Device and method for improving OFDR frequency domain sampling rate

Abstract

The invention relates to a device and a method for improving an OFDR frequency domain sampling rate. The device comprises a sweep-frequency laser device, an optical fiber coupler, a measurement module, an auxiliary module, a data acquisition card, and a computer. In the measurement module, a reference arm signal and a measuring arm are subjected to beat frequency interference, and a generated beatfrequency signal is acquired by means of the data acquisition card which is controlled by means of an external clock signal generated in the auxiliary module in an equal frequency domain manner. Themethod comprises the steps of: dividing N times of sampling according to the magnitude of the measurement length, utilizing a frequency shifter for adjustment under the condition that the two arm frequency difference of an interferometer of the auxiliary module is fixed, and sequentially subjecting sampled signals to frequency translation for data acquisition; and performing FFT operation after superposing the data acquired repeatedly to obtain a finally result. The method improves the OFDR frequency domain sampling rate, is conductive to expand the OFDR measurement range, can adjust the measurement range according to user needs, is convenient, has precise results, and can meet the requirements of various measurement environments.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, and more specifically, to a device and a frequency domain sampling method for increasing OFDR frequency domain sampling rate. Background technique [0002] As the most promising technology in the field of distributed optical fiber sensing, the research and application of optical frequency domain reflectometry technology has always been a hot issue of widespread concern. Based on the combination of frequency domain analysis and optical heterodyne technology, compared with traditional OTDR technology, OFDR technology has higher resolution and larger dynamic range, and is widely used in optical communication measurement, strain and temperature sensing in engineering and medical fields have a broad vision of application. [0003] The OFDR system uses a swept source. Affected by factors such as temperature changes and device vibrations, the output laser spectral lines will change, and ...

AI Technical Summary

Problems solved by technology

If you want to expand or reduce the measurement range, you must remake and replace the auxiliary interferometer, otherwise there will be problems such as over-range measurement or measuring short-distance optical fibers with a large-range system, resulting in long measurement time and slow speed.

Moreover, since the spatial resolution of OFDR is usually at the micron level, a single acquisition of data points can reach tens of millions during long-distance measurement, and the sampling frequency interval is small. It is difficult for conventional data acquisition cards and computers to meet the requirements of data acquisition and calculation processing. Use high-performance modules, which will increase the cost of the OFDR system

Images