Maximum Average Output Power Research Articles

Passively Q-switched 3 μm erbium-doped solid state lasers using gold nanorods as broadband saturable absorber

The gold nanorods with an average aspect ratio of 30 were grown by the three-step seed-mediated wet chemistry growth method, resulting in a broadband spectral response in 3 μm region. Passive Q-switching operation of LD pumped 2.8 μm Er:YSGG and 2.9 μm Er:YAP laser was successfully realized by using the gold nanorods as saturable absorber. With regard to the Er:YSGG laser, the passively Q-switched pulses at 2796 nm with a maximum average output power of 234 mW, a minimum pulse width of 270.8 ns and a pulse repetition rate of 280.4 kHz were achieved. For the combination of Er:YAP and gold nanorods saturable absorber, a maximum average output power of 415 mW was obtained at 2919 nm. The minimum pulse width and pulse repetition rate were 313.2 ns and 196.8 kHz, respectively. The experimental results show that large-aspect-ratio gold nanorods can be used as a promising broadband saturable absorber to generate 3 μm short pulses.

Research on optimization model of wave energy transmission device

As a pollution-free renewable resource with great energy conversion potential, wave energy is attracting more and more attention from the society. There is an existing wave energy power generation energy output device. Considering the motion stability of the device in the ocean and the energy conversion problem, this paper will introduce the principle and establish a mathematical model around two main problems. Under the condition that only the heave motion is considered, this paper establishes the motion period model of the float and the vibrator based on the linear wave principle, analyzes the force on the float and the vibrator respectively, mainly based on the second-order constant coefficient differential equation of time t established by Newton's second law, and gives the displacement and velocity of the float and the vibrator in heave motion at,,, and under different damping coefficient conditions according to the condition solution. When the damping coefficient is constant, the damping coefficient at the maximum average output power is obtained. In this paper, based on the differential equation obtained from the motion state of the float and vibrator, an optimization model with the average output power as the objective function is established. The damping coefficient is taken as the decision variable, and the decision variable is optimized through genetic algorithm. When the damping coefficient is constant, the damping coefficient is, and the maximum power is. When there is a power exponential relationship between the damping coefficient and the relative velocity, it is found that when the damping coefficient is, the maximum power is.

High-power femtosecond laser generation from an all-fiber linearly polarized chirped pulse amplifier

Abstract An all-fiber high-power linearly polarized chirped pulse amplification (CPA) system is experimentally demonstrated. Through stretching the pulse duration to a full width of approximately 2 ns with two cascaded chirped fiber Bragg gratings (CFBGs), a maximum average output power of 612 W is achieved from a high-gain Yb-doped fiber that has a core diameter of 20 μm with a slope efficiency of approximately 68% at the repetition rate of 80 MHz. At the maximum output power, the polarization degree is 92.5% and the M2 factor of the output beam quality is approximately 1.29; the slight performance degradations are attributed to the thermal effects in the main amplifier. By optimizing the B-integral of the amplifier and finely adjusting the higher-order dispersion of one of the CFBGs, the pulse width is compressed to 863 fs at the highest power with a compression efficiency of 72%, corresponding to a maximum compressed average power of 440.6 W, single pulse energy of 5.5 μJ and peak power of about 4.67 MW. To the best of our knowledge, this is the highest average power of a femtosecond laser directly generated from an all-fiber linearly polarized CPA system.

Zirconium pentatelluride as saturable absorber for 2 μm ultrafast solid-state laser

2 μm ultrafast pulses as short as 4.8 ps are obtained with a maximum average output power of 767 mW. This is the highest average output power achieved so far, for a passively mode-locked laser at 2 μm using a two-dimensional saturable absorber.

Maximum output power design of wave energy based on particle swarm optimization algorithm

As human exploration of the ocean continues to deepen, wave energy as an important marine resource has entered people's view. In order to explore the basic relationship between the relevant variables in the wave energy conversion device, this paper starts from the force analysis of the system and establishes the mathematical model of the kinematic equations of float and oscillator to solve the corresponding problems. Not only the vertical swing of the float and oscillator, but also their longitudinal rocking, i.e., both translational and rotational, are considered. By numerical integration, the average output power is calculated for a certain time period. With the objective of maximizing the average output power, the particle swarm optimization algorithm is applied to obtain the maximum average output power with relatively smooth power.

Generation of soliton molecules in mode-locked erbium-doped fiber laser by InSb saturable absorber

Conventional solitons (CSs), and soliton molecules (SMs) consisting of two and three CSs in a passively mode-locked erbium-doped fiber (EDF) laser based on InSb saturable absorber (SA) are demonstrated. The InSb SA coated on tapered single-mode fibers by magnetron-sputtering deposition (MSD) method possesses linear transmittance of 93.39 %, modulation depth of 2.8 %, and saturation peak power of 3.18 W, respectively. In the CSs operation, the oscillating wavelength is centered at 1570.38 nm with pulse duration of 540.74 fs, pulse repetition rate of 28.38 MHz and maximum average output power of 5.51 mW. In the SMs operation, tight bound SMs consisting of two solitons, and loose bound SMs consisting of two and three solitons are achieved and analyzed in detail. It’s concluded that the initial temporal separation between neighboring solitons (TSNS) is totally decided by the cavity parameters. In the formed SMs, the ratio of TSNS to soliton pulse duration can even be as large as several hundreds of times. The adoption of real SA is more advantageous than effective one to realize the modulation of initial TSNS and hence facilitates the generation of different types of SMs. The work, for the first time, verifies the feasibility and stability of SMs generation by InSb-based SA, which not only enriches the insight of InSb two-dimensional (2D) materials, but also achieves an in-depth understanding of SMs.

Watt-level widely tunable narrow-linewidth pulsed mid-infrared MgO:PPLN optical parametric oscillator with a F-P etalon

A watt-level, widely tunable, narrow-linewidth pulsed MgO:PPLN optical parametric oscillator using a single etalon is demonstrated above 3 µm for the first time, to the best of our knowledge. The pump source is an acousto-optical Q-switched Nd:YAG laser at 1064 nm with a pulse duration of 220 ns and a repetition rate of 10 kHz. Employing a V-shaped cavity configuration, the emission wavelengths of the OPO can be tuned in the range of 3.64 µm − 3.8 µm and 1478 nm − 1503 nm by varying the temperatures of the MgO:PPLN crystal between 37℃ and 146℃. Under a pump power of 22.5 W, a maximum average output power of 2.12 W at 3.74 µm is achieved with a theoretical linewidth of 0.3 nm at the temperature of 79.6℃, corresponding to a pulse width of 145 ns and a peak power of 1.46 KW. At the same time, a maximum signal power of 2.86 W at 1486.66 nm is obtained with a linewidth of 0.03 nm, corresponding to a pulse width of 190 ns and a peak power of 1.51 KW.

Passively mode-locked fiber laser based on GeTe as a saturable absorber.

In this work, we fabricate a saturable absorber based on GeTe with saturation intensity and modulation depth of 12.6M W/c m 2 and 7%, respectively. We obtain stable conventional soliton and stretched soliton mode-locking operation. For the conventional soliton state, the average output power increased from 0.93 to 8.70mW with the increase of pump power, and the fundamental repetition rate was 7.8351MHz. Its central wavelength and 3dB bandwidth were 1564.72 and 4.78nm, respectively. For the stretched soliton state, when the pump power was increased from 87.4 to 420.3mW, the average output power increased from 2.05 to 10.46mW. When the maximum average output power reached 10.46mW, the maximum average single-pulse energy was 0.86nJ. The experimental results show that GeTe nanosheets will have broad application potential in the field of ultrafast photonics.

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.

Q-switched pulse operation in erbium-doped fiber laser subject to CdS nanoparticles-based saturable absorber deposit directly on the fiber ferrule

In this work, we demonstrate the performance of a Q-switched erbium-doped fiber laser (EDFL) using a cadmium-sulfide (CdS) nanoparticle-based saturable absorber (SA). The CdS nanoparticles were deposited on the fiber ferrule using the adhesion effect of the index matching gel. By incorporating the CdS nanoparticles on the fiber ferrule, a self-starting and stable Q-switched operation started under 11.2 mW pump power. As the pump power of EDFL based on the CdS-SA was increased from 11.2 to 297 mW, the emission wavelength varied from 1564.16 nm to 1568.83 nm, the pulse repetition rates, and pulse duration ranged from 20 to 90.25 kHz and 15.2 to 3.5 μs, respectively. The maximum average output power, pulse energy, and peak power were measured as 2.55 mW, 28.26 nJ, and 8.07 mW, respectively at a maximum available pump power of 297 mW. Furthermore, the stability of EDFL based on CdS nanoparticles based SA was further investigated. This study suggests that CdS nanoparticles-based SA offers an easy fabrication and integration of SA inside the laser cavity to generate a pulse operation in fiber lasers.

Dissipative soliton resonance and noise-like pulse in a self-pulsing fiber laser

In this paper, a self-pulsing Er-doped fiber laser operating in the dissipative soliton resonance (DSR) regime is firstly reported. By adjusting the pumping power and intracavity pulse polarization, the generated mode-locking pulse could evolve between soliton pulse, dissipative soliton resonance pulse and noise-like pulse (NLP). In the dissipative soliton resonance mode-locking regime, the generated rectangular-shaped pulses centered at 1570.5 nm with a maximum average output power of 20.6 mW and a pulse duration of 8.9 ns. Meanwhile, in the NLP regime, the maximum average output power is 49.9 mW, corresponding to a pulse energy of 2.5 nJ. The self-pulsing evolving dynamics can be analyzed using weak NPR effect by simultaneously considering the polarization dependent loss from the polarization controller and the reabsorption loss of the un-pumped gain fiber.

Generation of 1216 nm and 608 nm laser emission using cascaded Raman shifts in Nd:YVO4

We report the design and operation of two self-Raman lasers optimized for emission at 1216 nm and 608 nm, utilizing a combination of Raman shifts at 890 and 259 cm−1 in c-cut Nd:YVO4 crystal. Key to the efficient operation of these lasers was the use of a double-end diffusion-bonded Nd:YVO4 composite crystal. This enabled the generation of a maximum average output power of 2.6 W at 1216 nm (with a diode-Stokes conversion efficiency of 14.7%) from the Stokes-optimized cavity. With the incorporation of a non-critically phase matched LBO crystal and a slight cavity re-design, the Stokes field at 1216 nm was frequency doubled to the orange part of the visible spectrum (608 nm), where a maximum average output power of 1.71 W was achieved with a diode-orange conversion efficiency of 9.7%.

Quasi-linear polarized high-efficient diode-end-pumped actively Q-switched Nd:YAG/Nd:YVO4 laser

We propose and experimentally demonstrate a high-efficient and high-polarization-ratio acousto-optic (AO) Q-switched dual-crystal hybrid gain laser. Combing the advantages of Nd:YAG and Nd:YVO4 crystals, it exhibits excellent power performance across a broad pulse repetition frequencies (PRFs) range while maintaining satisfactory polarization characteristics without the aid of additional polarized optical components. Under 42.00-W incident pump power, the maximum average output power rises from 12.10 W to 19.64 W as the PRFs variates from 10 kHz to 200 kHz. The corresponding optical-to-optical efficiency increases from 28.81% to 46.76%. The pulse durations at maximum average output powers are 28.2 ns, 17.2 ns and 24.2 ns, respectively, when the laser operates at the PRFs of 10 kHz, 110 kHz and 200 kHz. The laser polarization ratios at maximum average output power are accordingly ∼7.6, ∼10, and ∼11.

Power and energy scaling of an acousto-optically Q switched Raman deep-red laser.

An efficient high-power nanosecond pulsed deep-red laser at 745 nm is produced by intracavity frequency-doubling an acousto-optically Q switched Nd:YLF/KGW Raman laser using a lithium triborate (LBO) crystal. The critically phase-matched type-I LBO crystal with an optimized length of 25 mm is adopted to enable efficient second-harmonic generation and to suppress unwanted cascaded Stokes fields. Under a repetition rate of 4 kHz, the maximum average output power of 4.1 W is obtained with the launched pump power of 50 W, resulting in an overall optical power conversion efficiency of 8.2%. The average beam quality factor is determined to be M2 = 1.46. The pulse energy is scaled up to 3.3 mJ at the repetition rate of 1 kHz, corresponding to a pulse width of 4.2 ns and a peak power of up to 0.8 MW. Moreover, we theoretically investigate the dependence of the conversion efficiency on the walk-off angle as well as the fundamental and first-Stokes losses, which will guide further optimization of experimental devices.

Tm:GdScO3: A promising crystal for continuous-wave and passively Q-switched laser at 2 μm

Thulium-doped orthorhombic gadolinium scandate, Tm:GdScO3, is promising for efficient linear polarized continuous-wave (CW) and passively Q-switched lasers near 2 μm. The polarized characteristics of different lasing propagation were verified by both the emission spectra and the laser experiments. Under diode pumping at 793 nm, linear polarized lasers of electric field direction (E) parallel to a- and b-axis are obtained with the maximum output power of 1.87 W and 2.00 W and with the slope efficiency of 27.5 % and 28.4 %, respectively. Stable passive Q-switching of the Tm:GdScO3 laser using SnS2 is demonstrated for the first time, to the best of our knowledge. With different output couplers, the 1.99 μJ/460 ns pulses at ∼2 μm were achieved with a maximum average output power of 0.175 W and a peak power of 4.32 W. Tm:GdScO3 is promising to be the candidate for 2 μm ultrashort lasers.

Epitaxial Nd3+:YAG/YAG waveguide laser

Solid state lasers with a planar Nd,Lu,Ga:YAG/YAG waveguide structure have been created using liquid phase epitaxy. The method used to produce such epitaxial structures ensures obtaining Nd3+ ions concentration in the range from 1 at.% to 3 at.% in waveguiding thin films. Spectroscopic characterization of active films was performed. The Nd,Lu,Ga:YAG waveguide for each neodymium ions concentration exhibited lasing operation at room temperature at a wavelength of 1064 nm with impulse laser diodes pumping at 808 nm and 885 nm. The maximum average output power Pav = 2.6 mW and 72.2% slope efficiency was obtained for 1 at.% Nd3+ waveguide pumped at 885 nm.

Mid-Infrared Dual-Wavelength Passively Q-Switched Er: SrF2 Laser by CsPbCl3 Quantum Dots Absorber

A passively Q-switched compact dual-wavelength Er: SrF2 laser, operating at a 2729.73 nm and 2747.2 nm wavelength, was demonstrated by utilizing CsPbCl3 quantum dots (QDs) as a saturable absorber (SA). The maximum average output power with the shortest duration of 510 ns and a repetition rate of 45 kHz was achieved at 190 mW, and the corresponding maximum single pulse energy and the peak power were 73.69 μJ and 141.7 W, respectively. The results present an efficient dual-wavelength laser source, and the halogen perovskite quantum dot has the potential to be employed as an excellent saturable absorber in mid-infrared pulsed solid-state lasers.

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.

Indium Selenide as passive saturable absorber for Q-switching in Erbium-doped fiber lasers

• Demonstrated erbium-doped fiber laser Q-switched using Indium Selenide. • The Q-switched performances were achieved at the maximum pump power of 125.63 mW with a repetition rate of 109.2 kHz and a minimum pulse width of 2.89 µs. • The higher pulse energy obtained is 73.8 nJ, with a maximum average output power of 8.06 mW. Q switching was demonstrated in an Erbium-doped fiber laser by utilizing Indium Selenide (In 2 Se 3 )-PVA as a passive saturable absorber (SA). The In 2 Se 3 PVA thin film was sandwiched between two fibre ferrules using 980 nm laser diode at the operating wavelength of 1550 nm. Stable Q-switched pulse started to generate at the threshold pump power of 24.13 mW with centre wavelength of 1558.7 nm. The Q-switched performances were achieved at the maximum pump power of 125.63 mW with a repetition rate of 109.2 kHz and a minimum pulse width of 2.89 µs. The higher pulse energy obtained is 73.8 nJ, with a maximum average output power of 8.06 mW. Our findings suggest that In 2 Se 3 has merciless performance in acting as passive saturable absorber in mid-infrared regime and will provide useful guidance for future ultra-fast optical devices.

Simulation and experimental investigation of a 6.6 ps passively mode-locked TEM00 Nd:YVO4/KTP green laser based on SESAM

The design, construction, and characterization of a diode-pumped SESAM mode-locked green laser were reported. Based on the simulation results, the technical route for the construction and optimization of the resonator was determined. A KTP was used as the intracavity frequency doubling crystal. The maximum output average power at 532 nm was 500 mW with a repetition rate of 82 MHz at a pump power of 5 W. In addition, the measured and simulated beam quality was about , indicating the single-mode operation of the laser. Moreover, the spectral characteristics of the laser at 1064 nm and 532 nm were analyzed. The time duration of the pulses at 1064 nm was about 9.4 ps. The theoretical calculations based on the time-bandwidth product evaluation method predicted the time duration of 6.6 ps for the pulses at 532 nm.