利用电光强度调制器频移特性实现可调延迟

Adjustable delay analysis using frequency shift characteristics of electro-optic intensity modulator

针对光纤通信系统中数据同步处理时对脉冲可调延迟的要求,提出了一种可调延迟器的结构设计方案。对电光强度调制器(EOIM)的光频移特性进行了研究,基于EOIM对各级边带和强度的调制作用,利用EOIM对受激布里渊散射慢光装置中的泵浦光进行强度调节,从而实现延迟量可调。建立了可调延迟的数学模型,通过实验研究分别得出了在一定微波调制功率下EOIM调制深度和直流偏置电压随脉冲延迟量的变化关系。从实验结果中可以看出:在引起失真的主要因素为零的情况下,当直流偏置电压为半波电压的1/2时,脉冲相对群延迟随调制深度的增大逐渐减小;当调制深度为1.39时,脉冲相对群延迟随直流偏置电压的增大逐渐增大,延迟量最大可达到未调制情况下的1.106倍,实现了较大范围的延迟量调节。

To meet the requirements of the adjustable delay of the pulse in the data synchronization processing of optical communication systems, a structural design scheme of adjusting the delay has been proposed. The light frequency shift characteristics of electro-optic intensity modulator （EOIM） have been analyzed, and based on the modulation of EOIM to the sideband and the light intensity, the delay adjusting could be achieved by regulating the pump light of the stimulated Brillouin scattering slow light. The mathematical model of the pulse delay has been established, and the modulation depth and the DC bias voltage varying with the pulse delay have been stimulated respectively at a fixed microwave frequency. From the experimental results, it is shown that the pulse delay gradually decreases with the increasing of modulation depth when the size of the DC bias voltage is half of the half-wave voltage, and the pulse delay gradually increases with the increasing of the DC bias voltage when the modulation depth is 1.39. The maximum delay can attain to 1.106 times the delay without modulation, which means adjustable delay is achieved effectively.