共查询到20条相似文献,搜索用时 15 毫秒
1.
Jieguang Miao Baoshan Wang Jiying Peng Huiming Tan Huikun Bian 《Optics & Laser Technology》2008,40(1):137-141
Diffusion bonded Nd:YAG/Cr:YAG composite laser crystal has been employed to perform a compact diode-pumped passively Q-switched laser. At the incident pump power of 3.3 W and pulse repetition rate of 16.3 kHz, the maximum average output of 592 mW has been obtained, corresponding to an optical-to-optical conversion efficiency of 18%. Stable passively Q-switched operation with peak power of 6.5 kW and pulse duration of 6 ns was also achieved. It has been experimentally revealed that Nd:host/Cr:YAG composite structure is a promising material for compact cost-effective Q-switched laser sources with high-peak power and short pulse duration. In addition, thermal lens effect (TLE) in the active medium and its impact on the Q-switched laser performance have been analyzed. 相似文献
2.
Haynes Pak Hay Cheng Ole Bjarlin Jensen Peter Eskil Andersen Bernd Sumpf Christian Pedersen 《Optics Communications》2010,283(23):4717-20461
Using a tunable external cavity tapered diode laser (ECDL) pumped quasi-three-level Nd:YAG laser, a fivefold reduction in threshold and twofold increase in slope efficiency is demonstrated when compared to a traditional broad area diode laser pump source. A TEM00 power of 800 mW with 65% slope efficiency is obtained, the highest reported TEM00 power from any 946 nm Nd:YAG laser pumped by a single emitter diode laser pump source. A quantum efficiency of 0.85 has been estimated from experimental data using a simple quasi-three-level model. The reported value is in good agreement with published values, suggesting that the model is adequate. Improvement of the 946 nm laser due to the ECDL's narrow spectrum proves to be less significant when compared to its spatial quality, inferring a broad spectrum tapered diode laser pump source may be most practical. Experimental confirmation of such setup is given. 相似文献
3.
An approximate analytic solution of strongly pumped Yb-doped double-clad fiber lasers without neglecting the scattering loss 总被引:6,自引:0,他引:6
A theoretical analysis of strongly pumped Yb-doped double-clad fiber lasers is presented and an approximate analytic function of distributed laser along the whole fiber with the scattering loss is obtained for the first time. A comparison is made between the analytic solution and the exact numerical solution. The results have shown that the analytic function of distributed laser within the fiber is accurate and explicit. With the analytic solution the losses caused by laser scattering are shown in three different pump modes. The results verify that the backward pumping can get the highest output power in strongly pumped fiber lasers. 相似文献
4.
C. Li J. Boyaval M. Warenghem P. Carette 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(3):449-456
We report operation of a Nd3+-doped fiber-laser using a cholesteric liquid crystal acting as a narrow band reflector. The aim of this work is to apply
to a fiber-laser the particular optical properties of an helical structure, whatever is the medium exhibiting this structure,
either a liquid crystal or either any other material. The advantage of the use of these mediums in the design of fiber-lasers
is that they can favourably take the place, in an easy and compact way, of several optical elements such as a polarizer and
a quarter-wave plate at one and the same time. This technology promises to design rugged compact low cost tunable coherent
sources the lasing range of which can easily be adjusted. We emphasize here the particular part played by the cholesteric
liquid crystal-glass interface in the laser action of the fiber.
Received 21 October 1999 and Received in final form 7 February 2000 相似文献
5.
The thermal stress effects of the diode-end-pumped Nd:YLF slab laser crystals are numerically investigated. The theoretical model is established by considering the divergence of the pump beam in the slab and the additional heat generated in the upconversion. Using the three dimensional finite element analyses, accurate numerical solutions based on the theoretical model are achieved. Our analyses focuses on the thermal fracture damage of the Nd:YLF slab under both the lasing and non-lasing conditions, and the predicted values are compared with the experimental results. 相似文献
6.
Shuaiyi Zhang Haitao Huang Lin Xu Weibiao Chen Bin Zhao 《Optics Communications》2011,284(5):1342-1345
Diode end-pumped continuous-wave and passively Q-switched Nd:Lux(x = 0.5)Y1 − xVO4 mixed crystal lasers were demonstrated. At the pump power of 12.6 W, the maximum output power of 6.7 W around 1066.5 nm was obtained with the output transmission of 27%. The optical conversion efficiency is 53.2%, corresponding to a slope efficiency of 55.8%. For pulsed operation, the shortest pulse width attained was 8.6 ns, with the pulse repetition frequency of 99 kHz, and the single pulse energy and the peak power were estimated to be 25.5 μJ and 2.96 kW, respectively. 相似文献
7.
Numerical analysis and experimental results of output performance for Nd-doped double-clad fiber lasers 总被引:10,自引:0,他引:10
Nam Seong Kim Toshihiro Hamada Mahendra Prabhu Cheng Li Jie Song Ken-ichi Ueda Anping Liu Hong Jin Kong 《Optics Communications》2000,180(4-6):329-337
Numerical analysis is investigated for the high-power double-clad fiber lasers and experimental results using different microscope objectives for focusing into a Nd-doped rectangular double-clad fiber also performed. The numerical analysis includes dependence of output power on output mirror reflectivity, absorbed pump power, loss, and fiber length and pump power distribution for the cases of one-end and two-end pumps with 20 dB/km loss. Calculated conversion efficiencies are 76.36%, 69.73%, and 63.84% for lossless, two-end pump, and one-end pump fiber lasers, respectively. Slope efficiencies from absorbed pump power/output powers measured using microscope objectives are 16.8%/182 mW, 53.8%/351 mW, 24.9%/1240 mW, and 13.9%/649 mW for magnifications of 5×, 10×, 20×, and 40×, respectively. 相似文献
8.
Bingyuan Zhang Jinlong Xu Jingliang He Wenjun Wang Dunlu Sun Shaotang Yin 《Optics Communications》2011,284(24):5734-5737
The performance of continuous wave (CW) and passively Q-switched Nd:GYSGG lasers was investigated for the first time. The CW output powers of 4.2 W with dual wavelength of 1058.4 nm and 1061.5 nm were obtained under the diode pump power of 17 W with slope efficiencies of 26%. By using Cr4+:YAG wafer as saturable absorber, Q-switching operation was performed and the short pulse with pulse width of 6.6 ns was obtained with the peak power of 9.97 kW. 相似文献
9.
10.
Fiber lasers have attracted considerable attention when their power can realistically be scaled to kilowatt level and beyond.
In this paper, we assumed that the fiber core and first clad are exposed to a pump source with a super-Gaussian profile of
order four. The effects of this non-uniform heat deposition on thermal, stress and thermooptics properties such as temperature-dependent
change of refractive index and thermally induced stress have been comprehensively studied and their equations analytically
derived. 相似文献
11.
Modsching N Kadwani P Sims RA Leick L Broeng J Shah L Richardson M 《Optics letters》2011,36(19):3873-3875
We describe lasing of a thulium-doped polarizing photonic crystal fiber. A 4 m long fiber with 50 μm diameter core, 250 μm diameter cladding, and d/Λ ratio of 0.18 was pumped with a 793 nm diode and produced a polarized output with a polarization extinction ratio (PER) of 15 dB and an M(2) of <1.15. An intracavity polarizer and half-wave plate minimally increased the PER to 16 dB. The output power had 35% slope efficiency relative to the absorbed pump power. The maximum cw output power was limited to 4 W due to the quantum defect heating of the fiber. 相似文献
12.
High power Q-switched Yb-doped photonic crystal fiber laser producing sub-10 ns pulses 总被引:3,自引:0,他引:3
J. Limpert N. Deguil-Robin S. Petit I. Manek-Hönninger F. Salin P. Rigail C. Hönninger E. Mottay 《Applied physics. B, Lasers and optics》2005,81(1):19-21
We report on a Q-switched fiber laser producing pulse durations well below 10 ns by using a short-length ytterbium-doped rod-type
photonic crystal fiber as gain medium. At repetition rates up to 100 kHz pulse energies up to 0.5 mJ and average powers in
excess of 30 W have been obtained in single-transverse mode beam quality. The compact short pulse laser system possesses further
power and energy scaling potential. 相似文献
13.
Addressing fiber Bragg grating sensors with wavelength-swept pulse fiber laser and analog electrical switch 总被引:1,自引:0,他引:1
A pulse train with a wavelength dependent time sequence is generated in a fiber laser configuration, which contains a cascaded wavelength-division-multiplexing (WDM) fiber Bragg grating (FBG) array and a tunable F-P filter. By distributing pulses to corresponding channels with a 1 × N analog electrical switch, a novel FBG sensors interrogation technique with advantages of high signal-to-noise ratio (SNR) and high interrogation speed is experimentally demonstrated. Then, a FBG sensing system based on this interrogation technique and the mature unbalanced scanning Michelson interferometer (USMI) demodulation technique is realized. The system has shown a sensitivity of 1.610°/με, for the 1555 nm FBG, which agrees well with the theoretical value of 1.674°/με. 相似文献
14.
We demonstrate a multiwavelength 10 GHz pulse source using a dispersion-tuned actively mode-locked fiber ring laser incorporated with a semiconductor optical amplifier and an erbium-doped fiber amplifier. Simultaneous seven-wavelength operation of the laser is obtained. The side-mode suppression of all wavelengths is above 30 dB. Smooth wavelength tuning is achieved over more than 12 nm by changing the modulation frequency or the length of the optical delay line. Pulse characteristics are almost constant over the entire tuning span. Wavelength spacing can also be varied from 0.9 to 10 nm by adjusting the dispersion of the cavity. These experimental observations agree well with theoretical analyses. 相似文献
15.
A study on fiber Bragg grating (FBG) strain sensor, based on erbium-doped fiber (EDF) laser, is presented. A strain-sensing element, FBG, also acts as the lasing wavelength selecting component. When strain is applied on the FBG, the laser cavity loss changes, leading to a modification of the laser transient. Strain measurements are obtained in the time domain by simply measuring the EDF laser build-up time. Relative variation in the build-up time of up to 190%, for a strain range from 0 με to 2350 με, is achieved with a resolution corresponding to a strain of better than 2.35 με. This study demonstrates a novel fiber sensor concept and the technical feasibility to develop fiber strain measurement. 相似文献
16.
Threshold conditions of coherently combined fiber lasers, joint by fiber couplers (FCs), have been studied. After considering the phase change of a light wave crossing the fiber inside the FC, it has been shown that, at the two input ports of the coupler connecting with the amplifying fibers, the phase difference between the two incoming fields should be equal to −π/2 if the threshold gain of the compound system is to be minimized. Starting from these input ports, following the circulations of waves, threshold conditions can be established. Expressions for the output and leakage powers, and optimum coupler splitting ratio nullifying the leakage when constituent fiber lasers giving different free-running powers have been derived. And, the threshold gain reductions of individual lasers after being coherently combined have been predicted. 相似文献
17.
18.
T.-H. Yang T.-S. Lim J.-L. Chern K. Otsuka 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(3):365-371
Random chaotic burst generation was experimentally observed in a single-mode microchip Nd:YVO4 laser with fiber feedback. As the feedback strength was increased, a transition from stable relaxation oscillation state
to unstable random chaotic burst state appeared. Furthermore, the non-stationary characteristic of probability association
was experimentally identified at the transition of the two states while similar characteristics were reported only by numerical
simulations of simple dynamical systems. This implies the general feature of non-stationary property of the dynamic switching
between two states at transition. The observed chaotic burst generation and non-stationary nature were reproduced numerically
based on the Lang-Kobayashi model.
Received 28 March 2001 and Received in final form 5 June 2001 相似文献
19.
The thermal effects of the diode end-pumped Nd:YVO4 slab laser crystal are investigated both analytically and numerically. The theoretical model is established with considering the divergence of the pump beam in the slab. A detailed theoretical analysis of the temperature, stress and the focal length of thermal lens are presented. Using 3D finite element analysis, an accurate numerical solution based on the theoretical model is achieved. Our analysis includes the thermal fracture damage of the thermally and optically anisotropic slab and the predicated values are compared with the experimental results. 相似文献
20.
A theoretical modeling of Yb-doped double-clad fiber lasers under various pumping modes including arbitrary numbers of end-pump and side-pump is introduced. Approximate analytic expressions of distributed lasers along the whole fiber are derived, and their accuracies are investigated. The effect of the pumping mode on the output performance of fiber lasers is discussed. The numerical results show that the approximate analytic solution is in excellent agreement with the exact numerical solution of the rate equations, the output power in the side-pump scheme is lower than that in end-pumping scheme, and more uniform distributions of laser and pump powers can be achieved by adopting the distributed pump mode and optimizing the arrangement of pump powers. However, further flattening the pump distribution by using more pump points can degrade the laser efficiency. 相似文献