Method for manufacturing ultra-low birefringence optical fibre and rotary stretching tower

Abstract

The invention relates to a method for manufacturing an ultra-low birefringence optical fibre, which comprises a step of manufacturing an optical fibre preform and a step of drawing the optical fibre preform and is characterized by further comprising the following steps of: before the step of drawing the optical fibre perform, at least locally heating and softening the manufactured optical fibre preform and rotating and stretching the manufactured optical fibre preform along an axial direction, and rotating, stretching and fixing the formed optical fibre preform in the cooling process of the optical fibre preform. A rotary stretching tower for manufacturing the ultra-low birefringence optical fibre comprises an upper clamping head, a lower clamping head, an upper end and a lower end, wherein the upper clamping head and the lower clamping head are vertically arranged; the upper end and the lower end are respectively used for clamping the optical fibre preform; the upper clamping head and the lower clamping head can rotate about the axis of the optical fibre preform respectively; furthermore, the upper clamping head and the lower clamping head can translate along the axis of the optical fibre perform respectively; and a heating furnace capable of translating along the axis of the optical fibre preform is also arranged between the upper clamping head and the lower clamping head and used for at least locally heating and softening the optical fibre preform.

Description

technical field [0001] The invention relates to a low birefringence optical fiber, in particular to a method for manufacturing an ultra-low birefringence optical fiber and a rotating drawing tower used in the method. Background technique [0002] Since the invention of optical fiber, it has been used in many technical fields, especially in the field of optical fiber communication. Various optical fiber products, including multimode optical fiber, single-mode optical fiber, dispersion compensation optical fiber, etc., have been widely used. In the field of sensing, optical fibers also play a unique role. Sensing optical fiber technology includes many aspects. Taking advantage of the sensitivity of optical fibers to different physical quantities, optical fiber sensing products for measuring different physical quantities have been developed, such as optical fiber sensors for temperature, humidity, pH value, refractive index, stress, and angular velocity. . [0003] It is well...

AI Technical Summary

Problems solved by technology

[0006] There are some insurmountable problems in the circular polarization-maintaining optical fiber and its manufacturing process proposed in the above-mentioned patents: due to the use of an indefinite number of stress units in the optical fiber, the manufacturing process of the optical fiber preform, the drawing process and the subsequent optical fiber fusion processing process All are difficult, especially the manufacture of special-shaped preforms is difficult, and it is easy to burst and be scrapped

In addition, the method of reducing the birefringence of the optical fiber by rotating the optical fiber preform is also difficult to achieve in the actual optical fiber production process.

As pointed out in the patent application documents with publication number CN 1663922, since the part of the preform rod in the wire drawing furnace in the wire drawing process is heated above 1800°C and is in a molten state, the centrifugal force generated by any rotation of the preform rod will make the Its deviation from the center line will affect the quality of the optical fiber. Practice has proved that the rotation speed of the preform in the drawing state must be controlled below 100r / min, otherwise the high-temperature melting part of the preform may be thrown off the center line and the drawing furnace will be scrapped. Considering that the rotation pitch of the birefringent fiber (the rotation pitch is defined as the length of the periodic rotation of the fiber) is about 3mm, so by rotating the preform, the fiber drawing speed is only about 0.3m / min, such a low speed drawing The mechanical properties of the optical fiber made by the system cannot meet the needs of actual use.

Images