JPS60205517A - Optical fiber core and its production - Google Patents

Abstract

PURPOSE:To decrease the rate of elongation or contraction of a partial resin coating layer and to suppress the increase in transmission loss by providing the discontinuous or partial resin coating layer between a primary coat and a secondary coating layer. CONSTITUTION:A primary coat 12 consisting of a silicone resin or Al, etc. is continuously provided over the entire surface of a bare optical fiber 11. A cylindrical partial resin coating layer 13 is provided partially and intermittently on the fiber 11 in the axial direction thereof. The layer 13 is provided to 100- 500mum thickness and 5-300mm. length in the longitudinal direction thereof and at specified or random intervals. The resin constituting the layer 13 may be either thermoplastic or thermosetting resin. A secondary coating layer 14 is provided on the layer 13. The layer 14 consists of a resin or metal, is provided continuously over the entire length of the core wire and is formed intermittently with a gap layer 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cored optical fiber having good temperature characteristics and a method for producing the same.

There are two types of optical fiber structures: solid type and loose type. As shown in FIG. 1, the solid type has a structure in which a primary coat 21 made of silicone rubber or the like is provided on a bare optical fiber 1, and a secondary coating layer 3 made of nylon resin or the like is further provided thereon. In addition, the loose type has a structure in which the optical fiber loincloth wire 1 is loosely accommodated in a pipe 4 such as a metal pipe with a larger diameter via a gap (air layer) 5, as shown in Fig. 2. be.

By the way, the temperature characteristics of the above-mentioned solid type optical fiber core wire are not necessarily good. primary code) 2
At low temperatures below about -60°C, which is the embrittlement temperature of the silicone rubber or nylon resin that constitutes the secondary coating layer 31, or at high temperatures above about 80 to 100°C, which is the glass transition point of these resins, the resin may shrink at low temperatures or Due to softening, transmission loss is reduced to 0~
The increase in transmission loss is 2 to 3 times that at 20℃.On the other hand, with loose low-core optical fibers, there is no increase in transmission loss in the low and high temperature ranges that is seen in solid type fibers, but if this is made into a cable, Alternatively, if the cable is installed, the structure may collapse due to bending or the like, which may increase transmission loss.

This invention was made in view of the above circumstances.

The object of the present invention is to provide an optical fiber core wire that has good temperature characteristics and whose structure does not collapse even when subjected to bending, etc., and a method for manufacturing the same.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The third factor shows an example of the optical fiber 6 of the present invention, and reference numeral 11 in the figure is a bare optical fiber.

A primary coat 12 made of ordinary modified silicone resin, urethane resin, etc., or metal such as aluminum, indium wax, silicon, etc. is continuously provided on the entire surface of the bare optical fiber 11. A cylindrical partial resin coating layer 13 is provided on the primary coat 12 (-t, partially interrupted in the longitudinal (axial) direction of the bare optical fiber 11. The coating layer 13 has a thickness of 100 to 500 μm, a length in the longitudinal direction of 5 to 300 ms, and an interval between R of 20 to 15001+Ll, which is constant or random. The resin constituting the partial resin coating layer 13 may be either a thermoplastic resin or a thermosetting resin.In order to construct the partial resin coating layer 13, a thermoplastic resin can be used. The partial resin coating layer 13 is inserted and fixed at predetermined intervals.
can be provided.

In addition, in order to construct the thermosetting W resin, it is particularly desirable to use ultraviolet curable resin.
Bile fluid is applied to the entire original fiber A-line 11 in which a primary coat 12 has been formed in advance, and while running it, an ultraviolet lamp is flashed to intermittently irradiate ultraviolet rays to partially cure the fiber, and then uncure it. By dissolving and removing the parts with an organic solvent, the partial resin coating (ilE
This is because the layer 13 can be provided, and the secondary coating 114 is provided on this partial resin coating layer 13 . This secondary coating layer 14 is made of resin or metal, and is provided in rapid succession over the entire length of the core wire, so that the primary coat 12
There are intermittent gaps between the and the secondary covering layer 14! 1115・
... will be formed. When the secondary covering layer 141 is made of resin, a loose extrusion W5 method is used, and when it is made of metal, a method such as winding a metal tape or vertically attaching a metal tape is used.

The original fiber core wire with such a structure has a broken type between a solid type and a loose type, so that the partial resin coating layer 13 is not continuous even at low temperatures, resulting in less shrinkage and transmission loss. The increase in In addition, even if this core wire is bent, the structure is not disturbed because there are partial resin coating layers 13 in some places, and the bare optical fiber fli91
11 is always correctly positioned on the central axis of the core wire, and transmission loss does not increase.

FIG. 4 shows an example of a manufacturing apparatus used in the method of manufacturing a coated optical fiber according to the present invention.

An optical fiber base material 16 obtained by VAD method, MCVD method, etc. is placed in a spinning furnace 17, and its lower end is heated by a heater 17a to melt and spin the bare optical fiber 1.
1 is obtained. The bare optical fiber 11Vi is then continuously guided to the primary applicator 18, where a resin liquid for the primary coat 12 is applied, and then the baking furnace 1
9, the resin liquid is heated and solidified to form a primary coat 12. This primary code-1
The bare optical fiber 11 provided with 12 is then guided to a secondary applicator 2o that applies an ultraviolet curing type 411@ liquid that will become the partial resin coating layer 13, and is then guided to a secondary applicator 2o that applies an ultraviolet curing type 411 @ liquid that will become the partial resin coating layer 13, and is applied to the primary coat 1.
2. UV curing resin reducing solution is applied to the entire top. The ultraviolet curing wall resin liquid used here is, for example, one consisting of an unsaturated polyester resin made of maleic anhydride, fumaric acid, etc., a styrene compound, and a photosensitizer, or one made of polyisocyanate 1 and an acrylic monomer having a hydroxyl group content. It is preferable to use a solvent-free type, such as one consisting of an addition polymer (frethane acrylic), an acrylic monomer, and a photosensitizer, and a curing time of several to several tens of seconds.

The optical fiber 11 coated with the uncured ultraviolet curable resin liquid is then introduced into the ultraviolet curing furnace 21. This ultraviolet curing furnace 21 has ultraviolet light sources 21a such as fluorescent chemical lamps and high-pressure mercury lamps arranged in a circumferential manner, and the above-mentioned optical fiber stock line 11 feet is run through the center of the ultraviolet light sources 21a. 21a blinks at predetermined intervals.

By running the bare optical fiber 11 coated with the ultraviolet curable m finger pad at a predetermined speed and blinking the ultraviolet light source 21a at a predetermined interval, the ultraviolet curable resin liquid is cured in the longitudinal direction of the single fiber ridge line 11. The hardened portions and the unhardened portions occur at predetermined intervals. Tsuiku, r-
The optical fiber Ti wire 11 in this state is sent to an uncured resin melting and removal tank 22. In this uncured resin dissolution and removal tank 22,
It is filled with an organic solvent or acid aqueous solution that dissolves the uncured ultraviolet curable resin @, and if the bare uni-fiber wire 11 is run while being immersed in the organic solvent or acid aqueous solution, the uncured portion is dissolved and removed. An optical fiber probe 11 is obtained in which a one-part resin coating 1113... is provided on the primary coat 12. The optical fiber probe 11 in this state is 1
After it is once wound up by the winding machine 23, it is further moved to a cloth (not shown) by an extrusion mill equipped with a rad die, such as nylon resin, etc. A secondary coating layer 14 is provided by loosely extruding coating, or by winding or vertically attaching a metal tape such as aluminum, and the objective is Y:
According to this method of producing a coated optical fiber, the resin coating layer 13 is partially formed by applying an ultraviolet curable resin liquid and flashing an ultraviolet light source while running the coated resin. Since this is carried out by partially curing and dissolving and removing the uncured portion, the partial resin VtQ layer 13 can be formed very easily, and can be done at low cost without requiring any special manufacturing equipment. Also.

Since ultraviolet curable resin liquids are generally fast-curing and solvent-free, they can speed up the work and do not contaminate the working atmosphere.

Hereinafter, a specific explanation will be given by showing examples.

[Example 1] Urethane fi! single mode light 7742 wire with a diameter of 125 μm! Grease was applied to a thickness of 2 μm and baked to form a briny coating. This material was coated with ultraviolet curable epoxy acrylic resin to a thickness of 300 μm. While running this material in an ultraviolet curing furnace at a linear speed of 20 twr/min, a high-pressure mercury lamp with a length of 30 twr was turned on for 1 second and then turned off for 5 seconds to partially cure it. This resulted in a cured part with a length of 30 t* and an uncured part with a length of 160 cm. After dissolving and removing the uncured portion, a secondary coating layer made of nylon resin with an inner diameter of 300 μm and an outer diameter of 700 μm was provided using a loose extrusion coating method. The loss was measured at 7'C, and the results indicated by A in FIG. 5 were obtained. The results are shown for BIIi in the figure, a full-length core wire with a primary coat made of ordinary silicone resin and a secondary coated layer made of nylon resin. From the graph of FIG. 5, it is clear that fJll of this invention)
(It is important to note that core wires have lower loss than conventional wires in low and high temperature ranges.

[Example 2] Optical fiber with a diameter of 125 μm/<C1> Cone resin was applied to the bare wire to a finished diameter of 230 μm, and a briny coat was provided. Next, in a separate process, UV crosslinkable silicone resin was applied to a finished diameter of 420 μm, and this was applied at a linear speed of 30 μm.
Partial curing was carried out by turning on an ultraviolet lamp with a length of 5 mm for 1 second and turning it off for 1 second while running at a speed of about 100 mm/min.

This results in 5 crn of hardened portion-6 for every 50 willow lengths.
s formed. After dissolving and removing the uncured portion, the inner diameter is 420 μm and the outer diameter is 900 μm using a loose extrusion coating method.
A secondary coating layer made of nylon 66 resin was provided to form a core wire. The temperature characteristics of this core were as excellent as those obtained in Example 1.

[Example 8] CV coating of aluminum on bare optical fiber with a diameter of 125 μm
It was coated by method D to form a ply Y 17-coat with a diameter of 160 μm. After applying ultraviolet crosslinkable silico-y resin to this material so as to have a finished diameter of 880 μm, it was partially cured under the same conditions as in Example 2. Then, in the same manner as in Example 2, a secondary coating layer made of nylon 12N# was provided.

The transmission loss of this optical fiber core wire is shown in C in the 61st Nae.

The middle part of the figure shows the transmission loss of a core wire made by directly coating the same aluminum coated optical fiber with nylon 12 resin.

As is clear from FIG. 6, the metal coated 4° optical fiber of the present invention has lower transmission loss over a wider wavelength range than the conventional solid metal coated optical fiber.

As explained above, since the optical fiber core of the present invention is provided with a partial resin coating layer that is not continuous with the primary coat and the secondary coating layer at 1 Jfl, the optical fiber core wire of the present invention has a partial resin coating layer that is not continuous with the primary coat and the secondary coating layer. Since the resin coating layer is not continuous, there are fewer telescopic needles and the increase in transmission loss is slight. Furthermore, even if this core wire is bent, since there are partial resin coating layers at key points, the structure will not be disturbed or collapsed, and transmission loss will not increase as a result. In addition, in the manufacturing method of this six-fiber core wire, the above-mentioned partial resin wave mWI is formed by applying an ultraviolet curable resin liquid, and this
Since it is partially cured with ultraviolet light and the uncured portion is dissolved and removed, it is possible to obtain the optical fiber core wire having the above structure very easily and at low cost without requiring any special manufacturing equipment.

[Brief explanation of drawings]

Figure 1 is a schematic cross-section showing a conventional solid-type optical fiber.
Fig. M and Fig. 2 are schematic sectional views showing the same loose type, Fig. S is a sectional view cut along the longitudinal direction of the optical fiber showing an example of the optical fiber core of the present invention, and Fig. 4J is a schematic cross-sectional view showing an example of the optical fiber core of the present invention. -f of the manufacturing equipment used in the manufacturing method of Hikari 7 IPA core wire
A schematic configuration diagram showing Il gold. FIG. 5 is a graph showing the temperature dependence of transmission loss between the original fiber core of the present invention and the conventional solid-type optical fiber core d. 3 is a graph showing the wavelength dependence of transmission loss with the T-fiber core wire (3 coats of mold). 11......n°0 fiber maintenance, 12...
- Brimary coat t113...Partial resin coating layer, 14...Secondary coating layer, 15...Void layer, 16...Optical fiber base material, 17...
...Spinning furnace, 18...-Next applicator. 19... Baking furnace, 20... Secondary applicator. 21... Ultraviolet curing furnace, 21a... Ultraviolet source. 22...Uncured resin dissolution and removal tank. Applicant Fujikura tυ Nihon Kame Co., Ltd. (i! Telephone Public Corporation rw −+ −−−−* −,,, −y J”:',)
',''...'>1 Figure 4 Figure 5 ε ＼ Throat-60-40-20020406080to. □l attack υ

Claims (2)

[Claims] (1) Put a primary coat t on the bare optical fiber and X in the longitudinal direction of the optical fiber maintenance! I! An optical 7-iper core wire comprising a partial resin coating layer that is not continuous and a secondary coating l- made of resin or metal that is continuous in the longitudinal direction of the bare optical fiber. (2) The optical fiber core m7 according to claim 1, wherein the partial resin coating layer is formed of an ultraviolet curable hardening resin (3) Forming a primary core on the optical fiber and fiber bare wire, Next, an ultraviolet curable resin liquid is continuously applied to the entire surface of the primary knee 1, and is partially cured with ultraviolet light in the longitudinal direction of the optical fiber. - A method for producing an optical fiber core, which comprises dissolving and removing the bare optical fiber, and then forming a secondary coating layer made of resin or metal that is continuous in the longitudinal direction of the bare optical fiber.