A method and system for simulation verification of a model-configurable optical fiber optical comb

Abstract

A method and system for simulating and verifying a model-configurable fiber optic optical comb, belonging to the field of fiber laser technology. In the present invention, oscillator sub-functions are respectively written based on typical laser structures with different mode-locking mechanisms, and corresponding function models are called according to the mode-locking type of the laser actually studied during specific operations to meet the simulation requirements of the fiber optic optical comb structure.

Description

Technical Field

[0001] The present invention relates to a method and system for simulating and verifying a fiber optic frequency comb with configurable models, belonging to the technical field of fiber lasers. Background Art

[0002] Due to its unique advantages, fiber optic frequency combs have received extensive attention and rapid development in laboratory research and commercial applications. The nature of using optical fibers as the transmission medium also makes the simulation research on fiber optic frequency combs relatively flexible and variable. A common research method is to use commercial simulation software, with the basic optical element model as the smallest granularity, and select appropriate components or cases according to the application scenario to build the simulation object of the fiber optic system. It has the advantages of convenient use and friendly interface, and is commonly used in the simulation applications of mature fiber optic systems, such as fiber optic communication. However, when the component library cannot cover the key devices involved in the system, or when the simulation pays more attention to the signal evolution process (such as involving nonlinear dynamics research) or has higher requirements for parameter flexibility, a research method of numerically solving under the framework of the Ginzburg-Landau equations and the Nonlinear equations is often adopted. However, most of the current research reports mainly focus on the separate simulation of the theoretical verification of fiber lasers or soliton dynamics research, and have not been carried out for the complete fiber optic link system of fiber optic frequency combs. However, the actual output of fiber optic frequency combs is the coupled result of multi-stage effects including the oscillation stage, pulse amplification stage, pulse width compression stage, and spectral broadening stage. Therefore, it is an urgent problem to be solved in the efficient research and design of fiber optic frequency comb fiber optic links to ensure both the data consistency of the test modules and the inheritance of input and output when the simulation is oriented to the same system, and to have a certain degree of structural flexibility and adaptability, and then establish a simulation verification method and system with configurable models. Summary of the Invention

[0003] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, providing a method and system for simulating and verifying a fiber optic frequency comb with configurable models, respectively writing corresponding oscillator sub-functions based on the typical laser structures of different mode-locking mechanisms, and calling the corresponding function models according to the mode-locking type of the laser actually studied during specific operations to complete the simulation requirements of the fiber optic frequency comb structure.

[0004] The technical solution of the present invention is: a method for simulating and verifying a fiber optic frequency comb with configurable models, including:

[0005] Select the mode-locking mechanism of the oscillator, configure the corresponding operation model, and set the number of operation cycles, which corresponds to the number of running cycles of the oscillator output signal in the oscillator cavity; display the result of the oscillator output signal, confirm that the oscillator operation meets the requirements, and assign a loss coefficient for the oscillator output signal to be transmitted to the next operation process;

[0006] Use the oscillator output signal after attenuation assignment as the input signal for the amplifier stage operation process. First, identify the number of amplifier stages and assign values to key parameters; display the result of the amplifier stage output signal, confirm that the amplifier stage operation meets the requirements, and assign a loss coefficient for the amplifier stage output signal to be transmitted to the next operation process;

[0007] Use the amplifier stage output signal after attenuation assignment as the input signal for the compression stage operation process. First, set the step length of the fiber calculation and assign values to preset key parameters; display the result of the compression stage output signal, identify the compression fiber length experienced at the narrowest pulse width, confirm the selected compression fiber length, output the pulse signal at this length as the operation result of this stage, and assign a loss coefficient for this signal to be transmitted to the next operation process;

[0008] Use the compression stage output signal after attenuation as the input signal for the high-nonlinear fiber spectral broadening stage operation process. First, set the step length of the fiber calculation and assign values to preset key parameters; display the result of the output signal of the high-nonlinear fiber spectral broadening stage, confirm that the broadening stage operation meets the requirements, and complete the simulation of the optical part of the fiber optic comb from the generation of the oscillator seed light to the generation of the supercontinuum required for signal detection. ceo Simulation of the generation of the supercontinuum required for signal detection.

[0009] Furthermore, the starting signal of the simulation is a pulse signal or a superposition signal of a pulse signal and random noise, or a random noise signal.

[0010] Furthermore, the oscillator mode-locking mechanism includes SA mode-locking, NPE mode-locking, and NALM mode-locking.

[0011] Furthermore, if it is SA mode-locking, at this time, the oscillator includes a gain fiber, a single-mode fiber, a beam splitter, and a semiconductor saturable absorber mirror; first, identify the fibers and devices actually included in the laser, modify the transmission functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and saturable absorbers, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the absorption coefficient and saturation power intensity of the saturable absorber.

[0012] Further, if it is NPE mode-locking, at this time, the oscillator includes a polarization controller, a polarization-dependent isolator, a gain fiber, a single-mode fiber, and a beam splitter; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign key parameters related to the optical devices, fibers, and polarization, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the angle between the optical axis adjusted by the polarization controller and the fast axis of the fiber.

[0013] Further, if it is NALM mode-locking, at this time, the oscillator includes a Sagnac loop beam splitter, a non-reciprocal phase shifter, a gain fiber, a single-mode fiber, a mirror, and a beam splitter for signal output; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign key parameters related to the optical devices, fibers, and polarization, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the fiber beam splitter forming the Sagnac loop, the beam splitting ratio of the signal output beam splitter; the phase shift amount of the non-reciprocal phase shifter and the reflection coefficient of the mirror.

[0014] A model-configurable fiber optic comb simulation and verification system includes:

[0015] An oscillator module for the modeling and simulation of a fiber laser that provides seed light for the fiber optic comb, selects and calls the model of the corresponding mode-locking mechanism according to the simulation requirements, obtains the laser output after the operation of the simulated laser cavity circulation, and obtains the evolution process data;

[0016] A pulse amplification module for simulating the power amplification of the oscillator output signal, setting the amplification stage according to needs, recording the time-frequency domain evolution process of the signal amplification under the setting of the fiber transmission operation step value, and finally outputting the operation result of the amplification stage;

[0017] A pulse compression module for the simulation and verification of pulse compression to obtain the nonlinear fiber spectral broadening effect that meets the octave-spanning condition, outputting a high pulse peak power through precise control of dispersion; under the setting of the fiber transmission operation step value, recording the time-frequency domain evolution process of the pulse compression, identifying the compression length experienced at the narrowest pulse width as the recommended value, and finally outputting the operation result of the compression stage;

[0018] A spectral broadening module is used to simulate the process of generating supercontinuum spectrum in a nonlinear optical fiber. Under the setting of the operation step value of fiber transmission, it records the time-frequency domain evolution process of spectral broadening. Through the optimization of parameter settings, a supercontinuum spectrum spanning more than an octave is finally obtained, completing the simulation verification of the all-fiber link of the fiber optic comb.

[0019] Furthermore, the starting signal for the simulation is a pulse signal or a superposition signal of a pulse signal and random noise, or a random noise signal;

[0020] The mode-locking mechanism of the oscillator includes SA mode-locking, NPE mode-locking, and NALM mode-locking;

[0021] If it is SA mode-locking, at this time, the oscillator includes a gain fiber, a single-mode fiber, a beam splitter, and a semiconductor saturable absorber mirror. First, identify the fibers and devices actually included in the laser, delete and modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign key parameters to the optical devices, fibers, and saturable absorbers, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the absorption coefficient and saturation power intensity of the saturable absorber;

[0022] If it is NPE mode-locking, at this time, the oscillator includes a polarization controller, a polarization-dependent isolator, a gain fiber, a single-mode fiber, and a beam splitter. First, identify the fibers and devices actually included in the laser, delete and modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign key parameters to the optical devices, fibers, and polarization-related components, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the angle between the optical axis adjusted by the polarization controller and the fast axis of the fiber;

[0023] For NALM mode locking, at this time, the oscillator includes a Sagnac loop beam splitter, a non-reciprocal phase shifter, a gain fiber, a single-mode fiber, a mirror, and a beam splitter for signal output; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign values to the key parameters related to the optical devices, fibers, and polarization, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the splitting ratio of the fiber beam splitter constituting the Sagnac loop, the splitting ratio of the beam splitter for signal output; the phase shift amount of the non-reciprocal phase shifter, and the reflection coefficient of the mirror.

[0024] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for simulating and verifying a fiber optic comb with configurable model are implemented.

[0025] A device for simulating and verifying a fiber optic comb with configurable model includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for simulating and verifying a fiber optic comb with configurable model are implemented.

[0026] The advantages of the present invention compared with the prior art are as follows:

[0027] The method and system for simulating and verifying a fiber optic comb with configurable model provided by the present invention can flexibly and efficiently carry out research on the optical link parameters of the fiber optic comb according to actual needs, and provide an efficient and convenient research means for optimizing device selection and dispersion control.

[0028] 1. The simulation and verification method of the present invention is based on the transmission equations of discrete devices and fibers for numerical operations, and modularizes the oscillation stage, pulse amplification stage, pulse width compression stage, and spectral broadening stage according to the functions of the optical part of the fiber optic comb, and writes them as directly callable sub-function files respectively. Because this simulation and verification method and system are closer to the operation logic of the real transmission model, the research granularity of the fiber optic comb is smaller, the pertinence is stronger, and it can be refined to the specific parameter items of the devices and fibers. At the same time, the simulation method can flexibly call functions according to the actual situation, quickly configure the model and change the configuration, has wide applicability, provides an effective means for the parameter optimization design of the fiber optic comb under research, and greatly improves the optical link design efficiency.

[0029] 2. The simulation verification method and system of the present invention cover the complete process of signal transmission in the optical fiber optical comb optical link structure. Since the output result of the optical fiber optical comb optical path is a coupling result affected by the structures and parameters of each level of modules, the simulation verification method and system of the present invention ensure the data consistency of the tested modules under the same system, ensure the inheritance of data input and output, and have certain practical guiding significance for the precise time-frequency domain regulation of pulses by using dispersion and nonlinear effects in the optical fiber optical comb. At the same time, the simulation verification method and system of the present invention can observe data for each level of operation, and the time-frequency domain evolution process of signal transmission is visible, providing a simulation observation platform for the research of the pulse nonlinear dynamics evolution process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic block diagram of a model-configurable optical fiber optical comb simulation verification method.

[0031] Figure 2 It is a schematic diagram of the optical fiber optical comb optical fiber link structure of a typical NALM mode-locked fiber laser based on a "9" - shaped cavity.

[0032] Figure 3 It is a schematic flow diagram of a model-configurable optical fiber optical comb simulation verification method.

[0033] Figure 4 It is the time-frequency domain evolution process of signal transmission of each module obtained by using the simulation verification method and system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] In order to better understand the above technical solutions, the technical solutions of the present application will be described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0035] The following further details the model-configurable optical fiber optical comb simulation verification method provided by the embodiments of the present application with reference to the accompanying drawings of the specification. The specific implementation manner may include (as Figures 1 to 4 shown):

[0036] Step 1: Select the oscillator mode-locking mechanism (1.a SA mode-locking, 1.b NPE mode-locking, and 1.c NALM mode-locking), configure the corresponding operation model, and set the number of operation cycles, corresponding to the number of running cycles of the oscillator output signal in the oscillator cavity.

[0037] In the aforementioned Step 1, the starting signal of the simulation can be defined as a small pulse signal or a superimposed signal of a small pulse signal and random noise. Moreover, the type of pulse is not restricted and can be set as Gaussian, Lorentzian, or hyperbolic secant according to the actual situation, or it can also be defined as a random noise signal.

[0038] Function 1.a: SA mode-locking mechanism. The oscillator under this function mainly includes a gain fiber, a single-mode fiber, a beam splitter, and a semiconductor saturable absorber mirror (SESAM). First, identify the fibers and devices actually included in the laser. Delete and modify the transfer functions involved in the model according to requirements. At the same time, modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and saturable absorber, mainly including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the absorption coefficient and saturation power intensity of the saturable absorber, etc.

[0039] Function 1.b: NRE mode-locking mechanism. The oscillator under this function mainly includes a polarization controller (PC), a polarization-dependent isolator (PD-ISO), a gain fiber, a single-mode fiber, and a beam splitter. First, identify the fibers and devices actually included in the laser. Delete and modify the transfer functions involved in the model according to requirements. At the same time, modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and polarization-related ones, mainly including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the angle between the optical axis adjusted by the polarization controller and the fast axis of the fiber, etc.

[0040] Function 1.c: NALM mode-locking mechanism. The oscillator under this function mainly includes a Sagnac loop beam splitter, a non-reciprocal phase shifter, a gain fiber, a single-mode fiber, a mirror, and a signal output beam splitter. First, identify the fibers and devices actually included in the laser. Delete and modify the transfer functions involved in the model according to requirements. At the same time, modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and polarization-related ones, mainly including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the fiber beam splitter forming the Sagnac loop, the beam splitting ratio of the signal output beam splitter; the phase shift amount of the non-reciprocal phase shifter and the reflection coefficient of the mirror, etc.

[0041] In Step 1, the operation programs of three common mode-locked lasers are respectively written as callable sub-function files, and the configuration selection of the first operation module in the fiber optic comb simulation process is realized through function calls. Inside the function, numerical simulation operations are carried out based on the transmission equations of discrete devices and optical fibers according to the signal transmission sequence.

[0042] Step 2: Display the results of the output signal of the oscillator, mainly including the time-frequency domain operation results, confirm that the oscillator operation meets the requirements, and assign a loss coefficient for the output signal to be transmitted to the next operation process (amplification stage).

[0043] Step 3: Use the output signal of the oscillator after being attenuated by assignment as the input signal for the operation process of the amplification stage. First, identify the number of amplification stages and assign values to key parameters, mainly including the fiber length of each single-mode fiber, the small-signal gain coefficient of the gain fiber, the fiber length, etc.

[0044] Step 4: Display the results of the output signal of the amplification stage, mainly including the time-frequency domain operation results of pulse amplification, confirm that the amplification stage operation meets the requirements, and assign a loss coefficient for the output signal to be transmitted to the next operation process (compression stage).

[0045] Step 5: Use the output signal of the amplification stage after being attenuated by assignment as the input signal for the operation process of the compression stage. First, set the step length of fiber calculation and assign values to key parameters, mainly including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the compression fiber, etc.

[0046] Step 6: Display the results of the output signal of the compression stage, mainly including the pulse width change curve during the transmission of the compression fiber, identify the length of the compression fiber experienced at the narrowest pulse width, confirm the selected length of the compression fiber, output the pulse signal at this length as the operation result of this stage, and assign a loss coefficient for this signal to be transmitted to the next operation process (compression stage).

[0047] Step 7: Use the output signal of the compression stage after attenuation as the input signal for the operation process of the highly nonlinear fiber spectral broadening stage. First, set the step length of fiber calculation and assign values to key parameters, mainly including the transmission loss, group velocity dispersion, dispersion slope, nonlinear parameter, the first moment of the nonlinear effect function, and the fiber length of the highly nonlinear fiber, etc.

[0048] Step 8: Display the results of the output signal of the highly nonlinear fiber spectral broadening stage, mainly including the time-frequency domain operation results of the spectral broadening process, and confirm that the broadening stage operation meets the requirements. Thus, the simulation operation process of the optical part of the fiber optic comb from the generation of the oscillator seed light to the generation of the supercontinuum required for signal detection is completed. ceo The simulation operation process of the supercontinuum required for signal detection.

[0049] Based on the same inventive concept, the present invention also provides a model-configurable fiber optic comb simulation verification system, including: Figure 1 The oscillator module is used for the modeling and simulation of a fiber laser that provides seed light for the fiber optic comb, selects and calls the model of the corresponding mode-locking mechanism according to the simulation requirements, obtains the laser output after the operation of the simulated laser cavity circulation, and obtains the evolution process data;

[0050] The pulse amplification module is used to simulate the power amplification of the oscillator output signal, sets the amplification stage according to the needs, records the time-frequency domain evolution process of the signal amplification under the setting of the fiber transmission operation step value, and finally outputs the amplification stage operation result;

[0051] The pulse compression module is used for the pulse compression simulation verification to obtain the nonlinear fiber spectral broadening effect that meets the octave-spanning condition, outputs a high pulse peak power through precise regulation of dispersion; under the setting of the fiber transmission operation step value, records the time-frequency domain evolution process of the pulse compression, identifies the compression length experienced at the narrowest pulse width as the recommended value, and finally outputs the compression stage operation result;

[0052] The spectral broadening module is used to simulate the process of generating supercontinuum spectrum in the nonlinear fiber, records the time-frequency domain evolution process of the spectral broadening under the setting of the fiber transmission operation step value, and finally obtains the octave-spanning supercontinuum spectrum through the optimization of parameter settings, completing the simulation verification of the all-fiber link of the fiber optic comb.

[0053] In the solution provided by the embodiments of the present application, the flow block diagram of the simulation verification method is as shown in the appendix

[0054] However, since the fiber link configurations of fiber optic combs vary widely (mainly the oscillator), there are slight differences in the specific operation implementation settings accordingly. Therefore, by referring to the appendix Figure 1 as shown, Figure 2The specific steps of applying this simulation verification method to non - restrictive embodiments are described in detail. The optical link of this fiber optic comb includes an oscillation stage, an amplification stage, a compression stage, and a spectral broadening stage. Among them, the oscillation stage is a fiber optic oscillator based on the NALM mode - locking mechanism, mainly including a first signal input terminal 1, a fiber coupler 2, a first single - mode fiber 3, a first gain fiber 4, a non - reciprocal phase shifter 5, a fiber mirror 6, and a first signal output terminal 7. Among them, the fiber coupler 3 is a 2×2 polarization - maintaining fiber coupler with four ports ① - ④. The amplification stage is two - stage amplification, including a second signal input terminal 8, a first isolator 9, a second gain fiber 10, a second isolator 11, a third gain fiber 12, and a second signal output terminal 13. The compression stage includes a third signal input terminal 14, a compression fiber 15, and a third signal output terminal 16. The spectral broadening stage includes a fourth signal input terminal 17, a highly nonlinear fiber 18, and a fourth signal output terminal 19.

[0055] Based on the above - mentioned optical link structure of the fiber optic comb, the implementation process of the simulation verification method of the present invention can be summarized as shown in the appendix Figure 3 shown. An operation program is written based on Matlab, and the specific implementation steps include:

[0056] Step 1: Select and configure the NALM operation model according to the oscillator mode - locking mechanism, complete the function model configuration of the first simulation operation module, and enter Step 1.c.

[0057] Step 1.c: Use Gaussian random white noise as the starting operation signal of the oscillator, that is, select Gaussian random white noise at the first signal input terminal 1. After this signal passes through the fiber coupler 2, the first single - mode fiber 3, the first gain fiber 4, and the non - reciprocal phase shifter 5, it passes through the fiber coupler 3 again. One path is reflected by the mirror 6 and then re - enters the ring cavity through the fiber coupler 2 for bidirectional transmission, and the other path is output from the first signal output terminal 7 as the seed light of the fiber optic comb to the subsequent module for further operation processing.

[0058] In the said Step 1.c, assuming that the coupling ratio of the fiber coupler 2 is α, the transmission process of the signal through the fiber coupler 2 is calculated using the Jones matrix, and its expression is as follows:

[0059]

[0060] The evolution of the signal in the first single - mode fiber 3 follows the simplified Nonlinear Schrödinger Equation (NLSE), and its expression is:

[0061]

[0062] Specifically, in the formula, A represents the slowly - varying envelope amplitude, z is the transmission distance, α represents the fiber loss, β2 is the fiber group - velocity dispersion, iγ|A| 2A represents the self-phase modulation term characterizing the fiber nonlinear effect, where γ is the fiber nonlinear parameter. T is the introduced reference frame moving with the pulse (i.e., the so-called retarded frame), and there is g along with

[0063] The amplification and transmission process of the signal in the first gain fiber 4 is described by the Ginzburg - Landau equation, and the equation expression is:

[0064]

[0065] In the formula, g is the gain coefficient, and T2 is the dipole relaxation time.

[0066] In step 1.c, according to the actually selected fiber and the performance indexes of fiber devices, assign values to the key parameters required for the operation, and at the same time set the number of loop operations in the ring cavity. Then the operation program will solve the time - frequency domain evolution process of signal transmission based on the split - step Fourier method.

[0067] Step 2: Output the signal operation result at the first signal output end 7, including the time - frequency domain evolution process, and confirm whether the simulation verification process of the oscillator is inherited by subsequent operations. If the operation continues, assign a transmission coefficient to this signal according to the actual situation, and this signal will continue the simulation operation as the input signal of the amplification stage.

[0068] In step 2, the transmission coefficient takes into account the transmission losses of devices such as the first isolator 9 in the actual optical link, and the oscillator output may add beam splitting to meet the signal monitoring requirements in actual experiments.

[0069] Step 3: The signal at the second signal input end 8 inherits the oscillator operation result and is used as the input signal of the amplification stage for operation. First, confirm the number of amplification stages, and assign values to the key parameters of each stage of gain fiber. Here, it is set to two - stage amplification.

[0070] In step 3, the operation method of the signal transmission process through the second gain fiber 10 and the third gain fiber 12 is similar to that in step 1.c. Use the split - step Fourier method to solve the Ginzburg - Landau equation to obtain the evolution process of the signal transmission in the fiber.

[0071] Step 4: Output the signal operation result at the second signal output end 13, including the time - frequency domain evolution process, and confirm whether the simulation result of the amplification stage is inherited by subsequent operations. If the operation continues, assign a transmission coefficient to this signal according to the actual situation, and this signal will continue the simulation operation as the input signal of the compression stage.

[0072] Step 5: The signal at the third signal input terminal 14 inherits the operation result of the amplification stage and is used as the input signal of the compression stage for operation. Assign values to the key parameters and length of the compression optical fiber.

[0073] In the said Step 5, the operation method of the signal during the transmission process through the compression optical fiber 15 is similar to that in Step 1.c. The split-step Fourier method is used to solve the NLSE equation to obtain the variation process of the signal (mainly the pulse width) with the optical fiber transmission.

[0074] Step 6: Output the operation result of the signal at the third signal output terminal 16, mainly the variation curve of the pulse width with the optical fiber transmission distance, and confirm whether the simulation result of the compression stage is inherited by the subsequent operation. If the operation continues, assign a transmission coefficient to this signal according to the actual situation, and this signal will be used as the input signal of the spectral broadening stage to continue the simulation operation.

[0075] In the said Step 6, the time-frequency domain characteristics of the pulse are regulated through precise dispersion control to obtain the highest possible pulse peak power, which is beneficial to generating an octave-spanning spectrum in the highly nonlinear optical fiber, thus providing the prerequisite for carrying out f ceo Signal detection work. Observe the operation process data of the compression stage, select appropriate parameters (especially the optical fiber length) from it, usually with the narrowest pulse width being the optimal, as the input pulse signal injected into the highly nonlinear optical fiber.

[0076] Step 7: The signal at the fourth signal input terminal 17 inherits the operation result of the compression stage and is used as the input signal of the spectral broadening stage for operation. Assign values to the key parameters and length of the highly nonlinear optical fiber.

[0077] In the said Step 7, the evolution of the signal in the highly nonlinear optical fiber 18 follows the generalized NLSE, and its expression is:

[0078]

[0079] In the formula, the nonlinear effect terms (self-steepening term and Raman effect term) ignored in the single-mode optical fiber transmission are added. β3 is the third-order dispersion, and T R is the first moment of the nonlinear response function.

[0080] Step 8: Output the operation result of the signal at the fourth signal output terminal 19, mainly the generation process of the octave-spanning spectrum with the optical fiber transmission distance, and judge whether the operation process of this simulation verification method ends according to whether the operation result meets the f ceo Signal detection condition. According to this example, the main operation results as shown in the appendix can be obtained by using the simulation verification method of the present invention. Figure 4 are shown.

[0081] So far, this simulation verification method has realized the complete layout of the optical fiber link structure according to the design requirements. At the same time, by tracking the evolution process of the signal transmission in the optical fiber, a set of index systems for experimental design optimization can be referred to, providing an efficient and reliable guiding means for the system development of optical fiber optical combs.

[0082] The present application provides a computer-readable storage medium storing computer instructions, which, when run on a computer, cause the computer to execute Figure 1 the method described above.

[0083] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program code.

[0084] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0085] These computer program instructions can also be stored in a computer-readable memory capable of guiding a computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including instruction means, and the instruction means implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0086] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable devices provide means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1Steps of the functions specified in one or more boxes.

[0087] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these changes and modifications.

[0088] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A method for simulating and verifying an optically configurable fiber optic comb, characterized in that, Including: Select an oscillator mode-locking mechanism, configure an operation model, and set the number of operation cycles, corresponding to the number of runs of the oscillator output signal in the oscillator cavity; display the result of the oscillator output signal, confirm that the oscillator operation meets the requirements, and assign a loss coefficient for the oscillator output signal to be transmitted to the next operation process; Use the oscillator output signal after being assigned attenuation as the input signal for the amplifier stage operation process. First, identify the number of amplifier stages and assign values to key parameters; display the result of the amplifier stage output signal, confirm that the amplifier stage operation meets the requirements, and assign a loss coefficient for the amplifier stage output signal to be transmitted to the next operation process; Use the amplifier stage output signal after being assigned attenuation as the input signal for the compressor stage operation process. First, set the step length of the fiber calculation and assign values to preset key parameters; display the result of the compressor stage output signal, identify the length of the compression fiber experienced at the narrowest pulse width, confirm the selected compression fiber length, output the pulse signal at this length as the operation result of this stage, and assign a loss coefficient for this signal to be transmitted to the next operation process; Use the compressor stage output signal after attenuation as the input signal for the highly nonlinear fiber spectral broadening stage operation process. First, set the step length of the fiber calculation and assign values to preset key parameters; Show the results of the output signal of the high-nonlinear fiber spectral broadening stage, confirm that the broadening stage operation meets the requirements, and complete the simulation of the optical part of the fiber optic comb from the generation of the oscillator seed light to the generation of the supercontinuum required for signal detection. ceo Simulation of supercontinuum generation required for signal detection.

2. A method for simulating and verifying an optically configurable fiber optic comb according to claim 1, wherein The starting signal of the simulation is a pulse signal or a superposition signal of a pulse signal and random noise, or a random noise signal.

3. A method for simulating and verifying an optically configurable optical fiber optical comb according to claim 1, characterized in that, The oscillator mode-locking mechanism includes SA mode-locking, NPE mode-locking, and NALM mode-locking.

4. A method for simulating and verifying an optical fiber optical comb with configurable model according to claim 3, characterized in that If it is SA mode-locking, at this time, the oscillator includes a gain fiber, a single-mode fiber, a beam splitter, and a semiconductor saturable absorber mirror; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and saturable absorber, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the absorption coefficient and saturation power intensity of the saturable absorber.

5. A method for simulating and verifying an optically configurable fiber optic comb according to claim 3, characterized in that If it is NPE mode-locking, at this time, the oscillator includes a polarization controller, a polarization-dependent isolator, a gain fiber, a single-mode fiber, and a beam splitter; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and polarization-related, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the angle between the optical axis adjusted by the polarization controller and the fast axis of the fiber.

6. A method for simulating and verifying an optical fiber optical comb with configurable model according to claim 3, characterized in that In the case of NALM mode locking, at this time, the oscillator includes a Sagnac loop beam splitter, a non-reciprocal phase shifter, a gain fiber, a single-mode fiber, a mirror, and a beam splitter for signal output; First, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign key parameters to the optical devices, fibers, and polarization-related ones, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the splitting ratio of the fiber beam splitter constituting the Sagnac loop, the splitting ratio of the signal output beam splitter; the phase shift amount of the non-reciprocal phase shifter, and the reflection coefficient of the mirror.

7. A model-configurable optical fiber optical comb simulation and verification system for implementing the optical fiber optical comb simulation and verification method according to any one of claims 1 to 6, characterized in that, Including: An oscillator module for the modeling and simulation of a fiber laser that provides seed light for a fiber optic comb, selects and calls the model of the corresponding mode locking mechanism according to the simulation requirements, and obtains the laser output and the evolution process data after the operation of simulating the laser cavity cycle; A pulse amplification module for simulating the power amplification of the oscillator output signal, setting the amplification stage according to needs, recording the time-frequency domain evolution process of signal amplification under the setting of the fiber transmission operation step value, and finally outputting the operation result of the amplification stage; A pulse compression module for the simulation verification of pulse compression to obtain the nonlinear fiber spectral broadening effect that meets the octave-spanning condition, outputting a high pulse peak power through precise control of dispersion; recording the time-frequency domain evolution process of pulse compression under the setting of the fiber transmission operation step value, identifying the compression length experienced at the narrowest pulse width as the recommended value, and finally outputting the operation result of the compression stage; A spectral broadening module for simulating the process of generating supercontinuum spectrum in a nonlinear fiber, recording the time-frequency domain evolution process of spectral broadening under the setting of the fiber transmission operation step value, and finally obtaining an octave-spanning supercontinuum spectrum through parameter setting optimization to complete the simulation verification of the all-fiber link of the fiber optic comb.

8. The model-configurable optical fiber optical comb simulation and verification system according to claim 7, characterized in that The starting signal of the simulation is a pulse signal, or a superposition signal of a pulse signal and random noise, or a random noise signal; The oscillator mode locking mechanisms include SA mode locking, NPE mode locking, and NALM mode locking; In the case of SA mode locking, at this time, the oscillator includes a gain fiber, a single-mode fiber, a beam splitter, and a semiconductor saturable absorber mirror; First, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to make it conform to the actual configuration of the oscillator, and assign key parameters to the optical devices, fibers, and saturable absorber, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the splitting ratio of the signal output beam splitter; the absorption coefficient and saturation power intensity of the saturable absorber; For NPE mode locking, at this time, the oscillator includes a polarization controller, a polarization-dependent isolator, a gain fiber, a single-mode fiber, and a beam splitter; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and polarization, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the signal output beam splitter; the angle between the optical axis adjusted by the polarization controller and the fast axis of the fiber. For NALM mode locking, at this time, the oscillator includes a Sagnac loop beam splitter, a non-reciprocal phase shifter, a gain fiber, a single-mode fiber, a mirror, and a signal output beam splitter; first, identify the fibers and devices actually included in the laser, modify the transfer functions involved in the model according to requirements, and at the same time modify the operation order of the optical devices and fibers to conform to the actual configuration of the oscillator, and assign values to the key parameters of the optical devices, fibers, and polarization, including the transmission loss, group velocity dispersion, nonlinear parameter, and fiber length of the single-mode fiber; the transmission loss, central wavelength, gain bandwidth, pulse saturation energy, small-signal gain coefficient, group velocity dispersion, nonlinear parameter, and fiber length of the gain fiber; the beam splitting ratio of the fiber beam splitter forming the Sagnac loop, the beam splitting ratio of the signal output beam splitter; the phase shift amount of the non-reciprocal phase shifter and the reflection coefficient of the mirror.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

10. A model-configurable optical fiber optical comb simulation and verification device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

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