JPH04138406A - Heat resistant optical fiber - Google Patents

Abstract

PURPOSE:To maintain the heat resistance of the optical fiber and to allow the easy peeling of a polyimide resin and org. metallic polymer by coating the surface of the optical fiber with a resin consisting of carbon, hydrogen and nitrogen, then heating the fiber in an inert atmosphere to carbonize the resin and to form a carbide layer, then coating the layer with the polyimide resin or org. metallic polymer. CONSTITUTION:The surface of the single mode optical fiber (SMF) 1 formed by heating and stretching the SMF is coated with the UV curing resin consisting of the carbon, hydrogen and nitrogen, for example, urethane acrylate and thereafter the fiber is passed in an electric furnace of an N2 atmosphere to form the carbide layer 2. The surface of this carbide layer 2 is coated with the polyimide resin layer or the org. metallic polymer layer 3 and this layer is cured, by which the coated optical fiber 4 is perfected. The heat resistance is maintained in this way and the carbide layer plays the role of slipping. The peeling of the coating material at the time of connection is thus facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-resistant optical fiber, and particularly to improving the releasability of a polyimide resin or an organometallic polymer coating the optical fiber.

[Prior Art] Optical fibers are used in a variety of places, not only indoors and outdoors, because of their advantages such as being lighter in weight than conventional electric wires, having no electromagnetic induction, and having low transmission line loss.

Especially when used in harsh environments such as outdoors,
Demand for heat-resistant optical fibers that can be used at high temperatures is increasing. Furthermore, when connecting optical fibers, the coating must be easily peeled off and the strands of the optical fibers must not be damaged.

To cope with these problems, conventional optical fibers are coated with polyimide resin or organic metal polymer to make them heat resistant.

[Problem to be Solved by the Invention 1] However, when connecting optical fibers, it is necessary to remove the polyimide resin. Silicone and ultraviolet curing resin can be easily rubbed off by impregnating gauze with alcohol, and there is also a method of swelling them in an organic solvent.
It is difficult to easily peel polyimide resin using the above method. Therefore, either thermal oxidation decomposition is performed using oxygen plasma, or
Alternatively, there is a method of stripping with a strong alkaline solvent such as NH-NH2 (N2 H4: hydrazine), but this is not suitable for connection work because the solvent is toxic and dangerous and may melt the glass.

In addition, organometallic polymers can only be removed by mechanical operations such as shaving off parts of the organic metal polymer that become ceramic when they are burnt. There was a problem in that the optical fiber deteriorated and the optical fiber often broke during connection work.

The present invention has been made in view of the above-mentioned problems, and its purpose is to maintain the heat resistance of an optical fiber and to be able to easily peel off a polyimide resin and an organometallic polymer at a ratio of 11,'1:1. Our mission is to provide heat-resistant optical fibers.

[Means for Solving the Problems] In order to achieve the above objects, the present invention improves the coating structure of an optical fiber.

In other words, in a heat-resistant optical fiber in which the optical fiber is coated with a coating material made of polyimide resin or organometallic polymer, the surface of the optical fiber is coated with a resin made of carbon, hydrogen, and nitrogen, and then heated in an inert atmosphere to carbonize it. The method is characterized in that after a carbonized layer is formed, a polyimide resin or an organic metal polymer is coated.

Further, specifically, it is preferable to use polytitanocarbosilane as the organometallic polymer.

Furthermore, it is desirable that the thickness of the carbonized layer be 3 μm or more.

[Function 1] According to the present invention, by providing a carbonized layer between the optical fiber and the coating material such as polyimide resin or organic metal polymer, heat resistance is maintained and the carbonized layer acts as a slippery material during connection. The coating material can be easily removed.

[Embodiment 1] Hereinafter, a preferred embodiment according to the present invention will be described using FIG. 1.

Single mode optical fiber (SMF) with a wavelength of 1.3 μm
) 1 heated and stretched at about 200 degrees Celsius, and then UV (ultraviolet light) consisting of carbon, hydrogen, and nitrogen is applied to the surface of SMF with an outer diameter of 125 μm.
After applying a cured resin such as urethane acrylate (manufactured by Nippon Rubber Co., Ltd., trade name 950Y110), it is passed through an electric furnace in an N2 atmosphere to form a carbonized layer 2. Here, polyimide or nylon can also be used instead of the urethane acrylate. Next, a polyimide resin layer or an organic metal polymer layer 3 is coated on the carbonized layer 2 and cured to complete the optical fiber core 4.

Here, the thickness of the carbonized layer 2 is 3 μm, and the polyimide resin layer 3 is
was formed to have a thickness of 10 μm. Further, a carbonized layer 2 was formed to a thickness of 5 μm using the same method, and then a polytitanocarbosilane was formed to a thickness of 10 μm as an organometallic polymer layer 3.

In each case, the transmission loss of the optical fiber after each of the above formations was 0.35 dB1 km when measured at a wavelength of 1.3 μm, and a low-loss optical fiber was obtained.

In the case of coating with the polyimide resin layer 3, it became possible to cut the carbonized layer 2 at a thickness of 10 μm and pull it out.

Furthermore, when polytitanocarbosilane, which is an organometallic polymer, is used instead of polyimide resin, the thickness of the carbonized layer 2 is made thicker (5 μn1), so that it can be rubbed off with gauze, which increases the strength of the optical fiber. did not deteriorate. This is because the carbonized layer 2 plays a sliding role.

[Effect of the invention] As described above, the present invention exhibits the following effects.

Since the carbonized layer is provided between the optical fiber and the coating material, the polyimide resin and organometallic polymer coating can be easily peeled off, and the optical fiber can be connected after peeling without reducing its strength.

Therefore, in the current situation where information transmission using optical fibers is becoming widespread, there is an effect that the work of connecting optical fibers becomes easier.

In addition, since commercially available polyimide resins and organometallic polymers are used, it is easy to put them into practical use.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical fiber core 4 according to the present invention.

Claims (3)

[Claims] (1) In a heat-resistant optical fiber in which the optical fiber is coated with a coating material made of polyimide resin or organometallic polymer, the surface of the optical fiber is coated with a resin made of carbon, hydrogen, and nitrogen, and then heated in an inert atmosphere. A heat-resistant optical fiber characterized in that it is carbonized to form a carbonized layer and then coated with a polyimide resin or an organic metal polymer. (2) The heat-resistant optical fiber according to claim 1, wherein the organometallic polymer is polytitanocarbosilane. (3) The heat-resistant optical fiber according to claim 1 or 2, wherein the thickness of the carbonized layer is 3 μm or more.