Files
oopt-gnpy/gnpy/core/parameters.py
EstherLerouzic 50603420fc ROADM: rework equalization
On a ROADM, the code would previously set the same per-carrier power
regardless of the channel spectrum width. With this patch, carriers are
equalized either by their:

- absolute power (same as before),
- power spectral density (PSD).

Also, it's possible to apply a per-channel power offset (in dB) which
will be applied to a specified channel on top of the selected
power-level or PSD strategy. The same offset can be also selected
through the `--spectrum` option via the `default_pdb` parameter.

The equalization policy can be set via the ROADM model (in the equipment
config) as well as on a per-instance basis.

The PSD is defined as the absolute power over a spectral bandwidth,
where the spectral bandwidth corresponds to the actual spectrum
occupation (without any applicable guard bands), as approximated by the
symbol rate. PSD is specified in mW/GHz. As an example, for a 32 GBaud
signal at 0.01 mW, the PSD is 0.01/32 = 3.125e-4 mW/GHz.

This has some implications on the power sweep and ROADM behavior. Same
as previously (with absolute power targets), the ROADM design determines
the power set points. Target power is usually the best (highest) power
that can be supported by the ROADMs, especially the Add/Drop and express
stages' losses, with the goal to maximize the power at the booster's
input. As such, the `--power` option (or the power sweep) doesn't
manipulate with ROADM's target output power, but only with the output
power of the amplifiers. With PSD equalization, the `--power` option is
interpreted as the power of the reference channel defined in equipment
config's `SI` container, and its PSD is used for propagation. Power
sweep is interpreted in the same way, e.g.:

      "SI":[{
            "f_min": 191.3e12,
            "baud_rate": 32e9,
            "f_max":195.1e12,
            "spacing": 50e9,
            "power_dbm": 0,
            "power_range_db": [-1,1,1],
            "roll_off": 0.15,
            "tx_osnr": 40,
            "sys_margins": 2
            }],

...and with the PSD equalization in a ROADM:

    {
      "uid": "roadm A",
      "type": "Roadm",
      "params": {
        "target_psd_out_mWperGHz": 3.125e-4,
      }
    },
    {
      "uid": "edfa in roadm A to toto",
      "type": "Edfa",
      "type_variety": "standard_medium_gain",
      "operational": {
        "gain_target": 22,
        "delta_p": 2,
        "tilt_target": 0.0,
        "out_voa": 0
      }
    },

then we use the power steps of the power_range_db to compute resulting
powers of each carrier out of the booster amp:

 power_db = psd2powerdbm(target_psd_out_mWperGHz, baud_rate)
 sweep = power_db + delta_power for delta_power in power_range_db

Assuming one 32Gbaud and one 64Gbaud carriers:

                   32 Gbaud        64 Gbaud
roadmA out power
(sig+ase+nli)      -20dBm         -17dBm

EDFA out power
range[
        -1          1dBm            4dBm
         0          2dBm            5dBm
         1          3dBm            6dBm
]

Design case:

Design is performed based on the reference channel set defined in SI
in equipment config (independantly of equalization process):

      "SI":[{
            "f_min": 191.3e12,
            "baud_rate": 32e9,
            "f_max":195.1e12,
            "spacing": 50e9,
            "power_dbm": -1,
            "power_range_db": [0,0,1],
            "roll_off": 0.15,
            "tx_osnr": 40,
            "sys_margins": 2
            }],

`delta_p` values of amps refer to this reference channel, but are applicable
for any baudrate during propagation, e.g.:

    {
      "uid": "roadm A",
      "type": "Roadm",
      "params": {
        "target_psd_out_mWperGHz": 2.717e-4,
      }
    },
    {
      "uid": "edfa in roadm A to toto",
      "type": "Edfa",
      "type_variety": "standard_medium_gain",
      "operational": {
        "gain_target": 22,
        "delta_p": 2,
        "tilt_target": 0.0,
        "out_voa": 0
      }
    },

Then the output power for a 64 Gbaud carrier will be +4 =
= lin2db(db2lin(power_dbm + delta_p)/32e9 * 64e9)
= lin2db(db2lin(power_dbm + delta_p) * 2)
= powerdbm + delta + 3 = 4 dBm

Signed-off-by: EstherLerouzic <esther.lerouzic@orange.com>
Change-Id: I28bcfeb72b0e74380b087762bb92ba5d39219eb3
2023-01-17 12:26:50 +01:00

322 lines
12 KiB
Python

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
gnpy.core.parameters
====================
This module contains all parameters to configure standard network elements.
"""
from scipy.constants import c, pi
from numpy import asarray, array
from gnpy.core.utils import convert_length
from gnpy.core.exceptions import ParametersError
class Parameters:
def asdict(self):
class_dict = self.__class__.__dict__
instance_dict = self.__dict__
new_dict = {}
for key in class_dict:
if isinstance(class_dict[key], property):
new_dict[key] = instance_dict['_' + key]
return new_dict
class PumpParams(Parameters):
def __init__(self, power, frequency, propagation_direction):
self.power = power
self.frequency = frequency
self.propagation_direction = propagation_direction.lower()
class RamanParams(Parameters):
def __init__(self, flag=False, result_spatial_resolution=10e3, solver_spatial_resolution=50):
""" Simulation parameters used within the Raman Solver
:params flag: boolean for enabling/disable the evaluation of the Raman power profile in frequency and position
:params result_spatial_resolution: spatial resolution of the evaluated Raman power profile
:params solver_spatial_resolution: spatial step for the iterative solution of the first order ode
"""
self.flag = flag
self.result_spatial_resolution = result_spatial_resolution # [m]
self.solver_spatial_resolution = solver_spatial_resolution # [m]
class NLIParams(Parameters):
def __init__(self, method='gn_model_analytic', dispersion_tolerance=1, phase_shift_tolerance=0.1,
computed_channels=None):
""" Simulation parameters used within the Nli Solver
:params method: formula for NLI calculation
:params dispersion_tolerance: tuning parameter for ggn model solution
:params phase_shift_tolerance: tuning parameter for ggn model solution
:params computed_channels: the NLI is evaluated for these channels and extrapolated for the others
"""
self.method = method.lower()
self.dispersion_tolerance = dispersion_tolerance
self.phase_shift_tolerance = phase_shift_tolerance
self.computed_channels = computed_channels
class SimParams(Parameters):
_shared_dict = {'nli_params': NLIParams(), 'raman_params': RamanParams()}
def __init__(self):
if type(self) == SimParams:
raise NotImplementedError('Instances of SimParams cannot be generated')
@classmethod
def set_params(cls, sim_params):
cls._shared_dict['nli_params'] = NLIParams(**sim_params.get('nli_params', {}))
cls._shared_dict['raman_params'] = RamanParams(**sim_params.get('raman_params', {}))
@classmethod
def get(cls):
self = cls.__new__(cls)
return self
@property
def nli_params(self):
return self._shared_dict['nli_params']
@property
def raman_params(self):
return self._shared_dict['raman_params']
class RoadmParams(Parameters):
def __init__(self, **kwargs):
self.target_pch_out_db = kwargs.get('target_pch_out_db')
self.target_psd_out_mWperGHz = kwargs.get('target_psd_out_mWperGHz')
equalisation_type = ['target_pch_out_db', 'target_psd_out_mWperGHz']
temp = [kwargs.get(k) is not None for k in equalisation_type]
if sum(temp) > 1:
raise ParametersError('ROADM config contains more than one equalisation type.'
+ 'Please choose only one', kwargs)
self.per_degree_pch_out_db = kwargs.get('per_degree_pch_out_db', {})
self.per_degree_pch_psd = kwargs.get('per_degree_psd_out_mWperGHz', {})
try:
self.add_drop_osnr = kwargs['add_drop_osnr']
self.pmd = kwargs['pmd']
self.pdl = kwargs['pdl']
self.restrictions = kwargs['restrictions']
except KeyError as e:
raise ParametersError(f'ROADM configurations must include {e}. Configuration: {kwargs}')
class FusedParams(Parameters):
def __init__(self, **kwargs):
self.loss = kwargs['loss'] if 'loss' in kwargs else 1
# SSMF Raman coefficient profile normalized with respect to the effective area (Cr * A_eff)
CR_NORM = array([
0., 7.802e-16, 2.4236e-15, 4.0504e-15, 5.6606e-15, 6.8973e-15, 7.802e-15, 8.4162e-15, 8.8727e-15, 9.2877e-15,
1.01011e-14, 1.05244e-14, 1.13295e-14, 1.2367e-14, 1.3695e-14, 1.5023e-14, 1.64091e-14, 1.81936e-14, 2.04927e-14,
2.28167e-14, 2.48917e-14, 2.66098e-14, 2.82615e-14, 2.98136e-14, 3.1042e-14, 3.17558e-14, 3.18803e-14, 3.17558e-14,
3.15566e-14, 3.11748e-14, 2.94567e-14, 3.14985e-14, 2.8552e-14, 2.43439e-14, 1.67992e-14, 9.6114e-15, 7.02180e-15,
5.9262e-15, 5.6938e-15, 7.055e-15, 7.4119e-15, 7.4783e-15, 6.7645e-15, 5.5361e-15, 3.6271e-15, 2.7224e-15,
2.4568e-15, 2.1995e-15, 2.1331e-15, 2.3323e-15, 2.5564e-15, 3.0461e-15, 4.8555e-15, 5.5029e-15, 5.2788e-15,
4.565e-15, 3.3698e-15, 2.2991e-15, 2.0086e-15, 1.5521e-15, 1.328e-15, 1.162e-15, 9.379e-16, 8.715e-16, 8.134e-16,
8.134e-16, 9.379e-16, 1.3612e-15, 1.6185e-15, 1.9754e-15, 1.8758e-15, 1.6849e-15, 1.2284e-15, 9.047e-16, 8.134e-16,
8.715e-16, 9.711e-16, 1.0375e-15, 1.0043e-15, 9.047e-16, 8.134e-16, 6.806e-16, 5.478e-16, 3.901e-16, 2.241e-16,
1.577e-16, 9.96e-17, 3.32e-17, 1.66e-17, 8.3e-18])
# Note the non-uniform spacing of this range; this is required for properly capturing the Raman peak shape.
FREQ_OFFSET = array([
0., 0.5, 1., 1.5, 2., 2.5, 3., 3.5, 4., 4.5, 5., 5.5, 6., 6.5, 7., 7.5, 8., 8.5, 9., 9.5, 10., 10.5, 11., 11.5, 12.,
12.5, 12.75, 13., 13.25, 13.5, 14., 14.5, 14.75, 15., 15.5, 16., 16.5, 17., 17.5, 18., 18.25, 18.5, 18.75, 19.,
19.5, 20., 20.5, 21., 21.5, 22., 22.5, 23., 23.5, 24., 24.5, 25., 25.5, 26., 26.5, 27., 27.5, 28., 28.5, 29., 29.5,
30., 30.5, 31., 31.5, 32., 32.5, 33., 33.5, 34., 34.5, 35., 35.5, 36., 36.5, 37., 37.5, 38., 38.5, 39., 39.5, 40.,
40.5, 41., 41.5, 42.]) * 1e12
class FiberParams(Parameters):
def __init__(self, **kwargs):
try:
self._length = convert_length(kwargs['length'], kwargs['length_units'])
# fixed attenuator for padding
self._att_in = kwargs.get('att_in', 0)
# if not defined in the network json connector loss in/out
# the None value will be updated in network.py[build_network]
# with default values from eqpt_config.json[Spans]
self._con_in = kwargs.get('con_in')
self._con_out = kwargs.get('con_out')
if 'ref_wavelength' in kwargs:
self._ref_wavelength = kwargs['ref_wavelength']
self._ref_frequency = c / self._ref_wavelength
elif 'ref_frequency' in kwargs:
self._ref_frequency = kwargs['ref_frequency']
self._ref_wavelength = c / self._ref_frequency
else:
self._ref_wavelength = 1550e-9 # conventional central C band wavelength [m]
self._ref_frequency = c / self._ref_wavelength
self._dispersion = kwargs['dispersion'] # s/m/m
self._dispersion_slope = \
kwargs.get('dispersion_slope', -2 * self._dispersion / self.ref_wavelength) # s/m/m/m
self._beta2 = -(self.ref_wavelength ** 2) * self.dispersion / (2 * pi * c) # 1/(m * Hz^2)
# Eq. (3.23) in Abramczyk, Halina. "Dispersion phenomena in optical fibers." Virtual European University
# on Lasers. Available online: http://mitr.p.lodz.pl/evu/lectures/Abramczyk3.pdf
# (accessed on 25 March 2018) (2005).
self._beta3 = ((self.dispersion_slope - (4*pi*c/self.ref_wavelength**3) * self.beta2) /
(2*pi*c/self.ref_wavelength**2)**2)
self._effective_area = kwargs.get('effective_area') # m^2
n2 = 2.6e-20 # m^2/W
if self._effective_area:
self._gamma = kwargs.get('gamma', 2 * pi * n2 / (self.ref_wavelength * self._effective_area)) # 1/W/m
elif 'gamma' in kwargs:
self._gamma = kwargs['gamma'] # 1/W/m
self._effective_area = 2 * pi * n2 / (self.ref_wavelength * self._gamma) # m^2
else:
self._gamma = 0 # 1/W/m
self._effective_area = 83e-12 # m^2
default_raman_efficiency = {'cr': CR_NORM / self._effective_area, 'frequency_offset': FREQ_OFFSET}
self._raman_efficiency = kwargs.get('raman_efficiency', default_raman_efficiency)
self._pmd_coef = kwargs['pmd_coef'] # s/sqrt(m)
if type(kwargs['loss_coef']) == dict:
self._loss_coef = asarray(kwargs['loss_coef']['value']) * 1e-3 # lineic loss dB/m
self._f_loss_ref = asarray(kwargs['loss_coef']['frequency']) # Hz
else:
self._loss_coef = asarray(kwargs['loss_coef']) * 1e-3 # lineic loss dB/m
self._f_loss_ref = asarray(self._ref_frequency) # Hz
self._lumped_losses = kwargs['lumped_losses'] if 'lumped_losses' in kwargs else []
except KeyError as e:
raise ParametersError(f'Fiber configurations json must include {e}. Configuration: {kwargs}')
@property
def length(self):
return self._length
@length.setter
def length(self, length):
"""length must be in m"""
self._length = length
@property
def att_in(self):
return self._att_in
@att_in.setter
def att_in(self, att_in):
self._att_in = att_in
@property
def con_in(self):
return self._con_in
@con_in.setter
def con_in(self, con_in):
self._con_in = con_in
@property
def con_out(self):
return self._con_out
@property
def lumped_losses(self):
return self._lumped_losses
@con_out.setter
def con_out(self, con_out):
self._con_out = con_out
@property
def dispersion(self):
return self._dispersion
@property
def dispersion_slope(self):
return self._dispersion_slope
@property
def gamma(self):
return self._gamma
@property
def pmd_coef(self):
return self._pmd_coef
@property
def ref_wavelength(self):
return self._ref_wavelength
@property
def ref_frequency(self):
return self._ref_frequency
@property
def beta2(self):
return self._beta2
@property
def beta3(self):
return self._beta3
@property
def loss_coef(self):
return self._loss_coef
@property
def f_loss_ref(self):
return self._f_loss_ref
@property
def raman_efficiency(self):
return self._raman_efficiency
def asdict(self):
dictionary = super().asdict()
dictionary['loss_coef'] = self.loss_coef * 1e3
dictionary['length_units'] = 'm'
if not self.lumped_losses:
dictionary.pop('lumped_losses')
if not self.raman_efficiency:
dictionary.pop('raman_efficiency')
return dictionary
class EdfaParams:
def __init__(self, **params):
self.update_params(params)
if params == {}:
self.type_variety = ''
self.type_def = ''
# self.gain_flatmax = 0
# self.gain_min = 0
# self.p_max = 0
# self.nf_model = None
# self.nf_fit_coeff = None
# self.nf_ripple = None
# self.dgt = None
# self.gain_ripple = None
# self.out_voa_auto = False
# self.allowed_for_design = None
def update_params(self, kwargs):
for k, v in kwargs.items():
setattr(self, k, self.update_params(**v) if isinstance(v, dict) else v)
class EdfaOperational:
default_values = {
'gain_target': None,
'delta_p': None,
'out_voa': None,
'tilt_target': 0
}
def __init__(self, **operational):
self.update_attr(operational)
def update_attr(self, kwargs):
clean_kwargs = {k: v for k, v in kwargs.items() if v != ''}
for k, v in self.default_values.items():
setattr(self, k, clean_kwargs.get(k, v))
def __repr__(self):
return (f'{type(self).__name__}('
f'gain_target={self.gain_target!r}, '
f'tilt_target={self.tilt_target!r})')