Detection method of residual cladding thickness of side-polished fiber

Abstract

The invention discloses a detection method of residual cladding thickness of a side-polished fiber. The method is characterized in that the method comprises the following step that: (1), a March-Zehnder transmission type off-axis holographic imaging system is used for shooting an off-axis hologram containing side-polished fiber structure information; (2), phase reconstruction is carried out on the off-axis hologram; (3), unwrapping is carried out on a phase after reconstruction to obtain a phase diagram; (4), the side-polished fiber is removed based on the step (1) and a background hologram is shot, and phase reconstruction and unwrapping are carried out according to the step (2) and the step (3), thereby obtaining a background phase diagram; (5), compensation is carried out on the phase diagram obtained at the step (3) by using the background phase diagram obtained at the step (4) to eliminate phase inclination, thereby obtaining a phase diagram of the side-polished fiber; and (6), structure information is extracted from the phase diagram of the side-polished fiber to obtain a distance between a polishing surface and a fiber core, thereby obtaining a residual cladding thickness. According to the invention, with the method, on-line and nondestructive measurement can be realized; and the distance between the fiber core and the polishing surface can be directly measured.

Description

technical field [0001] The invention relates to a thickness detection method. Background technique [0002] In recent years, all-fiber devices are being researched and used more and more. Generally, all-fiber devices are widely used in optical fiber sensing and optical communication, etc., which have the advantages of high integration and easy fusion with optical fibers. Side-polished fiber is a common fiber optic component used to make all-fiber devices. [0003] The light transmission characteristics of the side-polished fiber are closely related to the remaining thickness of the cladding (that is, the distance between the fiber core surface and the polished surface). Studies have shown that when the residual thickness of the cladding is less than 5 microns, the fiber loss increases significantly. The smaller the residual thickness of the cladding of the side-polished fiber, the more sensitive its optical transmission characteristics are to changes in the external envir...

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Problems solved by technology

The power measurement method is greatly affected by the refractive index of the external environment, temperature, and the stress on the opt

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