A 1.7-ps pulse mode-locked Yb3+:Sc2SiO5 laser with a reflective graphene oxide saturable absorber

By using a reflective graphene oxide as saturable absorber,a diode-pumped passively mode-locked Yb3+:Sc2Si O5(Yb:SSO)laser has been demonstrated for the first time.Without extra negative dispersion compensation,the minimum pulse duration of 1.7 ps with a repetition rate of 94 MHz was obtained at the central wavelength of 1062.6 nm.The average output power amounts to 355 m W under the absorbed pump power of 15 W.The maximum peak power of the mode-locking laser is up to 2.2 k W,and the single pulse energy is 3.8nJ.     

Diode-Pumped Passively Mode-Locked 1079 nm Nd:CaGdAlO_4 Laser

We demonstrate a diode-pumped passively cw mode-locked NdiCaGdAlO_4 laser operating at 1079 nm with a semiconductor saturable absorber mirror for the first time to the best of our knowledge.The threshold pump power of the laser is 180 mW.A maximum average output power of 93 mW is obtained under the pump power of1.94 W.The pulse duration of the mode-locked pulses is 3.1 ps and the repetition rate is 157 MHz.     

Dissipative soliton operation in diode pumped ultrafast Yb:GdYSiO5 oscillator

We demonstrate the dissipative soliton mode locking in a diode pumped Yb：GdYSiO~（Yb：GYSO） laser operating in the positive dispersion regime. We obtain stable passively mode-locked pulses with strong positive chirp and with very steep spectral edges. The central wavelength is 1050 nm with bandwidth of about 4 nm, autocorrelation trace shown the typical pulse duration is about 3.5 ps. We obtain the maximum average power of 558 mW for a 3.3-W absorbed pump power, with 22% slope efficiency, and a 78-MHz pulse repetition frequency.     

高效三倍频全固态Nd∶YAG/LBO紫外激光器

报道了一种侧面泵浦Nd∶YAG、声光调Q、LBO晶体腔外倍频和三倍频的355 nm准连续波紫外激光器.采用结构简单、紧凑的平-凹腔设计,在152 W的泵浦功率下,重复频率5 kHz时,获得平均功率1.62 W的355 nm TEM00模激光输出,三倍频的转换效率为25%;重复频率1 kHz时,获得平均功率518 mW、单脉冲能量518 μJ、脉宽17 ns、峰值功率高达30 kW的紫外激光输出.     

基于10 m光子晶体光纤的放大自相似锁模振荡器研究

基于单根10 m大模场面积保偏光子晶体光纤, 搭建了带有色散图的放大自相似振荡器; 通过仔细调节腔内色散量的大小以及位于色散补偿端的端镜前的狭缝位置和大小, 实现了稳定的锁模运转, 获得了抛物线形脉冲输出. 输出脉冲的重复频率为8.6 MHz, 脉冲宽度为6.2 ps, 光谱宽度为3.84 nm, 平均功率820 mW, 对应单脉冲能量95 nJ. 这是第一次在自相似振荡器中直接获得重复频率在10 MHz 以下的脉冲输出, 95 nJ也是目前自相似振荡器直接输出的最高脉冲能量. 通过数值模拟证实了在第一个光栅的零级反射处和狭缝滤波后可以分别实现抛物线型脉冲和高斯脉冲的两种锁模脉冲输出.     

Yb:CaF2–YF3 transparent ceramics ultrafast laser at dual gain lines

Yb³⁺:CaF₂-YF₃ transparent ceramics with excellent optical quality was successfully fabricated by hot-pressed method. Pulsed laser properties of this ceramics were investigated for the first time. Laser diode (LD) was applied as the pump source to generate a dual-wavelength mode-locked (ML) laser. The maximum average output power was 310 mW, which represents the highest output power of ultrafast calcium fluoride ceramic laser. The spectrum separated at 1048.9 nm and 1049.7 nm with a total pulse duration of 8.9 ps. The interval period between the beating signals was about 4.3 ps, corresponding to a 0.23 THz beat pulse repetition rate. These results demonstrate its potential in producing dual-wavelength ultrashort pulses. These Yb³⁺:CaF₂-YF₃ ceramics with low-cost and short-preparation period are ideal candidate materials for ultrafast lasers.     

Experimental Observation of Bright and Dark Solitons Mode-Locked with Zirconia-Based Erbium-Doped Fiber Laser

We demonstrate the generation of dark and bright solitons with our homemade zirconia-based erbium-doped fiber and graphene oxide(GO) saturable absorber in anomalous dispersion region.The GO is fabricated using an abridged Hummer's method,which is combined with polyethylene oxide to produce a composite film.The film is sandwiched between two optical ferrules and embedded in the laser cavity to enhance its birefringence and nonlinearity.The self-starting bright soliton is easily generated at pump power of 78 mW with the whole length cavity of 14.7 m.The laser produces the bright pulse train with repetition rate,pulse width,pulse energy and central wavelength being 13.9 MHz,0.6 ps,2.74 p J and 1577.46 nm,respectively.Then,by adding the 10 m of single mode fiber into the laser cavity,dark soliton pulse is produced.For the formation of dark pulse train,the measured repetition rate,pulse width,pulse energy and central wavelength are 8.3 MHz,20 ns and 4.98 p J and1596.82 nm,respectively.Both pulses operate in the anomalous region.     

Stable mode-locked fiber laser using 49 cm long bismuth oxide based erbium doped fiber and slow saturable absorber

A stable mode-locked fiber laser employing a 49 cm long bismuth oxide based erbium doped fiber (Bi-EDF) by using a slow saturable absorber is demonstrated. Near transform limited short pulses with a repetition rate of 8.27 MHz are obtained at a wavelength of 1560 nm with a maximum spectral width of 15 nm. Results indicate that pulse characteristics are strongly dependent on pump power rather than spectral width. Moreover the Time-Bandwidth products (TBWP), pulse duration, the energy fluctuation and timing jitter decrease with increasing pump power. The pulse width is continuously varied from 1.2 ps to less than 300 fs. It produces stable mode locking with a maximum spectral width of 15 nm, minimum timing jitter of 4 ps and energy fluctuations of 2.5%. The pulse train was amplified using a two-stage amplifier up to 447 mW average power corresponding to peak powers of 177.3 kW.     

MW级峰值功率掺钛蓝宝石激光振荡器

在常规重复频率77 MHz掺钛蓝宝石飞秒激光器的基础上,通过腔内引入Herriott型多通望远镜系统增加总腔长及对腔内色散的深入分析和实验控制,实现了低重复频率、高脉冲能量飞秒激光振荡的稳定运行.在连续功率8.2 W的532 nm激光抽运下,得到了重复频率11 MHz、单脉冲能量达72.73 nJ、对应峰值功率MW量级的结果.相对80 MHz重复频率下6.25 nJ的单脉冲能量及150 kW的峰值功率,其输出能力提高了约一个量级. 关键词： 飞秒激光 掺钛蓝宝石激光器 低重复频率 MW     

宽光谱全正色散锁模掺镱光纤激光器

介绍了一种全正色散宽光谱被动锁模掺镱光纤激光器,利用非线性偏振旋转技术实现全正色散掺镱光纤激光器的被动锁模.当泵浦功率输出为500mW时,激光脉冲输出功率大于139mW,重复频率约为28.1MHz,脉冲宽度为3.8ps.为了进一步研究全正色散光纤激光器的宽光谱输出特性,在腔内熔接50m单模光纤,同时去除双折射滤波片,在泵浦功率为500mW时,观察到稳定锁模单脉冲耗散孤子,光谱范围为1 005~1 140nm,输出激光脉冲最大平均功率为90mW,重复频率为3.58MHz,脉冲宽度为519ps.     

Supercontinuum generation in seven-core photonic crystal fiber pumped by a broadband picosecond pulsed fiber amplifier

We report a supercontinuum source generated in seven-core photonic crystal fibers(PCFs) pumped by a self-made all-fiber picosecond pulsed broadband fiber amplifier. The amplifier's output average power is 60 W at 1150 nm with spectral width of 260 nm, and its repetition rate is 8.47 MHz with pulse width of 221 ps. With two different lengths of seven-core PCF, different output powers and spectra are obtained. When a 10 m long seven-core PCF is chosen, the output supercontinuum covers the wavelength range from 620 nm to 1700 nm, with the output power of 11.7 W. With only 2 m long seven-core PCF used in the same experiment, the wavelength of the supercontinuum spans from 680 nm to 1700 nm,with the output power of 20.4 W. The results show that the pulse width is 385 ps in the 10 m long seven-core PCF and 255 ps in the 2 m long one, respectively, due to the normal dispersion of the PCF.     

Switchable different operation states in an erbium-doped fiber laser cavity with normal dispersion

We demonstrate different operation states which can be switched by the polarization control in an erbium-doped fiber laser cavity with normal dispersion, including passive single-pulse and multiple-pulse mode-locking, coherent pulse pattern, and passive Q-switching. The mode-locked single pulse has a smooth and broad rectangular-shaped spectrum. With increasing pump power, multiple pulses appear and finally six pulses are observed, where the pulses have no interaction with each other. Keeping the pump power at 407 mW and adjusting the polarization state, we observe the coherent pulse pattern with the pulse numbers from 2 to 5. It is the first time five coherent pulses in the 1.55 μm normal dispersion cavity have been observed, to our knowledge. The mode-locked spectra are highly modulated and the largest pulse separation of 31.9 ps is observed for the two-pulse case. When the pump power exceeds 180 mW, the mode-locked operation can be switched to the passively Q-switched operation by controlling the polarization state. The repetition rate and pulse width can be changed by pump power variation, and the spectrum is tunable in the range of 8.45 nm.     

基于金纳米笼的1106 nm被动调Q Nd:GAGG激光器

成功制备了金纳米笼溶液并将其作为饱和吸收体,实现了中心波长为1106 nm的Nd:GAGG激光器的调Q运转。在输出镜透过率为3%的激光器中,在泵浦功率6.70 W下获得的最大平均输出功率为98 mW,此时对应的脉冲重复率为206 kHz,最短脉冲宽度为436 ns;在输出镜透过率为7%的激光器中,当泵浦功率为7.69 W时,得到的最大平均输出功率为121 mW,最短脉冲宽度为370 ns,对应的脉冲重复率为170 kHz。实验结果证明了金纳米笼在近红外波段激光器中用作饱和吸收体的巨大潜力。     

Wideband All-Polarization-Maintaining Yb-Doped Mode-Locked Fiber Laser Using a Nonlinear Optical Loop Mirror

We report on a wide-band and stable mode-locked all-polarization-maintaining fiber iaser configuration using a noniinear optical loop mirror.The central wavelength of the laser is 1080.14 nm and the 3dB bandwidth is 20.29 nm.The repetition rate of the pulse is 3.28 MHz and the pulse width is 848 ps.By tuning the pump power,which is centered at 980 nm,from 300 mW to 380 mW,we obtain a linearly changed output power from 6mW to 7.12 mW.The all-polarization-maintaining fiber configuration is fundamental to the stability of the output power.     

High-efficiency 17 W, 80 MHz repetition rate,passively mode-locked TEM<Subscript>00</Subscript> Nd:YAG oscillator pumped at 885 nm

We report on a passively mode-locked TEM₀₀ Nd:YAG oscillator with the beam quality at M ² = 1.1 by a semiconductor saturable absorber mirror under 885 nm laser diode direct pumping for the first time. A maximum average output power of 17 W at a repetition rate of 80 MHz with 39 ps pulse width was obtained under the absorbed pump power of 38 W, corresponding to an optical-optical efficiency of 44% and the slope efficiency of 69%, respectively.     

Passively Mode-Locked Quasi-Three-Level Nd:LuVO4Laser with Semiconductor Saturable Absorber Mirror

We demonstrate a passively a Z-folded resonator. Using device, we achieve stable cw average output power under cw mode-locked Nd：LuVO4 laser operating on the quasi-three-level at 916nm with a semiconductor saturable absorber mirror （SESAM） as the passive mode-locking mode locking with 6.7ps pulse duration at repetition rate of 133 MHz and 88mW the pump power of 17.1 W.     

超低阈值Q调制，锁模Yb3+光纤环形腔激光器

 在一种掺镱（Yb³⁺）光纤锁模激光器中。谐振腔采用近“8”字形环形结构，并巧妙地引入半导体可饱和吸收镜（SESAM），腔内引入起偏器和偏振控制器，利用非线性偏振旋转的被动锁模机理，结合SESAM慢可饱和吸收体的自启动作用，在极低的泵浦功率下，实现了稳定的调Q脉冲输出和锁模输出。当泵浦功率为18 mW时，调Q脉冲重复频率为16 kHz，脉冲宽度4 μs，光谱宽度为2.34 nm。当泵浦功率为60 mW时，实现了激光器连续锁模，输出功率8 mW，重复频率20 MHz，光谱宽度3.54 nm，脉宽在ps和亚ps量级，而且在调整偏振控制器的角度时，观察到了波长的调谐现象，调谐范围为1 028~1 530 nm。     

Observation of stable bound soliton with dual-wavelength in a passively mode-locked Er-doped fiber laser

A phase-locked bound state soliton with dual-wavelength is observed experimentally in a passively mode-locked Erdoped fiber(EDF) laser with a fiber loop mirror(FLM). The pulse duration of the soliton is 15 ps and the peak-to-peak separation is 125 ps. The repetition rate of the pulse sequence is 3.47 MHz. The output power is 11.8 mW at the pump power of 128 mW, corresponding to the pulse energy of 1.52 nJ. The FLM with a polarization controller can produce a comb spectrum, which acts as a filter. By adjusting the polarization controller or varying the pump power, the central wavelength of the comb spectrum can be tuned. When it combines with the reflective spectrum of the fiber Bragg grating, the total spectrum of the cavity can be cleaved into two parts, then the bound state soliton with dual-wavelength at 1549.7 nm and 1550.4 nm is obtained.     

High-pulse-energy passively mode-locked Nd:YVO4 laser without spatial hole burning effect

We report on a high-pulse-energy 888 nm diode-pumped passively mode-locked TEM₀₀ Nd:YVO₄ oscillator without spatial hole burning (SHB) effect in active medium. At a pump power of 40 W, the oscillator produced pulse energy up to 270 nJ at a repetition rate of 50 MHz, corresponding to average power of 13.5W with 34% optical-to-optical efficiency. To the best of our knowledge, it is the highest pulse energy obtained at the same pump power. The pulse duration produced varied from 16 to 59 ps. By varying the pump power, we observed a pulse duration ranging from 52 to 59 ps while the time-bandwidth product remained 0.88, and the factors that affect the pulse duration were also discussed. Meanwhile, a novel method of adjusting output coupling (OC) was introduced, which can simplify the structure of laser.     

An Actively Mode-Locked Ho:YAG Solid-Laser Pumped by a Tm-Doped Fiber Laser

An actively mode-locked Ho:YAG laser pumped by a diode-pumped Tm-doped fiber laser is reported.For the cw operation,we obtain the maximum output power of 3.43 W with a central wavelength 2022.2 nm at the maximum incident pump power of 11.4 W,corresponding to a slope efficiency of 34.5%.The beam quality factor M2 is 1.16,and the output beam is close to fundamental TEM_(00) In the case of the CWML operation,a stable pulse train is generated with an average output power up to 3.41 W with a slope efficiency of 34.3%at the incident pump power of 11.4 W and a pulse duration of 294 ps at a repetition rate of 81.92 MHz.In addition,the maximum single pulse energy is 41.6 n J.