折射率非线性调制的双重光纤光栅特性

利用耦合模理论 ,系统分析了双重光纤光栅在折射率深度调制或非线性调制情况下的光谱特性。结果发现 ,在折射率非线性调制情况下 ,双重光纤光栅具有规则的多波长反射特性 ,同时 ,其反射光谱中的二次谐波也变得非常强 ,因此 ,它是一种实现多通道波分复用器、分插复用器及多波长激光器等的潜在技术。

Dual Overwritten Fiber Gratings Characteristics with Nonlinear Modulation of Refractive Index

The dual overwritten fiber Bragg gratings have been found the significant applications in telecommunications and fiber sensors. In this paper, the nonlinear perturbation to the refractive index induced by dual overwritten fiber Bragg grating is analyzed, and the spectral characteristics that can be achieved in dual overwritten fiber gratings with nonlinear modulation of refractive index are investigated by numerical simulation based on the coupled-mode theory. It is found that multi-wavelength reflection and strong second harmonics will occur in dual written fiber Bragg gratings when the nonlinear index perturbation becomes strong, which is very useful for multichannel wavelength-division-multiplexing. The method described in this paper is conducive to the fabrication and applications of dual overwritten fiber Bragg gratings.