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propagate_raman_fiber function introduced

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Alessio Ferrari
2019-06-11 13:39:41 +02:00
parent f9bd6310f1
commit ff82c5171b
1 changed files with 56 additions and 0 deletions
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56
gnpy/core/science_utils.py
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@@ -44,6 +44,62 @@ class SimParams():
self.raman_params = RamanParams(params=params['raman_parameters'])
self.nli_params = NLIParams(params=params['nli_parameters'])
fib_params = namedtuple('FiberParams', 'loss_coef length beta2 gamma raman_efficiency temperature')
pump = namedtuple('RamanPump', 'power frequency propagation_direction')
def propagate_raman_fiber(fiber, *carriers):
sim_params = fiber.sim_params
# apply input attenuation to carriers
attenuation_in = db2lin(fiber.con_in + fiber.att_in)
chan = []
for carrier in carriers:
pwr = carrier.power
pwr = pwr._replace(signal=pwr.signal / attenuation_in,
nonlinear_interference=pwr.nli / attenuation_in,
amplified_spontaneous_emission=pwr.ase / attenuation_in)
carrier = carrier._replace(power=pwr)
chan.append(carrier)
carriers = tuple(f for f in chan)
fiber_params = fib_params(loss_coef=2*fiber.dbkm_2_lin()[1], length=fiber.length, beta2=fiber.beta2(),
gamma=fiber.gamma, raman_efficiency=fiber.params.raman_efficiency,
temperature=fiber.operational['temperature'])
# evaluate fiber attenuation involving also SRS if required by sim_params
raman_params = fiber.sim_params.raman_params
if 'raman_pumps' in fiber.operational:
raman_pumps = tuple(pump(p['power'], p['frequency'], p['propagation_direction'])
for p in fiber.operational['raman_pumps'])
else:
raman_pumps = None
if raman_params.flag_raman:
raman_solver = RamanSolver(raman_params=raman_params, fiber_params=fiber_params)
stimulated_raman_scattering = raman_solver.stimulated_raman_scattering(carriers=carriers,
raman_pumps=raman_pumps)
fiber_attenuation = (stimulated_raman_scattering.rho[:, -1])**-2
else:
fiber_attenuation = tuple(fiber.lin_attenuation for _ in carriers)
# evaluate Raman ASE noise if required by sim_params and if raman pumps are present
if raman_params.flag_raman and raman_pumps:
raman_ase = raman_solver.spontaneous_raman_scattering.power[:, -1]
else:
raman_ase = tuple(0 for _ in carriers)
# evaluate nli and propagate in fiber
attenuation_out = db2lin(fiber.con_out)
nli_params = fiber.sim_params.nli_params
nli_solver = NliSolver(nli_params=nli_params, fiber_params=fiber_params)
for carrier, attenuation, rmn_ase in zip(carriers, fiber_attenuation, raman_ase):
pwr = carrier.power
if carrier.channel_number in sim_params.list_of_channels_under_test:
carrier_nli = nli_solver.compute_nli(carrier, *carriers)
else:
carrier_nli = np.nan
pwr = pwr._replace(signal=pwr.signal/attenuation/attenuation_out,
nonlinear_interference=(pwr.nli+carrier_nli)/attenuation/attenuation_out,
amplified_spontaneous_emission=((pwr.ase/attenuation)+rmn_ase)/attenuation_out)
yield carrier._replace(power=pwr)
class RamanSolver:
def __init__(self, raman_params=None, fiber_params=None):
""" Initialize the fiber object with its physical parameters