Q-switched Thulium-doped Fiber Laser Research Articles

Advancing Q-switched pulse generation in the 1.9 µm wavelength region using novel thulium-doped fiber gain medium and MXene Nb2CTx saturable absorber

This paper presents the first demonstration of a Q-switched Thulium-doped fiber laser (TDFL) utilizing our newly developed Thulium-doped fiber (TDF) and a MXene niobium carbide - polyethylene oxide (Nb2CTx-PEO) thin film as a gain medium and saturable absorber (SA), respectively. The TDF core glass contains 6.15 wt% Al2O3, 2.2 wt% Y2O3, 0.47 wt% Tm2O3, 2.12 wt% GeO2, 1.57 wt% HfO2 and 0.05 wt% Bi2O3 with the absorption of 30 dB/m at 1550 nm. The outcome was the realization of a stable pulsed laser operating at a central wavelength of 1888.3 nm. The Q-switched pulses exhibited a maximum repetition rate of 46.7 kHz and a minimum pulse width of 1.995 µs at a pump power of 731.41 mW. The Q-switched operation maintained a signal-to-noise ratio (SNR) of 45 dB, confirming its stability. This breakthrough highlights the laser system's potential for diverse applications, including free-space optical communication, spectroscopy, and medical fields.

Generation of bright-dark pulses in a Q-switched thulium-doped fiber laser by using 8-HQCdCl2H2O

Generation of bright-dark pulses in a Q-switched thulium-doped fiber laser by using 8-HQCdCl2H2O

MAX phase V4AlC3 for generating Q-switched pulses in 2 µm region

A stable Q-switched Thulium-doped fibre laser (TDFL) operating at 1978.14 nm is demonstrated using a MAX phase thin film as a saturable absorber (SA). The MAX phase film is fabricated by embedding the Vanadium Aluminium Carbide (V4AlC3) compound into polyvinyl alcohol (PVA) via a drop-casting technique. The MAX Phase V4AlC3 thin film is characterized to has a saturable absorption, non-saturable loss, and saturation intensity of about 30 %, 45 %, and 0.07 MW/cm2, respectively. It is sandwiched between two fibre ferrules and integrated into TDFL cavity to induce Q-switching. The pulse train generated records the highest pulse energy of 161.33 nJ, narrowest pulse duration of 2.14 µs, and a maximum repetition rate of 58.45 kHz at the maximum input power of 750 mW. The corresponding signal-to-noise ratio (SNR) of the fundamental frequency is obtained at 55 dB, which indicates a stability of the pulse. The results indicate the MAX phase material has a great potential to serve as SA in future photonics systems.

Q-Switched Thulium-Doped Fiber Laser with Molybdenum–Aluminum-Boride-Based Saturable Absorber

Q-Switched Thulium-Doped Fiber Laser with Molybdenum–Aluminum-Boride-Based Saturable Absorber

Passively Q-switched 2 µm fiber laser with WO3 saturable absorber

We have successfully demonstrated a reliable and simple passively Q-switched Thulium-doped fiber laser (TDFL) utilizing tungsten oxide (WO3) as a saturable absorber (SA). The SA film was fabricated by embedding WO3 material into Polyvinyl alcohol (PVA) host polymer. The saturable absorption and saturation intensity of the fabricated WO3-based SA are about 20 % and 0.04 MW/cm2, respectively. The Q-switched TDFL pulses operate at a central wavelength 1960.2 nm with a 3 dB bandwidth of 1.4 nm, pulse duration of 2.32 μs, maximum repetition rate of 64.27 kHz, maximum output power of 8.2 mW, and maximum pulse energy of 127.58 nJ. To our knowledge, this is the first time that WO3 has been used as a Q-switcher for operation in 2 μm region.

The Dynamics of Multi-Peak Pulsed Generation in a Q-Switched Thulium-Doped Fiber Laser

We demonstrate a detailed theoretical and experimental study of a thulium-doped fiber laser being Q-switched by means of an acousto-optic modulator. The processes leading to the generation of discontinuous multi-peak pulses with an energy of up to 5 μJ and a nanosecond structure are described. The dynamics of the multi-peak structure’s evolution is demonstrated and a method of switching to a single-pulse mode is proposed.

2 Μm Passively Q-Switched Thulium-Doped Fiber Laser by 8-Hqcdcl2h2o Based Saturable Absorber

2 Μm Passively Q-Switched Thulium-Doped Fiber Laser by 8-Hqcdcl2h2o Based Saturable Absorber

Tunable S+/S band Q-switched thulium-doped fluoride fiber laser using tungsten ditelluride (WTe2)

A tunable, passively Q-switched thulium-doped fluoride fiber laser (TDFFL) using a tungsten ditelluride (WTe2) thin film based saturable absorber (SA) was proposed and its operational efficacy demonstrated. At a maximum pump power of 250 mW, a Q-switched output at 1494 nm with a 3-dB bandwidth of 3 nm was obtained. The repetition rate was measured to be 36.5 kHz with a minimum pulse width of 3.7 µs, as well as a signal-to-noise ratio (SNR) of approximately 42 dB. Utilizing a tunable bandpass filter (TBPF), tunable Q-switching operation was achieved from 1459 to 1513 nm, giving a tuning range of 54 nm. The proposed laser would have significant use for systems operating in the S-band region, particularly for optical communications networks.

Q-switched Thulium-doped fiber laser at 1860 nm and 1930 nm using a Holmium-doped fiber as an amplified spontaneous emission filter

This work demonstrates an all fiber, passively Q-switched Thulium-doped fiber (TDF) laser with a center operating wavelength at 1860 nm and 1930 nm. The laser initially generates an output at ~1930 nm which is then shifted to ~1860 nm by integrating a Holmium-doped fiber (HDF) into the cavity to serve as an amplified spontaneous emission filter. Q-switching operation is achieved using a molybdenum tungsten disulfide or MoWS2 thin film acting as a passive optical modulator. At 1930 nm, the generated Q-switched laser has a high repetition rate of 66.3 kHz and a narrow pulse width of 2.1 µs. After the Holmium-filter is employed, the wavelength shifts to 1860 nm while still retaining a modulated output with a maximum repetition rate of 48.9 kHz as well as narrowest pulse width of 2.3 µs. This work demonstrates the use of the absorption characteristics of HDF to access the shorter wavelength region of the TDF.

Q-switched Thulium-doped fiber laser with Bismuth-doped fiber saturable absorber

We demonstrate a passive Q-switched all-fiber ring configuration in thulium-doped fiber laser (TDFL) cavity using a bismuth-doped fiber (BDF) as a saturable absorber (SA). A piece of 20 cm long BDF was spliced and incorporated in the laser cavity for Q-switching pulse generation. By raising the pump power from 454 mW to 564 mW, the repetition rate of the laser is tunable within a range from 18.10 kHz to 25.22 kHz while the pulse width reduces from 9.04 µs to 6.98 µs. At maximum pump power, the Q-switched TDFL has output power, a slope efficiency, pulse energy and peak power of 5 mW, 3.53 %, 0.2 µJ and 28.40 mW, respectively.

Q-switched Thulium-doped fibre laser using Bismuth (III) Telluride-based saturable absorber

We demonstrate a passive Q-switched thulium-doped fibre laser (TDFL) pulse generation using bismuth (III) telluride (Bi2Te3) thin film as saturable absorber. The Bi2Te3 was fabricated by a simple processing technique; simply by embedding the Bi2Te3 into the polyvinyl alcohol (PVA) film. By sandwiching 1 mm x 1 mm Bi2Te3 thin film between two fibre ferrules in a TDFL ring cavity, a stable Q-switching pulses train was generated. The repetition rate and pulse width were tuneable from 10.72 kHz to 39.9 kHz and 13.08 µs to 5.98 µs, respectively, as the pump power increased from 309 mW to 454 mW. The slope efficiency was 4.51%, while, the maximum pulse energy was calculated as 0.17 µJ.

Samarium (III) oxide thin film as a saturable absorber for the passively Q-switched Tm-doped fiber laser

We have demonstrated a passive Q-switched Thulium-doped fiber laser (TDFL using samarium oxide (Sm2O3) nanomaterial as saturable absorber (SA). The Sm2O3 based SA was fabricated by simply mixing the Sm2O3 powder solution with polyvinyl alcohol (PVA) solution. The homogeneously mixed solution was spread and dry to form a thin film. A piece of 1 mm x 1 mm of the SA thin film is sandwiched between two fiber ferrules and incorporated into a TDFL ring cavity for pulses generation. By controlling the loss and gain in the cavity, stable Q-switching operation was generated. The repetition rate was tunable from 17.62 kHz to 29.20 kHz by varying the pump power from 619 mW to 784 mW. The smallest pulse width of 3.54 µs and the highest pulse energy of 0.20 uJ were obtained at the highest pump power.

Passively Q-switched thulium-doped fiber laser based on oxygen vacancy MoO3-x saturable absorber

We reported on a passively Q-switched double-clad thulium-doped fiber laser by using oxygen vacancies (OVs) enriched with MoO3-x as a saturable absorber (SA). The MoO3-x was successfully embedded in polyvinyl alcohol and acted as the SA for a stable Q-switching operation in the 2 µm wavelength region. Stable Q-switched pulses were obtained at a central wavelength of ∼1992.1 nm with a maximum output power of ∼62.7 mW, maximum pulse energy of ∼1.63 µJ and a minimum pulse duration of ∼2 µs. The repetition rate of the pulses can be tuned from ∼15.5 kHz to ∼38.5 kHz with increasing the pump power. Our experiment was the first demonstrated use of MoO3-x as a SA for pulse laser generation, in which OVs were considered as the original reason for the optical saturable absorption. Moreover, it provides a novel idea for optical SA preparation by controlling the vacancy defects in such materials.

1.8 µm passively Q-switched thulium-doped fiber laser

This work demonstrates a simple and reliable passively Q-switched thulium-doped fiber laser capable of generating an output with a peak wavelength at 1.8 µm. Lasing is realized from the shorter wavelength region of a thulium-doped silica fiber gain medium by suppressing lasing at longer wavelengths in combination with a tunable bandpass filter. The laser is modulated by a single-walled carbon nanotube film saturable absorber. The generated Q-switched laser is capable of achieving a high repetition rate of 67.9 kHz and a narrow pulse width of 1.2 µs. As most work on the 1.6–1.8 µm waveband focuses on continuous-wave and mode-locked lasers, to the best of the author’s knowledge, this is the first demonstration of a passively Q-switched thulium-doped fiber laser operating at 1.8 µm with an all-silica fiber setup. The demonstrated laser has potential for various applications including biomedical surgery and polymer-based welding applications.

Evanescent field interaction with Fe3O4 nano-particle for passively Q-switched thulium-doped fiber laser at 1.94 μm

We experimentally demonstrate the use of Fe3O4-based saturable absorber (SA) to generate self-starting, passively Q-switched pulses at 1943 nm. The Fe3O4 particles were characterized with scanning electron microscopy with energy dispersive spectroscopy. The size distribution of Fe3O4 particles was varied from ∼150 nm to 980 nm. The proposed SA was fabricated with combination of a side-polished fiber and the Fe3O4 particle by using evanescent field interaction between the side-polished fiber and the Fe3O4 particle. The insertion loss and polarization dependent loss of the proposed SA were measured as ∼4 dB and 0.3 dB, respectively at a wavelength of 1930 nm. The stable passively Q-switched pulses were readily generated from thulium-doped fiber laser incorporating the proposed SA at 1943 nm. The pulse width was changed from ∼8.1 μs to ∼880 ns while the repetition rate was changed from ∼61 kHz to ∼87 kHz. The tuning capability of both pulse width and repetition rate was also shown according to pump power.

All fibre Q-switched Thulium-doped fibre laser incorporating Thulium–Holmium co-doped fibre as a saturable absorber

A novel all fibre Q-switched Thulium-doped fibre laser (TDFL) is reported which includes a short length of a Thulium–Holmiumco-doped fibre (THDF) as a saturable absorber. A high repetition rate (27.26 kHz) coupled with a low pulse width (19.06μs) is obtained for single wavelength Q-switched pulse operation at an output wavelength of 1911.5 nm using a pump power of 200 mW. Increasing the pump power from 200 mW to 700 mW results in the repetition rate increasing from 27.26 kHz to 99.67 kHz and the pulse width decreasing from 19.06μs to 920 ns. The centre wavelength of the single Q-switched pulse was also red shifted from 1911.5 nm to 1932.5 nm with increasing the pump power. A 45 m length single-mode fibre (SMF-28) provided dispersion compensation, and effectively an SMF-THDF-SMF structure is inserted in the cavity which operates in a similar manner to an SMF-MMF-SMF structure, providing a strong multimode interference effect which supports dual-wavelength operation. A stable dual-wavelength Q-switched pulse was achieved at a threshold pump power of 213 mW. The dual-wavelength Q-switched pulse operation was generated at 1911.5 nm and 1914.5 nm with a repetition rate of 8.45 kHz and pulse width of 20.02μs. The dual-wavelength spacing of this pulse operation was 3 nm, which was in good agreement with calculations based on the multimode interference effect induced by the THDF. The repetition rate increased from 8.45 kHz to 70.65 kHz and the pulse width decreased from 20.02μs to 870 ns with increasing pump power. At the maximum pump power of 700 mW, the maximum output power was measured as 27.4 mW. The experimental results confirm that the THDF can be utilized as a SA to generate a stable and tunable single-wavelength Q-switched pulse output as well as dual-wavelength Q-switched pulse in the 2.0μm wavelength region.

Q-switched and mode-locked thulium doped fiber lasers with nickel oxide film saturable absorber

A passively Q-switched and mode-locked fiber laser based on thulium-doped fiber laser (TDFL) cavity was demonstrated utilizing nickel oxide (NiO) nanoparticles as a saturable absorber (SA). The NiO synthesis was carried out by using a facile sonochemical method and the prepared NiO thin film was sandwiched between two optical fiber ferrule connectors in the TDFL ring cavity. By controlling the loss and gain in the cavity, stable Q-switching operation was obtained. The repetition rate and pulse width were tunable from 6.71 kHz to 19.58 kHz and from 9.16 μs to 4.24 μs respectively, at different pump powers, ranging from 528 mW to 711 mW. The Q-switched TDFL was centered at 1900.52 nm and had maximum pulse energy and slope efficiency of 0.31 μJ and 2.58%, respectively. On the other hand, self-starting mode-locked TDFL was achieved by employing 10 m scandium-doped fiber into the ring cavity and remained stable within a pump power range of 821–967 mW. The TDFL mode-locked had a central wavelength of 1928.81 nm, at a threshold pump power of 821 mW. The repetition rate and pulse width were 8.10 MHz and 61.27 ns, respectively, while the slope efficiency was measured to be 2.20 %.

Pure gold saturable absorber for generating Q-switching pulses at 2 µm in Thulium-doped fiber laser cavity

Abstract We experimentally demonstrate Q-switched Thulium-doped fiber laser operating at 1949.19 nm using pure gold saturable absorber (Au-SA) as a Q-switcher. The Au-SA was fabricated by depositing gold particles molecules using electron beam evaporation on the surface of a polyvinyl alcohol (PVA) film. Subsequently, stable Q-switched pulses were obtained within the 1552 nm pump power range from 343.1 to 467.3 mW, with repetition rate tuned from 11.7 kHz to 21.95 kHz. At 467.3 mW pump power, the TDFL produced pulses train with the pulse width of 2.6 μs and the maximum pulse energy of 89.8 nJ. These results propose that pure gold could be a promising saturable absorber for pulse generation in 2 µm wavelength region.

Q-Switched Thulium-Doped Fiber Laser with Pure Titanium-Film-Based Saturable Absorber

ABSTRACTWe demonstrate the generation of Q-switching pulse train in thulium-doped fiber laser (TDFL) cavity by employing titanium-based saturable absorber (Ti-SA). The Ti-SA was fabricated by depositing titanium particles molecules using electron beam evaporation on the surface of a polyvinyl alcohol (PVA) film. Subsequently, stable Q-switched pulses were obtained within the 1,552 nm pump power range from 272.1 to 467 mW, with repetition rate tuned from 21.8 to 39.1 kHz. At the maximum pump power, the TDFL showed that the pulse duration of 2.22 μs and the maximum pulse energy of 124 nJ.

Nickel Oxide as a Q-switcher for Short Pulsed Thulium Doped Fiber Laser Generation

A passive Q-switched Thulium doped fiber laser (TDFL) is demonstrated using nickel oxide (NiO) nanoparticles as saturable absorber (SA). The NiO were synthesized by a facile sonochemical method to fabricated SA and then a piece of 1 mm x 1 mm is sandwiching between two fiber ferrule connectors in the TDFL ring cavity. By controlling the loss and gain in the cavity, stable Q-switching operation were generated. The repetition rate was tunable from 11.79 kHz to 22.16 kHz at the different pump power from 528 mW to 711 mW. The obtained maximum pulsed width and pulse energy of 3.13 µs and 0.58 nJ respectively, with the slope efficiency of 3.74 % at the same variation of pump power.