光纤中无波分裂脉冲的平坦超连续谱产生  

Flat supercontinuum generation via wave-free breaking pulse in the optical fiber

作　　者：任行 王天枢 杜垒 李鑫 肖林 周见红 Ren Hang;Wang Tianshu;Du Lei;Li Xin;Xiao Lin;Zhou Jianhong(Institute of Space Optoelectronic Technology,School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022,China;Department of Optical Engineering,School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022,China)

机构地区：[1]长春理工大学光电工程学院空间光电技术研究所,吉林长春130022 [2]长春理工大学光电工程学院光学工程系,吉林长春130022

出　　处：《红外与激光工程》2023年第5期357-365,共9页Infrared and Laser Engineering

基　　金：国家自然科学基金(61975021);吉林省自然科学基金(YDZJ202101,ZYTS139)。

摘　　要：基于无波分裂脉冲产生的平坦超连续谱被报道。笔者采用非线性偏振旋转(NPR)作为锁模方法来实现耗散孤子脉冲和无波分裂脉冲的切换输出。在0.3 W的泵浦功率下,获得了耗散孤子脉冲。脉冲宽度为5.8 ps,脉冲间隔为54 ns,与11.05 m的腔长一致,信噪比为55 dB,压缩后的脉冲宽度为0.61 ps。值功率可以被提升到1.18 kW。通过适当调整腔偏振态和增加泵浦功率,耗散孤子可以演化为无波分裂脉冲。随着泵浦功率的提高,脉冲宽度从11.7 ps增加到20.2 ps,几乎增加了两倍。经过计算,时间带宽积从23.9增加到53.43。较大的啁啾可以抵抗非线性相移的影响,从而避免脉冲分裂。无波分裂脉冲的脉冲能量可以提高到3.89 nJ,是耗散孤子脉冲能量的五倍。随后,使用耗散孤子和无波分裂脉冲作为种子源去获得超连续谱。结果表明,在锥形高非线性光纤中,无波分裂脉冲产生的超连续谱范围和平坦度均优于耗散孤子脉冲。基于耗散孤子脉冲和无波分裂脉冲产生的超连续谱范围为1400~2000 nm,覆盖了S波段、C波段、L波段三个主要通信波段,20 dB带宽分别为310.3 nm和426.4 nm。这项工作将有助于高能量脉冲光纤激光器的发展,并提高其在超连续谱产生和光通信领域的潜在应用。Objective Supercontinuum light source has the advantages of wide spectral range and good spatial coherence.Thus,it is widely applied in optical communication,optical frequency comb,optical fiber sensing,spectrum detection,and other fields.With the development of new technology such as optical coherence tomography and fluorescence lifetime imaging,supercontinuum light source has become an interesting research field.Although the combination of 1.55μm mode-locked pulse and highly nonlinear fiber can realize all-fiber near-infrared supercontinuum light source.However,due to the low output energy of the mode-locked pulse,the energy of the supercontinuum light source is mainly concentrated in the spectral region of the pump wavelength.How to enhance the coverage and flatness of the near-infrared supercontinuum is a problem need to be solved.For this purpose,we designed a high-energy erbium-doped fiber laser.Methods The generation of flat supercontinuum via wave-free breaking pulse is proposed.Nonlinear polarization rotation(NPR)is employed as a mode-locking way to switch the output of dissipative soliton pulse and wave-free breaking pulse(Fig.1).Dissipative soliton pulse is obtained at 0.3 W pump power(Fig.3).The pulse width is 5.8 ps,and the pulse interval is 54 ns corresponding to the cavity length of 11.05 m.The signal-to-noise ratio is 55 dB,and the compressed pulse width is 0.61 ps(Fig.4).The pulse peak power can be increased to 1.18 kW.By properly adjusting the cavity polarization state and increasing the pump power,the dissipative soliton pulse can evolve into wave-free breaking pulse(Fig.5).With the increase of pump power,the pulse width increases almost twice from 11.7 ps to 20.2 ps.After calculation,the time bandwidth product increases from 23.9 to 53.43.The larger chirp can resist the influence of nonlinear phase shift,avoiding pulse splitting.The pulse energy of wavefree breaking pulse can be increased to 3.89 nJ,which is five times of the pulse energy of dissipative soliton(Fig.6).Results and Discussions

关 键 词：超连续谱 非线性偏振旋转 耗散孤子 无波分裂脉冲 平坦度 

分 类 号：TN248[电子电信—物理电子学]