Yonggang Wang

All-normal dispersion passively mode-locked Yb-doped fiber laser with Bi2Te3 absorber

Abstract. An all-normal dispersion passively mode-locked Yb-doped fiber laser with a Bi2Te3 absorber is presented. The modulation depth of this kind of saturable absorber was measured to be 8.4%. By incorporating a Bi2Te3/PVA film into a Yb-doped fiber laser oscillator, a mode-locked fiber laser oscillator was achieved. The repetition rate and the central wavelength are 25.6 MHz and 1052.7 nm, respectively. The 3-dB spectral width is 0.45 nm and the pulse duration is 417 ps. The results indicate that topological insulator Bi2Te3 possesses the potential for ultrafast fiber laser application.

Single-walled carbon nanotube solution-based saturable absorbers for mode-locked fiber laser

Abstract. The report proposed a saturable absorber based on a D-shaped fiber embedded in a single-walled carbon nanotube solution. Such a saturable absorber solution method with a D-shaped fiber has the virtues of good antioxidant capacity, excellent scattering resistance, high heat dissipation, and high damage threshold. The nonsaturable loss of this kind of saturable absorber was evaluated to be 3%. To the best of our knowledge, this is the lowest value compared with other carbon nanotube saturable absorbers. By incorporating the saturable absorber into a Yb-doped fiber laser cavity, a mode-locked fiber laser was achieved with a central wavelength of 1054.16 nm. The repetition rate was 23 MHz with a signal-to-noise ratio of 60 dB, and the pulse duration was measured to be 194 ps. The long-term working stability of working is also good. The results indicated that the solution method with a D-shaped fiber possesses a potential for fiber laser stability applications.

End-pumped continuous-wave passively modelocked Nd : YVO4 laser with low pump power

A simple cw mode-locked solid-state laser, which is end-pumped by a low-power laser diode, was demonstrated by optimizing the laser-mode size inside the gain medium. The optimum ratio between mode and pump spot sizes inside the laser crystal was estimated for a cw mode-locked laser, taking into account the input pump power. Calculation and experiment have shown that the optimum ratio was about 3 when the pump power is 2 W, which is different from the value regularly used in passively mode-locked solid-state lasers. This conclusion is also helpful in increasing the efficiency of high-power ultrashort lasers