Boron carbon oxynitride coated arc-shaped fiber as an optical modulator for passively mode-locked fiber lasers at 1.5 and 2 μm wavelength

Two-dimensional (2D) materials have recently been explored as potential saturable absorbers (SAs) due to their remarkable optoelectronic and nonlinear optical properties. In this work, we have experimentally reported 2D boron carbon oxynitride (BCNO) as a potential mode-locker in erbium-(EDFL) and thulium-doped fiber lasers (TDFL) for the first time. The BCNO-coated arc-shaped fiber was explored as a novel optical loss modulator and exhibited a modulation depth of 8.2% and 5% at 1.5 mu m and 2 mu m, respectively. Mode-locking was achieved by the BCNO-coated arc-shaped fiber in EDFL having a pulse width, repetition rate, and center wavelength of 1.56 ps, 19.14 MHz, and 1562.2 nm, respectively. Mode-locked pulses of 1.456 ps duration were achieved by incorporating BCNO-coated arc-shaped fiber in TDFL, operated at center wavelength, repetition rate, and signal-to-noise ratio (SNR) of 1944 nm, 13 MHz, and 70.3 dB, respectively. These results prove BCNO to be a promising low-cost 2D material to be further explored for laser-related applications.