Generation of mode-locked pulses based on D-shaped fiber with CdTe as a saturable absorber in the C-band region

Abstract

This study demonstrates the potential of cadmium telluride (CdTe), a part of the quantum dot (QD) family, as a saturable absorber (SA) to generate ultrashort pulses at the C-band region. The SA was fabricated by drop-casting the CdTe material onto the exposed core of the D-shaped fiber. The nonlinear property of the fabricated SA has a modulation depth of 1.87% and saturation intensity of 6.0 kW cm⁻². The mode-locked laser was generated after the SA was integrated into the erbium-doped fiber laser (EDFL) cavity at a threshold pump power of 192.1 mW giving a center wavelength of 1559 nm and a pulse duration of 770 fs. The maximum average output and peak power were measured to be 2.8 mW and 0.208 kW, respectively. The mode-locked fiber laser generated a signal-to-noise ratio (SNR) of 67.7 dB, proving that the generated mode-locked pulses were very stable. The current work indicates that the novel CdTe device can provide stable mode-locked lasers in the C-band region.