不同泵浦方式下Er^(3+)/Yb^(3+)共掺光纤放大器的自发辐射谱

Amplified Spontaneous Emission of Er^(3+)/Yb^(3+) co-doped Fiber Amplifier with Different Pump Lasers

用改进的MCVD法和湿法掺杂技术设计制作了2种不同Er3+、Yb3+浓度比的Er3+/Yb3+共掺光纤(EYDF),利用980 nm和1 480 nm泵浦LD对Er3+/Yb3+共掺光纤放大器(EYDFA)的放大自发辐射(ASE)谱进行了研究。利用980 nm LD泵浦时,这2种光纤在C波段的ASE强度都很弱,吸收系数小的EYDF在C波段的荧光强度比吸收系数大的光纤大2个量级。用1 480 nm LD对吸收系数大的EYDF进行泵浦,优化光纤长度,此时C波段荧光强度比用980 nm泵浦时大5个量级。这是由于对于EYDF在976 nm附近Yb3+有很强的非饱和吸收,导致能量传输效率差,因此980 nm LD不适合做高浓度EYDFA的泵浦源。而1 480 nm泵浦时,Yb3+不再作为敏化剂而只起到克服成对Er3+间的浓度淬灭问题,同时起到提高Er3+在石英基光纤中的溶解度的作用。

Two Er^3＋/Yb^3＋ co-doped fibers with different ion ratio were fabricated through the MCVD and solution doping method. We explored the amplified spontaneous emission （ASE） of Er^3＋/Yb^3＋ co-doped fiber amplifier（EYDFA） with 980 nm and 1 480 nm pump schemes. The measurement results showed that ASE spectrum was very weak when the pump light wavelength was near 976 nm. The EYDF with low absorption coefficient has higher intensity than that with high absorption coefficient. This unexpected result is caused by Yb^3＋ unsaturable absorption and low energy transfer efficiency when pump wavelength is at 976 nm. But the ASE intensity of EYDFA pumped by 1 480 nm LD is strong,which is about 5 orders of that pumped by 980 nm LD.