【摘要】 提出栅格周期、光栅长度、级联间距不同的两个长周期光纤光栅级联(CLPG)模型,采用传输矩阵法和耦合模理论对两个长周期光纤光栅级联的光谱特性进行了研究。理论分析表明,级联间距对CLPG透射谱损耗峰的位置影响很小;在一定波长范围内,对特定结构的CLPG,其数值模拟的透射谱为一条直线,出现"光栅透明"现象;依据建立的理论模型,分析并推导出"光栅透明"条件。在CLPG写制实验中,适当调整光栅周期和光栅长度,使其满足"光栅透明"条件,测量光谱显示CLPG透射率几乎为0 dB,实验证明了"光栅透明"现象的存在。更多还原

【Abstract】 The model of two long-period gratings cascaded with different periods,lengths and gap is proposed.The transmission spectrum is analyzed by utilizing transfer matrix and coupled-mode theory.Theoretical analysis indicates the gap of cascaded long-period gratings(CLPG) has the least effect on the position of loss peaks.In certain wavelengths region the simulative spectrum is a straight line for particular structure of CLPG.The transparent phenomenom is observed and the condition of gratings transparency is obtained according to the model proposed.The transmissivity of CLPG is almost 0 dB as the periods and lengths of gratings are properly adjusted to match the transparent condition.The transparent phenomenom is verified by experiment.更多还原