Nanosecond Pulses Generation with Samarium Oxide Film Saturable Absorber

Nanosecond pulse generation is demonstrated in a mode-locked erbium-doped fiber laser(EDFL) utilizing a samarium oxide(Sm_2O_3) film. The Sm_2O_3 film exhibits a modulation depth of 33%, which is suitable for modelocking operation. The passively pulsed EDFL operates stably at 1569.8 nm within a pumping power from 109 to 146 m W. The train of generated output pulses has a pulse width of 356 nm repeated at a fundamental frequency of 0.97 MHz. The average output power of 3.91 m W is obtained at a pump power of 146 m W, corresponding to 4.0 nJ pulse energy. The experimental result indicates that the proposed Sm_2O_3 saturable absorber is viable for the construction of a flexible and reliably stable mode-locked pulsed fiber laser operating in the 1.5 m region.     

980-nm all-fiber mode-locked Yb-doped phosphate fiber oscillator based on semiconductor saturable absorber mirror and its amplifier

A 980-nm semiconductor saturable absorber mirror(SESAM) mode-locked Yb-doped phosphate fiber laser is demonstrated by using an all-fiber linear cavity configuration. Two different kinds of cavity lengths are introduced into the oscillator to obtain a robust and stable mode-locked seed source. When the cavity length is chosen to be 6 m, the oscillator generates an average output power of 3.5 m W and a pulse width of 76.27 ps with a repetition rate of 17.08 MHz. As the cavity length is optimized to short, 4.4-m W maximum output power and 61.15-ps pulse width are produced at a repetition rate of 20.96 MHz. The output spectrum is centered at 980 nm with a narrow spectral bandwidth of 0.13 nm. In the experiment, no undesired amplified spontaneous emission(ASE) nor harmful oscillation around 1030 nm is observed. Moreover,through a two-stage all-fiber-integrated amplifier, an output power of 740 m W is generated with a pulse width of 200 ps.     

6.5-ns actively Q-switched Nd:YVO_4 laser operating at 1.34 μm

With a plano-concave cavity,diode-pumped continuous-wave(CW) and actively Q-switched Nd:YVO4 laser operating at 1.34 μm is demonstrated.Maximum CW output power of 4.76 W and Q-switched average output power of 2.64 W are obtained with output coupler(transmission T = 3.9%).For the Q-switching operation,the theoretically calculated pulse energy and pulse width,with a pulse repetition frequency(PRF) range of 5-40 kHz,coincide with the experimental results.With a T = 11.9% output coupler,the maximum peak power of 24.3 kW and minimum pulse width of 6.5 ns are obtained when the PRF is 10 kHz.To the best of our knowledge,this is the shortest actively Q-switched pulse duration ever obtained in a 1.3-μm Nd-doped vanadate laser.     

37 fs、 0.94 μm钛宝石自锁模激光器的研究

报道了低增益区Ｔｉ＾３＋：Ａｌ２Ｏ３红外飞秒激光器的连续及自锁模运转情况,采用四镜折叠像散补偿腔,对于连续波运转,泵浦阈值功率为５．８Ｗ,其调谐范围为０．９－０．９７μｍ。     

Efficient continuous wave and Q-switched operation of a dual-end-pumped <Emphasis Type="Italic">c</Emphasis>-cut Tm:YAP laser

An efficient continuous wave (CW) and Q-switched c-cut Tm:YAP laser is reported in this letter. With the dual-end-pumped convex-concave resonator, CW output power up to 13.6 W at 1.99 μm was obtained under a total incident pump power of 50 W. The corresponding slope efficiency was 34.3% and conversion efficiency was 27.2%. The active Q-switched operation of the laser had an average output power of 12.5 W at 10 kHz pulse repetition frequency, with a minimum pulse width of 126 ns. With 6 kHz pulse repetition frequency, the maximum pulse energy of 1.6 mJ was obtained. In addition, using the Tm:YAP laser as a pumping source for gain-switched Cr:ZnSe laser, as much as 4 W output power in the wavelength range of 2.5–2.6 μm was obtained.     

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.     

LD泵浦Nd∶GdVO4/GaAs被动调Q激光器研究

报道了采用大功率半导体激光器端面泵浦Nd∶GdVO4晶体,利用GaAs晶片兼作饱和吸收被动调Q元件和输出耦合镜,实现了1.06 μm激光的被动调Q运转.在泵浦功率为13.9 W时,获得最高平均输出功率为3.6 W,脉冲宽度为252 ns,单脉冲能量为27 μJ以及峰值功率为107 W的激光脉冲.     

LD泵浦Nd∶LuVO4/Cr4+∶YAG被动调Q激光器

采用大功率半导体激光器端面泵浦Nd∶LuVO4晶体，利用Cr4+∶YAG晶体作为可饱和吸收元件，实现了1.06 μm激光的被动调Q运转.在泵浦功率为19.1 W时，获得最高平均输出功率为4.58 W，脉冲宽度为84 ns，单脉冲能量为36.6 μJ以及峰值功率为436.2 W的激光脉冲.     

同步三通道激光告警光学系统有效孔径的确定及截获能量的估算

为了确定一种同步三通道激光告警光学系统的有效孔径并估算截获能量,建立了激光辐照远场传输模型,仿真研究了远场光斑半径、单通道入瞳半径和通道间相对能量差之间的数值关系.仿真结果表明:各通道之间最大相对能量差与远场光斑中心能量密度的大小无关,在激光远场光斑边沿处各通道之间的相对能量差最大;最大相对能量差限定时,远场光斑半径越大,允许的单通道入瞳半径也越大,但相应系统截获的脉冲能量或脉冲功率却相对减小;最大能量差限定为1%,远场光斑半径分别为2.5 m,4.0 m和7.5 m时,允许的最大单通道入瞳半径分别为3 mm, 5 mm和10 mm,相应系统截获的最大脉冲能量为1.14×10-5 J,7.54×10-6 J和2.68×10-6 J,最大脉冲功率为1.63 W, 1.08 W和0.38 W.     

Actively Q-switched intracavity frequency-doubled Nd:LuVO<Subscript>4</Subscript>/LBO green laser with an acousto-optic modulator

This work presents experimental results concerning an actively Q-switched intracavity frequency-doubled Nd:LuVO₄/LBO green laser with an acousto-optic modulator operated at the wavelength of 0.53 μm. The green average output power of 2.8 W was obtained at a pump power of 16.3 W and a pulse repetition rate of 20 kHz, resulting in an optical conversion efficiency of 17%. When the pulse repetition rate is operated at 5 kHz, the shortest pulse width and the highest peak power at 0.53 μm were measured to be 26.5 ns and 8.43 kW, respectively.     

Q-switched NYAB laser end-pumped by a high-power diode-laser array

A diode-laser array end-pumped acousto-optically Q-switched NYAB laser operating at both 1.06 and 0.53 μm has been demonstrated. An average output power of 1.3 W at 1.06 μm at a pulse repetition frequency (PRF) of 60 kHz was obtained with an optical conversion efficiency of 18.1% and a slope efficiency of 21.3%. At the incident pump power of 6.1 W, the 1.06 μm shortest laser pulse was reached at PRF of 20 kHz with FWHM width measured to be 32 ns, yielding a largest pulse energy of 30 μJ, and a highest peak power of 938 W. The attainable maximum average green power was found to be 185 mW, with an optical conversion efficiency of 3%.     

二极管端面泵浦的附加脉冲锁模的Nd：YLF激光器

研究了二极管端面泵浦的附加脉冲锁模的Ｎｄ：ＹＡＧ激光器并分析了脉冲压缩原理及自启动机制,在最大泵浦功率为２．４Ｗ时,得到重复频率为１３４ＭＨｚ、脉宽为２ｐｓ、有效输出功率７６ｍＷ、相应峰值继２８３Ｗ、波长为１．０５３μｍ、波长为１．０５３μｍ的稳定的连续模脉冲序列。     

Compact and efficient diode-pumped passively Q-switched Nd:GdVO_4 laser at 1.06μm

Diode-pumped passively Q-switched Nd:GdVO4/Cr4+:YAG lasers with a simple flat-flat cavity were demonstrated. The maximum average output power at 1.06 μm was 1.25 W. The highest peak power and pulse energy were 7.56 kW and 75μJ, respectively, with the pulse repetition rate of 11.1 kHz and pulse width of 10 ns at the incident pump power of 8 W.     

A compact 1.06/1.32/2.94 μm pulsed laser for dentistry

A three-wavelength pulsed laser for dental application is developed. The laser houses the Nd:YAG resonator (1.06/1.32 μm) for soft-tissue treatment and Er:YAG resonator (2.94 μm) for caries removal and fits and fissure treatment. Two heads share the cooling unit and two identical high-voltage power supply modules in order to achieve compactness. The Nd:YAG laser has 10 W at 1.06 μm and 7 W at 1.32 μm with a pulse duration of 100 μs. An Er:YAG laser of 2.94 μm has 3.5 W, 20 Hz and a pulse duration of 250 μs. The beams are delivered through fibers and the laser size is 75×55×32.5 cm.     

高功率2 μm波长可调谐超短脉冲光纤激光器

高功率2 μm波长可调谐的超短脉冲激光具有峰值功率高、脉冲宽度窄、波长可调谐等优势,在医疗手术、大气通信、光电对抗等领域具有广泛的应用。利用高峰值功率的掺铒光纤放大器泵浦高非线性光纤,在全光纤化结构中获得了1895～2165 nm可调谐的拉曼孤子输出。采用啁啾脉冲放大技术对拉曼孤子的脉冲能量进行提升,放大后拉曼孤子的单脉冲能量为1.56 μJ,平均功率达到50.6 W,脉冲宽度为83 ps。经过光栅对压缩后,脉冲宽度降低至1.23 ps,平均功率为22 W,峰值功率达到0.55 MW。放大后的脉冲仍具有波长调谐的能力,当输出功率为5 W和50.6 W时,脉冲的波长调谐范围分别为38 nm和8 nm。     

Demonstration of fiber pulsed light source at 1.6 μm with adjustable pulse duration

A novel practical 1.66-μm pulse light source with adjustable pulse duration is proposed. A 2.5-km Raman fiber is placed into a ring type Q-switched erbium-doped fiber laser (Q-EDFL), serving as both delay line fiber and Raman gain medium so that in addition to the wavelength shifted to 1.6μm, the pulse duration and the buildup time can be relatively extended. By properly controlling the fall edge of the acousto-optic switch (AOS), the pulse duration of 30-345 ns for ～ 770-Hz repetition frequency with power of 1-1.6 W is achieved.     

1.319μm连续固体锁模激光器

报道了１．３１９μｍＮｄ：ＹＡＧ连续锁模激光器的技术研究。激光器的谐振腔为低热敏腔，用声光振幅调制器作为锁模元件，泵浦腔具有较高的泵浦效率和输出稳定性，获得了重复频率１００ＭＨｚ，平均功率～０．５４Ｗ，脉宽＜１７０ｐｓ的光脉冲。     

High-power picosecond LiB3O5 optical parametric oscillators tunable in the blue spectral range

The paper reports on an experimental investigation and numerical analysis of noncritically and critically phasematched LiB₃O₅ (LBO) optical parametric oscillators (OPOs) synchronously pumped by the third harmonic of a cw diode-pumped mode-locked Nd:YVO₄ oscillator–amplifier system. The laser system generates 9.0 W of 355-nm mode-locked radiation with a pulse duration of 7.5 ps and a repetition rate of 84 MHz. The LBO OPO, synchronously pumped by the 355-nm pulses, generates a signal wave tunable in the blue spectral range 457–479 nm. With a power of up to 5.0 W at 462 nm and 1.7 W at 1535 nm the conversion efficiency is 74%. The OPO is characterized experimentally by measuring the output power (and its dependence on the pump power, the transmission of the output coupler and the resonator length) and the pulse properties (such as pulse duration and spectral width). Also the beam quality of the resonant and nonresonant waves is investigated. The measured results are compared with the predictions of a numerical analysis for Gaussian laser and OPO beams. In addition to the blue-signal output visible-red 629-nm radiation is generated by sum-frequency mixing of the 1.535-μm infrared idler wave with the residual 1.064-μm laser radiation. A power of 1.25 W of 1.535-μm idler radiation and 5.7 W of 1.064-μm laser light generated a red 629-nm output power of 2.25 W. Received: 2 February 2000 / Revised version: 28 July 2000 / Published online: 22 November 2000     

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.     

Ultrawide tunable Er soliton fiber laser amplified in Yb-doped fiber

A Raman-shifted and frequency-doubled high-power Er-fiber soliton laser for seeding an efficient high-power Yb fiber femtosecond amplifier is demonstrated. The Raman-shifted and frequency-doubled Er-soliton laser is tunable from 1.00 to 1.070microm and produces bandwidth-limited 24-pJ pulses at a repetition rate of 50 MHz with a FWHM pulse width of 170 fs at 1.040microm . The Yb(3+) amplifier has a slope efficiency of 52% and generates 3-ps linearly chirped pulses with an average power of 0.8 W at 1.05microm . After pulse compression, 74-fs bandwidth-limited pulses with an average power of 0.4 W and a pulse energy of 8 nJ are generated.