JPH0233123B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method of forming a terminal end of a metal-coated optical fiber, and particularly to a method for sealing and reinforcing the terminal end. [Prior Art] Metal-coated optical fiber is a bare optical fiber with a metal coating layer made of a single metal such as aluminum, indium, tin, lead, zinc, nickel, silicon, or an alloy of these metals. It has characteristics such as water resistance, heat resistance, long life, and high reliability, making it suitable for use under adverse environmental conditions. [Problems to be Solved by the Invention] By the way, in the termination treatment of such a metal-coated optical fiber, it is necessary to prevent moisture from entering the interface between the bare optical fiber and the metal coat layer, and to terminate the metal-coated optical fiber. It is necessary to provide reinforcement to compensate for the decrease in mechanical strength of the optical fiber itself and to avoid damage to the bare optical fiber. In the case of multi-core optical fiber cables, such termination processing inevitably becomes complicated because the number of cores increases. Therefore, there is a need for a processing method that can be easily and quickly performed, provides sufficient watertightness and reinforcing effects, and does not cause damage to the bare optical fiber. [Means for Solving the Problems] In the present invention, the terminal end of the metal coated optical fiber is covered with a metal sleeve, the space between the metal sleeve and the metal coated optical fiber is filled with a silicone compound, and then the metal coat is applied. The metal coating layer of the optical fiber and the metal sleeve are brazed using a wax having a melting point lower than the melting point of either of these metals, and then a bracket is formed from the sheath of the metal coated optical fiber to the metal sleeve to seal and cover them. By providing this, the above problem is solved. Hereinafter, the present invention will be explained in detail with reference to the drawings. FIGS. 1 and 2 show an example of a method for forming a terminal end according to the present invention in the order of steps, and reference numeral 1 in the figures indicates a metal-coated optical fiber core wire. This metal-coated optical fiber core wire 1 consists of a metal-coated optical fiber wire 2 and a sheath 3 made of nylon resin or the like provided on the wire 2, and furthermore, the metal-coated optical fiber core wire 2 is a bare optical fiber. It consists of a wire 4 and a metal coating layer 5 provided thereon. As shown in FIG. 1, at the terminal end of the metal coated optical fiber core wire 1, a predetermined length of the sheath 3 is removed and the strands 2 are exposed. The exposed wire 2 is covered with a metal sleeve 6. The metal sleeve 6 is a pipe of a predetermined length made of the same metal as the metal coating layer 5 of the metal coated optical fiber strand 2 or a metal that can be brazed, and its inner diameter is the same as that of the metal coat layer 5 of the metal coated optical fiber strand 2. It is slightly larger than the outer diameter of the Next, the space 7 between the optical fiber wire 2 and the metal sleeve 6 is filled with a silicone compound such as silicone oil or silicone grease. Then, as shown in FIG.
A molten metal solder 8 is poured into the boundary between the metal coat layer 5 and the metal coat layer 5, and the metal coat optical fiber strand 2 and the metal sleeve 6 are joined and fixed. The metal solder 8 used here has a melting point (liquidus temperature) lower than the melting point of either the metal forming the metal coat layer 5 or the metal forming the metal sleeve 6. Ru. By using such metal solder 8, during brazing, the metal coating layer 5 will not be melted and damaged by the heat of brazing, and furthermore, the bare optical fiber 4 will not be damaged. . Examples of combinations that satisfy the above conditions are:

〔Effect of the invention〕

As explained above, the method for forming the terminal end of a metal-coated optical fiber according to the present invention involves covering the terminal end of the metal-coated optical fiber with a metal sleeve, and then forming an air gap between the metal sleeve and the metal-coated optical fiber.
After filling with a silicone compound, the metal coating layer of the metal coated optical fiber and the metal sleeve are combined.
The method involves brazing using a wax with a melting point lower than that of any of these metals, and then providing a bracket that seals and covers the metal-coated optical fiber from the sheath to the metal sleeve.
The terminal end is sufficiently mechanically reinforced and hermetically sealed, making the most of the inherent characteristics of metal-coated optical fibers. Even when used under adverse environmental conditions, problems will not occur at the terminal end, and high reliability can be maintained. . In addition, the work is easy and quick, and the finished product is compact and does not take up any extra space. Furthermore, since brazing is performed at a low temperature, there is no damage to the metal coating layer of the metal coated optical fiber or the bare fiber wire, and there is no inconvenience caused by this process such as increased transmission loss or peeling of the metal coat layer. Does not occur.

[Brief explanation of drawings]

1 and 2 are partially sectional front views illustrating an example of the method for forming a terminal end according to the present invention in the order of steps, and FIG. 3 is a schematic diagram showing a bracket used in another example of the method for forming a terminal end according to the present invention. FIG. DESCRIPTION OF SYMBOLS 1...Metal coated optical fiber core wire, 2...Metal coated optical fiber wire, 3...Sheath, 5...Metal coat layer, 6...Metal sleeve, 7...Empty,
8...metal wax, 9...metal bracket.

Claims (1)

[Claims] 1. Cover the terminal end of the metal-coated optical fiber with a metal sleeve, then fill the space between the metal sleeve and the metal-coated optical fiber with a silicone compound, and then connect the metal coat layer of the metal-coated optical fiber and the metal sleeve to each other. A terminal end portion of a metal-coated optical fiber, characterized in that the end portion of a metal-coated optical fiber is brazed using a wax having a melting point lower than the melting point of any metal, and then a bracket is provided from the sheath of the metal-coated optical fiber to a metal sleeve to seal and coat the two. How to form.