摘要
掺铒孔辅助导光光纤是由掺铒的高折射率纤芯、低折射率包层和少量的空气孔组成.采用有限元法分析了掺铒孔辅助导光光纤的模式特性;给出了数值计算截止波长和模场直径的方法;提出了改进的平均粒子数反转度迭代算法来数值计算掺铒光纤放大器的增益和噪声系数.研究空气孔对掺铒孔辅助导光光纤的截止波长、模场直径和放大器的增益系数的影响.发现:减小相对孔芯距的值,可使截止波长向短波长移动,减小模场直径的值;当孔的相对大小较大时,截止波长、模场直径和增益的最大值基本上不随孔的相对大小的增大而改变.最后,综合考虑掺铒光纤基模和二阶模的截止波长、与普通单模光纤的熔接损耗、放大器的增益和噪声系数等因素,优化设计了掺铒孔辅助导光光纤的四个结构参量——纤芯半径、纤芯与包层的折射率差、相对孔芯距和孔的相对大小.
Erbium-doped hole-assisted lightguide fiber （EDHALF） is composed of a high-index core doped with erbium, a low index cladding and a small number of air holes surrounding the core. The finite element method is applied for solving the modal field of the EDHALF. The numerical calculation methods of the cutoff wavelength and mode field diameter are described in detail. The modified average population inversion iteration method is proposed for calculating the gain and noise figure of erbium-doped fiber amplifiers. The effects of the air holes on EDHALFs＇ cutoff wavelengths, mode field diameters and the gain coefficients of fiber amplifiers are studied. It＇s found that decreasing the relative hole-to-core spacing can make the cutoff wavelength move to shorter wavelength and decrease the mode field diameter. When the relative size of air holes is relatively large, further enlarging it only slightly changes the cutoff wavelength, mode field diameter and the maximum of the gain coefficient. Finally, four structural parameters, namely the EDHALF-cove radius, the refractive index difference between the core and cladding, the relative hole-tocore spacing and the relative size of air holes are optimized in terms of the design criteria, which take into account the cutoff wavelengths of fundamental mode and the second order mode, the gain and noise figure of fiber amplifiers and the splice loss between the EDHALF and the conventional single-mode fiber.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第2期958-967,共10页
Acta Physica Sinica
基金
国家高技术研究发展计划(863)(批准号:2002AA312190
2004AA31g200)资助的课题~~
关键词
孔辅助导光光纤
掺铒光纤
光纤放大器
有限元法
hole-assisted lightguide fiber, erbium-doped fiber, fiber amplifier, finite element method
