JPS5844620B2 - Hikarif Aibano Seizou Sochi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing a low-loss optical fiber used for communications.

Optical communication using optical fibers is viewed as extremely promising due to the reduction in transmission loss of optical fibers and the improvement in the performance of optical semiconductors.

Conventionally, it has not been possible to measure the transmission loss, which is the most important characteristic of optical fibers used in such optical fiber communications, at the same time as manufacturing.

That is, an optical fiber is first manufactured, and then the transmission loss of the manufactured optical fiber is measured.

Such a conventional method in which optical fiber manufacturing and transmission loss measurement are performed in separate processes causes the following problems.

The first problem is that the longitudinal change in transmission loss of a manufactured optical fiber cannot be determined without destructive testing of the optical fiber.

This is due to the method used to measure optical fiber transmission loss.

Generally, transmission loss is determined from the ratio of the intensity of light entering an optical fiber and the intensity of light exiting from the optical fiber.

In this measurement method, even if there is a part of the optical fiber under test with a large transmission loss, only the transmission loss of the entire optical fiber is determined, and the change in transmission loss in the length direction of the fiber is calculated. Not asked for.

Therefore, in the past, when it was desired to determine the change in transmission loss in the longitudinal direction, it was determined by breaking the optical fiber.

In other words, the process of inputting light into the optical fiber that is the object to be measured and measuring the intensity of the emitted light is repeated each time the optical fiber is broken from the output end of the optical fiber. The change in transmission loss in the longitudinal direction was determined from the rate of change in intensity.

However, since this method is a destructive test, it cannot be used as a product inspection method.

The second problem is that it takes a lot of time to manufacture an optical fiber into a product because it is not possible to simultaneously manufacture the optical fiber and measure the transmission loss.

The third problem is that the transmission loss measurement cannot be carried out at the same time as manufacturing, and therefore the manufacturing conditions of the optical fiber cannot be appropriately changed during manufacturing.

Therefore, the purpose of this invention is to
It enables non-destructive measurement of changes in optical fiber transmission loss in the longitudinal direction, and by being able to manufacture optical fibers and measure transmission loss at the same time, the process time can be shortened.
Another object of the present invention is to provide an optical fiber manufacturing apparatus that can change optical fiber manufacturing conditions during manufacturing so that transmission loss is uniformly low.

According to the present invention, in an optical fiber manufacturing apparatus equipped with a heating section for heating and stretching an optical fiber material and a winding drum for winding up the optical fiber, an optical fiber spun from a heated optical fiber material is spun. It is possible to obtain an optical fiber manufacturing apparatus characterized in that it includes a light intensity measurement section that measures the intensity of propagated light.

Next, this invention will be explained with reference to the drawings.

The figure is a configuration diagram showing an embodiment of the present invention, in which 11 is an optical fiber material, 12 is a heating unit that heats the optical fiber material 11,
13 is a winding drum, 14 is an optical fiber, 15 is a tip of the optical fiber, 16 is a condensing lens, 17 is an optical chopper,
18 is an optical filter 19 which is a photoelectric conversion element, 20 is a synchronous amplifier, 21 is a logarithmic converter, and 22 is a recorder.

When heating and stretching an optical fiber material, one end of the optical fiber material is heated and kept at a high temperature.

Therefore, the heated optical fiber material emits heat radiation.

A portion of this thermal radiation propagates through the heated and stretched optical fiber.

The tip 15 of this optical fiber is wrapped around the fiber winding drum 13.
It is set on the winding drum 13 so that it almost coincides with the zero rotation axis.

Therefore, even if the fiber winding drum 13 rotates, the position of the optical fiber tip 15 hardly changes.

The intensity of the light emitted from the tip 15 of this optical fiber is determined by a condenser lens 16, an optical filter 18, an optical chopper 17, a synchronous amplifier 20, a logarithmic converter 21. It is recorded by using a recorder 22.

When the winding drum 13 is rotated, the optical fiber begins to be manufactured, and as the distance of the fiber increases, the intensity of the light propagating through the optical fiber attenuates.

When the attenuation of the light intensity is uniform, the optical fiber has a uniform transmission loss, and when the attenuation changes, the optical fiber has an uneven transmission loss.

In this way, variations in transmission loss along the length of an optical fiber can be measured non-destructively, and since transmission loss measurement and optical fiber manufacturing can be performed simultaneously, the process is shortened and the transmission loss is increased. Since this is known during manufacturing, the manufacturing conditions of the optical fiber can be appropriately changed during manufacturing.

The optical fiber material shown in the above embodiments may be silica glass or low melting point glass, and the heating method may be high frequency heating, direct current heating, laser heating, or burner heating.

When optical fibers are manufactured using such optical fiber manufacturing equipment, changes in transmission loss along the length can be determined non-destructively, and if the transmission loss is bad in only one part of the optical fiber, it is possible to determine where in the optical fiber the transmission loss deteriorates. In order to know whether
It becomes possible to cut out only the bad parts and use the good parts as is, increasing the yield of the product.

In addition, since transmission loss measurement and optical fiber manufacturing can be carried out simultaneously, the process time can be shortened, making it suitable for industrial applications.

[Brief explanation of drawings]

The figure is a configuration diagram showing an embodiment of an optical fiber manufacturing apparatus according to the present invention, in which 11 is an optical fiber material, 12 is a heating section, 1
3 is a winding drum, 14 is an optical fiber, 15 is a tip of the optical fiber, 16 is a condensing lens, 17 is an optical chopper, 1
8 is an optical filter, 19 is a photoelectric conversion element, 20 is a synchronous amplifier, 21 is a logarithmic converter, and 22 is a recorder.

Claims (1)

[Claims] 1. In an optical fiber manufacturing device equipped with a heating unit for heating and stretching the optical fiber material and a winding drum for winding the optical fiber, the light propagating through the optical fiber spun from the heated optical fiber material is 1. An optical fiber manufacturing device characterized by being provided with a light intensity measuring section for measuring intensity.