High power external-cavity surface-emitting laser with front and end pump

High power optically pumped vertical-external-cavity surface-emitting lasers with front and end pump are re- ported. The gain chip consists of 15 repeats of In0.26GaAs/GaAsP0.02 multiple quantum wells and 30 pairs of Alo.2GaAs/Alo.98GaAs distributed Bragg reflectors. The maximum output power of 3 W, optical-to-optical conversion efficiency of 22.4%, and slope efficiency of 29.8% are obtained with 5-℃ heatsink temperature under the front pump, while the maximum output power of 1.1 W, optical-to-optical conversion efficiency of 23.2%, and slope efficiency of 30.8% are reached with 5-℃ heatsink temperature under the end pump. Influences of thermal effects on the output power of the laser with front and end pump are discussed.

Intracavity third-harmonic generation in a continuous-wave/self-mode-locked semiconductor disk laser

The high peak power of picosecond pulses produced by a self-mode-locked semiconductor disk laser can effectively improve the efficiency of nonlinear frequency conversion.This paper presents the intracavity frequency tripling in a self-mode-locked semiconductor disk laser,and a picosecond pulse train at 327 nm wavelength is achieved.The pulse repetition rate is 0.49 GHz,and the pulse width is 5.0 ps.The obtained maximum ultraviolet output power under mode locking is 30.5 m W,and the corresponding conversion efficiency is obviously larger than that of continuous-wave operation.These ultraviolet picosecond pulses have high spatial and temporal resolution and can be applied in some emerging fields.

Noise-like pulse with a 690 fs pedestal generated from a nonlinear Yb-doped fiber amplification system

Noise-like pulses having a pedestal of 690 fs and a spike of 59.6 fs were generated in a nonlinear Yb-doped fiber amplification system. The seed source is a mode-locked Yb-doped fiber laser by nonlinear polarization rotation,and dissipative soliton pulses were obtained in it. Then, the dissipative soliton pulses passed through a 7.6 m dispersive fiber to enhance the dispersion and nonlinearity. Further on, the dissipative soliton pulses were launched into a Yb-doped fiber nonlinear amplifier, and stable noise-like pulses with a pedestal of 6.26 ps and a spike of 227 fs were achieved. Finally, by a grating pair, the pedestal and spike of the noise-like pulses were effectively compressed to 690 fs and 59.6 fs, respectively. To the best of our knowledge, this is the shortest pedestal demonstrated in noise-like pulses operating at 1 μm.

Dynamics of multi-state in a simplified mode-locked Yb-doped fiber laser

The dispersive Fourier transform technique provides feasibility of exploring non-repetitive events and the buildup process in ultrafast lasers.In this paper,we report a new buildup process of dissipative solitons in a simplified mode-locked Yb-doped fiber laser,which includes more complex physics stages such as the Q-switching stage,raised and damped relaxation oscillation stages,noise-like stage,successive soliton explosions stage,and soliton breathing stage.Complete evolution dynamics of noise-like pulse and double pulse are also investigated with dispersive Fourier transform.For the noise-like pulse dynamics process,it will only experience the Q-switching and relaxation oscillation stages.In the case of dissipative soliton and noise-like pulse,the double pulse buildup behavior is manifested as the replication of individual pulses.A weak energy migration occurs between two pulses before reaching steady state.Meanwhile,real-time mutual conversion of the dissipative soliton and noise-like pulse has been experimentally observed,which appears to be instantaneous without extra physical processes.To the best of our knowledge,this is the first report on these physical phenomena observed together in a mode-locked fiber laser.The results further enrich the dynamics of mode-locked fiber lasers and provide potential conditions for obtaining intelligent mode-locked lasers with controllable output.

Er-doped all-fiber laser mode-locked by graphitic carbon nitride nanosheets

Few-layer graphitic carbon nitride （g-C-N-） nanosheets were fabricated and utilized as a saturable absorber for mode-locking in an Er-doped fiber laser with net normal dispersion. Tile g-CaN,-/polyvinyl alcohol （PVA） hybrid-film-based saturable absorber has a modulation depth of 4.01% and a saturation intensity of 7.5 MW/cm2. By integrating g-C3N4-PVA mode-locker into the laser cavity, a mode-locked operation could be obtained. The achieved mode-locking pulse centered at 1530.3 nm has a pulse width of 530 ps. Its repetition rate is 40.8 MHz, and the corresponding signal-to-noise ratio is about 55 dB.