiber and the connection. A part is installed in a jelly placed in a container, and a part of the silica-based optical fiber extends outside the container.

(2) The container comprises a container body and a lid, and at least the connecting portion is fixed by interposition of an elastic body arranged on the inner surface of the container.

According to the above-mentioned means (1), since the surface of the non-quartz optical fiber is covered with the jelly, it is possible to suppress the infiltration of water into the surface of the non-quartz optical fiber and to attach the water. It is possible to prevent breakage of the optical fiber due to.

Further, since the non-silica optical fiber, the connecting portion and the silica optical fiber portion connected to the connecting portion are located in the jelly having high viscosity, the jelly acts as a buffer and careless connection is made. The movement of parts (mechanical deformation) and the occurrence of vibration can be suppressed.

According to the above-mentioned means (2), since the connecting portion is elastically fixed to the container main body by the elastic body arranged on the inner surface of the container, mechanical deformation and vibration of the connecting portion are surely ensured. It can be prevented.

[0017]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

In all the drawings for describing the embodiments, parts having the same functions are given the same reference numerals, and their repeated explanation is omitted.

(Embodiment 1) FIG. 1 is a schematic plan view showing an accommodated state of an optical fiber in an optical component according to an embodiment (Embodiment 1) of the present invention, and FIG. FIG. 3 is an exploded perspective view, FIG. 3 is an explanatory view showing a state in which a non-quartz optical fiber, a connecting portion and the like of the optical component of the first embodiment are accommodated in a container, and FIG. 4 is a perspective view showing an appearance of the optical component of the first embodiment. FIG. 5 and FIG. 5 are views showing a connection state between the non-silica optical fiber and the silica optical fiber in the production of the optical component of the first embodiment.

In the present embodiment, an example in which the present invention is applied to an amplification optical fiber section (optical component) in an optical fiber amplifier will be described.

The appearance of the amplification optical fiber portion (optical component) 1 of the first embodiment is, as shown in FIG. 4, a rectangular container 2
And two silica-based optical fibers 3 and 4 protruding from one side of the container 2. Although not shown, one silica-based optical fiber 3 is connected to a pumping light / signal light multiplexing fiber coupler located on the input side, and the other silica-based optical fiber 4 is connected to an optical isolator on the output side. .

The container 2 is, as shown in FIGS. 2 and 4,
It is composed of a container body 5 and a lid 6, and has a screw 7 and a washer 8.
It is integrated by screwing. Therefore, holes 4 into which the screws 7 are inserted are provided at the four corners of the lid 6, and screw holes 11 into which the screws 7 are screwed are provided at the four corners of the container body 5.

As shown in FIG. 2, the container body 5 has a circular recess 15 on its upper surface, rectangular recesses 16 provided on both sides of the circular recess 15, and a fiber guide groove 17 connected to the rectangular recess 16. It is provided. The fiber guide groove 17 guides each of the silica-based optical fibers 3 and 4 to the outside of the container 2.
Has reached to the edge of the upper surface of. Further, a fiber guide groove 18 for guiding one optical fiber is provided between the rectangular recess 16 and the circular recess 15.

The optical fiber contained in the container 2 is
As shown in FIG. 3, it comprises a non-silica optical fiber 20 and silica optical fibers 3 and 4 connected to both ends of the non-silica optical fiber 20. In the rectangular recess 16, a non-silica optical fiber 20 and silica optical fibers 3, 4 are provided.
The connection portion 21 for connecting with and the silica optical fibers 3 and 4 are accommodated. The tips of the silica-based optical fibers 3 and 4 are put in the fiber guide grooves 17, but the tips are put so as to project to the outside of the container body 5. Further, the non-quartz optical fiber 20 is accommodated in the central circular recess 15 in a bundled state or in a state of being wound around a bobbin. A non-quartz optical fiber 20 is inserted in the fiber guide groove 18.

The circular recess 15, the rectangular recess 16 and the fiber guide groove 17 are filled with jelly 22 so as to cover the surfaces of the non-silica optical fiber 20 and the silica optical fibers 3, 4. FIG. 1 is a schematic diagram showing a state in which the lid 6 is removed and the container body 5 is in a plan view. Also, as a convenient representation, it is a diagram showing a connecting portion 21 between the non-silica optical fiber 20 and the silica optical fibers 3 and 4.

The jelly 22 is composed of a grease-like compound, and for example, one in which silica is dispersed in a high molecular polymer or one in which a mixture of silica and sodium salt is dispersed in a petroleum-based polymer is used. To do. This jelly 22 suppresses the infiltration of water into the surface of the optical fiber, especially the non-quartz optical fiber 20,
The breakage of the non-quartz optical fiber 20 is prevented.

In the first embodiment, the non-silica optical fiber 2 is used.
A fluoride optical fiber was used as 0. The fluoride optical fiber is a ZBLYAN-based fluoride optical fiber containing ZrF ₂ as a main component (the relative refractive index difference between the core and the cladding is 2.5%,
A cutoff wavelength of 0.95 μm) was used. The clad diameter is 125 μm, the coating is UV curable resin and the outer diameter is 25
0 μm. The length of the non-quartz optical fiber 20 (fluoride optical fiber) is 10 m, and the total loss at a wavelength of 1.3 μm is 0.5 dB.

The silica-based optical fibers 3 and 4 have Ge at the core.
A silica-based optical fiber using O ₂ -doped quartz glass and non-doped silica glass in the cladding portion (core-clad relative refractive index difference 2.5%, cutoff wavelength 0.95 μm) was used. The clad diameter is 125 μm, the coating is a UV curable resin, and the coating outer diameter is 250 μm. Quartz optical fiber 3,4
Is estimated to be 0.0009 dB in total based on the loss characteristics of the fiber, but it can be substantially ignored.

As shown in FIG. 5, the non-quartz optical fiber 20 and the quartz optical fibers 3 and 4 are connected to the bottoms of the V grooves 32 and 33 of the blocks 30 and 31, respectively, by the non-quartz optical fiber 20 and the quartz. After fixing the system optical fiber 3 (4) and optically polishing the end surface of the fiber, aligning them so that the positions of the core portions of the fibers are aligned so that they face each other, and then U
It is fixed by a V-curing adhesive 34. The loss of the two connecting portions 21 was 0.1 dB per connection.

When assembling the amplification optical fiber portion 1 of the first embodiment, first, the circular recess 1 of the container body 5 is first assembled.
5, after a thin jelly is applied to the entire surface of the rectangular recess 16 and the fiber guide groove 17, an optical fiber composed of the non-silica optical fiber 20 and the silica optical fibers 3, 4 is formed into the circular recess 15, the rectangular recess 16, It is accommodated in the fiber guide groove 17. At this time, the tips of the silica-based optical fibers 3 and 4 are projected on the extension of the fiber guide groove 17. After that, as shown by the dots in FIG. 1, the jelly 22 is poured onto the non-silica optical fiber 20, the connecting portion 21 and the silica optical fibers 3 and 4, then the surfaces are leveled, the lid 6 is overlapped and screwed. To do. As a result, the amplification optical fiber portion 1 as shown in FIG. 4 is manufactured. The jelly 22 is filled in the container 2 without any gap.

The amplification optical fiber section 1 of the first embodiment is
The following tests gave good results. That is, in the amplification optical fiber portion (optical component) 1 of the first embodiment, an optical component sample in which the jelly is changed to four types as described below is prepared, and a temperature / humidity cycle test and a vibration test are performed. And the mechanical strength of the fluoride optical fiber after the test were measured.

The four types of jelly are petroleum-based base polymers mixed with silica and sodium salts (A,
B, C) and a mixture of polypropylene glycol and ultrafine silica particles (D) were used.

(Temperature / Humidity Cycle Test) The temperature / humidity cycle was carried out for a total of 5 cycles with the condition shown in FIG. 6 as one cycle. FIG. 7 shows the result of measuring the loss change (indicated by the solid line) of the fiber during the test. As can be seen from this, the change in loss is 0.1 dB or less, indicating that the present jelly filling structure is effective.

FIG. 8 is a plot of a Weibull distribution obtained by performing a tensile test using the non-quartz optical fiber portion before and after the temperature / humidity cycle test. The Weibull distribution of the fiber after the test (indicated by ●) is almost the same as that before the test (indicated by ○), indicating that this jelly-filled structure is effective.

(Vibration test) The container was fixed to a vibration exciter, the total amplitude was 1.5 mm, the frequency was 10 to 2000 Hz, and three directions were 1
Twice (20 minutes each). The loss change during the test was 0.
It is 1 dB or less, indicating that the present jelly filling structure is effective.

(Comparative Example) The same fiber sample and container as in the first embodiment were used, and the one without jelly filling was prepared, and the same temperature / humidity cycle test and vibration test as in the first embodiment were performed.

The results show that for the temperature / humidity cycle test,
When the temperature fell below 70 degrees during the first first cycle, it was confirmed visually that water droplets had adhered to the outside of the container, and at the same time, the fiber loss rose above the measurement limit.
At this point, when the fiber was taken out, it was confirmed that the fluoride optical fiber (non-quartz optical fiber) was broken at several places. This occurred in all 10 prepared fiber samples.

Also in the vibration test, immediately after the vibration was applied, the spliced portion was displaced and an unreasonable force was generated in the non-silica optical fiber, and the fiber was broken near the spliced portion.

(Embodiment 2) In Embodiment 2, a fluorophosphoric acid optical fiber is used as the non-quartz optical fiber.
The composition of the fiber is P ₂ O ₅ -Al ₂ O ₃ containing fluorine.
An optical fiber (having a relative refractive index difference between the core and the clad of 2.5% and a cutoff wavelength of 0.95 μm) whose main component is is used. The clad diameter is 125 μm, the coating is a UV curable resin, and the coating outer diameter is 250 μm. The length of the non-quartz optical fiber (fluorophosphoric acid optical fiber) is 10 m, and the total loss at the wavelength of 1.3 μm is 3 dB. Other configurations are the same as those of the first embodiment, and the temperature / humidity cycle test and the vibration test were also performed under the same conditions.

As a result, the loss change amount during the temperature / humidity cycle test was 0.2 dB, the loss change during the vibration test was 0.1 dB or less, and the Weibull obtained by the tensile test of the fluorophosphoric acid optical fiber part before and after the temperature / humidity cycle test. The distributions were consistent.

As a result of the same test in the structure not filled with jelly, almost all of the fluorophosphoric acid optical fiber was broken at the temperature drop from 70 ° C. in the third cycle in the temperature / humidity cycle test, and in the vibration test. When the first vibration was applied, all the fluorophosphoric acid optical fibers were broken in the vicinity of the spliced portion.

From this result, it was found that the present invention is also effective in the fluorophosphoric acid optical fiber.

(Embodiment 3) In Embodiment 3, as a non-quartz optical fiber, a fluoride optical fiber containing In as a main component (core-clad relative refractive index difference 2.5%, cutoff wavelength 0. 95 μm) was used. Clad diameter is 1
25 μm, coating is UV curable resin, coating outer diameter is 250 μm
It is. The length of the non-quartz optical fiber (fluoride optical fiber containing In as a main component) is 10 m, and the total loss at the wavelength of 1.3 μm is 5 dB. Other configurations are the same as those of the first embodiment, and the temperature / humidity cycle test and the vibration test were also performed under the same conditions.

As a result, the loss change amount during the temperature / humidity cycle test was 0.2 dB, the loss change during the vibration test was 0.1 dB or less, and the pulling of the fluoride optical fiber portion containing In as a main component before and after the temperature / humidity cycle test was performed. The Weibull distribution determined by the test was in agreement.

As a result of the same test in the structure not filled with jelly, in the temperature / humidity cycle test, almost all of the fluoride optical fiber containing In as a main component was broken when the temperature dropped from 70 degrees in the first cycle. However, in the vibration test, all the fluoride optical fibers were broken in the vicinity of the connection portion when the first vibration was applied.

From this result, it was found that the present invention is also effective in the fluoride optical fiber containing In as a main component.

(Embodiment 4) The amplifying optical fiber portion (optical component) 1 of Embodiment 4 has a structure in which the space between the container body 5 and the lid 6 is different from that of Embodiment 1 as shown in FIGS. 9 and 10. It has a structure in which the elastic body 12 is interposed. An elastic body 19 is also arranged on the bottom of the rectangular recess 16.

As a result, the non-silica optical fiber 20 housed in the container 2, a part of the silica optical fibers 3 and 4, the silica optical fibers 3 and 4 and the non-silica optical fiber 20.
The elastic body 12 elastically presses the connecting portion 21 to the container main body 5 to prevent mechanical movement and vibration of the optical fiber portion including the connecting portion 21.

In particular, the connecting portion 21 between the silica-based optical fibers 3 and 4 and the non-silica-based optical fiber 20 housed in the rectangular recess 16 and the non-silica-based optical fiber 20 and the silica-based optical fiber connected to this connecting portion 21. Since some of the fibers 3 and 4 are elastically sandwiched and held by the elastic body 12 and the elastic body 19,
The effect of preventing mechanical movement and vibration is further enhanced. An elastic body may be installed on the bottom of the circular recess 15 if necessary.

As shown in FIGS. 9 and 10, the container 2 is composed of a container body 5 and a lid 6, which are integrated by screwing with a screw 7 and a washer 8. Also,
The elastic body 12 has the same size as the container body 5 and the lid 6. Therefore, holes 13 into which the screws 7 are inserted are also provided at the four corners of the elastic body 12.
The elastic body 12 and the elastic body 19 are formed of, for example, a silicon rubber sheet having a thickness of 0.5 mm.

By interposing the elastic body 12 between the container body 5 and the lid 6, the closed container 2 has a closed structure, and the jelly 22 contained in the container 2 does not leak out of the container. .

In assembling the amplification optical fiber portion 1 of the fourth embodiment, first, the rectangular recess 1 of the container body 5 is assembled.
An elastic body 19 is installed on the bottom of 6. After that, a thin jelly is applied to the entire surface of the circular recess 15, the rectangular recess 16, and the fiber guide grooves 17 and 18, and then the optical fiber composed of the non-silica optical fiber 20 and the silica optical fibers 3 and 4 is circular. Depression 15, rectangular depression 16, fiber guide groove 1
It is housed in 7 and 18. At this time, the silica-based optical fibers 3, 4
The tip of is projected on the extension of the fiber guide groove 17.

After that, the jelly 22 is poured onto the non-quartz optical fiber 20, the connecting portion 21 and the quartz optical fibers 3 and 4, the surfaces are leveled, and the elastic body 12 and the lid 6 are overlapped and screwed. . As a result, the amplification optical fiber portion 1 as shown in FIG. 9 is manufactured. Jerry 2
2 is filled in the container 2 without any gap.

The amplification optical fiber section 1 of the fourth embodiment is
The loss change during the temperature / humidity cycle test is 0.1 dB or less, which shows that the amplification optical fiber unit 1 of the fourth embodiment is effective.

The Weibull distribution of the fluoride optical fiber after the temperature / humidity cycle test is substantially the same as that before the test, showing that the amplification optical fiber section 1 of the fourth embodiment is effective.

Furthermore, no loss change occurs during the vibration test.

From these, it can be seen that the jelly filling and the elastic body interposing structure of the fourth embodiment are effective.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. In the above-described embodiment, an example in which a fluoride optical fiber, a fluoride optical fiber containing In as a main component, or a fluorophosphoric acid optical fiber is used as the non-quartz optical fiber has been described, but breakage occurs due to moisture. The same can be applied to other non-quartz optical fibers, which can prevent the non-quartz optical fiber from being broken by moisture.

Further, in the above-mentioned embodiment, the optical fiber in which the silica-based optical fibers are connected to both ends of the non-silica-based optical fiber is sealed in the container by the jelly, but the silica-based optical fiber is provided only at one end. Even if the optical fiber portion to which the optical fiber is connected is sealed in the container with jelly, the same effect as in the above embodiment can be obtained.

Furthermore, the present invention can be applied to optical parts other than the amplifying optical fiber portion of the optical fiber amplifier.

[0061]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

(1) Since the non-quartz optical fiber that is easily broken by the adhesion of water is installed in the jelly in the container, the water is blocked by the highly viscous jelly and reaches the surface of the non-quartz optical fiber. It disappears and becomes difficult to break.

(2) Due to the high viscosity of jelly,
The connection between the non-quartz optical fiber and the quartz optical fiber becomes difficult to move within the container and also difficult to vibrate.
Connection loss will not fluctuate. As a result, stable operation is performed as the amplification optical fiber section.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an accommodated state of an optical fiber in an optical component according to an embodiment (Embodiment 1) of the present invention.

FIG. 2 is an exploded perspective view of the optical component according to the first embodiment.

FIG. 3 is an explanatory diagram showing a state in which a non-quartz optical fiber, a connecting portion, and the like of the optical component of the first embodiment are accommodated in a container.

FIG. 4 is a perspective view showing an appearance of the optical component according to the first embodiment.

FIG. 5 is a diagram showing a connection state between a non-silica optical fiber and a silica optical fiber in the production of the optical component of the first embodiment.

FIG. 6 is a diagram showing experimental conditions of a temperature / humidity cycle in the optical component of the first embodiment.

FIG. 7 is a diagram showing loss changes during a temperature / humidity cycle experiment in the optical component of the first embodiment.

FIG. 8 is a diagram showing Weibull distribution characteristics before and after a temperature / humidity cycle experiment in the optical component of the first embodiment.

FIG. 9 is a perspective view showing the external appearance of the optical component according to the fourth embodiment.

FIG. 10 is an exploded perspective view of an optical component according to a fourth exemplary embodiment.

[Explanation of symbols]

1 ... Optical fiber part for amplification (optical component), 2 ... Container, 3, 4
... quartz optical fiber, 5 ... container body, 6 ... lid, 7 ... screw, 8 ... washer, 10 ... hole, 11 ... screw hole, 12 ... elastic body, 13 ... hole, 15 ... circular recess, 16 ... rectangular recess 1
7, 18 ... Fiber guide groove, 19 ... Elastic body, 20 ... Non-quartz optical fiber, 21 ... Connection part, 22 ... Jerry, 3
0, 31 ... Block, 32, 33 ... V groove, 34 ... UV curing adhesive.

Front Page Continuation (72) Inventor Makoto Yamada 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Kazuo Fujiura 1-1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Nihon Telegraph Telephone Co., Ltd. (72) Inventor Shoichi Sudo 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Makoto Shimizu 1-14-5, Kichijojihoncho, Musashino-shi, Tokyo Entiti In Electronics Technology Co., Ltd. (72) Inventor Motohiro Nakahara 1-14-5, Kichijojihonmachi, Musashino-shi, Tokyo NTT Electronics Electronics Co., Ltd.

Claims (2)

[Claims] 1. An optical component having a non-silica optical fiber and a silica optical fiber connected to at least one end of the non-silica optical fiber, wherein at least the whole non-silica optical fiber and the connecting portion. Is placed in a jelly placed in a container, and a part of the silica-based optical fiber extends outside the container. 2. The optical component according to claim 1, wherein the container comprises a container body and a lid, and at least the connecting portion is fixed by interposition of an elastic body arranged on the inner surface of the container. .