S-band Q-switched fiber laser using MoSe2 saturable absorber

A passively Q-switched S-band fiber laser using Molybdenum Diselenide (MoSe2) saturable absorber (SA) is proposed and demonstrated. The SA is fabricated by depositing MoSe2 onto two fiber ferrules using the drop-cast method before heating and connecting the two fiber ferrules to form the SA. The passively Q-switched fiber laser designed using the MoSe2 SA has an operational range of 1491.0–1502.0 nm. The output pulse train has a pulse-width ranging from 2.0 μs to 1.0 μs and corresponding repetition rate of between 34.5 kHz and 90 kHz with increasing pump powers, as well as a signal-to-noise of about 35.97 dB. The peak performance of the proposed laser is between 1480.0 and 1490.0 nm, corresponding to the first peak gain region with the S-band

Passively Q-switched S+/S band fiber laser with copper telluride saturable absorber

A Q-switched S-band fiber laser based on a thulium-fluoride fiber gain medium and copper telluride (Cu2Te) based saturable absorber (SA) is demonstrated. The Cu2Te based SA is fabricated as a thin film and at the maximum pump power, the generated Q-switched output has a minimum pulse width of 3.2 µs and highest pulse energy of 56.7 nJ. The pulse train varies from 20.9 kHz to 30.2 kHz at the highest pump power. The wavelength of the generated output can be tuned over a range of 32 nm from 1470 nm to 1502 nm. The demonstrated laser has a high potential for industrial applications focusing on the S-band region

Tunable Q-switched thulium-doped fiber laser (TDFL) in 2.0 µm region based on gallium selenide saturable absorber

A tunable Q-switched thulium-doped fiber laser (TDFL) using a Gallium Selenide (GaSe) based saturable absorber (SA) is proposed and demonstrated for operation in the 2.0 µm region. The Q-switched TDFL operates from 1960.0 nm to 1998.0 nm, covering a wavelength range of 38.0 nm. The generated output pulses have a repetition rate from 14.9 kHz to 40.9 kHz and minimum pulse width of 4.9 µs at the maximum pump power of 126.6 mW, as well as a maximum pulse energy of 92.8 nJ. This is, to the author's knowledge, the first successful combination of a TDF and a GaSe based SA to generate tunable Q-switched pulses in 2.0 µm region

Passively Q-switched S-band thulium fluoride fiberlaser with multi-walled carbon nanotube

A stable, passively Q-switched thulium fluoride fiber laser (TFFL) using a multi-walled carbon nanotube (MWCNT)-based saturable absorber (SA) for operation in the S-band region is proposed and demonstrated. The proposed TFFL has a central lasing wavelength of 1486.4 nm and an input power range of 87.1-126.6 mW. The output pulses have a repetition rate and pulse width range of 30.1-40.0 kHz and 9.0-3.2 μs, respectively, with a maximum pulse energy of 28.9 nJ. This is the first time, to the author's knowledge, of the successful demonstration of a passively Q-switched S-band TFFL using an MWCNT-based SA

S+/S band passively Q-switched thulium-fluoride fiber laser based on using gallium selenide saturable absorber

A Q-switched thulium-fluoride fiber (TFF) laser using gallium selenide (GaSe) as a passive saturable absorber (SA) for operation in the S+/S band is demonstrated. The generated pulses can be tuned from 1454 nm to 1512 nm, giving a tuning range of 58 nm. At 1502 nm, stable Q-switching operation is obtained from a pump power of 76.2 mW and is observed until the maximum pump power of 133.6 mW is reached, with the repetition rate varying from 16.5 kHz to 33.3 kHz and having a narrowest pulse width at 2.7 µs. The highest pulse energy obtained in this work is 51.4 nJ and this is, to the knowledge of the authors, the first time that Q-switching operation in the S+/S band region is obtained from a TFF laser using a GaSe based SA

Spooling diameter dependent Q-switched output in depressed cladding erbium doped laser with MoWS2 saturable absorber

A tunable, Q-switched depressed-cladding erbium-doped fiber (DC-EDF) laser employing a molybdenum tungsten disulfide (MoWS2) thin film as a saturable absorber (SA) is reported. The output of the laser can be controlled by adjusting the spooling diameter of the gain medium, with continuous wave operation obtained from 1466 nm to 1502 nm and 1473 nm to 1525 nm for DC-EDF spooling diameters of 5.5 cm and 6.5 cm respectively. The Q-switched output, obtained by incorporating an MoWS2 based SA into the cavity shortens the tuning range to between 1476.0 nm and 1496.0 nm as well as 1486.0 to 1496.0 nm for the same spooling diameters. The outputs have repetition rates ranging from 21.7 kHz to 44.6 kHz and a minimum pulse width and maximum pulse energy of 2.4 µs and 11.0 nJ, for the DC-EDF with a spooling diameter of 5.5 cm. The DC EDF with a spooling diameter of 6.5 cm is able to generate pulses with a repetition rate of between 32.2 kHz and 40.9 kHz with a minimum pulse width and maximum pulse energy of 2.8 µs and 10.1 nJ

Nickel oxide nanoparticles grafted with Chitosan as saturable absorber for tunable passively Q-switched fiber laser in S+/S band

A tunable, passively Q-switched fiber laser using nickel oxide nanoparticles grafted onto a chitosan host (NiO/Chitosan) as saturable absorber (SA) is proposed and demonstrated for operation in the S+/S band region. The generated Q-switched pulses can be tuned from 1452 nm to 1515 nm, giving a tuning range of 63 nm. The pulses have a repetition rate from 12.3 kHz to 30.8 kHz as well as minimum pulse width and maximum pulse energy of 3.5 µs and 61.0 nJ, respectively at maximum pump power of 135.8 mW. To the best of the author's knowledge, this is the first time that tunable Q-switching operation in the S+/S band region is obtained using a NiO/Chitosan based SA

Passively Q-switched erbium-doped fiber laser using coated reduced graphene oxide on arc-shaped single mode optical fiber as a saturable absorber

A passively Q-switched erbium-doped fiber laser is demonstrated using saturable absorbers based on the evanescent light field interaction of reduced graphene oxide deposited on ground arc-shaped fiber. The Q-switched operation started at 32.42 mW with a lowest repetition rate of 34.48 kHz and a pulse width of 5.05 μs. A Q-switched pulse is obtained at different levels of pump power with corresponding repetition rates and pulse widths. From the obtained results, the repetition rate increases from 34.48 kHz to 54.10 kHz; in contrast, the pulse width decreases from 5.01 μs to 2.01 μs. The average output power and pulse energy are increased by enhancing pump power from 32.42 mW to 119.5 mW. Additionally, the fundamental frequency is maintained over time with the signal-to-noise ratio of ∼55 dB, thus indicating the Q-switched process is stable over a period of 90 min

Chitosan capped nickel oxide nanoparticles as a saturable absorber in a tunable passively Q-switched erbium doped fiber laser

Nickel oxide (NiO) nanoparticles successfully prepared from a nickel(ii) chloride hexahydrate precursor are used to form a chitosan capped NiO nanoparticle thin film to serve as a saturable absorber (SA) for the generation of passively Q-switched pulses in an erbium doped fiber laser (EDFL). The NiO/chitosan SA based EDFL is able to generate stable pulsed outputs at a low threshold pump power of 104.90 mW with a central wavelength at 1562 nm. The highest pulse energy obtainable by the system is 15.30 nJ at a repetition rate of 42.66 kHz and a pulse duration of 2.02 μs. The laser has a spectral range of 58 nm from 1522 to 1580 nm, covering the C and L bands and even portions of the S band. This study experimentally demonstrates that the potential of the NiO/chitosan film as an SA material for Q-switching operations, combined with the biocompatibility, non-toxicity and high thermal resistance of Chitosan, holds great prospects for a broad range of applications

Nickel phosphate as a C-band optical pulse modulator

This work discusses the fabrication of a nickel phosphate [Ni3(PO4)2]-polyvinyl alcohol (PVA) thin film and its application as an optical modulator for the generation of Q-switched pulses in the C-band region. A 50 cm long erbium-doped fiber with absorption coefficients of 250 dB/m and 16 dB/m at 980 nm and 1530 nm respectively was used as the gain medium. The modulation depth, saturable intensity and non-saturable loss were measured to be 56.43%, 0.15 kW/cm2 and 43.57%, respectively. Stable self-starting Q-switched pulses were observed at 1561.1 nm at an output power of 2.34 mW, a pulse width of 1.08 μs, and a repetition rate of 86.21 kHz, at the maximum pump power of 280.50 mW. The generated output was highly stable with a signal-to-noise ratio of 54.57 dB. The work undertaken has demonstrated the potential of Ni3(PO4)2 nanoparticles as an optically active material due to its excellent nonlinear saturable absorption characteristics, which translates to good laser performance. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature