High-power Pulse Amplification Research Articles

Generation of high-power parabolic pulses in quantum dot waveguide amplifiers

The self-similarity techniques are used to study pulse propagation in a quantum dot waveguide amplifier with an arbitrary longitudinal gain profile. Generation of high-power parabolic pulses are analyzed under different gain profiles by considering initial chirp-free and chirped pulses via numerical simulations. In particular, the periodic distributed gain enables us to obtain a fast amplification of high power pulses in parabolic state with the largest broadening and frequency chirp. Finally, a possible experimental protocol is proposed to generate the high-power parabolic pulses in realistic waveguides.

All-fiber high-power monolithic femtosecond laser at 1.59 µm with 63-fs pulse width

In this research, by adopting an alternative novel approach to ultra-short giant pulse generation which basically originated from difficulties with traditional employed methods, an optimized Er/Yb co-doped double-clad fiber amplifier is applied to boost output average power of single-mode output pulses to a high level of 2-W at 1.59-µm central wavelength. Output pulses of approximately 63-fs pulse width at 52-MHz repetition rate are obtained in an all-fiber monolithic laser configuration. The idea of employing parabolic pulse amplification for stretching output pulses together with high-power pulse amplification using Er/Yb co-doped active fibers for compressing and boosting output average power plays crucial role in obtaining desired results. The proposed configuration enjoys massive advantages over previously reported literature which make it well-suited for high-power precision applications such as medical surgery. Detailed dynamics of pulse stretching and compressing in active fibers with different GVD parameters are numerically and experimentally investigated.

Inversion behavior in core- and cladding-pumped Yb-doped fiber photodarkening measurements

Yb-doped fibers are widely used in applications requiring high average output powers and high power pulse amplification. Photodarkening of the Yb-doped silicate glass core potentially limits the lifetime or efficiency of such fiber devices. In many studies of photodarkening, two principal methods of controllably inducing an inversion are used, namely, cladding pumping and core pumping of the sample. We present simulation results describing the key differences in the inversion profiles of samples of different physical parameters in these two cases, and we discuss the problems and possibilities that arise in benchmarking fibers of various physical parameters. Based on the simulation and experimental work, we propose guidelines for photodarkening benchmarking measurements and show examples of measurements made within and outside of the guidelines.

Coherent effects in two-level amplifying and SRS-active media

Some results are reported on coherent propagation of optical pulses. In particular, a solution is presented of the Maxwell-Bloch equations for the case of amplification of high-power pulses with varying carrier frequency but with constant number of photons in the pulse.

Distortions of a fine-structure wave pattern due to self-focusing nonlinearity

Distortions due to a self-focusing nonlinearity of the medium are calculated for a beam with a strong gray angular divergence, i.e., with fine-structure inhomogeneities. The calculation is made by the method of perturbation of the mode solution. Ways of avoiding self-focusing in high-power pulse amplification are considered.