基于透射型体布拉格光栅衍射效率的研究  

Study of Diffraction Efficiency Based on Transmitting Volume Bragg Gratings

作　　者：李松柏[1] 杨敏[1] 

机构地区：[1]长江师范学院物理学与电子工程学院,重庆涪陵408100

出　　处：《西南大学学报（自然科学版）》2011年第9期67-71,共5页Journal of Southwest University(Natural Science Edition)

基　　金：重庆市教委科技基金资助项目(KJ091307)

摘　　要：基于Kogelnik耦合波理论,推导了透射体布拉格光栅的衍射效率方程,数值仿真分析了折射率调制幅度、晶体厚度、相位失配参量、角度偏移量和波长偏移量等光栅写入参数对体光栅衍射效率的影响.结果表明:当入射波和衍射波没有发生相位失配时,衍射效率最大;当以布拉格角入射时,衍射效率将随介质的厚度和折射率的空间调制幅度的增加而增加;当入射光满足布拉格条件时,不同厚度和折射率调制幅度的体光栅衍射效率为100%;只要入射光偏离布拉格条件一个很小的量,体光栅衍射效率就会迅速下降;当偏离量超出一定范围,衍射效率就降低为0.同时,并非是体光栅折射率的空间调制幅度越深,衍射效率越高.Based on Kogelnik＇s coupled-wave theory,Bragg grating diffraction efficiency equation of transmission body was derived.By numerical simulation,the effects on the grating diffraction of amplitude modulation of refractive index,crystal thickness,phase-mismatching parameters,offsets of angles and wavelengths were analyzed.The results showed that the maximal diffraction efficiency was obtained when phase-mismatching did not occur between the incident waves and the diffraction waves,and the diffraction efficiency would be improved at the incidence of Bragg angle with the increase in the thickness of the crystal and the spatial amplitude modulation of the refractive index.When the incident light met all Bragg conditions,the diffraction efficiency of the transmission bodies of various thicknesses and different amplitude modulations of refractive index was 100%.Whenever it deviated slightly from the Bragg conditions,the diffraction efficiency would sharply decline.When the deviation exceeded a certain range,the diffraction efficiency would drop to zero.Furthermore,it was noticed that deeper spatial amplitude modulation of the grating refractive index did not necessarily induce higher diffraction efficiency.

关 键 词：透射体光栅 耦合波理论 光栅参数 衍射效率 

分 类 号：TN29[电子电信—物理电子学]