Dispersion compensation method for broadband light source

Abstract

The invention discloses a dispersion compensation method for a broadband light source. A polarization-preserving fiber polarization coupling testing system based on a Michelson interferometer is formed by the broadband light source, and the Michelson interferometer compensates the optical path difference between an excitation mode and a coupling mode in the polarization-preserving fiber, and a detector acquires an interference signal; specifically, the method comprises the following steps of: intercepting the initial data acquired by the detector through a window function, and taking out the interference data Imain between the excitation modes and the interference data Icoupling between the excitation mode and the coupling mode; respectively executing Hilbert transformation and Gaussian fitting on the Imain and the Icoupling, obtaining envelopes (I)main and (I)coupling of the interference signal, getting a birefringence dispersion coefficient Delta D according to a ratio Eta of the width of the (I)main to the width of the (I)coupling at a 1 / e part, obtaining a phase factor needed for the dispersion compensation, and then multiplying the phase factor by a nonlinear frequency spectrum function with dispersion information to eliminate nonlinear phase items causing the widening of the interference signal envelopes; and finally, obtaining the dispersion compensated interference signal Icomp by executing Fourier inversion on the obtained linear frequency spectrum function.

Description

technical field [0001] The invention relates to a polarization-maintaining optical fiber polarization coupling test technology, in particular to a dynamic dispersion compensation method for a polarization-maintaining optical fiber polarization coupling test system built by a broadband light source, and belongs to the technical field of high-precision measurement. Background technique [0002] A broadband light source refers to a low-coherence light source with a certain spectral width and a short coherence length. Because the light source has a wide spectral width, the interference system built by it is often called a white light interference system. In commonly used photoelectric interferometry systems, the most commonly used light sources are various single-mode or narrow-band high-coherence lasers. Under precise measurement conditions, the system can obtain nanometer-level measurement accuracy, but the single-value dynamic range of this type of measurement system is gener...

AI Technical Summary

Problems solved by technology

The above dispersion compensation methods mostly use dispersion compensating fiber or electrical and optical phase modulation compensation methods. These methods can only compensate for optical fibers with fixed dispersion values, or due to factors such as their own limited frequency bands, they cannot Realize effective compensation for the dispersion of ultra-broadband optical signals, or the implementation device is complicated, and it is easy to introduce noise and errors, etc.

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