We report a study on pulse dynamics in figure-nine Tm-doped all-polarization maintaining fiber laser. We analyzed laser operation from self-starting with multi-pulse dynamic to single-pulse operation by decreasing the pump power from the mode-locking threshold. By choosing a reliable setting of waveplates, our laser was generating pulses at the central wavelength of 1985 nm with a half-width of the spectrum, pulse duration, and pulse energy equal 6.4 nm, 650 fs, 177 pJ for the output port and 19.2 nm, 1279 fs, 57 pJ for the reject port in the single-pulse state. In the multi-pulse state, we recorded optical spectra, temporal waveforms, and average power at both exit ports. By analyzing temporal traces and output to reject port ratio power, we can distinguish between eight states of operation which follow an exact pattern. In the case of the single-pulse regime, we performed a further laser characterization, including relative intensity noise.

To our knowledge, we report the first experimental demonstration of gain-managed nonlinear (GMN) amplification of femtosecond pulses in an erbium-doped fiber amplifier (EDFA). We investigated the GMN amplification using two different seed sources, operating at wavelengths of 1530 and 1560 nm. We obtained broadband output spectra spanning the entire C- and L-bands (1530–1620 nm). Our study shows that, in contrast to Yb-doped fiber amplifiers, it is not critical to choose a seed wavelength located at the short-wave edge of the gain bandwidth of the amplifier. Efficient and broadband GMN amplification can also be achieved with a seed located at 1560 nm wavelength.

We report our investigation on ultrashort laser pulse optimization using an AI algorithm in a system consisting of a mode-locked oscillator, a spectral phase shaper, and a highly nonlinear amplifier. We analyzed the performance of the pulse optimization process as a function of two main parameters: the resolution of spectral phase modulation and the number of agents in the algorithm. We showed that the algorithm could find an optimum phase profile for the seed pulse, which allowed for a reduction of the FWHM of the amplified pulse by 10 fs (from 46 to 36 fs), and significantly reduced the intensity of the side-pulse by a factor of 4.6. Importantly, the algorithm used does not require any training and optimizes the pulse shape without any knowledge about the input pulse parameters or the parameters of the amplifier. We believe the proposed system might be a convenient test bed for evaluating various AI-based algorithms in a pulse optimization task.

We present a highly birefringent silica fiber with normal dispersion up to 2334 nm, designed to control a net-cavity dispersion of pulsed fiber lasers at different wavelengths. The fiber is characterized by a large normal dispersion, slowly growing from -87 ps/nm/km at 1200 nm to -42 ps/nm/km at 2000nm, and high phase birefringence exceeding 1.9 × 10⁻⁴ in this spectral range which ensures a polarization extinction ratio as high as 28 dB for a 1 m long fiber section. The industrially fabricated fiber was examined in two all-polarization-maintaining mode-locked fiber oscillators operating at central wavelengths of 1560 nm and 1980nm. We confirmed the ability to manage the dispersion of the oscillators, which worked in both anomalous and normal dispersion, maintaining stable mode-locking. Employing the developed fiber with normal dispersion has resulted in a broadening of spectral full width at half maximum from 7.8 to 44.3 nm and from 5.5 to 25.8 nm for the erbium and thulium lasers, respectively. The ability to support operation in the range of tens of MHz allows for the application of the developed laser sources in systems reducing the repetition rate via e.g. pulse picking.

This experiment aimed to improve the pulse shape and the pulse duration, with phase modulation of the seed laser pulse with spatial light modulator before amplifier stage and the employment of Artificial Intelligence algorithms.

This experiment aimed to characterize Gain-Managed Nonlinear amplification (GMN) in Erbium-doped fibers. This effect has so far been presented in Ytterbium-doped fibers and only simulated on Erbium-doped fibers.