An Improved Coherent Peak Demodulation Method Applicable to Optical Fiber End-face Detection

Abstract

The invention discloses a modified coherence peak demodulation method for fiber end face detection, and belongs to the technical field of a fiber end face measuring instrument. The demodulation method comprises quickly limiting phase extraction in a zero order stripe through a modified extremum method, and reducing the random error caused by environment disturbance and CCD shot noise; and performing phase correction for the extracted light intensity maximum based on a Carre phase shift algorithm, and eliminating the influence of the linear phase shift error on the fiber end face height value. During the process for calculating the fiber end face height value, the modified coherence peak demodulation method has no demand for performing phase unwrapping operation, thus improving the calculating speed, and has the advantages of being insensitive to the linear error Epsilon of a phase shifter, and being high in precision.

Description

technical field [0001] The invention relates to an improved coherent peak demodulation method suitable for optical fiber end face detection, belonging to the technical field of optical fiber end face measuring instruments. Background technique [0002] The optical fiber end face measuring instrument is based on the principle of white light interference, and uses phase shift to realize the change of interference fringes on the end face of the optical fiber. Optical fiber end-face tester can accurately and quickly measure the surface topography of optical fiber without contact. As the transmission medium of optical signals, the shape of the fiber end face directly affects the transmission performance of the optical signal in the fiber. Therefore, the measurement of the end face shape of the fiber end face is very important in optical fiber sensing and transmission. Since the optical fiber end-face measuring instrument can meet the online testing requirements of optical fiber ...

AI Technical Summary

Problems solved by technology

However, when using the traditional Carré phase-shift algorithm to extract the phase, it is necessary to unwrap the phase, which requires a large amount of calculation and a relatively long time.

In the actually detected interferogram, due to environmental disturbance and CCD shot noise will bring random errors, affecting the positioning of zero-order fringes, and the linear error of the phase shifter will also affect the relative height demodulation

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