Abstract
A single-wavelength compact diode-pumped solid-state laser based on a single-mode waveguide with a diameter of 20
µ
m and graphene saturable absorber is presented in this work. The total ...reflection coefficient of the intracavity interferometer has a significant effect on the level of intracavity losses. By accurate controlling the intracavity losses a stable continuous wave passive mode-locking at wavelength of 1064 nm with a pulse repetition rate of 9.5 GHz was obtained.
•The GHz-pulse repetition rate is firstly realized in the wavelength region from 1962 nm to 2005 nm.•The shortest pulse duration is less than 500 fs in the GHz-harmonic mode-locking fiber ...oscillator.•The average output power reaches to above 340 mW from the GHz-harmonic mode-locking fiber oscillator.•Simulation agrees with the experimental results for the GHz-pulse amplification.
The gigahertz (GHz)-pulse repetition rate, 2-μm harmonic mode-locking (HML) Tm-doped fiber oscillator is realized with the nonlinear polarization rotation method. The fundamental pulse repetition rate is 95.8 MHz, which is further increased to 1.25 GHz at 1962 nm, 1.63 GHz at 1982 nm, and 1.05 GHz at 2005 nm with a high super-mode suppression above 37 dB respectively. It is believed to be the first report on the GHz Tm-doped fiber oscillators, which can optionally operate in < 2000-nm or > 2000-nm region. The HML fiber oscillator delivers maximum output powers of 480 mW, 538 mW and 340 mW and at each wavelength, which are the largest output powers never reported from previous GHz 2-μm fiber oscillators. The pulse durations in each wavelength are all < 500 fs. The laser pulse with the highest pulse repetition rate is further scaled up to ∼ 4 W. The observed spectral narrowing and soliton self-frequency shift in the fiber amplifier are further analyzed with a theoretical model, which matches well with the experimental results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
SESAM mode locked femtosecond laser at higher frequency up to gigahertz repetition rate suffers from the tendency for Q-switching instabilities. Increasing the pump power and decreasing the spot size ...at both the laser crystal and SESAM could help to stabilize the cw mode-locking of a gigahertz ultrafast laser. However, this is limited by the available laser diode pump power and may result in SESAM damage. Two photon absorption (TPA) effect in SESAM will generate ‘roll over’ effect of nonlinear reflectivity curve, which will decrease the critical pulse energy and critical pump power for cw mode-locking. By designing SESAM structures, we could optimize the ‘roll over’ effect and suppress the Q-switching instabilities. From simulation, we find out that enhanced SESAM with a cap layer thickness of 116nm and first GaAs layer thickness of 517nm will lead to a minimum critical pump power of 12.1W for our designed 1GHz laser cavity.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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