Broadband self-pulsating fiber laser based on soliton self-frequency shift and regenerative self-phase modulation

Abstract

We demonstrate experimentally and numerically the operation of a self-pulsating fiber laser based on the cascaded effects of soliton self-frequency shift and self-phase modulation spectral broadening. The combination of those two effects triggers and sustains the propagation of picosecond pulses in the cavity. At one of the outputs, the laser emits a supercontinuum with spectral width in excess of 150 nm at the repetition rate of 95 kHz.

Analysis of Self-Pulsating Sources Based on Cascaded Regeneration and Soliton Self-Frequency Shifting

“…Results provide the optimal filter bandwidth that maximizes the output SC bandwidth as well as the total output power. Shot-to-shot spectral measurements indicate, as previously assumed in [10], that the observed SC originates from the time-averaging of multiple spectra. These SCs, seeded by picosecond pulses, are extremely sensitive to initial conditions, and therefore their output spectra are unique [14].…”

“…This setup has similarities with the setup of Ref. [10], Fig. 1, but is improved with the use of tunable and adjustable filters for both BPF 1 and BPF 2 , replacing the fixed filter formed by the conjunction of an optical circulator and a Bragg grating, thereby adding two degrees of freedom.…”

“…The output properties of SPM-SSFS sources were studied in [10] for fixed filter spectral positions and bandwidths. The source was started from ASE, as the pump power of EDFA 1,2 was increased beyond a given power threshold.…”

“…Consequently, the repetition rate of the output pulses is not constrained to a pulse-to-pulse time interval dictated by the cavity free spectral range or one of its harmonics. Based on cascaded regeneration, a new method for generating short pulses in fiber lasers was also proposed and demonstrated experimentally in 2012 [10]. Sources of that kind, referred to as SPM-soliton self-frequency shift (SPM-SSFS) sources, are composed of two distinct regeneration stages.…”

“…Overall, SPM-SSFS sources compose an interesting new architecture, which so far has not been the subject of much investigation. In [10], numerical simulations were provided along with spectral measurements to support the possibility that a pulse originating from the first nonlinear stage is turned into several fundamental solitons, shifted in frequency by stimulated Raman scattering (SRS) during propagation in the anomalous dispersion region of a highly nonlinear fiber (HNLF). However, multishot spectral measurements have provided an averaged spectrum rather than a direct experimental observation of this process.…”