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Mode-locking is an ultra-short pulse laser generation technique. The range of pulse duration may vary from picoseconds to femtoseconds. Yttrium Oxide (Y2O3) based saturable absorber (SA) was appropriately revealed in the mode-locked method within the 1.55-micron regime. Y2O3 is perfect for strength, melting point, and chemical stability and can be used as a laminated insulator due to its properties. Moreover, Y2O3 also owns broadband service, switching speed, and engineering features. The Y2O3-PVA film was produced by combining the 50 mg Y2O3 powder into a 50 mL polyvinyl alcohol (PVA) solution and stirring it at room temperature for about 24 h. A mode-locked pulse was recorded with the integrated Y2O3-PVA SA in the erbium-doped fiber laser (EDFL) cavity, and the output spectrum optical spectrum analyzer displayed was around 1560.66 nm. In addition to the sustained mode-locked pulse, a nearly constant repetition rate of 1.01 MHz at a specific pump power begins from 175.87 mW to 228.04 mW while the pulse duration is 4.15 ps. Lastly, the mode-locked pulse had been evaluated, which showed the peak power started from 4.94 kW to 6.07 kW. [ABSTRACT FROM AUTHOR]

We have experimentally demonstrated the mode-locked and Q-switched fibre lasers based on MXene Ti3C2Tx as a saturable absorber (SA). MXene Ti3C2Tx was obtained using selective etching and then embedded into polyvinyl alcohol (PVA) to form the thin film. A stable soliton mode-locked laser was achieved when the Ti3C2Tx film was added in the Erbium-doped fibre laser cavity, and the pump power was adjusted between 55 and 144 mW. The pulse width of mode-locked laser was obtained to be 3.68 ps, while the repetition rate was 1.89 MHz. The maximum average output power and pulse energy were measured to be 24.42 mW and 12.92 nJ. After we decreased the cavity length by removing 100 m of SMF, the same SA could produce Q-switched laser instead of mode-locked laser. The Q-switched laser operated within the pump power of 19–66 mW, having the shortest pulse width and operating wavelength of 2.6 µs and 1557 nm, respectively. [ABSTRACT FROM AUTHOR]

Q-switched and mode-locked Erbium-doped fiber lasers (EDFLs) were demonstrated using Titanium dioxide (TiO2) film as a saturable absorber (SA). The prepared SA film is cut into small piece and sandwiched between two ferrules in EDFL (EDFL) cavity to generate a stable and compact Q-switched and mode-locked pulses. By increasing the 980 nm pump power from 104.6 mW to 145.8 mW, the repetition frequency of the Q-switched EDFL increases from 81.04 kHz to 90.58 kHz while the pulse width reduces from 5.08 µs to 4.12 µs. The maximum pulse energy of 22.63 nJ is generated at the pump power of 145.8 mW. Meanwhile, selfstarting mode-locked EDFL arises as 100 m long single-mode fiber is added into the laser cavity to balance the nonlinearity and the cavity dispersion. As the pump power was raised from 145.8 to 187 mW, the repetition rate and pulse width of the pulses are almost constant of 1.86 MHz and 3.34 ps, respectively. This experiment shows that TiO2 SA can be used to generate stable Q-switched and mode-locked pulsed lasers. [ABSTRACT FROM AUTHOR]

Q-switched and mode-locked pulses were obtained by utilizing a Samarium oxide (Sm2O3) film as saturable absorber (SA) in Erbium-doped fiber laser (EDFL) cavity. The Sm2O3 SA film has a modulation depth and saturation intensity of 30% and 90 MW/cm2, respectively. The proposed Q-switched EDFL operated stably at 1558.4 nm. The repetition rate was tunable in a range from 75.8 kHz to 99.5 kHz with the raise of pumping power from 81.0 mW to 131.9 mW. At the maximum pumping power of 131.9 mW, the highest pulse energy of 143.9 nJ and the lowest pulse width of 2.12 µs were attained. A stable soliton mode-locked laser was observed at a central wavelength of 1561.6 nm when an additional 100 m long single mode fiber was incorporated into the cavity. The mode-locking operation was maintained at pump power range within 91.2 mW to 142.0 mW with repetition rate of 1.88 MHz and pulse width of 3.40 ps. At 142.0 mW, the maximum pulse energy of 12.00 nJ and peak power of 3.53 kW were obtained. These show that the proposed Sm2O3 SA is viable for application in the construction of practical Q-switched and modelocked pulses operating in the 1.5 micron range. [ABSTRACT FROM AUTHOR]

We generated Q-switched and mode-locked pulses by making use of the saturable absorption characteristic of scandium oxide (Sc2O3) film, which was obtained by embedding Sc2O3 nanopowders into polyvinyl alcohol film. The Q-switched laser operated at center wavelength of 1560.5 nm with the maximum pulse energy of 65.6 nJ and 4.4% slope efficiency. With the addition of a 200 m extra single-mode fiber in the ring cavity, a self-starting mode-locked EDFL was implemented. The mode-locked pulses operated at a central wavelength of 1565.4 nm with a repetition rate of 1.0 MHz and a pulse duration of 3.50 ps. [ABSTRACT FROM AUTHOR]

Q-switched fiber laser was demonstrated by using tungsten disulfide (WS2), which was deposited onto D-shaped fiber as a passive saturable absorber (SA) to modulate the loss inside the laser cavity. The SA was produced by repeatedly dropping and drying the WS2 solution onto side-polished fiber to form a nanosheets layer. The SA is inserted into the ring laser cavity configured with a 2.4 m long Erbium-doped fiber as the gain medium to generate Q-switching pulses train operating at 1557.9 nm. The Q-switched laser produced a pulse train, which the repetition rate is tunable from 77.2 to 108.9 kHz as the pump power is increased from 84.0 to 182.9 mW. The minimum pulse width of 3.25 µs and the maximum pulse energy of 14.6 nJ was obtained at 182.9 mW pump power. The generated Q-switching pulses are stable and thus it is suitable for use in many practical applications. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate a passively Q-switched Ytterbium-doped fiber laser (YDFL) operation by using a Nickel oxide (NiO) nanoparticles as a saturable absorber (SA). As a kind of transition metal oxide, the NiO has a large nonlinear optical response with a fast response time for SA. By embedding the synthesized NiO5 into a poly ethylene glycol (PEO) film and incorporating in a laser cavity, a Q-switching pulses train was successfully generated to operate at 1070 nm wavelength. A stable passively Q-switched EDFL pulses with maximum output pulse energy of 0.69 nJ, repetition rate of 54.35 kHz, and pulse width of 2.27 μs are achieved when the incident pump power is 226 mW. The results indicate NiO nanoparticles can work as a Q-switcher for operation at 1 micron region. [ABSTRACT FROM AUTHOR]

Dual-wavelength Q-switched Erbium-doped fiber laser (EDFL) was shown by using tungsten disulfide (WS2), which was deposited onto a micro-sphere resonator (MSR) as a saturable absorber (SA). WS2 functions to modulate the cavity loss for Q-switching while the dual-wavelength operation was realized due to MSR, which allows only two wavelengths to oscillate in the resonator. MSR with the sphere diameter of 200 μm was fabricated at the tip of a standard single mode-fiber by employing a fiber fusion splicer machine. The SA was obtained by repeatedly dropping and drying of WS2 solution onto the MSR structure to form an active thin layer. The SA was incorporated into an EDFL cavity to realize a dual-wavelength Q-switched laser operating at 1554.0 nm and 1560.7 nm. The repetition rate of the pulse train is tunable from 72.4 kHz to 85.1 kHz as the pump power is increased from 104.6 mW to 145.8 mW. At 145.8 mW pump, the minimum pulse width and maximum pulse energy were obtained at 3.47 µs and 131.4 nJ, respectively. The dual-wavelength Q-switched laser was stable and thus it is suitable for use in airborne Lidar, environmental sensing, and terahertz applications. [ABSTRACT FROM AUTHOR]

We demonstrated Q-switched and soliton mode-locked pulses operating at 1569.51 nm and 1564.45 nm, respectively by using a newly developed Bismuth Telluride Polyvinyl Alcohol (Bi2Te3 PVA) film as saturable absorber (SA). By incorporating the SA into an Erbium-doped fiber laser (EDFL) cavity, Q-switched pulses were obtained within a pump power range from 101.90 to 175.82 mW. At the maximum pump power, the laser operated at repetition rate of 92.76 kHz and pulse width of 4.76 µs while producing the highest single pulse energy of 39.4 nJ. By incorporating an additional 200 m long single-mode fiber into the laser cavity, stable soliton mode-locked pulses were generated. It operated at repetition rate of 0.97 MHz with a pulse width of 2.97 ps and a signal-to-noise ratio (SNR) of 50.89 dB. [ABSTRACT FROM AUTHOR]

We demonstrated nanosecond pulsed fiber laser operating at 1563 nm by using a newly developed Bismuth (III) Telluride (Bi2Te3) based saturable absorber (SA). The SA was obtained by embedding Bi2Te3 material into polyvinyl Alcohol (PVA) film. By incorporating the SA into a 209 m long cavity Erbium-doped fiber laser (EDFL), a stable nanosecond pulses were generated. It operated at repetition rate of 1.8 MHz with a pulse width of 193 ns and a signal-to-noise ratio (SNR) of 58 dB. The newly developed Bi2Te3 SA has a potential to be further enhanced towards better generation of ultrashort pulse fiber lasers. [ABSTRACT FROM AUTHOR]