Bent insensitive photosensitive optical fiber for preparing weak grating array online and preparation method

Abstract

The invention discloses a bent insensitive photosensitive optical fiber for preparing a weak grating array online and a preparation method. The optical fiber is a germanium-doped type optical fiber; the refractive index distribution type of the optical fiber is a step type; the content of germanium doped in the core layer of the optical fiber, by weight percentage, ranges from 6.5% to 9%; the value added of the refractive index of the core layer ranges from 0.5% to 0.7% compared with that of a cladding layer; and the bending loss of the optical fiber is smaller than 0.1 dB. The bent insensitive photosensitive optical fiber of the invention can satisfactorily meet the requirements of a weak grating array of which the single-laser pulse inscribing reflectivity ranges from 0.1% to 2% and can be used for large-capacity and long-distance sensing arrays.

Description

Technical field [0001] The invention relates to the field of optical fiber and optical fiber grating preparation, in particular to a bending-insensitive photosensitive optical fiber used for online preparation of weak grating arrays and a preparation method. Background technique [0002] The large-capacity distributed optical fiber sensing system based on weak reflectivity fiber grating has broad application prospects. Its core preparation technology requires writing a large number of fiber gratings on a long-distance fiber while introducing as little loss as possible, such as welding loss and transmission. Loss and bending loss. The method of dynamic on-line continuous preparation of grating arrays effectively avoids the access loss caused by traditional welding preparation of fiber grating arrays, and is an efficient grating preparation method. [0003] However, the dynamic online continuous preparation of fiber grating technology is based on writing fiber gratings with a single...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is that the transmission loss of boron-germanium co-doped photosensitive optical fiber in the prior art is large, it is not suitable for the preparation of long-distance, large-capacity weak fiber grating sensing array, and the small-radius bending loss of optical fiber with standard refractive index distribution is large. Disadvantages, as well as the defect that the bend-insensitive optical fiber with a recessed groove in the refractive index is not suitable for the preparation of single-pulse gratings, and provides a combination of the unique characteristics of high refractive index of the core layer of germanium-doped optical fiber and good single-pulse photosensitive performance. On-line fabrication of bend-insensitive photosensitive optical fiber with weak grating array

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