Method and device for fasting measuring size of optical fiber

Abstract

The invention relates to a method and a device for fast measuring the length of an optical fiber. In the invention, an ordinary continuous semiconductor laser is used as an optical source; an electro-optic modulator and the optical fiber to be measured are all connected with a Sagnac loop; wherein, the electro-optic modulator is asymmetrically arranged in the Sagnac loop and near one opening of an optical fiber coupler; the electro-optic modulator is driven by a RF signal the frequency of which can be linearly scanned; when the RF signal frequency is changed, the transmittivity of a Sagnac interferometer is changed; the variable frequency of the transmittivity is relevant with the length of the optical fiber to be measured; the change of the transmittivity is measured by a photodiode; the output end of the photodiode is connected with a data collection card; The length of the optical fiber to be measured is obtained by fast Fourier change and relevant operations on the the data collected by the data collection card. The method and the device for fast measuring the length of the optical fiber overcome the defects of being incapable of simultaneously meeting the demand of measuring with large range and high precision and having a relative lower cost. As the optical fiber to be measured is connected with the Sagnac loop, the anti-external temperature fluctuation and the mechanical anti-disturbance performances of the device are high.

Description

technical field [0001] The invention belongs to the field of optical technology, relates to general optical fiber length measurement, and is especially suitable for optical fiber communication networks, optical fiber sensor networks, etc., which require rapid, large-scale and high-precision measurement of optical fiber length measurement methods and equipment, and especially relates to a The invention discloses a method for detecting the length of an optical fiber by using an electro-optic modulator to change the light wave frequency to cause an asymmetric effect of the interferometer structure and a device for realizing the method. Background technique [0002] In the field of fiber optics, especially in fiber optic communications, it is of great significance to develop a method for measuring the length of an optical fiber with high precision in a large range and a low-cost device. [0003] Traditional optical fiber length measurement instruments are based on fiber optic re...

AI Technical Summary

Problems solved by technology

[0003] Traditional optical fiber length measurement instruments are based on fiber optic reflectometers, including optical time domain reflectometer (OTDR), optical frequency domain reflectometer (OFDR), optical coherent reflectometer (OCDR), these methods or require extremely short pulse laser The cost of light source and extremely high-speed photoelectric probe is relatively high; or it cannot meet the requirements of high precision and large measurement range at the same time, and it is difficult to be used in practical applications.

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