In this letter, we demonstrate a single longitudinal mode (SLM) Brillouin fiber laser by using highly nonlinear fiber (HNLF) as the nonlinear medium in which the stimulated Brillouin scattering effect takes place. The first Stokes line is generated at a threshold power of 18 dBm with a wavelength shift 0.08 nm from the Brillouin pump. The signal-to-noise ratio of the first Stokes line is measured to be ~58 dB. To the best of the authors' knowledge, this is the first report of a 0.7 kHz ultra-narrow linewidth of an SLM Brillouin fiber laser, using HNLF as the nonlinear medium, which features a simple cavity configuration.

No abstract

Single longitudinal mode (SLM) erbium-doped fiber (EDF) laser operation using a commercialized ultranarrow bandwidth optical filter has been demonstrated. A 2-m long EDF with an absorption coefficient of 24 dB m −1 at the pump wavelength is used as gain medium. The ultra-narrow tunable filter is used for selection of a single longitudinal mode from the available spectrum of multiple modes, which originally exist in the FBG's reflection spectrum. Our approach provides a relatively simple and direct method for realization of SLM operation. A high-resolution optical spectral analyser with a resolution of 0.16 pm is used to observe the output spectrum. To verify the SLM operation, the delayed self-heterodyne method is used, giving a measured laser linewidth of 61.5 kHz.

No abstract

In this work, a Graphene slurry based passive Q-switcher fabricated from Graphene-Polylactic acid (PLA) filament which is used for 3D printing. To produce the Graphene slurry, the diameter of the filament was reduced and Tetrahydrofuran (THF) was used to dissolve the PLA. The Graphene-THF suspension was drop cast to the end of a fiber ferrule and the THF then evaporated to develop Graphene slurry based SA which is integrated in fiber laser cavity. At threshold input pump power of 30.45 mW, a Q-switched Erbium-doped fiber laser (EDFL) can be observed with the wavelength centered at 1531.01 nm and this remained stable up to a pump power of 179.5 mW. As the pump power was increased gradually, an increase in the repetition rates was recorded from 42 kHz to 125 kHz, while the pulse width was reduced to 2.58 μs from 6.74 μs. The Q-switched laser yielded a maximum pulse energy and peak power of 11.68 nJ and 4.16 mW, respectively. The proposed Graphene slurry based saturable absorber also produced a signal-to-noise ratio of 44 dB indicating a stable Q-switched pulsed laser.