Thulium-doped Fluoride Fiber Laser Research Articles

Michelson Interferometer-based Tunable Multiwavelength Thulium-doped Fluoride Fiber Laser in S-band for 5G networks

Abstract In this work, a multiwavelength thulium-doped fluoride fiber laser (TDFFL) has been reported for S-band region using the Michelson interferometer as an optical filter. Michelson interferometer was utilized as a comb-like filter, whereas dispersion-compensated fiber (DCF) of 10 km length was used to increase the number of lasing lines and reduce mode competition. Approximately, 61 lasing lines were achieved with a signal-to-noise ratio (SNR) of 40 dB in the wavelength region from 1501.36 to 1505.52 nm within 10 dB of maximum power. The stability of multiwavelength fiber laser was also recorded for the time duration of two hours, and it was found that all lasing lines were stable and equally spaced at the free spectral range (FSR) of 0.07 nm. The variation in optical power was less than 0.5 dB, however the wavelength shift was about 0.01 nm. Tunability of multiwavelength laser has also been observed up to the broader transmission span of 57 nm by incorporating the tunable band pass filter (TBPF). Moreover, FSR was observed to be tunable within the range of 0.02 to 0.14 nm by using the optical delay line (ODL) with a Michelson interferometer. Additionally, the proposed laser can generate frequency signals from 2.65 GHz to 18.54 GHz according to the obtained range of FSR.

Generation of mode-locked thulium doped fluoride fiber laser using graphene-zinc oxide (G-ZnO) coated dual arc-shaped fiber

In this work, mode-locked laser generation at the S-band region was achieved using a graphene-zinc oxide (G-ZnO) coated dual arc-shaped fiber as a saturable absorber (SA) within a thulium-doped fluoride fiber (TDFF) ring cavity. Two-step polishing was implemented to fabricate a dual arc-shaped fiber, and a G-ZnO solution was then deposited on the dual arc region via the drop-casting method to form the SA. Mode-locked pulses were generated by incorporating the G-ZnO-based SA into the TDFF ring cavity, with the pulses having a central wavelength, 3 dB bandwidth and pulse duration of 1503.4 nm, 0.68 nm and 3.52 ps, respectively. At the maximum pump power of 202 mW, an average output power of 2.47 mW was obtained with a maximum pulse energy of 6.16 nJ and a peak power of 1.75 kW. At this pump power, the generated pulses have a frequency of 401.6 kHz with a signal-to-noise ratio (SNR) of 54 dB. The mode-locking threshold was at a pump power of 118 mW. The results obtained in this work indicate the potential of a new class of 2D composite materials which can be used as nonlinear optical devices.

Broadly tunable dual-wavelength thulium-doped fluoride fiber laser covering S-band region from 1472 to 1506 nm

Dual-wavelength fiber lasers have gained the interest of researchers in practical applications such as fiber-optic sensors and optical telecommunication. This work demonstrated a broadly tunable dual-wavelength thulium-doped fluoride fiber laser (TDFFL) at the S-band region. Two tunable-bandpass filters (TBPFs) were incorporated in the TDFFL cavity to achieve dual-wavelength fiber laser (DWFL) operation. Two identical peaks with a balanced signal-to-noise ratio (SNR) were acquired by tuning TBPFs and an attenuator within the cavity. The DWFL covers a significant portion of S-band TDFFL gain from 1472.9 to 1506.5 nm with a wide tunability in wavelength spacing from 0.95 to 33.6 nm. The narrowest possible DWFL was achieved with the spacing of 0.95 nm at the operating wavelengths of 1489.2 and 1490.15 nm, with a frequency bandwidth of 128 GHz. The broadest spacing of 33.6 nm was achieved at operating wavelengths of 1472.9 and 1506.5 nm, with a frequency bandwidth of 4.79 THz.

Tunable S-band mode-locked thulium-doped fluoride fiber laser using nickel phosphorus trisulfide (NiPS3) saturable absorber

Nickel Phosphate Trisulfide (NiPS3) prepared using the LPE technique was used as a saturable absorber (SA) in a thulium-doped fluoride fiber laser for the generation of mode-locked pulses. The polishing method was used to prepare the arc-shaped fiber before the NiPS3 solution was drop-casted onto it to form the SA device. The SA exhibited nonlinear optical properties, with modulation depth and saturation intensity of 29.44 % and 0.547 kW/cm2 respectively. Insertion of the SA in the TDFF cavity produced mode-locked pulses with central wavelength and 3-dB bandwidth of 1505 nm and 0.68 nm respectively, with a pulse width of 3.56 ps. The mode-locking operation also has a repetition rate of 582 kHz and an SNR of about 58 dB at a pump power of 280 mW. The maximum average output power measured was 2.4 mW at maximum pump power, with maximum pulse energy and peak power at 4.12 nJ and 1.16 kW respectively. Due to the optical interaction between NiPS3 and the evanescent wave in this arrangement, a larger damage threshold can be achieved, enabling the laser performance to operate at higher output power. Tunability was achieved by simultaneous adjustment of extinction and wavelength knob on the tunable Mach-Zehnder Filter (TMZF). The shape of spectra remained unchanged and continued exhibiting Kelly’s sidebands throughout the tunability range of about 2 nm. These results provide the first demonstration of tunable mode-locked pulses in the S-band region.

S-band Mode-locked Thulium-doped fluoride fiber laser using FePS3 as saturable absorber

• erformance of FePS 3 as a saturable absorber was investigated. • Generation of mode-locked in Thulium-doped fluoride fiber laser at 1504.8 nm. • FePS 3 exhibits a modulation depth of 14.59 % at 1550 nm. • The pulse width generated was 3.90 ps with a peak power of 1.93 kW. A demonstration of iron phosphate trisulfide (FePS 3 ) as a saturable absorber (SA) for mode-locked pulse generation in a thulium-doped fluoride fiber (TDFF) laser was demonstrated in this work. An arc-shaped fiber was prepared using the polishing method, and the FePS 3 solution was then deposited via the drop-casting method. The SA shows a nonlinear optical absorption with a modulation depth of 14.59 % and a saturation intensity of 0.006 MW/cm 2 . Integration of the SA into the TDFF ring cavity resulted in mode-locked pulses with a central wavelength of 1504.8 nm, a 3 dB bandwidth of 0.704 nm, and a 3.90 ps pulse width. At the pump power of 280 mW, the generated pulses demonstrated a high signal-to-noise ratio (SNR) of 45 dB at a fundamental frequency of 400.6 kHz. At this maximum pump power, the maximum average output power produced was 3.01 mW, with maximum pulse energy and peak power of 7.51 nJ and 1.93 kW, respectively. A higher damage threshold can be achieved in this configuration due to the optical interaction between FePS 3 and the evanescent wave, thus providing a better laser performance. These findings can shed light on the applicability of a novel class of 2D material as a reliable SA for photonics applications.

Ti2C MXene for multi-wavelength enhancement in S-band Q-switched thulium doped fluoride fiber laser

A titanium carbide (Ti2C)-based saturable absorber was demonstrated in a compact thulium-doped fluoride fiber laser (TDFFL) configured to generate stable microsecond pulses in single- and multiwavelength operations. An in-line Mach-Zehnder interferometer (MZI) based on a two-mode fiber was incorporated into the laser cavity to generate a birefringent effect that has a fixed free spectral range (FSR) and an extinction ratio (ER) of 0.83 nm and 6.17 dB, respectively. At the maximum pump power of 250 mW, the TDFFL generated single-wavelength Q-switched pulses with a maximum frequency of 35.20 kHz, a pulse width of 3.30 µs, and pulse energy of 2.55 nJ, respectively. In the multiwavelength Q-switching operation, the laser-generated pulses have a frequency, pulse width, and pulse energy of 27.02 kHz, 3.17 µs, and 1.79 nJ, respectively. The proposed single- and multiwavelength Q-switched fiber lasers were stable and compact, making them suitable for industrial applications.

MoTe2-PVA as saturable absorber for passively Q-switched thulium-doped fluoride and erbium-doped fiber laser

Passively Q-switched fiber lasers in the S- and C-band region were demonstrated using molybdenum ditelluride (MoTe2) as the saturable absorber (SA). The MoTe2 was prepared using liquid phase exfoliation method, which was then embedded in the polyvinyl alcohol (PVA) polymer to form a MoTe2 thin film SA. By incorporating the MoTe2 SA in the thulium-doped fluoride fiber laser (TDFFL) and erbium-doped fiber laser (EDFL) cavities, stable Q-switched pulses were observed in the S-band and C-band region with microsecond pulse durations and tens of kilohertz repetition rate. The modulation depth and the saturation intensity of the MoTe2 SA were ∼ 38 % and ∼ 0.314 MWcm−2, respectively. The Q-switched operation can be tuned by employing a tunable bandpass filter (TBPF), covering the S-band and C-band region from 1453 nm to 1572 nm. Thus, the finding validates the feasibility of MoTe2 as a promising SA for a broadband optical applications.

Multi- and dual-wavelength Thulium-doped fluoride fiber laser assisted by four-wave mixing in S-band region

In this work, multi-wavelength lasing in the S-band region using a Sagnac loop filter in a thulium-doped fluoride fiber laser (TDFFL) was demonstrated for the first time. The Sagnac loop served as a comb-like wavelength filter, while a 10-km long dispersion compensating fiber (DCF) was utilized to induce the four-wave mixing (FWM) effect in the cavity. The FWM effect was used to suppress mode competition in the TDFFL as well as to enhance the number of lasing lines. At its optimum polarization state, 17 stable lasing lines at peak powers of less than 10 dB from the highest peak power were observed, with these lasing lines having a uniform wavelength spacing of 0.23 nm. The multi-wavelength operation exhibited minimal wavelength drifts and power fluctuations of less than 0.01 nm and 1.2 dB respectively. A tunable dual-wavelength laser output was also demonstrated, with a constant wavelength spacing throughout the tuning range.

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.

S/S+-band tunable dual-wavelength thulium doped fluoride fiber laser

A simple S/S+-band dual-wavelength thulium doped fluoride fiber laser (DWFL) with tunable channel spacing is demonstrated. The system utilizes a 24 channel arrayed waveguide grating to control the spacing between the two lasing wavelengths. The widest spacing that can obtained between two lasing wavelengths is 17.49 nm, while the narrowest is 0.75 nm. The cavity loss in the DWFL is controlled using two variable optical attenuators to equalize the power of the two lasing wavelengths. The DWFL has a maximum signal to noise ratio (SNR) of approximately 49.60 dB and good stability over long periods of operation, with only minor SNR fluctuations of less than 5.00 dB observed. The DWFL’s output also has side-mode suppression ratio (SMSR) of between 0.12 dB and 1.56 dB, indicating that there is little to no suppression of one wavelength over another, as well as a balanced power output that is highly desirable when used as reference or signal sources.

Mechanically exfoliated In2Se3 as a saturable absorber for mode-locking a thulium-doped fluoride fiber laser operating in S-band.

The rise of 2D materials since the discovery of graphene has been exponential. Their mechanical, electrical and optical properties are exceptional, similar to their 3D counterparts. In this paper, an α-In2Se3 crystal is mechanically exfoliated and transferred directly onto a fiber ferrule to serve as a saturable absorber (SA). A thulium-doped fluoride fiber is used as a gain medium to generate mode-locked pulses together with the In2Se3-based SA. The SA has a modulation depth of 14.6% and a saturation intensity of 0.4 kW/cm2. The passively generated mode-locked pulses have a repetition rate of 6.93MHz and a pulse width of 5.79ps. The mode-locked pulses also have a signal-to-noise ratio of 65.4dB and a time-bandwidth product of 0.36. The pulse energy and peak power are 0.179nJ and 27.2W, respectively.

Switchable 10, 20, and 30 GHz region photonics-based microwave generation using thulium-doped fluoride fiber laser

In this work, switchable 10, 20, and 30 GHz region photonics-based microwave generation in a fiber laser cavity is proposed and demonstrated. The microwave generation is based on the beating of a dual-wavelength thuliumdoped fluoride fiber laser. With the aid of a micro-air gap in an adapter, single, double, and triple Brillouin spacing can be generated in a single fiber laser cavity without re-routing the cavity. The wavelength spacing of the dual wavelengths that are induced by the single, double, and triple Brillouin spacing are 0.084, 0.166, and 0.254 nm, respectively, at a center wavelength of 1490 nm. In addition, a numerical calculation is performed using MATLAB to prove the generation of microwave signals at 11.34, 22.44, and 34.3 GHz. With the advantage of switchability among the 10, 20, and 30 GHz regions, the proposed photonics-based microwave generation is promising for the advancement of 5G technologies.

Stable dual-wavelength thulium-doped fluoride fiber laser at S-band region with WS2 as birefringence element

In this work, the generation of dual-wavelength fiber laser at S-band region has been demonstrated with thulium-doped fluoride fiber as gain medium and WS2 thin film as a stabilizer. The generated dual-wavelength fiber laser is achieved in the simple ring cavity with WS2 acted as a birefringence element to suppress mode-hopping and mode competition. A stable dual wavelength fiber laser of spacing approximately 1.17nm is achieved at the pump power of 76.44mW. An OSNR of 31.9dB and maximum peak power difference of 0.5dB are attained at oscillating wavelengths of 1500.08nm and 1501.25nm. The proposed DWFL exhibits maximum wavelength drifting as low as 0.06nm and 0.05nm at 1500.8 08nm and 15001.25nm respectively. This indicates the WS2 is highly potential to be used in optoelectronics technology.

Passive mode-locking at S-band by single-mode thulium-doped fluoride fiber using a thin film PtAg/N-G saturable absorber

We report, for the first time to our knowledge, the usage of platinum silver bimetallic alloy forms on the synthesized N-Gns (PtAg/N-G) as a saturable absorber (SA) for the mode-locking of a thulium-doped fluoride fiber laser. The experimental results have demonstrated that PtAg/N-G exhibits saturable absorption in the 1.5-μm wavelength range and supports ultrashort pulse generation. Mode-locking occurred when the pump power rose to 340 mW, and the output spectrum had a peak at 1506 nm with the 3-dB bandwidth of ∼0.76 nm. The mode-locked pulse train against a cavity roundtrip time of 146 ns that corresponds to a pulse repetition rate around 6.85 MHz. The autocorrelation trace 7.43 ps with a full width at half maximum pulse width of 4.8 ps, and experimental data were closely fit with a sech2 pulse shape and it indicates the generation of soliton pulse. The output power of this fiber laser is 3.24 mW; hence, the pulse energy is 0.31 nJ and peak power is about 56.9 mW as well. We demonstrate graphene-polymer nanocomposites could be an appropriate SA for high-power fiber laser mode-locking.

23 W single transverse mode thulium-doped ZBLAN fiber laser at 1480 nm

A 2.3 W single transverse mode thulium-doped fluoride fiber laser based on fiber Bragg gratings is presented. The laser has a conversion efficiency of 65% to be compared to the quantum limit of 72%. The performances of the laser are compared for two pump wavelengths of 1040 and 1064 nm and are analyzed based on a rate equation analysis.

A 1.6-μm pumped 1.9-μm thulium-doped fluoride fiber laser and amplifier of very high efficiency

Results are presented for color center, and semiconductor, laser pumping of the 1.82 /spl mu/m transition in a thulium-doped fluoride fiber. As an amplifier small signal gain efficiencies of 8.1 dB/mN were attained with a maximum gain of 36.5 dB being achieved for around 17-18 mW of launched pump power. As a laser a maximum slope efficiency of 84% and a minimum threshold for oscillation of 330 /spl mu/W was also demonstrated for this system. Furthermore by suppressing all reflections down to <36 dB superfluorescent or ASE output was observed. In achieving efficient operation with a diode laser pump source this system shows strong commercial potential.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>