Output Power Ratio Research Articles

Orthogonally polarized dual-wavelength Nd:LiYF4 laser at 1777 and 1789 nm with 1:1 output power ratio

Abstract A diode-pumped continuous-wave orthogonally polarized dual-wavelength Nd:LiYF4 (Nd:YLF) laser on 4F3/2 → 4I15/2 transition is studied. The output power ratio can be adjusted using two intracavity uncoated glass plates. At an incident pump power of 20 W, a dual-wavelength laser operating at 1777 nm in π-polarization and 1789 nm in σ-polarization was realized. The total output power of the dual-wavelength laser was more than 1.16 W with a 1:1 output power ratio. The total slope efficiency and total optical conversion efficiency with respect to the incident pump power were 4.6% and 2.9%, respectively. To the best of our knowledge, this is the first work realizing mid-infrared wavelength operation in Nd:YLF lasers on 4F3/2 → 4I15/2 transition.

Optimization strategies for bifacial floating photovoltaic systems on different water bodies: A 10E performance evaluation

This study investigates the performance and optimization of standalone floating bifacial solar photovoltaic systems through a comprehensive 10E analysis, covering energy, exergy, economic, environmental, energo-economic, exergo-economic, enviro-economic, energo-environmental, exergo-environmental, energy payback time, and embodied energy factors. The research evaluates energy efficiency, economic feasibility, and environmental impact using various water coolants. Fresh water emerged as the best performer, delivering the highest output power (399 W), final yield (371.94 W), and performance ratio (59.082). Capacity utilization factors were comparable, with fresh water (0.517) and black water (0.516) leading. Fresh water also showed the lowest energy loss (−365.64) and highest exergy efficiency (32.10%). It achieved the lowest levelized cost of energy at 3.39 $/MWh and the highest enviro-economic parameter (243.497). The exergo-environmental analysis demonstrated consistent efficiency, with energy payback time ranging from 37.28 to 37.36, and the embodied energy for the panels was 2840.67 units. Optimization techniques such as random forest, gradient boosting, XGBoost gain, neural network, and response surface methodology were used to identify optimal panel heights, water depths, and azimuth angles. Fresh water was identified as the most effective coolant, balancing high energy efficiency, minimal energy loss, and environmental sustainability. Response surface methodology proved to be the most accurate method for predicting power output and bifacial gain. This study provides valuable insights into improving the efficiency and sustainability of floating bifacial photovoltaic systems under various environmental conditions.

Orthogonally polarized dual-wavelength Pr:LiYF4 lasers in 1.3 μm region

We report a continuous-wave (CW) orthogonally polarized dual-wavelength Pr:LiYF4 laser in 1.3 μm region pumped by a Yb-doped fiber laser. The gain and loss of the wavelengths in the orthogonally polarized directions were balanced by an inclined etalon inserted into the cavity. At an absorbed pump power of 9.2 W, a dual-wavelength laser operating at 1310 nm in π-polarization and 1326 nm in σ-polarization with 2.26 W of total output power was achieved. Moreover, by continuing to adjust the tilt angle of the etalon, the three other pairs of dual-wavelengths (1289 and 1306 nm, 1289 and 1306 nm, and 1306 and 1310 nm) were also obtained. The output power ratio of each pair of dual wavelengths was nearly 1:1. To the best of our knowledge, this is the first work realizing the Pr:LiYF4 laser operating in 1.3 μm region.

Cardiac power output ratio: Novel survival predictor after percutaneous ventricular assist device in cardiogenic shock.

Currently, there is limited data on prognostic indicators after insertion of percutaneous ventricular assist device (PVAD) in the treatment of cardiogenic shock (CS). This study evaluated the prognostic role of cardiac power output (CPO) ratio, defined as CPO at 24h divided by early CPO (30min to 2h), in CS patients after PVAD. Consecutive CS patients from the QEH-PVAD Registry were followed up for survival at 90days after PVAD. Among 121 consecutive patients, 98 underwent right heart catheterization after PVAD, with CPO ratio available in 68 patients. The CPO ratio and 24-h CPO, but not the early CPO post PVAD, were significantly associated with 90-day survival, with corresponding area under curve in ROC analysis of 0.816, 0.740, and 0.469, respectively. In multivariate analysis, only the CPO ratio and lactate level at 24h remained as independent survival predictors. The CPO ratio was not associated with age, sex, and body size. Patients with lower CPO ratio had significantly lower coronary perfusion pressure, worse right heart indices, and higher pulmonary vascular resistance. A lower CPO ratio was also significantly associated with mechanical ventilation and higher creatine kinase levels in myocardial infarction patients. In post-PVAD patients, the CPO ratio outperformed the absolute CPO values and other haemodynamic metrics in predicting survival at 90days. Such a proportional change of CPO over time, likely reflecting native heart function recovery, may help to guide management of CS patients post-PVAD.

High average output power, dual-wavelength synchronously self-mode-locked Ho:LLF laser operating at 2068.5 and 2069.2 nm.

A dual-wavelength synchronously self-mode-locked Ho:LLF laser operating at 2068.5 and 2069.2 nm was demonstrated. The maximum average output power was as high as 2.6 W with a pulse repetition frequency of 3.03 GHz. Meanwhile, the output power ratio of the dual-wavelength lasers can be effectively controlled by varying the incident pump power. To the best of our knowledge, this is the first dual-wavelength synchronously self-mode-locked Ho-doped fluoride solid state laser; moreover, our current experimental results represent the highest average output power from a GHz self-mode-locked oscillator in the 2 µm wave band.

Improved evaluation model for macro-bending loss and power variation in single-mode fiber

It is challenging to calculate the macro-bending loss of optical fiber when the bending radius is reduced to sub-millimeter levels, based on Marcuse's theory and its derivative theories. Furthermore, these theories are limited in their ability to assess the distribution and changes of the optical field within the fiber, focusing solely on the analysis of loss. To overcome these limitations, we proposed an evaluation model which can simultaneously provide results for both macro-bending loss and power variation in a bent single-mode fiber. Our model achieves this by conformally transforming the fiber's refractive index profile of the axis section according to the bending radius. The ratio of output power to input power exhibits oscillation with changes in the bending radius, thereby resolving the issue of inability of Marcuse's theory to obtain an oscillation loss curve for sub-millimeter bending radii. The proposed model was validated by finite element method. We also obtained the internal power variation along the axial distance of the bent fiber through this model. This research improves the current fiber macro-bending loss evaluation model and lays a foundation for further studies on bend-insensitive fibers and the design of sub-millimeter bending sensors.

Design of enlarged-asymmetric-power single-mode silicon evanescent lasers with asymmetric distributed feedback gratings

Great achievements in the bonded III–V lasers have pushed the productization process of silicon photonic chips. In this work, we report the design of silicon evanescent lasers with asymmetric gratings, which can provide high output power and stable single-longitudinal-mode operation. The high coupling efficiency and low threshold current density are achieved by linearly expanding the width of rib waveguide from 0.4 µm to 2 µm through 150 µm taper coupler. By optimizing the λ/4 phase-shift position ratio from conventional 0.50 to 0.64, the ratio of output power at both sides of the bonded lasers (P2/P1) is improved from1.0 to 5.0, and the normalized grating coupling coefficient (κL) remains at 2.78. By optimizing the duty cycle at one side of λ/4 phase-shift from 0.5 to 0.8 and another side remains at 0.5, P2/P1 is 3.3, and κL lowers from 2.78 to 2.21. Besides, keeping the phase-shift position ratio at 0.64 while changing the duty cycle to 0.7, P2/P1 increases significantly to 7.5 with κL of 2.59. This work provides a step forward towards the development of high-power silicon-based light sources.

Metabolic and Perceptual Responses to Constant Heart Rate Exercise at Vigorous Intensities in Women.

This study quantified the metabolic demands (oxygen uptake (V̇O 2 )), power output adjustments, changes in the V̇O 2 /power output ratio, and perceptual responses (rating of perceived exertion (RPE)) during constant heart rate (HR) exercise performed within the vigorous intensity range (77%-95% HR peak ). Twelve women (mean ± SD age, 22 ± 4 yr) performed a graded exercise test to exhaustion to determine peak parameters, and three randomly ordered, constant HR trials to exhaustion or for 60 min at the lower (HR L = 77% HR peak ), middle (HR M = 86% HR peak ), and higher (HR H = 95% HR peak ) end of the vigorous intensity range. Time course of changes and patterns of responses were examined for V̇O 2 , power output, V̇O 2 /power output, and RPE for the composite and for each subject. Across the HR L (time to exhaustion ( Tlim ) = 56.3 ± 9.9 min), HR M (51.8 ± 13.5 min), and HR H (27.2 ± 17.7 min) trials, V̇O 2 and power output decreased quadratically ( P < 0.05) relative to the initial value from 10% to 100% of Tlim , whereas the V̇O 2 /power output increased quadratically from 20% to 100% Tlim , and RPE increased linearly from 50% to 100% Tlim . The V̇O 2 and RPE, collapsed across time, for HR L (54.3% ± 3.3% V̇O 2peak , 11 ± 1.5 RPE) were lower than HR M (64.9% ± 4.5% V̇O 2peak , 14 ± 1.7 RPE), and both were lower than HR H (80.1% ± 4.1% V̇O 2peak , 17 ± 1.4 RPE). None of the 12 subjects at HR L , 6 at HR M , and 7 at HR H were within the vigorous V̇O 2 range. The HR L was not sufficient to meet the desired metabolic intensity for vigorous exercise, whereas the middle to higher end of the range elicited a V̇O 2 within the prescribed range of only ~50%-60% of the subjects. This study indicated that exercise held constant at a percentage of HR peak cannot consistently be used to prescribe a desired metabolic stimulus.

The integration of seawater desalination system with nuclear power plant: Operational flexibility enhancement and thermo-economic performances

To accommodate the high penetration of renewable power, nuclear power plants (NPPs) should participate in peak shaving services, which has become a key issue restricting the efficient and reliable operation of NPPs. To enhance the operational flexibility efficiently, the seawater desalination system is integrated within a NPP in this paper. Thermo-economic performances of the proposed system were evaluated. When the main steam, inlet reheat steam, and outlet reheat steam of the NPP are extracted to drive the LT-MED desalination system, and the output power ratios of the integrated system can be decreased to 12%, 65%, and 61%. Therefore, the operational flexibility of the NPP can be effectively enhanced with the integration of desalination system. Then, the capacity and configuration of the LT-MED system were optimized, and gain output ratio and water production cost were used to evaluate performances of the integrated system. The water production cost reaches its minimum value of 0.64 $/m3, when the LT-MED desalination system decreases the output power ratio of the integrated system to 65%. The exergy efficiency of the integrated system is 7.9%, 18.3%, and 25.6% higher than that of AP1000 when the extraction steam is main steam, outlet reheat steam, and inlet reheat steam.

A nanofluid-based hybrid photovoltaic-thermal -thermoelectric generator system for combined heat and power applications

This study investigates the use of nanofluid-cooled Thermoelectric Generators (TEGs) integrated with a Photovoltaic (PV) panel to enhance the overall energy efficiency of the system. Three cooling fluids — Water (W), CuO/W single Nanofluid (NF), and CuO-Fe/W hybrid NF — are examined at various flow rates for cooling the PV panel. The research studies the PVT-TEG-NF system considering both normal and concentrated solar irradiation in a 3D parallelly-cooled heat sink setup and comparing its electrical and thermal performance, which has not been previously addressed in the literature. The results demonstrate that by utilizing CuO-Fe/W, the PV temperature at irradiation of 935 W/m2 in the summer can be maintained at 31.7 °C, which is 8.8 % and 13 % lower than those achieved by using CuO/W and water, respectively. For 0.08 m/s of CuO-Fe/W inlet velocity, the total output power PV-TEG is about 9.5 W, with a heat removal rate of ∼37.2 W. Additionally, by utilizing the CuO-Fe/W compared to water, the combined efficiency of the system (the ratio of electrical and thermal power output to solar input) increases from 66.7 % to 76.7 %. In the second part, the study introduces a new approach to maintain a steady PV efficiency while increasing solar concentration by adjusting the cooling fluid flow rate. By increasing solar concentration from 1.5 suns to 2.5 suns, the PV temperatures could be maintained at 44.5 °C and 51.5 °C using CuO-Fe/W and water with 0.12 m/s of inlet velocity, respectively. This made it possible to enhance the power output of the PV and TEGs by 65.9 % and 187 %, respectively, by using CuO-Fe/W as coolant, while the temperature of the panel could be maintained at a safe level.

Variable-Speed Operation of Micro-Hydropower Plants in Irrigation Infrastructure: An Energy and Cost Analysis

Micro-hydropower plants have now become a way to decarbonise the power generation system. Older micro-hydropower plants generally operate at a fixed speed. When there is a lack of rainfall, these plants operate outside their design flow causing various problems (such as the occurrence of the phenomenon of cavitation, decreased turbine performance, and decreased operating hours), especially in micro-hydropower plants installed in irrigation infrastructure, where the priority for water use is crops. This study aims to carry out a comparative evaluation of several indicators (cavitation, investment costs, electricity production and economic benefit) of two types of control system on an asynchronous electric generator (a fixed speed control system (scenario 1) and a variable-speed control system (scenario 2)) at the same micro-hydropower plant. The Rebolluelo micro-hydropower plant (Spain) is used for this purpose as a case study. This micro-hydropower plant uses a semi-Kaplan turbine coupled to an asynchronous electric generator through a gearbox. The results show the advantages of using a variable-speed control system. The use of variable-speed technology: (i) eliminates the possibility of cavitation, (ii) increases the power output ratio (from 35.87% to 93.03%), and (iii) increases the economic benefit (from 29.31% to 108.72%). There are also, of course, disadvantages, such as an 11.96% increase in cost. This work demonstrated the superiority of variable speed technology at micro-hydropower plants for three of the four indicators evaluated. This work could be of assistance when making decisions regarding future micro-hydropower plant installations.

Fast two-layer nonlinear economic predictive control using machine learning for ORC systems with non-Gaussian disturbances

This study proposes a machine learning-based generalized correntropy two-layer nonlinear economic model predictive control (ML-GC-TL-NEMPC) algorithm to improve the computational speed for Organic Rankine Cycle (ORC) systems with non-Gaussian disturbances. In the upper layer, the ratio of the net output power to the total heat transfer area is used as the economic performance index to optimize the optimal reference trajectory. In the lower layer, the generalized correntropy-based MPC (GC-MPC) is used to track the optimal trajectory. To quickly obtain an optimal solution, a Deep Neural Network (DNN) neural network controller is combined with kernel support vector machine (SVM). It learns the possible optimal solution via off-line training. Then it can be quickly implemented on on-line applications, so it can save the optimal calculation time. The proposed ML-GC-TL-NEMPC is applied to ORC. Its computation and performance are faster and better than the traditional two-layer EMPC and single-layer EMPC.

Analysis of medium-frequency oscillation based on bifurcation theory and joint modelling of SVG and direct-drive wind turbine

With the expansion of wind power clusters in power system, medium and high frequency oscillations in wind farm area are preliminarily emerging. At present, linear analysis such as impedance analysis are mainly used to analyse the grid-connected oscillation of renewable energy generation. However, the explanation of the oscillation mechanism is not intuitive and does not take into account the nonlinearity of converter. Considering the influence of external loop control of SVG and direct-drive wind turbine on the medium-frequency characteristics of the parallel system, a reduced-order nonlinear model under voltage time scale is established. The conjoint analysis of Jacobi matrix, bifurcation diagram and phase space trajectory are applied to study the influence rule of machine-side output power and short-circuit ratio on the oscillation behaviour of the parallel system. In addition, the oscillation evolution process is analysed from the dynamic standpoint. It is found that the system operates on the limit-loop state when the medium-frequency oscillation occurs, which reveals the mapping relationship between the oscillation amplitude and the limit-loop trajectory. The experimental results ultimately validate the theoretical analysis conducted on the StarSim-HIL (hardware-in-the-loop) experiment platform.

Design and optimization of lightweight bending strain energy harvesters using irradiation cross-linked polypropylene ferroelectret

In this work, a concept for bending strain energy harvesting with lightweight ferroelectrets subject to metallic host structures is proposed. The energy harvester (EH) works with the ferroelectret irradiation cross-linked polypropylene (IXPP) and uses the piezoelectric δ 33-mode by transferring in-plane bending strain energy of a host structure to a compression of an IXPP stack. This is achieved with a simple and lightweight transmission made of structural steel. In this way, a high ratio of generated power per used EH mass can be achieved, being the main design goal of this paper. To demonstrate this, miniature EHs as unit cells for larger EH systems are investigated. The strain magnitude of the excitation in an aircraft wing of at 1.5 Hz from previous work is partly taken into account for calculations. In an analytical modeling approach, the energy conversion abilities of the presented concept is compared to concepts using lead zirconate titanate ceramics to stress the usefulness in cases where strain energy is the prominent source of vibration energy. Further, an optimization algorithm is presented for a static and a dynamic case without a host structure and for a dynamic case with an aluminum host structure. The optimized power output and power output per total EH mass for the three cases is calculated to and , 0.7 mW and 80 mW kg−1 as well as (at 1 N excitation magnitude) and (at 1 N excitation magnitude) respectively. Finally, experimental results for case three are presented to validate the model of the proposed and optimized EH topology up to 500 Hz. The results further show a good mechanical reproducibility of the measured transfer behavior and a fairly good reproducibility of the mechanical-electrical results due to deviations in material properties. A comparison of the model with the experimental results shows a good agreement. Therefore a linear ferroelectret model appears to be suitable to predict the system behavior in lower and higher frequency ranges as well as for high ferroelectret material strains. The optimized EH provides a comparably high ratio of power output per mass when added to a structure like an aircraft which is shown in a comparison to other research works. The performance in a real application can be further improved to 52 mW within a 1 m2 area using a clustering approach, discussed in the paper. Large deformations of lightweight structures like aircraft wings at low and high frequencies can thus be exploited to provide enough electrical power decentrally for low-power consumers.

Evaluation of transmission efficiency of the ECH/CD transmission lines in integrated commissioning phase on JT-60SA

An electron cyclotron heating and current drive (ECH/CD) system with two transmission lines (TLs), TL#1 (waveguide inner diameter ⌀=31.75 mm) and TL#2 (⌀=60.3 mm), has been installed and operated on JT-60SA for the integrated commissioning phase. In order to evaluate the transmission efficiency of the TLs, the theoretical loss of each TL component is calculated assuming pure HE11 mode. In addition, the millimeter wave power at the beginning and end of two TLs was measured experimentally by calorimetric dummy loads (DLs) at high-power of ∼ 400 kW for ∼ 0.3 s. The output power of the gyrotron is estimated by using the measured power at the beginning of each TL with the theoretical loss between the DL and the gyrotron. The injection power to the tokamak from a launcher is also estimated by using the measured power at the end of each TL with the theoretical loss between the DL and the launcher. Using these values, the transmission efficiencies, defined as the ratio of the gyrotron output power to the tokamak injection power, are evaluated for both TLs, which are ∼70% for TL#1 at 110 GHz, and 80 % (82 GHz), 82 % (110 GHz), and 84 % (138 GHz) for TL#2. The total power injected into the tokamak by the combination of TL#1 and TL#2 is expected to be 1.5 MW. It is found that the measured transmission efficiency of TL#2 shows a good agreement with the theory, while the measured transmission efficiency of TL#1 was slightly lower than the theoretical value. To investigate this result, power measurements are also performed at additional locations on the TL#1 with additional DLs.

Optimized multi-timescale energy management strategy of a novel all-electric aircraft power system unit based on decentralized control

This paper presents an optimized multi-timescale energy management strategy (MTEMS) for a novel all-electric aircraft (AEA) power system unit, which consists of a hybrid energy storage system comprising super-capacitor (SC), battery and fuel cell (FC), as well as a dual three phase permanent magnet synchronous motor (DTP-PMSM) system serving as the propulsion system. During transient states characterized by rapid load changes, the proposed strategy effectively allocates power from the low-frequency, medium-frequency, and high-frequency domains to their respective units, namely FC unit, battery unit, and SC unit. This power allocation is achieved through decentralized droop control implemented in the proposed MTEMS, ensuring a constant and stable bus voltage throughout the operation. In addition, during the steady-state after the change of the load power, a distributed optimization method of the proposed MTEMS can calculate the ratio of power outputs between the battery and FC to maximize the operational efficiency of the fuel cell while ensuring the battery operates in an economically optimal condition. This ultimately guarantees the entire system operates under optimal operating conditions. The achievement of the output power ratio is attainable through the implementation of decentralized droop control. Finally, a 1 kW experimental platform is constructed to validate the effectiveness of the proposed MTEMS and verify the analytical results.

Coupled responses of the flow-induced vibration and flow-induced rotation of a rigid cylinder-plate body

In this study, coupled responses of flow-induced vibration and rotation for an elastically mounted cylinder-plate body are numerically investigated at a low Reynolds number of 120. A wide vibrational reduced velocity range of Uy = 3–18 under four rotational reduced velocities Uθ = 5, 8, 12, and 18 are considered. The non-bifurcation responses, bifurcation only in rotation responses, and bifurcation in both vibration and rotation responses are identified. Typical vortex-induced vibration (VIV) responses are recognized when considering the passive rotations, different from the full interactions between VIV and galloping for the vibration-only case. As Uθ increases, the peak vibration amplitudes increase, the onset Uy of the lock-in region becomes larger, and the lock-in region is wider. The phase angles of displacements versus lift coefficients experience a jump from 0° to 180° in the lock-in region, and the larger the Uθ, the wider the Uy range of phase jump. Whether the instantaneous posture of the cylinder-plate body is streamlined or not is determined by oscillation amplitudes and phase differences between displacements versus rotation angles. Streamlined profiles can be achieved under small oscillation amplitudes or when the phase angles are nearly 90°. The 2S (two isolated vortices) vortex shedding mode dominates the initial and desynchronization branch, while the 2P (two pairs of vortices), 2S* (two isolated vortices with tendency to split), and 2T (two triplets of vortices) modes appear in the lock-in region. After the symmetry-breaking bifurcation, the reattachment behavior becomes simpler and the length of the recirculation region is significantly increased, as compared with those in non-bifurcation region. With the above study, a new method of improving energy harvesting from flow-induced vibration, by incorporating passive rotations simultaneously, is first introduced. It is found that passive rotations can enhance the vibration responses and thus lead to the increased output power and energy transfer ratio, although they make less contributions to the total power. Generally, this mechanical system presents a promising opportunity for energy harvesting through flow-induced vibration.

A Forward-Type Single-Stage Multi-Input Inverter With Series-Time-Overlapping Power Supply

A Forward type single-stage multi-input inverter with series-time-overlapping power supply is proposed. The circuit structure and topological family, energy management control strategy (EMCS), high frequency (HF) switching process analysis, the relationship between multiple duty cycles and power decoupling, common mode interference suppression between multiple inputs are fully studied. The circuit structure is composed of multi-input selection switches in series and an isolated bidirectional Forward type single input single output inverter. This topological family includes 6 circuits such as full-bridge type. A master-slave energy management SPWM compound control strategy with independent control of input source power based on input voltage feedforward and output voltage feedback is proposed. It realizes the energy management of the input source by controlling the instantaneous value of the output voltage and the output power ratio of the multiple inputs and achieves the smooth switching between the two power supply modes. The designed and developed 3kVA inverter prototype has excellent performances such as single-stage power conversion, HF electrical isolation, high conversion efficiency, small size and weight, wide duty cycle adjustment range, high output waveform quality, and strong load adaptability.

Metasurface‐Based Free‐Space Multi‐Port Beam Splitter with Arbitrary Power Ratio

AbstractA beam splitter (BS) is one of the most critical building blocks in optical systems. Despite various attempts of flat‐type BSs to miniaturize the conventional cube BS reported, it remains a challenge to realize an ultrathin optical BS with multi‐port output, non‐uniform splitting ratio, and steerable outgoing directions. Herein, a free‐space optical multi‐port beam splitter (MPBS) based on a polarization‐independent all‐dielectric metasurface is demonstrated. By applying an optimized phase‐pattern paradigm via a gradient‐descent‐based iterative algorithm to amorphous silicon (α‐Si) metasurfaces, a variety of MPBS samples with arbitrarily predetermined output port number (2–7), power ratio, and spatial distribution of output beams are prepared. The experimental results reveal that the fabricated MPBSs can achieve high total splitting efficiency (TSE, above 74.7%) and beam‐splitting fidelity (similarity, above 78.4%) within the bandwidth of 100 nm (1500–1600 nm). Such proposed MPBS can provide fabulous flexibility for optical integrated system and diverse applications.

A Model of Dual Fabry–Perot Etalon-Based External-Cavity Tunable Laser Using Finite-Difference Traveling-Wave Method

A physical model of an external-cavity tunable laser (ECTL) utilizing the vernier effect of a dual Fabry–Perot (FP) etalon is presented and simulated using the finite-difference traveling wave (FDTW) method. In this paper, we provide a detailed explanation of the physical principle and construction process of the model, as well as the simulation results for the laser. The model is precisely established by studying the time-dependent changes in the carrier concentration and optical field of different wavelengths inside the laser before reaching a steady state. By determining multiple parameters in the tuning region and gain region, the proposed model can calculate and predict various laser parameters, such as output power and side-mode suppression ratio (SMSR). Moreover, the FDTW method displays the change process of various parameters, such as carrier concentration and spectrum, in the convergence of various positions in the laser with femtosecond time resolution. This capability is promising for in-depth research on the inner mechanism of lasers.