Graphitic carbon nitride modulated short pulse generation in an Erbium-doped fiber laser

In the present study, a few layered graphitic carbon nitrides (g-C3N4) nano-sheets were successfully manufactured by the calcination method. It demonstrates nonlinear optical (NLO) property with modulation depths of ∼4.26% at 1.5 μ m. The index-matching gel adhesion effect was used to place the g-C3N4 nano-sheets on the fiber ferrule surface to produce short-pulsed lasers. The g-C3N4 saturable absorber (SA) based Q-switched erbium-doped fiber laser (EDFL) emits at 1560.5 nm wavelength with 1.2 nm of spectral bandwidth at 3 dB. The radio frequency's signal-to-noise ratio (SNR) is 42 dB at first harmonic, demonstrating excellent pulse stability. As the pump power increases, the frequency increases from 27.2 to 108 kHz, and the pulse shortens from 14.6 to 4.2 μ s, correspondingly. The highest pulse energy, peak power, and average output power are measured to be 48.7 nJ, 11 mW, and 5.18 mW at the highest pump power of 479.1 mW. Besides, the morphology and structure of g-C3N4 were characterized by scanning electron microscopy (SEM) and X-rays powder diffraction (XRD), photoluminescence (PL) spectra, Raman spectroscopy, Fourier transform infrared spectra (FT-IR), and UV- diffuse reflectance spectroscopy (DRS) have been also presented. Additionally, the stability of g–C3N4–SA was also measured. These findings suggest that few layered g-C3N4 nano-sheets have a substantial role as a SA in optical modulation devices and nonlinear optical properties at the near and mid-infrared band.