Grating preparation on-line monitoring method and system

Abstract

The invention provides a grating preparation on-line monitoring method and system. The method comprises the following steps that a j.i matrix is formed by equal-interval grating array data collected in one scanning period, wherein the row of the matrix represents wavelength steps, and the column represents sampling points, j is the total number of the wavelength steps, and i is the number of all the sampling points; peak finding is carried out on the j.i matrix column by column, and the actual position of the grating is obtained; according to the space position information of m gratings, the mcolumns of data in the corresponding positions in the equal-interval grating array data matrix are taken out to obtain a j-m matrix; each column of data is accumulated to obtain a new 1*i matrix [n1,n2, until ni], wherein ni is composed of j data points, and for each ni, [lambda]1-i until [lambda]j-i are compared in sequence to obtain the maximum values [x1, x2 until xi] of each column; assumingthat the initial wavelength of a scanning light source is set to be [lambda] 0, the wavelengths of the gratings to be measured are [lambda 1, lambda 2, until lambda i], wherein [lambda] i is equal to[lambda] 0+ xi / 1000; the weighted average value of the wavelengths of the gratings to be measured is taken to obtain an average wavelength value, and the difference value between the wavelengths of the gratings to be measured and the average wavelength is further obtained; and the wavelength difference value is compared with a standard difference value [delta] in sequence, wherein if the wavelength difference value is larger than the standard deviation value, the grating wavelength is abnormal.

Description

Technical field [0001] The invention belongs to the field of fiber grating sensing, combining wavelength division multiplexing (WDM) and optical time domain reflection (OTDR) technology, can timely feedback the reflectivity, wavelength consistency and sidelobe size of the grating, and realize the comparison of the prepared grating Performance indicators are monitored in real time. Background technique [0002] Grating demodulation belongs to a kind of optical fiber sensing technology. It forms a grating structure inside the optical fiber after irradiating the phase mask plate located above the optical fiber with ultraviolet laser. The wavelength of this area will be deviated under the action of temperature, strain, etc. By measuring the shift of the center wavelength, the temperature, pressure, strain and displacement can be accurately sensed. Summary of the invention [0003] In order to solve the problems of poor grating writing quality in the existing grating preparation syste...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problems of poor grating writing quality existing in the existing grating preparation system, the present invention proposes a real-time monitoring system, which performs wavelength demodulation on the reflection signal of the grating, and performs certain processing on the signal, and further obtains the engraved grating Quality information, including reflectivity, wavelength consistency, side lobes and other information, realizes real-time monitoring and feedback of engraved grating conditions, effectively improving the quality of engraved gratings

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