摘要
U波段(1 625~1 675 nm)高重频锁模光纤激光器在甲烷气体检测、扩展通信波段、光子显微镜、眼部手术等领域有广泛的应用前景。基于被动谐波锁模(Harmonic Mode-Locking, HML)的孤子自频移(Soliton Self-Frequency Shift, SSFS)技术是一种实现高重频U波段激光输出的有效方式。首先搭建了基于非线性偏振旋转(Nonlinear Polarization Rotation, NPR)的被动HML光纤激光器,并以此为种子源,通过级联的放大系统将输出功率最高放大至1.7 W。而后将放大的脉冲输入到一段反常色散的色散位移光纤(Dispersion-Shifted Fiber, DSF)中,利用SSFS效应将其中心波长频移至U波段。研究了其中三个重复频率(722.0、941.7、1 224.2 MHz)状态,系统地探究了脉冲重复频率对SSFS的影响。首次使用NPR被动HML光纤激光器作为SSFS效应种子源,实现了波长可覆盖整个U波段范围的GHz脉冲输出。
Objective U-band(1625-1675 nm)high repetition rate mode-locked fiber lasers have broad applications in expanding communication bands,methane and gas detection,photon microscopy,coherent Doppler lidar,and ocular surgery.At present,actively mode-locked fiber lasers based on SSFS can achieve 10 GHz U-band pulse output,but the high repetition rate U-band based on nonlinear polarization rotation(NPR)passively mode-locked has not been broken through.Passively harmonic mode-locking(HML)based on the soliton self-frequency shift(SSFS)is an effective approach for achieving high repetition rate pulses in the U-band.It is of great significance for practical applications.Methods A passively HML fiber laser system based on SSFS has been constructed(Fig.1).Initially,a passively HML fiber laser based on NPR is constructed as the seed source.Through a cascaded two-stage amplification system,the output power is amplified up to 1.7 W.Subsequently,the amplified pulses are input into a section of dispersion-shifted fiber(DSF)with anomalous dispersion,where the SSFS effect is stimulated to shift the central wavelength to the U-band.The residual part of the seed source is filtered out by a long pass filter(LPF),thereby achieving U-band passively HML pulse output.For the first time,a GHz pulse output with a wavelength that can cover the entire U-band range has been achieved using an NPR passively HML fiber laser as an SSFS effect seed source.Results and Discussions Repetition rate tuning of the seed source is achieved by adjusting the pump power and the polarization controller(PC).As the pump power increases from 31 mW to 862 mW,the laser source operates at harmonics spanning from 1st to 39th,corresponding to repetition rate ranging from 31.39 MHz to 1224.2 MHz(Fig.2).Three different repetition rate pulses(722.0 MHz,941.7 MHz,1224.2 MHz)are selected to be shifted to the U-band via SSFS,and the influence of pulse repetition rate on SSFS is investigated(Fig.3,Fig.4,Fig.7).Finally,a tunable high repetition rate U-band passively HML fiber l
作者
王明娇
黄千千
李卫淅
田昊晨
黄梓楠
牟成博
WANG Mingjiao;HUANG Qianqian;LI Weixi;TIAN Haochen;HUANG Zinan;MOU Chengbo(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Shanghai University,Shanghai 200444,China;Division of Time and Frequency Metrology,National Institute of Metrology,Beijing 100029,China;Key Laboratory of State Administration for Market Regulation(Time Frequency and Gravity Primary Standard),Beijing 100029,China;Key Laboratory of Space Active Opto-Electronics Technology,Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2024年第8期40-48,共9页
Infrared and Laser Engineering
基金
国家重点研发计划项目(2020YFB1805800)
国家自然科学基金项目(62135007,61975107)。
关键词
谐波锁模光纤激光器
U波段
孤子自频移
非线性偏振旋转
harmonic mode-locked fiber laser
U-band
soliton self-frequency shift
nonlinear polarization rotation
