It is recommended to import scgenerator in the following manner :
import scgenerator as sc
How to run a set of simulations
create a config file
run sc.run_simulation(config_file)
How to analyse a simulation
Load completed simulations with the SimulationSeries class. The path argument should be that of the last fiber in the series (of the form xx fiber A... where xx is an integer)
The SimulationSeries class has basic plotting functions available. See the class documentation for more info
series = sc.SimulationSeries(path_to_data_folder)
fig, ax = plt.subplots()
series.plot_2D(800, 1600, "nm", ax)
plt.show()
Environment variables
SCGENERATOR_PBAR_POLICY : "none", "file", "print", "both", optional
whether progress should be printed to a file ("file"), to the standard output ("print") or both, default : print
SCGENERATOR_LOG_FILE_LEVEL : "debug", "info", "warning", "error", "critical", optional
level of logging printed in $PWD/scgenerator.log
SCGENERATOR_LOG_PRINT_LEVEL : "debug", "info", "warning", "error", "critical", optional
level of logging printed in the cli.
Configuration
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, ...)
the root of the file has information concerning the whole simulation : name, grid information, input pulse, ...
Then, there must be a [[Fiber]] array with at least one fiber with fiber-specific parameters.
Parameters can be variable (either in the root or in one fiber). if at most one single [variable] dict is specified by section, all the possible combinations of those variable parameters are considered. Another possibility is to specify a [[variable]] array where the length of each set of parameter is the same so they're coupled to each other.
Examples :
n2 = 2.2e-20
a single simulation is ran with this value
[variable]
n2 = [2.1e-20, 2.4e-20, 2.6e-20]
3 simulations are ran, one for each value
n2 = 2.2e-20
[variable]
n2 = [2.1e-20, 2.4e-20, 2.6e-20]
NOT ALLOWED. You cannot specified the same parameter twice.
Here is an example of a configuration file
# these be applied to the whole simulation fiber PM1550_1 only
# fiber parameters specified here would apply to the whole simulation as well
# unless overridden in one of the individual fiber
name = "Test/Compound 1"
field_file = "Toptica/init_field.npz"
repetition_rate = 40e6
wavelength = 1535.6e-9
dt = 1e-15
t_num = 16384
tolerated_error = 1e-6
quantum_noise = true
z_num = 32
mean_power = 200e-3
repeat = 3
[[variable]]
spm = [true, false]
raman_type = ["agrawal", "stolen"]
[[Fiber]]
name = "PM1550_1"
n2 = 2.2e-20
dispersion_file = "PM1550/Dispersion/PM1550XP extrapolated 1.npz"
length = 0.01
effective_mode_diameter = 10.1e-6
[[Fiber]]
name = "PM2000D_2"
length = 0.01
n2 = 3.4e-20
A_eff_file = "PM2000D/PM2000D_A_eff_marcuse.npz"
dispersion_file = "PM2000D/Dispersion/PM2000D_1 extrapolated 0 4.npz"
[Fiber.variable] # this variable parameter will be applied to PM2000D_2
input_transmission = [0.9, 0.95]
this means that only (spm=true, raman_type="agrawal") and (spm=false, raman_type="stolen") are considered and not (spm=false, raman_type="agrawal") for example. In the end, 12 simulations are ran with this configuration.
Fiber parameters
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":
beta2_coefficients: list-like list of Taylor coefficients for the beta_2 function
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
dispersion_file : str path to the npz dispersion file
else, you can choose a mathematical fiber model
model: str {"pcf", "marcatili", "marcatili_adjusted", "hasan"}
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.
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.
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).
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.
and specify the parameters it needs
pcf :
pitch: float distance between air holes in m pitch_ratio: float 0.2 < pitch_ratio < 0.8 ratio hole diameter/pich
marcatili, marcatili_adjusted, hasan :
core_radius: float radius of the hollow core in m
marcatili, marcatili_adjusted :
he_mode: list, shape (2, ), optional mode of propagation. default is (1, 1), which is the fundamental mode
marcatili_adjusted :
fit_parameters: list, shape (2, ), optional parameters for the effective radius correction. Defaults are (s, h) = (0.08, 200e-9) as in the referenced paper.
hasan :
capillary_num : int number of capillaries
capillary_radius : float, optional if g is specified outer radius of the capillaries
capillary_thickness : float thickness of the capillary walls
capillary_spacing : float, optional if d is specified spacing between the capillary
capillary_resonance_strengths : list, optional list of resonance strengths. Default is []
capillary_resonance_max_order : int, optional max order of resonance strengths to be deduced
capillary_nested : int, optional how many nested capillaries. Default is 0
Other fiber parameters :
gamma: float, optional unless beta is directly provided nonlinear parameter in m^-1*W^-1. Will overwrite any computed gamma parameter.
effective_mode_diameter : float, optional effective mode field diameter in m
n2 : float, optional non linear refractive index in m^2/W
A_eff : float, optional effective mode field area
A_eff_file : str, optional file containing an A_eff array (in m^2) as function of a wavelength array (in m)
length: float, optional length of the fiber in m. default : 1
input_transmission : float, optional number between 0 and 1 indicating how much light enters the fiber, useful when chaining many fibers together, default : 1
zero_dispersion_wavelength : float, optional target zero dispersion wavelength for hollow capillaries (Marcatili only)
Gas parameters
this section is completely optional and ignored if the fiber model is "pcf"
gas_name: str name of the gas. default : "vacuum"
pressure: float pressure of the gas in the fiber. default : 1e5
temperature: float temperature of the gas in the fiber. default : 300
plasma_density: float constant plasma density (in m^-3). default : 0
Pulse parameters:
Mandatory
wavelength: float pump wavelength in m
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)
peak_power : float peak power in W
mean_power : float mean power of the pulse train in W. if specified, repetition_rate must also be specified
repetition_rate : float repetition rate of the pulse train in Hz
energy: float total pulse energy in J
width: float full width half maximum of the pulse in s. Will be converted to appropriate t0 depending on pulse shape
t0: float pulse width parameter
soliton_num: float soliton number
optional
field_file : str 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)
quantum_noise : bool whether or not one-photon-per-mode quantum noise is activated. default : False
intensity_noise : float relative intensity noise
noise_correlation : float correlation between intensity noise and pulse width noise. a negative value means anti-correlation
shape: str {"gaussian", "sech"} shape of the pulse. default : gaussian
Simulation parameters
2 of 3
dt: float resolution of the temporal grid in s
t_num: int number of temporal grid points
time_window: float total length of the temporal grid in s
optional
raman_type: str {"measured", "stolen", "agrawal"}, optional type of Raman effect. Specifying this parameter has the effect of turning on Raman effect
ideal_gas: bool if True, use the ideal gas law. Otherwise, use van der Waals equation. default : False
z_num : int number of spatial grid points along the fiber. default : 128
frep: float repetition rate in Hz. Only useful to convert units. default : 80e6
tolerated_error: float relative tolerated step-to-step error. default : 1e-11
step_size: float if given, sets a constant step size rather than adapting it.
parallel: bool whether to run simulations in parallel with the available resources. default : false
repeat: int how many simulations to run per parameter set. default : 1
interpolation_range : tuple[float, float] range over which dispersion is computed and interpolated in m. ex: (500e-9, 2000e-9)
interpolation_degree: int max degree of the Taylor polynomial fitting the dispersion data