Device and method for detecting defects of optical fiber drawing coating

Abstract

The invention discloses a device and a method for detecting defects of an optical fiber drawing coating. The device mainly comprises a detection light source, a coupling system and a detection system.Laser beams generated by a red laser and a green laser with specific numerical apertures and light spot sizes are coupled into an optical fiber preform; the output power of the red light beam and / orthe green light beam of the coated and cured optical fiber end face is measured, and the defects of bubbles, impurities, gas lines, scratches, non-uniform coating, coating and glass cladding concentricity and the like of the optical fiber coating can be judged. According to the device and method, the coating of the optical fiber can be monitored in real time, creeling testing and wiredrawing waiting are not needed, waste of optical fiber preforms and coatings is avoided, meanwhile, the equipment utilization efficiency is improved through the measuring method, and the yield of qualified opticalfibers is increased.

Description

technical field [0001] The invention belongs to the detection field of optical fiber prefabricated rod defects, and more specifically relates to a detection device and method for optical fiber drawing coating defects. Background technique [0002] An optical fiber usually consists of a doped core, a silica cladding, an inner coating, and an outer coating. Among them, the inner coating layer generally has a lower elastic modulus, which is used to protect the surface of the bare optical fiber from mechanical damage and buffer external stress; the outer coating layer has a higher elastic modulus, which is used to enhance the mechanical strength and wear resistance of the optical fiber, so The performance of the inner and outer coatings of the optical fiber directly determines the quality and life of the optical fiber. [0003] For double-clad fibers (such as passive matching fibers for fiber lasers, rare-earth-doped fibers, etc.), the inner coating also acts as an optical wave...

AI Technical Summary

Problems solved by technology

Red light detection is used to detect bright spots, bubbles, scratches, etc. on the surface of the optical fiber. This detection method is suitable for rapid and qualitative analysis of the coating of the optical fiber; microscope detection is to place the end face or surface of the optical fiber under a microscope to view the defects in the optical fiber coating. Bubbles, bright spots, concentricity, scratches, etc. This detection method is used to check the defect types of optical fiber defects. The detection speed is slow and the efficiency is low. Usually, the judgment of coating quality needs to combine these two detection methods

And this method of detecting the quality of the optical fiber coating is an off-line method, which is the measurement after the optical fiber is drawn and changed. The measurement takes a long time, and the drawing is still in progress at this time. If the coating is defective, For drawing special optical fibers (rare earth-doped double-clad optical fibers), this is a huge waste. For example, rare earth-doped preforms are usually only 500mm long, and a preform is drawn in about 1 hour. It takes 20 minutes to test , will lose one-third of the optical fiber, and the inner coating of the rare earth-doped double-clad optical fiber is quite expensive; if the tower is stopped during the drawing process, restart or draw at a slow speed, a considerable amount of optical fiber will also be lost

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