长周期光纤光栅谐振波长及耦合系数的研究

运用Matlab7.0软件进行建模,研究发现,当光栅周期确定后,波长改变时高次包层模与导模耦合的谐振波长处于长波长处,而低次包层模式与导模耦合的谐振波长处于短波长处;光纤参数的变化对耦合系数的影响程度不同,耦合系数对纤芯半径的变化更敏感,特别是纤芯半径变小时,奇次耦合系数的最大值所对应的模式次数向相反方向漂移.由此可见,光纤参数的变化对谐振波长和耦合系数会产生一定的影响,而这些影响会进一步引起透射谱损耗峰的漂移和分裂.

Study on Resonant Wavelength and Coupled-Coefficient based on Long Period Fiber Grating

Some useful conclusions by using Matlab 7.0 od of a LPFG, the resonant wavelengths locate at the software and calculating were drawn that with given perilong wave scope when coupling occur between high order cladding modes and the core transmitted mode, while the resonant wavelengths locate at the short wave scope when coupling occur between low order cladding modes and the core transmitted mode; different fiber parameters have different effect on the coupled-coefficients. They are found to be more sensitivity to the change of the radius of the fiber core. The order mode that corresponds to the maximum coupled-coefficient, shifts towards opposite direction, especially when the radius of fiber core decrease, the peak of the transmission spectrum is further shifted and split under these effects.