A design method of all-optical wavelength converter based on Bessel chirped grating structure

Abstract

The invention provides a design method of an all-optical wavelength converter based on a Bessel chirped grating structure. The method comprises the following steps: firstly, providing a periodically polarized lithium niobate (PPLN) crystal model with a polarization period which is changed according to a Bessel function; secondly, after setting constraint conditions of an all-optical wavelength conversion scheme based on a single-pass configuration cascading SHG+DFG effect, searching structure optimal design parameters of the PPLN crystal model with the Bessel chirped grating structure when the constraint conditions are met; and finally, determining the structure of the all-optical wavelength converter by utilizing the design parameters. In a design process of the all-optical wavelength converter, three types of wavelength conversion properties including conversion bandwidth, conversion efficiency and flatness of a conversion efficiency curve are comprehensively considered, so that the designed wavelength converter can have flat wavelength conversion efficiency, and the wavelength conversion bandwidth can also be extremely expanded.

Description

technical field [0001] The invention relates to a design method of an all-optical wavelength converter based on a Bessel chirped grating structure, which can make the all-optical wavelength converter have a large wavelength conversion bandwidth while maintaining a flat wavelength conversion efficiency, and belongs to the optical element technology field. Background technique [0002] With the continuous improvement of network technology, the business model is constantly changing, and the business volume is also increasing explosively. The optical network is rapidly developing into the next-generation all-optical communication network. The all-optical communication network must not only be able to realize super-large-capacity transmission of information, but also realize flexible and fast routing selection and optical path configuration. Wavelength Division Multiplexing (WDM:WavelengthDivision Multiplexing) optical network can not only meet the demand for transmission capaci...

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Problems solved by technology

Tehranchi et al. proposed a stepped chirped grating (SCG: Step ChirpedGrating) structure, and used this structure to obtain good flat characteristics, but the conversion bandwidth expansion effect is not obvious, only about 90nm

[0005] From the above research results, it can be seen that the feasibility and effectiveness of the wavelength conversion scheme based on QPM technology is beyond doubt, but there are still some shortcomings: For WDM optical fiber communication systems, it is hoped to obtain as large a conversion bandwidth as possible to cover multiple optical fibers communication window, while the conversion efficiency curve should be as flat as possible

Although the reported non-uniform QPM structures have achieved certain effects in expanding the conversion bandwidth or improving the flatness of the conversion efficiency, they still have the problem of insufficient bandwidth expansion or flatness to be improved.

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