JPH0715530B2 - Lens connector type feedthrough - Google Patents

Description

Description: (1) Technical Field of the Invention The present invention has an optical fiber connecting function for facilitating connection and replacement of a submarine optical fiber cable in an optical fiber introduction section of a submarine optical repeater housing. However, the present invention relates to a lens connector type feedthrough having excellent pressure resistance and airtightness.

(2) Conventional Technology FIG. 1 shows an example of the configuration of a submarine optical cable transmission type repeater. Here, 1 is a submarine optical cable, 2 is a T-T connection part, 3 is an optical feedthrough, 4 is a repeater circuit, 5 is an end face plate, 6 is a pressure-resistant housing, 7 is an optical fiber, and 8 is an optical fiber fusion bonding. The connecting portion 9 is a cable retractor.

The repeater may be laid on the seabed up to a depth of 8000m, and the optical feedthrough 3 withstands water pressure up to 800 atm, and is excellent for keeping the humidity inside the pressure-resistant housing 6 low. Airtightness is required.

The optical feedthrough 3 in FIG. 1 withstands water pressure, only introduces the optical fiber 7 into the pressure-resistant housing 6 while maintaining airtightness, and does not have the connection function of the optical fiber 7, so that the submarine optical cable side is separately provided. The TT connection part 2 for connecting and housing the optical fiber and the optical fiber on the repeater circuit side is required. Therefore, the size of the repeater housing is increased, and the connection between the optical fiber on the submarine optical cable side and the optical fiber on the repeater circuit side in the TT connection section 2 is performed with a highly accurate optical axis of 1 μm or less for a single mode optical fiber. There is a drawback that it takes a long time because the connection is performed by heat fusion with alignment.

In order to solve the above drawbacks, there is a proposal of an optical connector type feedthrough (Japanese Patent Application No. 55-169662). However, since the structure is such that the fiber cores of about 10 μm are directly aligned with each other, machining error, temperature change, vibration ， It is difficult to apply it to the undersea optical communication system that needs to reduce and stabilize the optical loss to the utmost limit because it has a great influence on the optical loss of dust and the like. The lens connector type feedthrough solves these drawbacks.

As a related art slightly related to this, an example in which a lens in which a repeater-side optical fiber is closely attached to a feedthrough is used like a window for the purpose of downsizing the repeater (Japanese Patent Application No.
-100872, Japanese Patent Application No. 53-36583, Japanese Patent Application No. 53-115113
No.), but the production requires a high precision in the connection between the lens and the optical fiber, and it takes a long time in the factory. Therefore, it is impossible to connect the cable and the repeater on board this part when repairing the cable trouble. Further, in the references (Japanese Patent Application No. 53-100872, Japanese Patent Application No. 53-36583, Japanese Patent Application No. 53-115113), a watertightness that can be used for up to 25 years under a severe seabed environment of up to 800 bar, There is no specific disclosure of the airtight structure, and any of them merely shows the concept of "fitting" or "adhering" the lens to the end plate in an abstract manner.

(3) Object of the Invention An object of the present invention is to have a connecting function using a rod lens that enables miniaturization of a repeater housing, shortening of connection time, and relaxation of machining accuracy around a connection portion. (EN) Provided is a lens connector type feedthrough having a water immersion prevention structure so that a cable can be immediately replaced when protecting and repairing a feedthrough portion when a cable is flooded, and a pressure resistant casing including a repeater can be reused. .

(4) Configuration of the Invention (4-1) Difference between Features of the Invention and Conventional Techniques The present invention provides a connection function with good workability by attaching a connector from a rod lens to an end face plate portion of a submarine optical repeater housing. When constructing a lens connector type feedthrough that includes, the rod lens connected to the optical fiber on the repeater circuit side is embedded in the end plate, and the metal-coated outer periphery is attached to the end plate in an airtight and watertight manner by soldering. That is the most main feature.

A conventional feedthrough using a lens does not have such a connecting function. In addition, there is no specific example of the method for hermetically attaching the lens.

(4-2) Example A basic structure of an example of the present invention will be described below.

FIG. 2 is a view for explaining the basic structure of one embodiment of the present invention, in which 10 is a rod lens A, 11 is a rod lens B, 12 is a rod lens guide A, 13 is a rod lens guide B, 14
Is the fiber on the cable side, 15 is the fiber on the repeater circuit side, 16
Is a metal coat, 17 is a hermetically sealed solder, and 18 is an adhesive layer. When the number of fibers 14 and 15 is plural, the structure shown in this figure is provided on the end face plate 5 in the vertical direction by the number of fibers.

The lens connector type feedthrough shown in FIG. 2 is normally located in a pressure resistant structure made of metal or the like and does not receive water pressure, but it may receive water pressure due to flooding due to cable breakage or the like. In FIG. 2, the left side of the end plate 5 is the high pressure side and the right side is the low pressure side.

On the repeater circuit side, in order to improve the wettability of the solder airtight seal 17 between the repeater circuit side fiber 15 and the metal of the end face plate 5 in advance, the outer circumference is formed by electrodeposition, ion plating, vacuum deposition, sputtering or the like. The rod lens A10 with the metal coat 16 is connected to and attached to the end plate 5 from the high voltage side.

Next, the airtight sealing portion 17 is formed by soldering in the gap between the metal coat 16 and the end face plate 5. Further, an adhesive layer 18 is provided for the purpose of preventing corrosion of the hermetically sealed portion 17, watertightness, and fixing the rod lens 10 and the end plate 5, and further, the rod lens guide A12 is fixed to the end plate 5 with an adhesive, for example. .

On the cable side, on the other hand, the rod lens B11 having an outer shape slightly smaller than the inner diameter of the rod lens guide B13 is connected to the cable side fiber 14, and the rod lens guide B13 and the rod lens B11 are fixed in advance by, for example, an adhesive.

The above steps are carried out in the factory when manufacturing the repeater and cable, and when constructing and repairing the transmission path, the rod lens guide B13 is simply inserted into the rod lens guide A12, and the cable and repeater are installed. Optical connection is possible. In addition, a matching material such as a polymer having a refractive index similar to that of the rod lens A10 and the rod lens B11 is interposed between the end surfaces of the rod lens A10 and the rod lens B11, or from the left side in FIG. If pressure is applied to the lens guide B13 by a spring or the like, air can be eliminated between the end surfaces of the rod lens A10 and the rod lens B11, and reflected light can be reduced.

The effects of the above basic structure are as follows:
In addition to relaxing the machining accuracy around the connection and simplifying the connection work, a metal coat 16 is applied to the outer periphery of the rod lens A10 and solder-sealed with the end face plate 5 to provide a highly reliable hermetically sealed portion for a long period of time. 17 can be formed.

FIG. 3 shows an example of realizing this structure in a small size, and 23 is a light guide path. On the repeater circuit side, the rod lens A10 having the metal coat 16 on the outer periphery and the end plate 5 are fixed by soldering, and the rod lens guide A12 having an inner diameter equal to or slightly larger than the outer diameter of the rod lens A10 is collectively included. The end face plate 5 is adhered and fixed by the adhesive layer 18. On the other hand, on the cable side, the rod lens B11 can be miniaturized by cutting the rod lens B11 in a range that does not interfere with the light guide path 23 and fixing the rod lens guide B13 by adhesion.

4 and 5 are views for explaining the basic structure of the embodiment of the present invention. Reference numeral 12 'is a partition wall fixed to the outer wall surface of the end plate 5 by screwing or the like.

Fig. 4 shows an example of maintaining watertightness by the pressure resistant structure. Fig. 5 does not cut off the pressure around the abutting portion of the rod lenses A10 and B11, but seawater etc. does not directly enter and exit. This is an example of keeping the watertight so that there is no water. Where 1
2'is a partition wall, 26 is a matching oil injection hole lid, 19 is an O-ring A, 20 is an O-ring B, 21 is an adhesive, 22 is a movable rubber stopper, 24 is a matching oil injection hole, and 25 is a matching oil.

In this embodiment, the partition wall 12 'also serves as a guide function for the rod lens B.

Hereinafter, FIG. 4 will be described. At least one O-ring A19 is provided between the rod lens guide A12 'and the rod lens guide B13, which is the water path at the time of flooding due to cable breakage, etc., and the optical fiber introduction part of the rod lens guide B13 is bonded by the adhesive 21. Withstand pressure sealing. As an experimental example of pressure-resistant sealing of the outer circumference of the fiber core with an epoxy adhesive, there is a track record of applying a water pressure of 2000 kg / cm ² for 10 days without any abnormality. When filling the matching oil 25 between the end surfaces of the rod lens A10 and the rod lens B11, a matching oil injection hole 24 is provided and an O-ring B20 is provided between the matching oil injection hole lid 26 and the matching oil injection hole lid 26. You can

In this embodiment, since the rod lens 10 and the hermetically sealed portion 17 do not receive pressure and do not touch seawater even when the cable is flooded due to an obstacle, the submarine optical repeater pressure-resistant housing containing the repeater circuit 4 is It can be reused immediately by replacing the cable.

Next, FIG. 5 will be described. When water pressure is applied due to a cable break or the like, pressure is applied to the movable rubber plug 22 from the outside of the rod lens guide A12 ', and the moving effect of the movable rubber plug 22 increases the pressure of the matching oil 25 to equalize the external pressure. At this time, since the compression rate of the matching oil 25 is extremely small, the movable region of the movable rubber plug 22 may be small.

In the embodiment shown in FIG. 5, since there is no pressure resistant space at all, the rod lens guide A12 'and other parts can be made thin, and the side surface of the rod lens B11 and the rod lens A10 can be reduced.
It is safe because no external force other than the uniform pressure due to seawater pressure is applied to the abutting portion of the rod lens B11 and the rod lens B11.

(5) Effects of the Invention As described above, according to the present invention, the rod lens A1
By sealing the outer periphery of 0 with the metal coat 16 and solder-sealing it with the end face plate 5, a highly reliable airtight sealing portion 17 is formed, and the repeater circuit inside the pressure-resistant housing can be protected from moisture for a long period of time. I can. In addition, since the feedthrough part of the submarine optical repeater housing that houses the repeater does not directly touch the infused seawater due to the cable failure, there is no risk of contamination or deterioration. It has a great effect that it can be reused immediately by replacing it with a cable.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a structure of a conventional submarine optical repeater housing, FIG. 2 is a vertical sectional view showing a basic structural portion of an embodiment of the present invention, and FIG. FIG. 4 is a vertical sectional view showing a basic structure portion of an embodiment of the present invention, and FIGS. 4 and 5 are vertical sectional views showing a structure of an embodiment of the present invention. 1 ... Submarine optical cable, 2 ... TT connection part, 3 ... Optical feedthrough, 4 ... Repeater circuit, 5 ... End plate, 6 ...
… Pressure resistant housing, 7 …… Optical fiber, 8 …… Optical fiber fusion splicing part, 9 …… Cable retractor, 10 …… Rod lens A, 11 …… Rod lens B, 12 …… Rod lens guide A, 12 '... Partition wall, 13 ... Rod lens guide B, 14 ...
… Cable side fiber, 15 …… Repeater circuit side fiber,
16 ... Metal coat, 17 ... Solder airtight sealing, 18 ... Adhesive layer, 19 ... O-ring A, 20 ... O-ring B, 21 ... Adhesive, 22 ... Movable rubber stopper, 23 ... … Light guide, 24 …… Matching oil injection hole, 25 …… Matching oil, 26 …… Matching oil injection hole lid.

Claims (1)

[Claims] 1. A focusing type rod lens A having a first optical fiber connected to a repeater circuit is attached to an end face plate of a submarine optical repeater housing, and the end face of the rod lens A is provided on the side of the submarine optical cable. By arranging the end faces of the focusing rod lens B, to which the second optical fiber is connected, facing each other, the first
Of the optical fiber and the second optical fiber are optically connected to each other, and on the end face plate from the submarine optical cable side, slightly thicker than the outer diameter of the rod lens A, and at a deeper portion. Is provided with a hole penetrating in a step shape slightly thicker than the outer diameter of the optical fiber led out from the repeater circuit and sufficiently thinner than the outer diameter of the rod lens A. The rod lens A has a metal coat on its outer periphery. The end face plate and the metal coat are hermetically sealed by soldering while being mounted in the stepped hole from the side of the submarine optical cable in the provided state, and a partition wall including the rod lens A is further provided on the end face plate. A lens connector type fiber which is fixedly formed and has a structure in which the periphery of the abutting portion of the rod lens A and the rod lens B inside the partition wall is kept watertight. Sul.