High optical quality transparent Yb:YAG laser ceramics have been successfully fabricated by a vacuum reactive sintering method. Commercial Al₂O₃ powder and co-precipitated Y₂O ₃ and Yb₂O₃ powders were used as the raw materials. In-line transmittances at 1300 nm and 400 nm were measured to be 83.6% and 81.8% respectively for a 3 mm thick mirror polished Yb:YAG ceramics sample. Continuous wave (CW) lasing at the wavelength of 1030 nm was achieved when pumped by a 940 nm fiber coupled laser diode. A slope efficiency as high as 62.7% was obtained.

Dewei Luo;Jian Zhang;Changwen Xu;Xianpeng Qin;定元 汤;Jan Ma

Optical Materials

2012-4

We report on a high-power diode-end-pumped polycrystalline Yb: Y2 O3 ceramic laser. Under the pump power of 27 W, continuous-wave output power of 9. 2 W at 1078 nm has been obtained by using an output coupler of R=96%. The laser had a threshold of 3.1 W and a slope efficiency of 41%. Comparative studies on the laser performance between the Yb: Y2 O3 ceramic and the Yb:yttrium aluminum garnet (YAG) single crystal show that at the same doping concentration of 8 at. %, higher laser efficiency can be obtained in the Yb: Y2 O3 ceramic laser than in the Yb:YAG single crystal laser.

J. Kong;定元 汤;B. Zhao;J. Lu;K. Ueda;H. Yagi;T. Yanagitani

Applied Physics Letters

2005-4-18

Soliton operation and soliton wavelength tuning of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated under various cavity dispersion conditions. It was shown that not only wide range soliton wavelength tuning but also soliton pulse width variation could be obtained in the fiber lasers. Our results show that the graphene mode locked erbium-doped fiber lasers provide a compact, user friendly and low cost wavelength tunable ultrashort pulse source.

H. Zhang;定元 汤;L. M. Zhao;Q. L. Bao;K. P. Loh;B. Lin;S. C. Tjin

Laser Physics Letters

2010-8

A diode-pumped passively mode-locked Yb:Lu ₂Si ₂O ₇ (Yb:LPS) laser is firstly demonstrated. Using a commercial SESAM as the mode-locker, stable mode locked pulses with femtosecond pulse duration at the wavelength of 1058nm are obtained. The shortest pulse achieved is about 96fs. We found that the Yb:LPS crystal could have small normal group velocity dispersion near the mode locking wavelength and a large nonlinear optical Ken-coefficient.

W. Xu;定元 汤;X. D. Xu;L. H. Zheng;J. Zhang;W. D. Tan;D. Z. Li;B. L. Su;军 徐

2011

We report on the experimental observation of dip-type spectral sidebands on the soliton spectra of a passively mode locked fiber laser. We point out that the formation of the dip sidebands is due to a four-wave-mixing type of parametric process between the soliton and dispersive waves induced by the periodic soliton parameter variation in the laser cavity. Numerical simulations have well reproduced the experimental results.

L. M. Zhao;定元 汤;X. Wu;H. Zhang;C. Lu;H. Y. Tam

Optics Communications

2010-1-15

Period-doubling of dispersion-managed soliton in Erbium-doped fiber ring lasers operating at near zero net cavity group velocity dispersion was experimentally observed, which suggests that the period-doubling is an intrinsic feature of the mode-locking fiber lasers.

L. M. Zhao;定元 汤;T. H. Cheng;H. Y. Tam;C. Lu

2007

We report on the experimental observation of dark-bright and antidark-bright vector solitons supported by third-order dispersion in a weakly birefringent cavity fiber laser. Using a cavity dispersion and birefringence management technique we constructed a weakly birefringent cavity fiber laser with near-zero net cavity dispersion. Operating the fiber laser in either the net normal or net anomalous dispersion regime, we found that both dark-bright and antidark-bright vector solitons could be simultaneously formed as a result of incoherent cross-polarization phase modulation. Our experimental results confirm the existence of antidark-bright vector solitons and the coexistence of dark-bright and antidark-bright vector solitons in a real physical system.

J. Guo;X. Hu;Y. F. Song;G. D. Shao;L. M. Zhao;定元 汤

Physical Review A

2019-6-24

We report on dissipative soliton (DS) generation in an Yb-doped (YDF) fiber laser passively mode locked with the nonlinear polarization rotation (NPR) technique. We found that even without the insertion of a physical bandpass filter in the cavity, not only could DSs be automatically formed in the laser but also the formed DSs have a spectral bandwidth that is far narrower than the Yb-fiber gain bandwidth. Numerical simulations well reproduced the experimental observations. Our results suggest that a physical intracavity bandpass filter is not a crucial component for the generation of DSs in all-normal-dispersion YDF lasers mode locked with the NPR technique.

Luming Zhao;定元 汤;Xuan Wu;Han Zhang

Optics Letters

2010-8-15

Experimental observation of different types of vector solitons such as the brigth-bright, dark-dark, and dark-bright vector soltions in single mode fiber lasers is reported. Experimental techniques for observing each of the vector solitons are explained. Special features of the vector solitons in fiber lasers are numerically simulated and compared with the experiments.

定元 汤;H. Zhang;L. M. Zhao;X. Wu

2009

A diode pumped ytterbium-doped lutetium aluminum garnet (Yb:LuAG) ceramic laser is reported for the first time to our knowledge. Using the solid state reactive vacuum sintering technique we have successfully fabricated high optical quality Yb:LuAG ceramics. We show that even with an uncoated Yb:LuAG ceramic sample a maximum output power of 7 W could be achieved under 13 W absorbed pump power, and the laser has a slope efficiency as high as 63%. Considering that Yb:LuAG has higher thermal conductivity than Yb:YAG under heavy doping situation, Yb:LuAG ceramic could be an attractive laser gain medium for the high power solid state lasers applications.

C. W. Xu;D. W. Luo;J. Zhang;H. Yang;X. P. Qin;W. D. Tan;定元 汤

Laser Physics Letters

2012-1