A segmented modeling simulation method of quantum well semiconductor optical amplifier based on space-time staggered half-step splitting

Abstract

A segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally staggered half-step partitioning is proposed. The method includes extracting and preprocessing parameter data of the quantum well semiconductor optical amplifier device and the quantum well electro-optic gain material; and performing stepwise segmentation of the optical amplification direction of the active region of the quantum well semiconductor optical amplifier using spatiotemporally staggered half-step partitioning. This method constructs a high-speed and efficient simulation design through novel spatiotemporally staggered half-step partitioning modeling and calculation, which can improve the efficiency of large-signal time-domain simulation calculation of devices such as quantum well semiconductor optical amplifiers and quantum well semiconductor lasers and reduce the time consumption of optimization design.

Description

Technical Field

[0001] This invention relates to the field of optical technology and its modeling and simulation, specifically to the field of quantum well semiconductor optical amplifiers and quantum well semiconductor lasers, and more specifically to a segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally staggered half-step partitioning. Background Technology

[0002] For broadband and short-haul fiber optic communications, including data center optical interconnects and fiber optic access networks, semiconductor laser amplifiers (SOAs) and SOA-based semiconductor lasers have been widely used. Due to the existence of quantum confinement, quantum well semiconductor optical amplifiers (QWSOAs) and QWSOA-based semiconductor lasers often exhibit high-bandwidth gain responses compared to bulk SOA-based devices, and are currently widely used in optical communications and optical sensing.

[0003] QWSOA has various applications in optical communication and optical sensing, but in most cases, it operates in a quasi-linear or nonlinear state, requiring optimized parameter design to meet specific needs. For example, coherent optical communication, commercially available since the 2010s, improves receiver sensitivity and reduces channel spacing between wavelength division multiplexing (WDM) channels compared to incoherent optical communication because it simultaneously utilizes amplitude and phase to transmit information. Coherent optical communication typically employs higher-order modulation formats such as 16-QAM, further significantly increasing communication transmission rates. Time-domain-based QWSOA models, with their ability to accurately simulate the time-domain evolution of amplitude and phase, have become essential tools for the design and optimization of coherent optical communication devices and systems.

[0004] More specifically, higher-order modulation formats such as N-QAM can Bits of information are modulated into a waveform. For M input waveforms with different amplitudes and phases, when the QWSOA is in a linear state, the amplitudes and phases of the M QWSOA output waveforms remain relatively constant, and the system performance is only affected by accumulated spontaneous emission (ASE) noise. However, at this time, the QWSOA only operates in the small-signal amplification range, resulting in a low signal-to-noise ratio and poor system performance. When the QWSOA is in a deep gain saturation state, the signal-to-noise ratio is high, but the amplitude and phase of the QWSOA output waveforms undergo significant distortion, greatly degrading system performance. Using a time-domain-based QWSOA model, the time-domain evolution of the waveform signal, including amplitude and phase, can be accurately simulated when the QWSOA is in gain saturation, allowing for the identification of the balance point between signal-to-noise ratio and waveform distortion, thus optimizing system performance.

[0005] Because QWSOA and QWSOA-based semiconductor lasers possess numerous geometric, physical, and signal parameters, and undergo various physical processes such as current injection, carrier transitions, and depletion, the modeling and design parameters are numerous. The joint optimization of these parameters is a significant challenge in QWSOA modeling and design: for example, when three parameters need to be jointly optimized, each taking 10 values, the simulation calculations required to traverse all combinations reach 10^10. 3 That is, 1000 times, which requires a huge amount of computation and time.

[0006] The long simulation computation time of large-signal time-domain QWSOA models severely restricts the device design efficiency and system optimization effect of QWSOA, a key component in optical communication and optical sensing. To address this, there is an urgent need for new modeling and simulation design methods that can dramatically improve the computational efficiency of large-signal QWSOA time-domain models, enabling high-speed traversal of the parameter space. This is of great significance not only for QWSOA and QWSOA-based semiconductor lasers, but also for the modeling, simulation, and optimization design of amplifiers and lasers in other fields, such as those based on quantum well semiconductors or non-semiconductor quantum wells. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporal staggered half-step partitioning. By constructing a high-speed and efficient simulation design through novel spatiotemporal staggered half-step partitioning modeling and calculation, this method can improve the efficiency of large-signal time-domain simulation calculations for devices such as quantum well semiconductor optical amplifiers and quantum well semiconductor lasers and reduce the time consumption for optimization design.

[0008] This invention provides a segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally misaligned half-step partitioning, specifically including the following steps performed sequentially:

[0009] (1) Extract parameter data of quantum well semiconductor optical amplifier devices and quantum well electro-optic gain materials and perform preprocessing;

[0010] (2) The light amplification direction of the active region of the quantum well semiconductor optical amplifier is segmented step by step in a spatiotemporally staggered half-step manner, and a time-domain mathematical and physical model of the light field and material gain segmentation is established. The simulation formula and algorithm based on the model are obtained, and the simulation calculation is carried out in combination with hardware or software.

[0011] (3) Perform data analysis and extraction on the simulation results of the quantum well semiconductor optical amplifier device to obtain the design parameters of the quantum well semiconductor optical amplifier device and its system;

[0012] (4) Use the system model containing the quantum well semiconductor optical amplifier to perform system-level simulation and calculation to obtain system simulation and optimization design results.

[0013] Furthermore, step (1) specifically includes the following steps:

[0014] (1.1) Modeling and simulating the electrical properties of quantum well electro-optic gain materials and extracting bandgap parameter data;

[0015] (1.2) Modeling and simulation of optical waveguides constructed from quantum well electro-optic gain materials and extraction of waveguide parameter data;

[0016] (1.3) Extraction of signal velocity and polarizability data of quantum well electro-optic gain material.

[0017] Furthermore, quantum well electro-optic gain materials include quantum well semiconductor electro-optic gain materials.

[0018] Furthermore, step (2) specifically includes the following steps:

[0019] (2.1) The initial value of the carrier concentration of the quantum well semiconductor optical waveguide is given by the carrier concentration at initial equilibrium;

[0020] (2.2) The quantum well semiconductor optical waveguide is mathematically divided into N segments along the optical signal transmission direction, each segment having a length of... The input optical signal to be simulated in time Mathematical segmentation of the above Segment, length of each segment At the same time, ensure , This represents the group velocity of the optical signal in the quantum well semiconductor medium, and samples are taken at the beginning of each signal segment to obtain... ;

[0021] (2.3) Establish the calculation point of the optical signal to be calculated , indicating in time, The electric field of the light signal at that location, The range of values ​​is Integers;

[0022] (2.4) Establish the calculation point for carrier concentration ,express time, The carrier concentration at the specified location is... and Both are greater than The half-integer; calculate the carrier concentration of each segment on the quantum well semiconductor optical amplifier as the light signal enters the active region. The value after the time interval indicates that the optical signal only enters the active and restricted regions. The effects on the active and confined regions are negligible; the carrier concentration remains constant in the dynamic equilibrium between electric pump injection and recombination, i.e. ;

[0023] (2.5) Calculate the carrier concentration in the active region of the quantum well semiconductor and restricted region carrier density The rate is satisfied, and the carrier concentration is iteratively processed;

[0024] (2.6) The optical signal and carrier concentration are iteratively calculated using the input optical signal, initial carrier concentration, and boundary response to the optical signal. As an output signal.

[0025] Further, step (2.5) specifically includes:

[0026] Calculating the carrier concentration in the active region of a quantum well semiconductor and restricted region carrier density Satisfied rate equation:

[0027]

[0028]

[0029] in and The volumes of the active and confinement regions are represented, and the spontaneous decay of charge carriers is also considered. ;

[0030] The iterative equation for carrier concentration is obtained as follows:

[0031]

[0032]

[0033] Select for , among them Can represent or .

[0034] The segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally misaligned half-step partitioning provided by this invention can achieve the following compared to existing technologies:

[0035] (1) By performing spatiotemporal misalignment half-step partitioning of the process of light amplification in the active region of the amplifier to eliminate the first-order error term, the simulation accuracy and computational efficiency are improved by orders of magnitude. This allows for more efficient modeling and faster simulation of complex QWSOA device physics. In a limited time, the number of optimization iterations and the range of parameter space traversed are increased by orders of magnitude. This can greatly improve the relevant electro-optical performance indicators of the designed optical communication quantum well semiconductor optical amplifier, quantum well semiconductor laser and similar quantum well semiconductor devices.

[0036] (2) The calculation points of the segmented quantum well semiconductor optical amplifier are shifted so that the calculation points of the electric field of the optical signal and the calculation points of the carrier density are shifted by half the width of the segmentation in both time and space. Second-order accuracy can be achieved through the lattice shift, which is a major improvement in the computational efficiency of the existing first-order accuracy modeling and simulation technology. Attached Figure Description

[0037] Figure 1 Schematic diagram of a common multi-quantum-well semiconductor laser amplifier;

[0038] Figure 2 Schematic diagram of segmentation and signal sampling of a quantum well semiconductor optical amplifier;

[0039] Figure 3 A schematic diagram of the simulation algorithm for a quantum well semiconductor optical amplifier;

[0040] Figure 4 A schematic diagram of a system instance with system optimization;

[0041] Figure 5 Flowchart of the system optimization design of a quantum well semiconductor optical amplifier;

[0042] Figure 6 Comparison of the output waveforms of the two partitioning methods and the true solution;

[0043] Figure 7 A comparison chart of the global errors of the two partitioning methods. Detailed Implementation

[0044] The specific implementation of the present invention will be described in detail below. It should be noted that the following implementation is only for further illustration of the present invention and should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0045] This invention provides a segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally misaligned half-step partitioning, the specific implementation of which is shown in the appendix. Figure 1-7 As shown below, a detailed introduction will follow.

[0046] As attached Figure 1 The diagram shows the structure of a common multi-quantum-well semiconductor laser amplifier, which mainly includes electrodes providing bias current, an active region, a confinement region, and an anti-reflection surface. After the optical signal is coupled into the QWSOA, the high-energy carriers in the active region amplify the optical signal due to stimulated emission. Simultaneously, due to the pumping of the bias current, the consumed high-energy carriers in the confinement region are continuously replenished, and the carriers in the confinement region are converted into high-energy carriers in the active region, ensuring the continuous amplification process. When the optical signal reaches the anti-reflection layer, the vast majority of the signal becomes the output signal, and only a very small portion becomes the back-propagating signal in the QWSOA. Generally speaking, even after amplification, the proportion of the reflected signal in the final output light is still less than the proportion of spontaneous emission noise in the output light, so it can be ignored in practice. Considering the reflected optical signal and its amplification, this invention performs accurate simulation of this effect.

[0047] Specifically, this invention provides a segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally misaligned half-step partitioning, which includes the following steps performed sequentially:

[0048] First, parameter data for quantum well semiconductor optical amplifier devices and quantum well electro-optic gain materials are extracted. Quantum well electro-optic gain materials include quantum well semiconductor electro-optic gain materials. Specifically, this includes: (1.1) modeling and simulating the electrical properties of quantum well semiconductors or other quantum well electro-optic gain materials and extracting bandgap parameter data; (1.2) modeling and simulating optical waveguides constructed from quantum well semiconductors or other quantum well electro-optic gain materials and extracting waveguide parameter data; (1.3) extracting signal velocity and polarizability data from quantum well semiconductors or other quantum well electro-optic gain materials.

[0049] Specifically, the extracted bandgap parameter data includes recombination coefficients (Shockley–Read–Hall recombination coefficient, Bimolecular recombination coefficient, Auger recombination coefficient, etc.), polarization decay rate, bandgap shrinkage, carrier mass, initial carrier concentration, carrier capture time, escape time, and other parameters. In industrial design applications, these parameters can also be obtained from laboratory tests. Parameters related to doping and other process modifications can be calculated using formulas or models found in relevant semiconductor physics textbooks, or obtained from laboratory tests. For the initial carrier concentration, an estimated value can be used. In the established model, with zero optical signal input as the input signal, the value at which the system reaches equilibrium after a simulation period is defined as the initial carrier concentration.

[0050] The extracted waveguide parameter data includes the length of the quantum well semiconductor optical amplifier (QWSOA), the area of ​​the active region, the area of ​​the confinement region, the confinement factor, the scattering loss coefficient of the waveguide, and the reflectivity of the incident and exit interfaces. Among these, the length, area of ​​the active region, area of ​​the confinement region, scattering loss coefficient, and reflectivity of the incident and exit interfaces are parameters that can be determined artificially during the design process of the QWSOA. These parameters are typically set to a certain range, and subsequent steps iterate through these parameter values ​​to design a QWSOA device that achieves system optimization. For parameters that can be artificially adjusted and require optimization, such as the length, width, and geometry of the active region, and the length of the device, a series of values ​​are set for simulation.

[0051] The limiting factor is:

[0052]

[0053] in and Representing electric field and magnetic field respectively, The direction of light propagation in the QWSOA. For the area element perpendicular to the propagation direction, there are two calculation methods: (1) By modeling the optical mode of the corresponding QWSOA structure through relevant FDTD electromagnetic simulation, the constraint factor of the corresponding structure can be calculated using the above formula; (2) For QWSOA structures with analytical solutions or approximate analytical solutions, the constraint factor can be calculated analytically / numerically.

[0054] The extracted waveguide parameter data includes the sensitivity constant parameter, carrier concentration and frequency response under transparent conditions, and signal group velocity and frequency response. The formula for the sensitivity constant parameter is:

[0055]

[0056] in For the reduced mass of the electron-hole pair, The electric dipole moment matrix, For the QWSOA device width, The vacuum permittivity, This is the reduced Planck constant. The carrier concentration and frequency response at transparency can be obtained from underlying physical simulations and laboratory tests, while the group velocity and frequency response of the signal can be obtained from optical waveguide calculations.

[0057] Secondly, the optical amplification direction of the active region of the quantum well semiconductor optical amplifier is progressively segmented using a spatiotemporally staggered half-step partitioning method. A time-domain mathematical and physical model of the segmented optical field and material gain is established, and simulation formulas and algorithms based on this model are obtained. Simulation calculations are then performed using hardware or software. Large-signal modeling and simulation of the quantum well semiconductor optical amplifier is the core step and is most computationally intensive due to the acquired parameters. Existing methods use integer partitioning of carrier concentration and electric field time synchronously. This invention, for the first time, employs a spatiotemporally staggered half-step partitioning method for carrier concentration and electric field to progressively segment the active region of the quantum well amplifier. The scope of this invention is not limited by the above description of the partitioning; for example, this invention is also applicable to partitioning of carrier concentration and electric field with other staggered step sizes.

[0058] Specifically, it includes the following steps:

[0059] Step 2.1: The initial value of the carrier concentration in the quantum well semiconductor optical waveguide is given by the carrier concentration at initial equilibrium. Preferably, the obtained carrier concentration is denoted as... p is the subscript used in carrier concentration calculation.

[0060] Step 2.2: Mathematically divide the quantum well semiconductor optical waveguide into N segments along the optical signal transmission direction, each segment having a length of... The input optical signal to be simulated in time Mathematical segmentation of the above Segment, length of each segment At the same time, ensure , This represents the group velocity of the optical signal in the quantum well semiconductor medium, and samples are taken at the beginning of each signal segment to obtain... .

[0061] It should be noted that, up to this point, the mathematical model is accurate for the physical process.

[0062] Step 2.3: Establish the calculation points for the optical signal to be calculated. ,express time, The electric field of the light signal at that location, The range of values ​​is Integers.

[0063] The differential equation satisfied by the physical model of the quantum well semiconductor optical amplifier is:

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] in This represents the electric field of the signal propagating in the forward (z-direction). This represents the electric field of the signal propagating in the opposite direction (the negative z-direction). The carrier density in the active region, Let be the photon frequency, and the other parameters in the formula are shown in Table 1.

[0070]

[0071] Table 1 Parameters

[0072] Based on the above equations, we can obtain the iterative equation for the calculation point of the optical signal: Preferably, the above formula is selected from... for Select for In contrast, the usual method is to select... for or Select for or .

[0073] Step 2.4, establish the calculation point for carrier concentration. ,express time, The carrier concentration at the specified location is... and Both are greater than The half-integer values ​​(i.e., 0.5, 1.5, 2.5, etc.) are used to calculate the carrier concentration of each segment on the QWSOA as the optical signal enters the active region. The value after the time interval indicates that the optical signal only enters the active and restricted regions. The effects on the active and confinement regions are negligible. Therefore, the carrier concentration remains constant in a dynamic equilibrium between electric pump injection and recombination. .

[0074] Step 2.5, determined by the carrier concentration in the active region of the quantum well semiconductor. and restricted region carrier density Satisfied rate equation:

[0075]

[0076]

[0077] in and The volumes of the active and confinement regions are represented, and the spontaneous decay of charge carriers is also considered. Other parameters are shown in Table 1.

[0078] The iterative equation for carrier concentration is obtained as follows:

[0079]

[0080]

[0081] Select for , among them Can represent or In contrast, conventional methods select carrier concentrations. Time indicators It should be an integer, not a half-integer. for or That is, the electric field component of the optical signal and the calculation point of the carrier concentration have the same time index.

[0082] The process of selecting calculation points for the optical signal electric field and carrier concentration in sections 2.3, 2.4, and 2.5 above is called spatiotemporal misalignment half-step partitioning. Spatiotemporal step size. and The closer it is to 0, the closer it is to the reality.

[0083] Step 2.6: Iteratively calculate the optical signal and carrier concentration using the input optical signal, initial carrier concentration, and boundary response to the optical signal. As an output signal.

[0084] Since the number of computation points does not increase, the computational load remains the same compared to conventional methods. This invention eliminates first-order error terms through spatiotemporally misaligned half-step segmentation of quantum well semiconductor optical waveguides, thereby improving simulation accuracy by orders of magnitude. It can achieve the same simulation accuracy by reducing the number of segments by orders of magnitude. This improves computational efficiency by orders of magnitude. It should be further noted that in each... In the waveguide segment, the optical signal propagates forward and backward, and is amplified by stimulated recombination of non-equilibrium carriers. The non-equilibrium carrier density evolves under the combined effects of applied current, optical signal, and spontaneous recombination. However, the above mathematical model has no analytical solution for arbitrary signals, so QWSOA is first divided into several lengths. We perform numerical calculations on small segments of the optical signal. Then, we proceed to the next step, spatially selecting the calculation points for each QWSOA. The midpoint or end point of the segment, the calculation point for carrier concentration is selected as QWESOA. The midpoint of the segment. Simultaneously, in terms of time, the calculation points for both are selected at the same moment. In this invention, the above numerical modeling method is called the synchronous partitioning modeling method, which essentially involves partitioning each QWSOA segment into its corresponding subdivision modeling point. The amplification of the optical signal on the segment is considered to be a result of stimulated emission of carrier concentration in the active region of that segment at the same instant. Furthermore, each QWSOA... The change in carrier concentration on the segment is calculated as the change at the same time. The role of the average signal strength at the center or both ends of the segment.

[0085] The above approximation of continuous distributed amplification as piecewise amplification is obvious, because it changes the actual physical transmission mechanism, thus causing computational simulation errors. When and When the value decreases, the simulation error decreases while the simulation accuracy increases. The simulation error gradually disappears as it approaches 0. However, when... and When the value decreases, the total number of steps required for calculation increases. and As the value decreases to 0, the total number of computation steps required approaches infinity, making computation, simulation, and optimization impossible.

[0086] The synchronous partitioning modeling method described above is a first-order method, that is... For every halving of the size, the simulation error decreases by a factor of two. To achieve a certain level of high simulation accuracy, the required... The size is usually very small, which results in a large number of calculation steps, leading to a long calculation and simulation time and low efficiency.

[0087] As attached Figure 3 As shown in Figure .b, the carrier concentration at the bottom of the rounded rectangle and the average of the electric field values ​​at the left and right ends are used to calculate the carrier concentration at the top of the rounded rectangle at the next moment. Similarly, the electric field value at the top right end is calculated using the electric field value at the bottom left corner of the convex frame, the carrier concentration at the midpoint, and the average of the electric field values ​​at the left and right ends at the current moment. For backpropagating signals, the same method is used for updating the calculation. This invention proposes... The asynchronous (half-step) segmentation method is a second-order method, which advances the calculation point of carrier concentration in time. The optical signal amplified on each segment of the quantum well semiconductor optical waveguide will be calculated as follows: The effect of carrier concentration on this waveguide segment is then considered. Furthermore, the change in carrier concentration on each segment of the quantum well semiconductor optical waveguide is calculated as follows: The effect of the average signal strength at both ends of the waveguide segment is then considered. The above-described mathematical modeling method for quantum well semiconductor optical amplifiers, along with the updated calculation methods for electric field values ​​and carrier concentrations, are collectively referred to as the preferred spatiotemporally misaligned half-step partitioning modeling and simulation method for quantum well semiconductor optical amplifiers.

[0088] From the appendix Figure 3 As can be seen and verified by computer simulation, compared with the synchronous partitioning method, the present invention achieves the same number of computational points and computational load, i.e., device length. equal, Under equal conditions, the computational complexity is comparable. However, computer simulations have verified that this half-step partitioning modeling method (the present invention) has second-order accuracy. Compared to the first-order accuracy of existing spatiotemporal synchronous partitioning modeling methods, the present invention, by changing the spatiotemporal location of the carrier concentration calculation point and performing the updated calculations of the electric field value and carrier concentration as described above, offsets the first-order error term, thereby improving the simulation accuracy by orders of magnitude. Therefore, at the same simulation accuracy, the number of segments can be reduced by orders of magnitude. This improves computational efficiency by orders of magnitude.

[0089] Specifically, for second-order methods, For every 2-fold reduction, the simulation error decreases by 2. 2 =4 times; For every 10-fold reduction, the simulation error decreases by 10%. 2 =100 times. To achieve a certain level of high simulation accuracy, it is necessary to... The computational efficiency can be greatly improved compared to the first-order method because the number of computation steps is smaller and the simulation time is shorter.

[0090] Next, the simulation results of the quantum well semiconductor optical amplifier device are analyzed and extracted to obtain the design parameters of the quantum well semiconductor optical amplifier device and its system. In a preferred embodiment, the design parameters include the input signal power, geometric parameters of the quantum well semiconductor optical amplifier such as length, and optimized device parameters such as pump current.

[0091] Specifically, for multiple input parameters, simulations are performed sequentially to calculate the corresponding error vector magnitude (EVM), and several parameter combinations with better performance are selected as candidate parameter spaces for the next step.

[0092] Finally, system-level simulations and calculations were performed using a system model incorporating a quantum well semiconductor optical amplifier to obtain system simulation and optimization design results. In practical application system simulations, for example, in the case of... Figure 4In the coherent optical communication system based on M-order quadrature amplitude modulation (QAM) shown, the fiber input power is a system-level candidate parameter that needs to be optimized, and the corresponding device candidate parameter for QWSOA can be the pump current. Using the modeling steps described above, the obtained candidate parameter space, such as the magnitude of the pump current, is traversed through system simulations to determine the final optimization result.

[0093] Numerical simulation verification of the segmented modeling and simulation design method for quantum well semiconductor optical waveguides based on half-step partitioning is presented, comparing it with the traditional synchronous partitioning method. Specifically, the parameters given in Appendix 1 can be used to establish the numerical simulation model. A set of binary numbers randomly generated by the computer is used as the transmitted data. This set of binary numbers is encoded into 512 symbols using a 16QAM modulation format. The signal interval corresponding to each symbol is... The samples are divided into several discrete values, forming a one-dimensional array. The traditional spatiotemporal synchronous partitioning modeling method is denoted as "split1," and the spatiotemporal staggered half-step partitioning modeling method mentioned in the patent is denoted as "split2." Simulations are performed using the synchronous partitioning method "split1" and the half-step partitioning method "split2," respectively, and the optical signal at the end of the quantum well semiconductor optical waveguide is recorded as the output signal. Note that its numerical precision depends on the chosen value. Normalized standard deviation (nsd) is used as the global error. The metric, but defined as a specific step size. The approximate solution and with a very small Or a very large number of steps per symbol The difference between the obtained "true solutions".

[0094] Using the split1 method and To simulate the "true solution" defined as the output signal, such as Figure 6 As shown, the output signal waveforms obtained by the two partitioning methods are compared with the true solution. The result of the half-step partitioning is closer to the true solution.

[0095] Number of steps used for each symbol Global error with NSD The relationship is as follows: Figure 7 As shown, the half-step partitioning method, i.e., split 2, is proven by simulation results to be a second-order method: when the step size is halved, the NSD error decreases to 1 / 4. The simultaneous partitioning method, i.e., split 1, has been proven to be a first-order method; to achieve the same NSD, it requires more simulation steps. At an accuracy or error level of 1e-3, the half-step partitioning method requires only 1 / 5 the number of partitions compared to the synchronous partitioning method. Since partitioning occurs in both time and space, the number of computational steps is only 1 / 25, resulting in an efficiency improvement of approximately 25 times. In optical communication using high-capability error-correcting codes, where higher accuracy is required, the misaligned half-step partitioning method may offer even greater speedup compared to the synchronous partitioning method.

[0096] Although exemplary embodiments of the invention have been described for illustrative purposes, those skilled in the art will understand that various modifications, additions, and substitutions in form and detail may be made without departing from the scope and spirit of the invention disclosed in the appended claims, and all such modifications and substitutions should fall within the scope of protection of the appended claims. Furthermore, the various parts of the product and the various steps of the method claimed in this invention can be combined in any combination. Therefore, the description of the embodiments disclosed in this invention is not intended to limit the scope of the invention, but rather to describe the invention. Accordingly, the scope of the invention is not limited by the above embodiments, but is defined by the claims or their equivalents.

Claims

1. A segmented modeling and simulation method for quantum well semiconductor optical amplifiers based on spatiotemporally staggered half-step partitioning, characterized in that, Specifically, the following steps are performed sequentially: (1) Extract parameter data of quantum well semiconductor optical amplifier devices and quantum well electro-optic gain materials and perform preprocessing; (2) The light amplification direction of the active region of the quantum well semiconductor optical amplifier is segmented step by step in a spatiotemporally staggered half-step manner, and a time-domain mathematical and physical model of the light field and material gain segmentation is established. The simulation formula and algorithm based on the model are obtained, and the simulation calculation is carried out in combination with hardware or software. (3) Perform data analysis and extraction on the simulation results of the quantum well semiconductor optical amplifier device to obtain the design parameters of the quantum well semiconductor optical amplifier device and its system; (4) Use the system model containing the quantum well semiconductor optical amplifier to perform system-level simulation and calculation to obtain system simulation and optimization design results.

2. The method as described in claim 1, characterized in that, Step (1) specifically includes the following steps: (1.1) Modeling and simulating the electrical properties of quantum well electro-optic gain materials and extracting bandgap parameter data; (1.2) Modeling and simulation of optical waveguides constructed from quantum well electro-optic gain materials and extraction of waveguide parameter data; (1.3) Extraction of signal velocity and polarizability data of quantum well electro-optic gain material.

3. The method as described in claim 2, characterized in that: Quantum well electro-optic gain materials include quantum well semiconductor electro-optic gain materials.

4. The method as described in claim 1 or 3, characterized in that, Step (2) specifically includes the following steps: (2.1) The initial value of the carrier concentration of the quantum well semiconductor optical waveguide is given by the carrier concentration at the initial equilibrium. (2.2) The quantum well semiconductor optical waveguide is mathematically divided into N segments along the optical signal transmission direction, each segment having a length of... The input optical signal to be simulated in time Mathematical segmentation of the above Segment, length of each segment At the same time, ensure , This represents the group velocity of the optical signal in the quantum well semiconductor medium, and samples are taken at the beginning of each signal segment to obtain... ; (2.3) Establish the calculation point of the optical signal to be calculated , indicating in time, The electric field of the light signal at that location, The range of values ​​is Integers; (2.4) Establish the calculation point for carrier concentration ,express time, The carrier concentration at the specified location is... and Both are greater than The half-integer; calculate the carrier concentration of each segment on the quantum well semiconductor optical amplifier as the optical signal enters the active region. The value after the time interval indicates that the optical signal only enters the active and restricted regions. The effects on the active and confined regions are negligible; the carrier concentration remains constant in the dynamic equilibrium between electric pump injection and recombination, i.e. ; (2.5) Calculate the carrier concentration in the active region of the quantum well semiconductor and restricted region carrier density The rate is satisfied, and the carrier concentration is iteratively processed; (2.6) The optical signal and carrier concentration are iteratively calculated using the input optical signal, initial carrier concentration, and boundary response to the optical signal. As an output signal.

5. The method as described in claim 4, characterized in that, The specific steps (2.5) are as follows: Calculating the carrier concentration in the active region of a quantum well semiconductor and restricted region carrier density Satisfied rate equation: in and The volumes of the active and confinement regions are represented, and the spontaneous decay of charge carriers is also considered. ; The iterative equation for carrier concentration is obtained as follows: Select for , among them Can represent or .

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