1、Estimation of Kerr Nonlinearity in an Anti-Resonant Hollow-Core Fiber by High-Order QAM TransmissionDawei Ge1(Presenting author)Shoufei Gao2,Mingqing Zuo1,Yuyang Gao3,Yinging Wang2,Baoluo Yan4,Bing Ye4,Dechao Zhang1,Wei Ding2,*,Han Li1,*and Zhangyuan Chen31 China Mobile Research Institute;2 Jinan Un

2、iversity;3 Peking University;4 ZTE Corp.2023.03.081W4D.62OutlinesBackground1Principle of nonlinear phase shift measurement by high-order QAM mod.2Experimental setup and results3What kind of methods did we use in the past to measure n2?High power and High power density of pulse laser in 0.8nm or 1.06

3、um were mandatory for the measurement of such small quantity like n2 in anti-resonant hollow-core fiber(AR-HCF).33rd harmonic generation1=1.055 mt=5ps,Ppeak=2 GW/cm2SPM spectroscopy =0.8 m(CPA)t=80 fsPpeak=tens of TW/cm2Pressure=0.1barSingle-shot spectral interferometry=0.8 mt=40 fs1 H.J.Lehmeier et

4、 al.,OC,56(1),1985.1=0.8 mt=120fs,Ppeak=200 GW/cm2Pump-probe method2 E.T.J.Nibbering et al.,JOSAB,14(3),1997.3 V.Loriot et al.,OE,17(16),2009.4 J.K.Wahlstrand et al.,PRA,85,043820,2012.Can we measure n2 of AR-HCF by using telecom band and continuous-wave?Continuous-wave method in solid-core fiberThe

5、 method is based on measurement of the nonlinear phase shift induced through the SPM effect,with a CW dual-frequency beat signal used as a pump signal.4Dual-frequency beating is not working,new method should be developed.?,?=2?cos?exp?exp?The beat signal propagation along the test fiberNonlinear pha

6、se shift?=2?=?2?+?2?2?+?2?Calculating n2 by measuring the ratio of spectral components:The ability of measuring I0/I1 decides the digit of n2 we could measure.for AR-HCF,the I0/I1 may be over 140dB,which is far larger than the dynamic range of any spectrum measuring equipment.5 A.Boskovic et al.,OL,