JPS6075810A - Reinforced optical fiber - Google Patents

Abstract

PURPOSE:To eliminate the transmission loss occuring in the compressive strain to be generated in the stage for forming a reinforced optical fiber and to improve reliability in product administration by providing tensile strain to the optical fiber strands in a reinforcing covering layer. CONSTITUTION:Tensile strain in about, for example, 0.01-0.10% range is provided to the optical fiber strands 1 in a reinforcing coating layer 2 consisting of plural reinforcing fiber materials 5 and a thermally cured thermosetting resin 6 impregnated therein and cured. If the tensile strain is provided to the strands 1 in the above-mentioned way, the generation of compressive stress to the strands 1 owing to the shrinkage of the layer 2 having a high Young's modulus occuring in a temp. change, external force, etc. is obviated and the problem of microbending is eventually eliminated. The high transmission characteristic of the optical fiber 3 is thus assured. The transmission loss of the fiber 3 is thus eliminated and the reliability in product administration is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a reinforced optical fiber in which the reinforcing coating layer around the outer periphery of the optical fiber is composed of a plurality of reinforcing fiber phases and a thermosetting resin that is impregnated into the reinforcing fiber phases and cured.

In the case of reinforced optical fibers (FRPMω optical fiber cores), which are being developed with emphasis on improving mechanical properties, they have mechanical strength against bending, etc., and are also good in terms of flexibility. However, regarding its transmission characteristics,
Problems caused by the manufacturing process remain.

In other words, when the reinforcing coating layer is formed around the outer periphery of an optical fiber, compressive strain is generated in the optical fiber due to molding shrinkage of the coating layer, and this turns into bending strain, causing microbends (transmission loss increase) in the optical fiber. causes) will occur.

In the case of general plastic-coated optical fibers, the Young's modulus of the planutinoku coating layer is small, so even if the above-mentioned compressive strain occurs, the coating layer gradually relaxes the stress, and the strain in the optical fiber is almost negligible. However, in the case of the above-mentioned reinforced optical fiber, the Young's modulus of the reinforced coating layer is large and stress relaxation is difficult, so the above-mentioned strain remains as is, resulting in a large transmission loss.

Usually, such distortion is referred to as process distortion of optical fiber, and when this process distortion is 0.00%, it is normal for a typical plastic-coated optical fiber with good adhesion between the coating layer and the optical fiber strand. , the difference between the coating layer length and the optical fiber length, and the optical path difference of the optical fiber are in good agreement with each other, and when controlling the product of the coated optical fiber, the optical path difference Ooo% should be treated as a process distortion of 0.0.
Predetermined management is carried out by regarding it as 0%.

The optical path difference of the optical fiber referred to herein is the difference between the optical fiber core length (unit length) before coating and the core length after coating, and is expressed as a percentage.

However, in the case of the above-mentioned reinforced optical fiber, because the adhesion between the reinforced coating layer and the optical fiber wire is insufficient, there are cases where the difference between the inside of the reinforced coating layer and the length of the optical fiber and the optical path difference of the optical fiber do not match. For example, when an optical fiber is meandering under a black load inside a reinforcing coating layer, even if a two-dimensional optical path difference of 0.00% is measured, the actual difference between the length of the reinforcing coating layer and the optical fiber Since the lengths are different and microbets are likely to occur, there is no reliability in terms of transmission characteristics based on the optical path difference.

The present invention deals with process strain (compressive strain) in reinforced optical fibers.
This system is designed to eliminate the increase in transmission loss caused by the transmission loss and also improve reliability in terms of product management.The configuration will be explained below with reference to the illustrated embodiment.

In FIGS. 1 and 2, reference numeral 1 indicates an optical fiber strand, and numeral 2 indicates a reinforcing coating layer formed around the outer periphery of the optical fiber strand 1. In FIG.

The optical fiber 1 mentioned above consists of a quartz-based optical fiber 3 and a coating layer 4 formed on its outer periphery. As an example, 50μrn/
It is 125 μm.

On the other hand, the coating layer 4 is made of a thermosetting resin such as silicone resin, or a photocuring resin such as acrylate compound wood, and its outer diameter is, for example, 400 mm.
7xn+.

In addition to having a function as a primary coat, this coating layer 4 may also have a function as a buffer coat. The coating layer is 2
Sometimes they are arranged in layers.

The reinforcing coating layer 2 has a plurality of elongated reinforcing fiber phases 5.5.6
... and a thermosetting resin 6, and these are mutually integrated using the thermosetting resin 6 as a binder.

The reinforcing fiber materials 5.5.5 used here are mainly glass fibers, and other materials such as carbon fibers, aramid fibers, fused fibers, ceramic fibers, and polyamide fibers can also be used singly or in combination. It is used as a symbol.

Furthermore, the reinforcing fiber fibers 6.5.5 are often in the form of roving.

On the other hand, the thermosetting resin 6 is made of resin such as polyester or epoxy.

The present invention relates to the reinforced optical fiber described in FIGS. 1 and 2, in which the optical fiber strand 1 has tensile strain, and the reinforcing coating layer 2 with a high Young's modulus is distorted due to temperature changes, external forces, etc. Even if the optical fiber 1 is shrunk, almost no compressive strain occurs in the optical fiber 1, and as a result, the problem of microbets is eliminated, and high transmission characteristics of the optical fiber 3 can be ensured.

Of course, there is a suitable range for the tensile strain mentioned above, and the optimal value is o, oi% to 0.10%. Less effective, 0.10%
If it exceeds this, the degree of fatigue of the optical fiber 3 will increase, making it more likely that a breakage accident will occur.

On the other hand, when the optical fiber strand 1 has the above tensile strain, it is impossible for the strand 1 to meander within the reinforced coating layer 2, but the optical path difference in the reinforced optical fiber is 000%. When the value is shown, the value can be trusted, and product management based on this value must be accurate.

Next, to briefly explain the manufacturing method of the reinforced optical fiber of the present invention, the optical fiber strand 1 and the reinforcing fibers 6,6,6, etc. in a roving state are supplied in one direction, and each reinforcing fiber 6,6, .6... is attached vertically to the outer periphery of the optical fiber 1, but before this longitudinal attachment, each reinforcing fiber 6.6.6...
6.5.6 Each fiber is passed through a resin liquid shield.
... is impregnated with uncured resin 6, or uncured (liquid) thermosetting resin 6 is applied to each of the fibers 5, 6, 6, etc. via a downward supply means during longitudinal splicing speed. impregnated,
After that, each reinforcement of the optical fiber 1 and resin impregnation is done.
The fibers 6.5.5... are passed through battens, molding dies, etc. as necessary, and then passed through a cylindrical heating curing furnace to form uncured thermosetting resin L. 6 is cured, and the reinforced optical fiber thus produced is taken up by a take-up machine and wound up by a winding machine.

Furthermore, when manufacturing a reinforced optical fiber in the above, for example, the supply speed V1 of the optical fiber strand 1 at the front stage of the heat-hardening furnace and the take-up speed V2 at the rear stage of the heat-hardening furnace are V
+ < V 2, thereby giving a predetermined tensile strain to the optical fiber strand 1 within the reinforcing coating layer 2. However, in a reinforced optical fiber made of a plurality of reinforcing fibers and a thermosetting resin impregnated and cured therein, the optical fiber concept in the reinforcing coating layer is characterized by having tensile strain. Therefore, even if the reinforcing coating layer shrinks due to temperature changes, there is almost no increase in transmission loss of the optical fiber, and it is also easy to manage products. Reliability will also be improved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a vertical side view and a vertical front view showing one embodiment of the reinforced optical fiber of the present invention. 1... Optical fiber strand 2... Reinforced coating layer 3... Optical fiber 4... Fist... Coating layer 5... Reinforced fiber system 6... Thermosetting resin patent applicant representative Patent attorney No. 1 Fuji acid No. 1 w1 jIZ Drawing procedure amendment (method) % formula % 3. Relationship with the case of the person making the amendment Patent applicant Furukawa Electric Co., Ltd. 4. Revision (Embedded 〒100 6, Column 7 of ``Title of Invention'' of the specification subject to amendment, The name of the invention in the specification of contents of the amendment is amended to ``Reinforced Optical Fiber.''

Claims (2)

[Claims] (1) In the reinforced optical fiber in which the reinforcing coating layer on the outer periphery of the optical fiber strand is composed of a plurality of reinforcing fiber phases and a thermosetting resin impregnated and cured therein, 1 [Reinforced optical fiber in which the optical fiber strands in the layers have tensile strain. (2) Tensile strain of optical fiber wire is 001 to 0.10
% of the reinforced optical fiber according to claim 1.