260 lines
8.6 KiB
Markdown
260 lines
8.6 KiB
Markdown
It is recommended to import scgenerator in the following manner :
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`import scgenerator as sc`
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# How to run a set of simulations
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create a config file
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run `sc.parallel_simulations(config_file)` or `sc.simulate(config_file)`
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# How to analyse a simulation
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load data with the load_sim_data method
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spectra, params = load_sim_data("varyTechNoise100kW_sim_data")
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to plot
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plot_results_2D(spectra[0], (600, 1450, nm), params)
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# Environment variables
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SCGENERATOR_PBAR_POLICY : "none", "file", "print", "both", optional
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whether progress should be printed to a file ("file"), to the standard output ("print") or both, default : print
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# Configuration
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You can load parameters by simply passing the path to a toml file to the appropriate simulation function. Each possible key of this dictionary is described below. Every value must be given in standard SI units (m, s, W, J, ...)
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The configuration file can have a ```name``` parameter at the root and must otherwise contain the following sections with the specified parameters. Every section ("fiber", "gas", "pulse", "simulation") can have a "variable" subsection where parameters are specified in a list INSTEAD of being specified as a single value in the main section. This has the effect of running one simulation per value in the list. If many parameters are variable, all possible combinations are ran.
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Examples :
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```
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n2 = 2.2e-20
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```
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a single simulation is ran with this value
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```
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[variable]
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n2 = [2.1e-20, 2.4e-20, 2.6e-20]
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```
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3 simulations are ran, one for each value
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```
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n2 = 2.2e-20
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[variable]
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n2 = [2.1e-20, 2.4e-20, 2.6e-20]
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```
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NOT ALLOWED
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note : internally, another structure with a flattened dictionary is used
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## Fiber parameters
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If you already know the Taylor coefficients corresponding to the expansion of the beta2 profile, you can specify them and skip to "Other fiber parameters":
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beta: list-like
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list of Taylor coefficients for the beta_2 function
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If you already have a dispersion curve, you can convert it to a npz file with the wavelength (key : 'wavelength') in m and the D parameter (key : 'dispersion') in s/m/m. You the refer to this file as
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dispersion_file : str
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path to the npz dispersion file
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else, you can choose a mathematical fiber model
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model: str {"pcf", "marcatili", "marcatili_adjusted", "hasan"}
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**PCF** : solid core silica photonic crystal fiber, as modeled in Saitoh, Kunimasa, and Masanori Koshiba. "Empirical relations for simple design of photonic crystal fibers." Optics express 13.1 (2005): 267-274.
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**marcatili** : Marcatili model of a capillary fiber : Marcatili, Enrique AJ, and R. A. Schmeltzer. "Hollow metallic and dielectric waveguides for long distance optical transmission and lasers." Bell System Technical Journal 43.4 (1964): 1783-1809.
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**marcatili_adjusted** : Marcatili model of a capillary fiber with adjusted effective radius in the longer wavelength : Köttig, F., et al. "Novel mid-infrared dispersive wave generation in gas-filled PCF by transient ionization-driven changes in dispersion." arXiv preprint arXiv:1701.04843 (2017).
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**hasan** : Hasan model of hollow core anti-resonance fibers : Hasan, Md Imran, Nail Akhmediev, and Wonkeun Chang. "Empirical formulae for dispersion and effective mode area in hollow-core antiresonant fibers." Journal of Lightwave Technology 36.18 (2018): 4060-4065.
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and specify the parameters it needs
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pcf :
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pitch: float
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distance between air holes in m
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pitch_ratio: float 0.2 < pitch_ratio < 0.8
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ratio hole diameter/pich
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marcatili, marcatili_adjusted, hasan :
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core_radius: float
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radius of the hollow core in m
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marcatili, marcatili_adjusted :
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he_mode: list, shape (2, ), optional
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mode of propagation. default is (1, 1), which is the fundamental mode
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marcatili_adjusted :
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fit_parameters: list, shape (2, ), optional
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parameters for the effective radius correction. Defaults are (s, h) = (0.08, 200e-9) as in the referenced paper.
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hasan :
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capillary_num : int
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number of capillaries
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capillary_outer_d : float, optional if g is specified
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outer diameter of the capillaries
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capillary_thickness : float
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thickness of the capillary walls
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capillary_spacing : float, optional if d is specified
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spacing between the capillary
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capillary_resonance_strengths : list, optional
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list of resonance strengths. Default is []
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capillary_nested : int, optional
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how many nested capillaries. Default is 0
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## Other fiber parameters :
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gamma: float, optional unless beta is directly provided
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nonlinear parameter in m^-1*W^-1. Will overwrite any computed gamma parameter.
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effective_mode_diameter : float, optional
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effective mode field diameter in m
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n2 : float, optional
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non linear refractive index in m^2/W
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A_eff : float, optional
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effective mode field area
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length: float, optional
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length of the fiber in m. default : 1
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input_transmission : float
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number between 0 and 1 indicating how much light enters the fiber, useful when chaining many fibers together, default : 1
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## Gas parameters
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this section is completely optional and ignored if the fiber model is "pcf"
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gas_name: str
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name of the gas. default : "vacuum"
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pressure: float
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pressure of the gas in the fiber. default : 1e5
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temperature: float
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temperature of the gas in the fiber. default : 300
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plasma_density: float
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constant plasma density (in m^-3). default : 0
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## Pulse parameters:
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### Mandatory
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wavelength: float
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pump wavelength in m
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To specify the initial pulse properties, either use one of 3 in (peak_power, energy, mean_power) together with one of 2 in (width, t0), or use soliton_num together with one of 5 in (peak_power, mean_power, energy, width, t0)
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peak_power : float
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peak power in W
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mean_power : float
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mean power of the pulse train in W. if specified, repetition_rate must also be specified
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repetition_rate : float
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repetition rate of the pulse train in Hz
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energy: float
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total pulse energy in J
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width: float
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full width half maximum of the pulse in s. Will be converted to appropriate t0 depending on pulse shape
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t0: float
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pulse width parameter
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soliton_num: float
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soliton number
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### optional
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field_file : str
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if you have an initial field to use, convert it to a npz file with time (key : 'time') in s and electric field (key : 'field') in sqrt(W) (can be complex). You the use it with this config key. You can then scale it by settings any 1 of mean_power, energy and peak_power (priority is in this order)
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quantum_noise: bool
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whether or not one-photon-per-mode quantum noise is activated. default : False
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intensity_noise: float
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relative intensity noise
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shape: str {"gaussian", "sech"}
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shape of the pulse. default : gaussian
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## Simulation parameters
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### 2 of 3
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dt: float
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resolution of the temporal grid in s
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t_num: int
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number of temporal grid points
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time_window: float
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total length of the temporal grid in s
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### optional
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behaviors: list of str {"spm", "raman", "ss"}
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spm is self-phase modulation
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raman is raman effect
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ss is self-steepening
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default : ["spm", "ss"]
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raman_type: str {"measured", "stolen", "agrawal"}
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type of Raman effect. Default is "agrawal".
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ideal_gas: bool
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if True, use the ideal gas law. Otherwise, use van der Waals equation. default : False
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z_num : int
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number of spatial grid points along the fiber. default : 128
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frep: float
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repetition rate in Hz. Only useful to convert units. default : 80e6
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tolerated_error: float
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relative tolerated step-to-step error. default : 1e-11
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step_size: float
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if given, sets a constant step size rather than adapting it.
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parallel: bool
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whether to run simulations in parallel with the available ressources. default : false
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repeat: int
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how many simulations to run per parameter set. default : 1
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lower_wavelength_interp_limit: float
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dispersion coefficients are computed over a certain wavelength range. This parameter
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sets the lowest end of this range. If the set value is lower than the lower end of the
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wavelength window, it is raised up to that point. default : 0
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upper_wavelength_interp_limit: float
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dispersion coefficients are computed over a certain wavelength range. This parameter
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sets the lowest end of this range. If the set value is higher than the higher end of the
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wavelength window, it is lowered down to that point. default : 1900e-9
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interp_degree: int
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max degree of the Taylor polynomial fitting the dispersion data
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readjust_wavelength : bool
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if a custom input field is set, it is likely that the maximum of its corresponding spectrum doesn't lies exactly at the
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set wavelength. If this setting is True, the program will override the wavelength parameter so that the maximum of the spectrum
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lies on the desired wavelength.
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