双包层掺Bi光纤的制备及其光谱特性研究

用改进的化学气相沉积方法和溶液掺杂方法制备了掺Bi双包层石英基光纤. 测试了掺Bi光纤预制棒切片的吸收光谱和掺Bi光纤在特定波长下的吸收系数,在不同波长的激光激发下, 研究了掺Bi光纤的近红外荧光光谱. 掺Bi光纤在976 nm激光激发下,其荧光光谱范围在1000---1400 nm之间, 荧光峰的峰值位于1140 nm附近,半高宽约为130 nm;在793和808 nm激光激发下得到了 1000---1700 nm的超宽带近红外荧光,半高宽超过250 nm.通过对掺Bi光纤预制棒切片进行900 ℃ 保温1 h的热处理后,发现在808 nm激光 激发下预制棒切片的荧光强度增加了近4倍.研究结果表明,具有超宽带荧光特性的双包层掺Bi光纤 有望作为超短脉冲激光器和可调谐激光器的增益介质.

Preparation and spectral characteristics of Bi-doped double cladding fiber

Bi-doped double cladding fiber preform is prepared by modified chemical vapor deposition and solution doping process.The absorption spectrum of preform and the near-infrared(NIR) luminescence spectrum of fiber are experimentally investigated.The luminescence spectrum of the fiber shows a peak emission band at 1140 nm with a full-width at half-maximum(FWHM) of 130 nm under 976 nm LD exciting.Under 808 or 793 nm LD exciting,an ultra-broad NIR emission with an FWHM of more than 250 nm is observed in the Bi-doped fiber,and the range of luminescence spectrum is from 1000 to 1700 nm.After the heat treatment of the Bi-doped fiber preform slice under 900°C for 1 h,under 808 nm LD exciting,the fluorescence intensity is about 4 times higher than that of the perform slice without heat treatment.The results indicate that the Bi-doped double cladding fiber is a promising gain medium used for ultrashort fiber lasers and tunable fiber lasers.