Noise-Like Square Pulses in Both Normal and Anomalous Dispersion Regimes

Abstract

Noise-like square pulses (NLSPs) have been experimentally investigated in both normal and anomalous dispersion regimes. A chirped fiber Bragg grating (CFBG) has been employed as a dispersion management element in the compact linear-cavity mode-locked Yb-doped fiber laser. The net cavity dispersion could be switched from large anomalous dispersion (-2.71 ps) to large normal dispersion (+5.33 ps 2), depending on the direction of CFBG inserting in laser cavity. Two kinds of NLSPs with different temporal profiles are achieved in the proposed laser. In anomalous dispersion regime, the square pulse duration can be tuned from 0.91 ns to 5.39 ns, and the maximum square pulse energy is 39.57 nJ. In normal dispersion regime, the top of the pulse is flatter, the square pulse duration can be tuned from 0.89 ns to 5.97 ns, and the maximum square pulse energy is slightly higher, up to 40.17 nJ. The output laser is linearly polarized.

Dual-wavelength square pulses fiber laser based on nonlinear effect

“…Various kinds of pulse shape, such as parabolic pulses [1], Gaussian pulses [2], sech-like pulses, and square pulses, have been generated to meet different demands [3]. Among them, square pulses with wide pulse width and high single-pulse energy are widely used in medical imaging, high-energy laser [4], all-optical square-wave clocks [5], ranging and optical sensing. Therefore, more and more researchers are paying attention to square pulses.…”