Tunable passively Q-switched erbium-doped fiber laser based on Ti3C2Tx MXene as saturable absorber

The passive generation of Q-switched pulses in an erbium-doped fiber (EDF) laser using a Ti3C2Tx MXene based saturable absorber (SA) was demonstrated. The SA was formed using Ti3AlC2 MAX phase as a precursor for Ti3C2Tx MXene which was obtained by etching Ti3AlC2 using a mixture of lithium fluoride and hydrochloric acid. The generated pulse output was obtained at a central wavelength of 1563 nm with a signal to noise ratio (SNR) of 51.1 dB at a pump power of 244.5 mW. Varying the pump power from 130.1 mW to 244.5 mW resulted in corresponding changes in the repetition rates and the pulse durations from 29.76 kHz to 48.74 kHz and 2.74 µs to 1.18 µs respectively. A pulse energy of 82.06 nJ was also obtained at the maximum pump power. Stable Q-switching could be observed up to 44 nm tuning range starting from 1532 nm to 1576 nm. The generated outputs indicated that the Ti3C2Tx based SA can generate high quality and stable Q-switched pulses in the EDF laser cavity, and has high potential for use in various optical telecommunications applications

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

Near-Infrared Soliton Mode-Locked Thulium Doped Fibre Laser Using WS2-ZnO Composite Material as Saturable Absorber

The generation of a highly stable passive mode locking laser is realized in a thulium doped fibre laser using a WS2-ZnO composite as a saturable absorber. Soliton mode locking pulses are generated with a central wavelength of 1936 nm and full-width half maximum (FWHM) of 3.06 nm. The first order Kelly's side band is located at around 5.65 nm from the central wavelength which gives the calculated pulse width value of 1.26 ps. This value corresponds well with the measured pulse width of 1.27 ps using the autocorrelator. The output power of the laser is around 0.44 mW with the peak power of 29.7 W and repetition rate of 9.96 MHz. This laser set-up is highly robust and realizes highly stable laser pulses in the mid-IR wavelength range for a multitude of applications. © 2009-2012 IEEE

Frequency switching multiwavelength Brillouin Raman fibre laser based on feedback power adjustment technique

A simple switchable multiwavelength Brillouin–Raman fibre laser (BRFL) was demonstrated. The laser was arranged in a half-open cavity configuration including a physical mirror device with an adjustable reflectivity at one side of the laser cavity. The impact of the feedback power adjustment on frequency switching was carried out by comparing the peak power difference between odd- and even-order Stokes lines. Up to 468 flat-amplitude lines with a 10 GHz frequency spacing and average optical signal to noise ratio (OSNR) of 33 dB were observed with mirror reflectivity values of ∼15% up to 60% at a 1534nm Brillouin pump power of 7 dBm and 0.9W Raman pump power of 0.9 W. Under the same pumping conditions, setting the mirror reflectivity at its OFF state (where reflectivity is nearly 0%) allows for up to 242 lines with 20 GHz spacing to be realized, with ONSR values of ∼35 dB

Narrow bandwidth optimization using a polymer microring resonator in a thulium–holmium fiber laser cavity

A thulium–holmium fiber (THDF) laser cavity has been demonstrated with a SU-8 polymer microring resonator (PMRR) in the cavity. The PMRR has a 500μm radius and fabricated using the lithography method, with the SU-8 polymer acting as a host material. The butt coupling method was used for the horizontal coupling of light from a ultra-high numerical aperture (UHNA) fiber to the polymer waveguide. Lasing in the cavity without the PMRR is obtained at a center wavelength of 1.910μm, 1.869μm when the PMMR is inserted into the cavity. A maximum power of -5 dBm was extracted from the laser oscillator, and the laser linewidth was measured to be ∼26.6 kHz by radio-frequency spectrum analyzer analysis. The PMRR was able to generate an output with a free spectral range of 0.79μm at a frequency of 59.25 GHz. © 2020 Elsevier B.V

155 nm-wideband and tunable q-switched fiber laser using an MXene Ti3C2TXcoated microfiber based saturable absorber

MXenes have recently gained significant research interest due to its graphene-like structure that allows for a multitude of applications such as electronics, batteries and optics to be realized. In this work, stable Q-switched pulses are passively obtained from a thulium-doped fiber laser using an MXene Ti3C2TX coated microfiber as a saturable absorber (SA). The generated pulses have center lasing wavelength 1976 nm with a pulse repetition rate and pulse width ranging between 16 kHz to 59 kHz and 13 µs to 2.4 µs respectively. The generated pulses can be tuned over a wavelength range of 155 nm from 1895 nm to 2050 nm. The MXene based SA has signficant potential for generating pulsed laser outputs that will find uses in the areas of sensing, medicine and spectroscopy around the 'eye safe' 2 µm region