L-band dual wavelength passively Q-switched erbium-doped fiber laser based on tellurium oxide nanoparticle saturable absorber

• Published in: Laser physics Vol. 30; no. 2; pp. 25101 - 25107
• Main Authors: Hassan, Hiba, Munshid, Mohammed A, AL-Janabi, Abdulhadi
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.2020
• Subjects: dual wavelength; erbium-doped fiber laser; nonlinear material; NPs; saturable absorber (SA); switching; tellurium oxide nanoparticles (TeO
• ISSN: 1054-660X; 1555-6611
• DOI: 10.1088/1555-6611/ab5a87

We experimentally demonstrate a compact dual wavelength passive Q-switched fiber laser created by an erbium-doped fiber active medium using tellurium oxide nanoparticles (TeO2 NPs) as a new saturable absorber (SA) material. The saturable absorption properties of the prepared TeO2 -PVA thin film were systematically measured, and the modulation depth and saturation intensity were 8% and 90 MW cm−2, respectively. By integrating the proposed SA in an all-fiber ring cavity, a dual wavelength laser with 1568.02 and 1569.09 nm wavelengths was observed without adding spectral filters or polarization maintaining fibers to control the suppression of the mode competition. A frequency difference of 0.13 THz was obtained located in the terahertz waveband. In the meantime, a stable Q-switched regime with a maximal pulse repetition rate of 45.7 kHz, a shortest pulse width of 2.69 µs and maximum pulse energy up to 39.4 nJ was attained at a maximum available pump power of 275 mW. The experimental setup using the TeO2 NP SA represents a step forward in terahertz development and nonlinear optics.