Switching among pulse-generation regimes in passively mode-locked fibre laser by adaptive filtering

Abstract

We show both numerically and experimentally that dispersion management can be realized by manipulating the dispersion of a filter in a passively mode-locked fibre laser. A programmable filter the dispersion of which can be software configured is employed in the laser. Solitons, stretched-pulses, and dissipative solitons can be targeted reliably by controlling the filter transmission function only, while the length of fibres is fixed in the laser. This technique shows remarkable advantages in controlling operation regimes in ultrafast fibre lasers, in contrast to the traditional technique in which dispersion management is achieved by optimizing the relative length of fibres with opposite-sign dispersion. Our versatile ultrafast fibre laser will be attractive for applications requiring different pulse profiles such as in optical signal processing and optical communications.

Design and Applications of In-Cavity Pulse Shaping by Spectral Sculpturing in Mode-Locked Fibre Lasers

“…When some normal dispersion was applied on the filter while keeping the net cavity dispersion anomalous, the spectral width of the pulses increased, which is in agreement with soliton-type pulse behaviour [49]. Adapted from [37].…”

“…In this section, we review the operation of an ultrafast passively-mode-locked fibre laser, which can be readily and reliably switched among conventional soliton, stretched-pulse and DS mode-locking regimes by changing the dispersion and bandwidth of an in-cavity programmable filter only, while no changes are made to the physical layout of the laser cavity [37]. Figure 6 shows a schematic of our passively-mode-locked EDF ring laser.…”

“…Simulated evolution of the rms temporal (red) and spectral (blue) widths of the pulse along the cavity for the (a) soliton, (b) DM soliton and (c) DS regimes. Adapted from [37].…”

“…As an application of this general approach, we show that the use of an in-cavity flat-top spectral filter makes it possible to directly generate sinc-shaped Nyquist pulses of high quality and of a widely-tunable bandwidth from the laser [36]. We also report on a recently-developed versatile erbium-doped fibre (EDF) laser, in which conventional soliton, DM soliton and DS mode-locking regimes can be selectively and reliably targeted by programming different GVD profiles and bandwidths on an in-cavity programmable filter [37].…”