摘要
设计了一种新型的六重准晶涡旋光光子晶体光纤,利用矢量有限元分析方法进行了数值模拟.研究结果表明光纤中模式有效折射率差?neff> 10-4,实现了7个本征矢量模(10个相位涡旋光)的稳定传输,并以HE21为对象,对光纤模式的传输特性进行了分析研究.研究结果表明,在波段1500—1600 nm内,涡旋光模式的限制性损耗在10–8—10–7量级,模场面积保持在40μm2,非线性系数在10–3量级.通过改变光纤中心空气孔的大小,能够实现特定波段的色散平坦趋势,当中心空气孔为1.9μm时,光纤能够在1500—1800 nm波段保持色散平坦,色散系数维持在63.51—65.42 ps·nm–1·km–1之间.
In an optical fiber communication system,vortex beams have aroused great interest in the last several decades.Vortex beams possess many intriguing properties.For example,they have the ability to carry orbital angular momentum(OAM)which is mutually orthogonal.The OAM is a fundamental physical quantity of light which can be used as information carriers for transmission channel of optical fiber.Combined with the existing multiplexing techniques such as wavelength division multiplexing technique,advanced multilevel amplitude modulation formats,etc.,the vortex beams provide an alternative to the increase of the transmission capacity and spectral efficiency of the optical fiber transmission system.Recently,long-length transmission of vortexbeam in optical fiber has been realized and there have also occurred some new designs of optical fiber on vortex beams,such as air-core ring shaped fiber,graded index vortex fiber,multi-ring fiber,and supermode fiber.Photonic crystal fiber(PCF)is flexible in design.Therefore,it is easy to regulate the transmission performance of PCF by adjusting the radius and the pitch of the air holes and so on.In this paper,we propose a newly designed sixfold photonic quasi-crystal fiber(SPQCF)to transmit vortex beams stably.Transmission characteristics of this newly designed fiber are simulated and calculated by using COMSOL multiphysics software.When the wavelength of the incident light is 1550 nm,the effective index difference between the vortex modes in a group is more than 10–4 which is large enough to preclude the LP modes from being formed,and to transmit 7 vector modes(10 OAM modes).Changing the radius and pitch of the air holes,we can regulate the dispersion characteristic and confinement loss of the SPQCF flexibly.At 1550 nm,the confinement loss of the SPQCF maintains 10–8-10–7 which is low enough to confine the vortex beams in the fiber core.When the incident light wavelength of HE21 ranges from 1500 nm to 1800 nm(r0=1.9μm),the dispersion coefficient of the SPQCF is between 63.51
作者
魏薇
张志明
唐莉勤
丁镭
范万德
李乙钢
Wei Wei;Zhang Zhi-Ming;Tang Li-Qin;Ding Lei;Fan Wan-De;Li Yi-Gang(School of Physics,Nankai University,Tianjin 300071,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第11期179-185,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11474170)
天津市自然科学基金(批准号:16JCYBJC16900)资助的课题~~
关键词
光子晶体光纤
涡旋光
色散
限制性损耗
photonic quasi-crystal fiber
vortex beams
dispersion
confinement loss
