JPS62238505A - Lens connector type feedthrough - Google Patents

Abstract

PURPOSE:To prevent a function of a watertight and airtight mechanism from being deteriorated due to a thermal shock, by packing a gap between a rod lens and ceramic parts with glass/ceramics adhesive solder. CONSTITUTION:A connecting function having a good workability is provided by installing a rod lens type connector to an end face plate part (mainly consisting of a beryllium copper alloy) of a submarine optical repeater housing. In order to exactly install rod lenses 10, 11 to an end face plate 5, ceramic parts 2, 13 are interposed between the rod lenses 10, 11 and the end face plate 5, and a gap between the rod lenses 10, 11 and the ceramic parts 12, 13 is sealed by glass/ceramics adhesive solder 16. In this regard, the rod lenses 10, 11 are exactly installed to the ceramic parts 12, 13, and subsequently, they are installed to a metal of the end face plate 5. In this way, by providing a connecting function by using the rod lenses 10, 11, a lens connector type feedthrough having a high reliability, which car miniaturize the repeater housing, can shorten the connection time, and can relax the machine work accuracy in the periphery of the connecting part is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field to which the invention pertains The present invention provides an optical fiber connection function to facilitate the connection and replacement of submarine optical fiber cables at the optical fiber introduction part of a submarine optical repeater housing. This invention relates to a lens connector type feedthrough that has excellent pressure resistance, airtightness, and heat resistance.

(2) Conventional technology and its problems Figure 1 shows an example of the configuration of a repeater for a submarine optical cable transmission system. 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 plate, 6 is a pressure-resistant housing, 7 is an optical fiber, 8 is an optical fiber fusion splicing part,
9 is a cable retention device.

The repeater may be installed on the seabed as far as 8,000 meters, and the optical feedthrough 3 can withstand water pressures of up to 800 atmospheres, and has excellent airtightness to keep the humidity inside the pressure-resistant housing 6 low. sexuality is required.

The optical feedthrough 3 in FIG. 1 only introduces the optical fiber 7 into the pressure-resistant housing 6 while maintaining water pressure and airtightness, and does not have the function of connecting the optical fiber 7.
Separately, a T-T connection part 2 is required to connect and accommodate the optical fiber on the submarine optical cable side and the optical fiber on the repeater circuit side. Therefore, the repeater housing becomes larger and the T.
- Because the connection between the optical fiber on the submarine optical cable side and the optical fiber on the repeater circuit side at the T connection part 2 is a connection by thermal fusion with highly accurate optical axis alignment of 1 μm or less for single mode optical fibers. , which had the disadvantage of requiring a long time.

The lens connector type feedthrough solves these drawbacks, and the conventional technology slightly related to this is:
A conventional example of a feedthrough (Japanese Patent Application No. 100872/1983) uses a lens with an optical fiber tightly attached like a window for the purpose of downsizing the repeater.

Japanese Patent Application No. 53-36583, Japanese Patent Application No. 53-115113
However, its manufacture requires high precision in connecting the lens and optical fiber, and takes a long time in the factory. Therefore, it is impossible to connect the cable and repeater on board at this part when repairing a cable fault or the like.

Furthermore, these conventional examples are watertight and can withstand up to 25 years of use under harsh seabed environments of up to 800 atmospheres.

There is no example that specifically discloses an airtight structure, and all of them merely abstractly show the concept of "fitting" or "adhering" the lens to the end plate.

(3) Purpose of the Invention The purpose of the present invention is to miniaturize the repeater housing by providing a connection function using a rod lens.

It is an object of the present invention to provide a highly reliable lens connector type feedthrough that enables shortening of connection time and relaxation of machining precision around the connection part.

(4) Structure of the invention (4-1) Differences between the characteristics of the invention and the conventional technology The present invention has the following features:
When constructing a lens connector type feedsle that provides an easy-to-work connection function by attaching a rod lens type connector to the end plate part of the submarine optical repeater housing (beryllium copper alloy is the mainstream), the rod lens is attached to the end plate part of the submarine optical repeater housing. The most important feature is that a ceramic component is interposed between the rod lens and the end plate to ensure secure attachment to the lens, and the gap between the rod lens and the ceramic component is sealed with glass-ceramic adhesive solder.

In order to attach a small-diameter rod lens made of glass-based material directly to the end plate, which is mainly made of beryllium copper alloy, in a watertight and airtight manner, there is a large difference in the coefficient of thermal expansion of the two materials. The rod lens is usually φl dragon ~ φ2m1
There is a problem because it has a small diameter of 11.

The present invention solves these problems by first reliably attaching the rod lens to the ceramic component and then attaching it again to the end plate metal. here,
There are the following two configuration examples of the mounting structure of the ceramic component and the end plate metal.

That is, firstly, a configuration example in which a ceramic material having a coefficient of thermal expansion intermediate between those of the rod lens and the end plate metal is selected, and the ceramic material is soldered to the end plate, and secondly, This is an example of a configuration in which a ceramic material having a coefficient of thermal expansion extremely close to that of the rod lens is selected, and a metal C ring is attached between the ceramic component and the end plate.

In contrast to these techniques, the conventional feedthroughs using the lenses described above do not have a connection function, and there are no examples that specifically show how to attach the lenses in an airtight manner.

(4-2) Example FIG. 2 is a diagram explaining the first basic structure of the present invention, in which 10 is a rod lens A, 11 is a rod lens B, 12
is ceramic part A, 13 is ceramic part B, 114 is metal coat, 15 is guide, 16 is solder for glass/ceramic, 17 is O ring, 18 is ceramic pipe, 19 is adhesive A, 21 is optical fiber A, 22 is the optical fiber B, and 23 is the solder sealing part.

In this basic structure, a material having a coefficient of thermal expansion between that of the rod lens and the end plate metal is selected as the material for the ceramic component A12, and is soldered to the end plate.

Figure 3 shows the range of expansion coefficients of each material.

The lens connector type feedthrough shown in FIG. 2 is normally located within a pressure-resistant structure made of metal or the like and is not exposed to water pressure, but it may be exposed to water pressure due to water intrusion 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.

The manufacturing method will be shown below in order of steps.

First, on the repeater circuit side, one end of a ceramic pipe 18 having an outer diameter smaller than the outer diameter of the rod lens AIO and an inner diameter larger than the outer diameter of the optical fiber A21 is attached to one end surface of the rod lens AIO with adhesive A19. stick.

To bond the rod lens AIO and the ceramic component A12 with the glass-ceramic bonding solder 16, for example, the sealing portion is immersed in the molten glass-ceramic bonding solder 16.
It is conceivable to apply ultrasonic vibration to seal the parts without intervening air bubbles. At this time, the glass-ceramic adhesive solder 16 attached to the end surface of the rod lens AIO on the submarine optical cable side reduces the axial length of the rod lens AIO by 1/1.
Remove by cutting or polishing into 4 or 3/4 pitch lengths.

Next, the ceramic component A12 is attached to the end plate 5. Here, pressure-resistant sealing is performed using an O-ring 17, and electrodeposition is performed in advance.
Airtightness is maintained by solder-sealing 23 the ceramic component A12 coated with metal 14 by ion blasting, vacuum evaporation, sputtering, etc. and the end plate metal.

Next, the rod lens AIO and the optical fiber A21 are connected. Here, for example, the optical fiber A21 is fixed inside the ceramic pipe B having an outer diameter smaller than the inner diameter of the ceramic pipe 18, and parallel light is incident from the end surface of the rod lens AIO on the submarine optical cable side. A method can be used in which the ceramic pipe B is moved within the pipe 18 and fixed at a position where the intensity of light incident on the optical fiber A21 is maximum.

In addition, in the same manner as the above method, parallel light is incident from the end face of the submarine optical cable to give eccentricity to the hole inside the ceramic pipe 18, and a ceramic eccentric having an outer diameter slightly smaller than the inner diameter of the ceramic pipe 18 is made. A double eccentric method in which optical axes are aligned by independently rotating a ceramic eccentric pipe C, which has an outer diameter slightly smaller than the inner diameter of the ceramic eccentric pipe B' and an optical fiber A21 fixed therein. [[Single mode fiber connector J NTT publication, research and practical application report, 28-6 (1979) p 9
99] is also effective.

Note that the connection between the rod lens AIO and the optical fiber A21 described above can also be performed before fixing the rod lens AIO and the ceramic component A12. In this case, the optical fiber A21 can be directly fixed inside the ceramic pipe 18. and the rod lens AIO and the ceramic pipe 18
may be glued.

In the same manner as the above process, the rod lens B11 on the submarine optical cable side. Ceramic part B13 and optical fiber B
22 connections are also possible. The above process is carried out in the factory during the manufacture of repeaters and cables, and when constructing or repairing transmission lines, a simple operation of matching ceramic part A12 and ceramic part B13 via guide 15 is carried out to connect the submarine optical cable and relay. Optical connection of devices becomes possible.

In addition, between the end faces of the rod lens AIO and the rod lens Bll, a matching material made of polymer or the like having a refractive index similar to that of the rod lens AIO and the rod lens Bll is interposed, or a matching material made of a polymer or the like is interposed between the end faces of the rod lens AIO and the rod lens Bll, or a matching material made of a polymer or the like is interposed between the end surfaces of the rod lens AIO and the rod lens Bll. By applying a pressing force such as a spring to the component B13, it is possible to eliminate the presence of air between the end faces of the rod lens A10 and the rod lens Bll, thereby reducing reflected light.

The effect of the above basic structure is that it is a rod lens.

By selecting the various materials mentioned above so that the coefficient of thermal expansion of the ceramic parts and end plate metal changes in stages, even if these parts are subjected to thermal shock during molding of the polyethylene coating structure applied to the outer periphery of the optical feedthrough, When the rod lens AIO is directly attached to the end plate 5, the stress applied to the glass-ceramic adhesive solder 16 between the rod lens AIO and the ceramic component A12 and the solder sealing portion 23 between the ceramic component AI2 and the end plate 5 is reduced. can be reduced compared to
It has the advantage of ensuring the desired highly reliable watertight and airtight functions. In addition, the environmental temperature during manufacturing and the subsequent usage environment (
There is little thermal strain caused by differences in seawater temperature (2 to 30°C), and long-term safety can be ensured.

FIG. 4 is a diagram illustrating the second basic structure of the present invention, in which reference numeral 20 represents an adhesive B 139 as a metal C ring, and 40 represents a ceramic component holder.

In this basic structure, a material with a thermal expansion coefficient extremely close to that of the rod lens AIO is selected as the material for the ceramic component A12, and an airtight space is created between the ceramic component AI2 whose surface is coated with a metal coat 14 and the end plate 5. A metal C-ring 39 is attached for the purpose of maintaining the O-ring 17 to protect it.
is provided on its high pressure side.

In this structure, adhesive B20 is filled between the ceramic pipe 18 and the ceramic component A12 as a backup for the glass-ceramic bonding solder 16.

As for this filling method, for example, a vacuum suction hole 32 for filling the adhesive is provided to perform suction, and the adhesive filling space is kept at a high vacuum, so that air bubbles are formed between the ceramic pipe 18 and the ceramic part A12 due to the viscosity of the adhesive. An effective method is to fill the adhesive without removing the adhesive.

According to the experiment of the inventor of the present application, the filling method described above is based on the fact that a hole with an outer diameter of 0.125 mm is placed inside a hole of approximately φ0.4 mm and a length of 1011 mm.
2000 kg/cr by fixing mm optical fiber
There is a track record that no abnormalities such as water leakage have occurred up to A.

With this structure, stress due to the difference in thermal expansion coefficient can be prevented from being applied to the glass-ceramic bonding solder 16 between the rod lens AIO and the ceramic component A12 in response to the thermal shock.

In addition, since the metal C ring 39 provides airtightness by elastically deforming and pressing the C ring, even if the difference in thermal expansion coefficient between the ceramic component A12 and the end plate 5 is large,
High airtightness can be maintained. This metal C ring 39 is difficult to attach directly to the outer periphery of a small-diameter rod lens AIO;
It can be attached to a relatively large-sized ceramic component A12 that has been attached with.

Through the above, the desired highly reliable watertight and airtight functions are ensured,
Moreover, there is an advantage that long-term safety can be ensured.

Note that, of course, the effects of the first and second basic structures are that the repeater casing can be made smaller, the machining accuracy around the connecting portion can be relaxed, and the connecting work can be simplified.

FIG. 5 is an example of the overall structure of a submarine optical feedthrough that can be constructed by applying the present invention.

24 is a pressure-resistant pipe that also serves as a power supply line, 25 is a solder connection part, 26
is metal part A, 27 is metal part B, 2nd is the joining pin, 2
9 is polyethylene, 30 is a polyethylene joint, 31 is a metal part C135 is mating oil, 36 is a power supply line,
37 is an oxidized mold, and 38 is a gold-plated film.

Here, from the submarine optical cable side, [24→26-27-
The power supply path connected to the repeater circuit via route 36] is completely covered with polyethylene 29, and an oxidation mold 37 is applied to the interface between the polyethylene 29 and the metal parts B27 and C31 to make it watertight. I keep it. Further, the metal part B27 also serves as a guide when the ceramic part A12 and the ceramic part B13 are butted together.

Furthermore, in this embodiment, matching oil 35 is filled between the ceramic component A12 and the ceramic component 813 as a refractive index matching agent to reduce reflected light that has an adverse effect on the light emitting elements of the repeater circuit.

As described above, since this structure uses the feedthrough structure of the present invention that is resistant to thermal shock, the distance between the outer polyethylene coating, which becomes hot during molding, and the rod lens portion can be shortened, that is, the entire structure can be made compact. In particular, by setting the polyethylene mold abutting part and the rod lens abutting part, which are the hottest, at almost the same position,
It has the advantage of simple structure and good workability.

(5) Detailed Description of the Invention As described above, the present invention provides a lens connector type feedthrough having an optical fiber connection function in an optical fiber introduction part of a submarine optical repeater housing. By interposing a ceramic part between the face plates and filling the gap between the rod lens and the ceramic part with solder for adhesion of glass and ceramic, the function of the watertight and airtight mechanisms is prevented from deteriorating due to thermal shock during molding of the polyethylene joint, and a high There is an advantage that a reliable optical feedthrough can be realized.

[Brief explanation of drawings]

Fig. 1 is a schematic longitudinal cross-sectional view showing an example of the structure of a conventional submarine optical repeater housing, Figs. 2 and 4 are longitudinal cross-sectional views showing an example of the basic structure of the present invention, and Fig. 3 is a schematic longitudinal cross-sectional view showing an example of the structure of a conventional submarine optical repeater housing. A characteristic diagram showing the coefficient of thermal expansion of various materials, and FIG. 5 is a longitudinal sectional view showing an example of the overall structure of a submarine optical feedthrough that can be constructed by applying the present invention. 1... Submarine optical cable, 2... T-T 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 retention device, IO...rod lens A,
11... Rod lens B112... Ceramic part A113... Ceramic part B, 14... Metal coat, 15... Guide, 16... Solder for glass/ceramic, 17... 0 ring, 18...Ceramic pipe, 19...Adhesive A, 20...Adhesive B, 21...Optical fiber A, 22...Optical fiber B123...Solder sealing part, 24...・Pressure-resistant pipe that also serves as a power supply line, 25...Solder connection part, 26...
・Metal part A, 27...Metal part B, 28...Joint bottle, 29...Polyethylene, 30...Polyethylene joint part, 31...Metal part C132...
Vacuum suction hole for filling adhesive, 35... Matsushigu oil, 36... Power supply line, 37... Oxidation treatment mold, 38... Gold plating film, 39... Metal C ring, 40... Ceramic parts holder.

Claims (1)

[Claims] In a submarine optical repeater housing, a converging rod lens A to which one or more optical fibers A derived from a repeater circuit are connected is attached to the end plate through ceramic parts in an airtight and watertight manner, and the rod It is configured to connect the optical fibers on the submarine optical cable side and the repeater circuit side by abutting the end surfaces of the focusing rod lenses B, each of which has one or more optical fibers B on the submarine optical cable side connected to the end surfaces of the lenses A. At the same time, the ceramic component extends over a certain depth from the submarine optical cable side to the rod lens A.
The rod lens A has a step-shaped hole that is thicker than the outer diameter of the rod lens A and deeper than the outer diameter of the optical fiber led out from the repeater circuit, and that penetrates through the hole in a step-like manner. A lens connector type feedthrough, characterized in that the rod lens A is attached from the submarine optical cable side, and the interface between the ceramic component and the rod lens A is bonded by glass-ceramic adhesive solder.