铌酸锂光纤声电光调制器

Lithium Niobate Optical Fiber Acousto-electro-optic Modulator

制作了一种新型光纤声电光调制器,在原有光纤声光调制器的基础上增加了一对直流电极,通过电光效应改变器件的中心频率,使应用更具有灵活性.声电光效应包括声光效应和电光效应,其中声光效应同时起到光调制与光偏转的作用.给出了声电光衍射效率的计算公式,讨论了最佳声电光工作模式的选定,计算了铌酸锂反常声光互作用几何关系,设计制作了铌酸锂光纤声电光调制器,测试了其相对衍射效率分别随电信号功率和直流电压变化的曲线,实验结果和理论相符.

A new kind of fiber acousto-electro-optic (AEO) modulator by using lithium niobate (LN) crystal is made. This device has an additional direct-current electrode compared with traditional fiber acousto-optic (AO) modulator. Its center frequency can be changed by electro-optic (EO) effect so that the use of the device be more flexible. The AEO effect includes AO effect and EO effect at the same time. The AO effect is used for light modulation and light deflection. The formula of diffraction efficiency of the AEO effect is given from a couple-wave equation of the AO effect. The optimum modes of the AEO effect are discussed. The geometric relations of anisotropic AO interaction in LN are calculated and a LN fiber AEO modulator is designed and made. Some curves of relative diffraction efficiency vs power of electric signals driving transducer and direct-current voltages driving electrode are given respectively. The experiment results are agreed with the theory.