Equipment description defines equipment types and those parameters. Description is made in JSON file with predefined structure. By default transmission_main_example.py uses eqpt_config.json file and that can be changed with -e or --equipment command line parameter. Parsing of JSON file is made with gnpy.core.equipment.load_equipment(equipment_description) and return value is a dictionary of format dict[‘equipment type’][‘subtype’]=object
Every equipment type is defined in JSON root with according name and array of parameters as value.
{"Edfa": [...],
"Fiber": [...]
}
Array of parameters is a list of objects with unordered parameter name and its value definition. In case of multiple equipment subtypes each object contains "type_variety":”type name” name:value combination, if only one subtype exists "type_variety" name is not mandatory and it will be marked with ”default” value.
{"Edfa": [{
"type_variety": "std_medium_gain",
"type_def": "variable_gain",
"gain_flatmax": 26,
"gain_min": 15,
"p_max": 23,
"nf_min": 6,
"nf_max": 10,
"out_voa_auto": false,
"allowed_for_design": true
},
{
"type_variety": "std_low_gain",
"type_def": "variable_gain",
"gain_flatmax": 16,
"gain_min": 8,
"p_max": 23,
"nf_min": 6.5,
"nf_max": 11,
"out_voa_auto": false,
"allowed_for_design": true
}
],
"Fiber": [{
"type_variety": "SSMF",
"dispersion": 1.67e-05,
"gamma": 0.00127
}
]
}Four types of EDFA definition are possible. Description JSON file location is in transmission_main_example.py folder:
- Advanced – with JSON file describing gain/noise figure tilt and gain/noise figure ripple. "advanced_config_from_json" value contains filename.
"Edfa":[{
"type_variety": "high_detail_model_example",
"gain_flatmax": 25,
"gain_min": 15,
"p_max": 21,
"advanced_config_from_json": "std_medium_gain_advanced_config.json",
"out_voa_auto": false,
"allowed_for_design": false
}
]
- Variable gain – with JSON file describing gain figure tilt and gain/noise figure ripple. ”default_edfa_config.json” as source file.
"Edfa":[{
"type_variety": "std_medium_gain",
"type_def": "variable_gain",
"gain_flatmax": 26,
"gain_min": 15,
"p_max": 23,
"nf_min": 6,
"nf_max": 10,
"out_voa_auto": false,
"allowed_for_design": true
}
]
- Fixed gain – with JSON file describing gain figure tilt and gain/noise figure ripple. ”default_edfa_config.json” as source file.
"Edfa":[{
"type_variety": "std_fixed_gain",
"type_def": "fixed_gain",
"gain_flatmax": 21,
"gain_min": 20,
"p_max": 21,
"nf0": 5.5,
"allowed_for_design": false
}
]
- openroadm – with JSON file describing gain figure tilt and gain/noise
- figure ripple. ”default_edfa_config.json” as source file.
"Edfa":[{
"type_variety": "low_noise",
"type_def": "openroadm",
"gain_flatmax": 27,
"gain_min": 12,
"p_max": 22,
"nf_coef": [-8.104e-4,-6.221e-2,-5.889e-1,37.62],
"allowed_for_design": false
}
]
Fiber element with its parameters:
"Fiber":[{
"type_variety": "SSMF",
"dispersion": 1.67e-05,
"gamma": 0.00127
}
]
A special variant of the regular Fiber where the simulation engine accounts for the Raman effect.
The newly added parameters are nested in the raman_efficiency dictionary.
Its shape corresponds to typical properties of silica.
More details are available from :cite:`curri_merit_2016`.
The cr property is the normailzed Raman efficiency, so it is is (almost) independent of the fiber type, while the coefficient actually giving Raman gain is g_R=C_R/Aeff.
The frequency_offset represents the spectral difference between the pumping photon and the one receiving energy.
"RamanFiber":[{
"type_variety": "SSMF",
"dispersion": 1.67e-05,
"gamma": 0.00127,
"raman_efficiency": {
"cr":[
0, 9.4E-06, 2.92E-05, 4.88E-05, 6.82E-05, 8.31E-05, 9.4E-05, 0.0001014, 0.0001069, 0.0001119,
0.0001217, 0.0001268, 0.0001365, 0.000149, 0.000165, 0.000181, 0.0001977, 0.0002192, 0.0002469,
0.0002749, 0.0002999, 0.0003206, 0.0003405, 0.0003592, 0.000374, 0.0003826, 0.0003841, 0.0003826,
0.0003802, 0.0003756, 0.0003549, 0.0003795, 0.000344, 0.0002933, 0.0002024, 0.0001158, 8.46E-05,
7.14E-05, 6.86E-05, 8.5E-05, 8.93E-05, 9.01E-05, 8.15E-05, 6.67E-05, 4.37E-05, 3.28E-05, 2.96E-05,
2.65E-05, 2.57E-05, 2.81E-05, 3.08E-05, 3.67E-05, 5.85E-05, 6.63E-05, 6.36E-05, 5.5E-05, 4.06E-05,
2.77E-05, 2.42E-05, 1.87E-05, 1.6E-05, 1.4E-05, 1.13E-05, 1.05E-05, 9.8E-06, 9.8E-06, 1.13E-05,
1.64E-05, 1.95E-05, 2.38E-05, 2.26E-05, 2.03E-05, 1.48E-05, 1.09E-05, 9.8E-06, 1.05E-05, 1.17E-05,
1.25E-05, 1.21E-05, 1.09E-05, 9.8E-06, 8.2E-06, 6.6E-06, 4.7E-06, 2.7E-06, 1.9E-06, 1.2E-06, 4E-07,
2E-07, 1E-07
],
"frequency_offset":[
0, 0.5e12, 1e12, 1.5e12, 2e12, 2.5e12, 3e12, 3.5e12, 4e12, 4.5e12, 5e12, 5.5e12, 6e12, 6.5e12, 7e12,
7.5e12, 8e12, 8.5e12, 9e12, 9.5e12, 10e12, 10.5e12, 11e12, 11.5e12, 12e12, 12.5e12, 12.75e12,
13e12, 13.25e12, 13.5e12, 14e12, 14.5e12, 14.75e12, 15e12, 15.5e12, 16e12, 16.5e12, 17e12,
17.5e12, 18e12, 18.25e12, 18.5e12, 18.75e12, 19e12, 19.5e12, 20e12, 20.5e12, 21e12, 21.5e12,
22e12, 22.5e12, 23e12, 23.5e12, 24e12, 24.5e12, 25e12, 25.5e12, 26e12, 26.5e12, 27e12, 27.5e12, 28e12,
28.5e12, 29e12, 29.5e12, 30e12, 30.5e12, 31e12, 31.5e12, 32e12, 32.5e12, 33e12, 33.5e12, 34e12, 34.5e12,
35e12, 35.5e12, 36e12, 36.5e12, 37e12, 37.5e12, 38e12, 38.5e12, 39e12, 39.5e12, 40e12, 40.5e12, 41e12,
41.5e12, 42e12
]
}
}
]
Roadm element with its parameters:
"Roadms":[{
"gain_mode_default_loss": 20,
"power_mode_pout_target": -20,
"add_drop_osnr": 38
}
]
Spans element with its parameters:
"Spans":[{
"power_mode":true,
"delta_power_range_db": [0,0,0.5],
"max_length": 150,
"length_units": "km",
"max_loss": 28,
"padding": 10,
"EOL": 0,
"con_in": 0,
"con_out": 0
}
]
Spectral information with its parameters:
"SI":[{
"f_min": 191.3e12,
"baud_rate": 32e9,
"f_max":195.1e12,
"spacing": 50e9,
"power_dbm": 0,
"power_range_db": [0,0,0.5],
"roll_off": 0.15,
"tx_osnr": 40,
"sys_margins": 0
}
]
Transceiver element with its parameters. ”mode” can contain multiple Transceiver operation formats.
Note that OSNR parameter refers to the receiver's minimal OSNR threshold for a given mode.
"Transceiver":[{
"frequency":{
"min": 191.35e12,
"max": 196.1e12
},
"mode":[
{
"format": "mode 1",
"baud_rate": 32e9,
"OSNR": 11,
"bit_rate": 100e9,
"roll_off": 0.15,
"tx_osnr": 40,
"min_spacing": 37.5e9,
"cost":1
},
{
"format": "mode 2",
"baud_rate": 66e9,
"OSNR": 15,
"bit_rate": 200e9,
"roll_off": 0.15,
"tx_osnr": 40,
"min_spacing": 75e9,
"cost":1
}
]
}
]
Network description defines network elements with additional to equipment description parameters, metadata and elements interconnection. Description is made in JSON file with predefined structure. By default transmission_main_example.py uses edfa_example_network.json file and can be changed from command line. Parsing of JSON file is made with gnpy.core.network.load_network(network_description, equipment_description) and return value is DiGraph object which mimics network description.
Network description JSON file root consist of three unordered parts:
- network_name – name of described network or service, is not used as of now
- elements - contains array of network element objects with their respective parameters
- connections – contains array of unidirectional connection objects
{"network_name": "Example Network",
"elements": [{...},
{...}
],
"connections": [{...},
{...}
]
}
Array of network element objects consist of unordered parameter names and those values. In case of "type_variety" absence "type_variety":”default” name:value combination is used. As of the moment, existence of used "type_variety" in equipment description is obligatory.
Transceiver element with its parameters.
{"uid": "trx Site_A",
"metadata": {
"location": {
"city": "Site_A",
"region": "",
"latitude": 0,
"longitude": 0
}
},
"type": "Transceiver"
}ROADM element with its parameters. “params” is optional, if not used default loss value of 20dB is used.
{"uid": "roadm Site_A",
"metadata": {
"location": {
"city": "Site_A",
"region": "",
"latitude": 0,
"longitude": 0
}
},
"type": "Roadm",
"params": {
"loss": 17
}
}Fused element with its parameters. “params” is optional, if not used default loss value of 1dB is used.
{"uid": "ingress fused spans in Site_B",
"metadata": {
"location": {
"city": "Site_B",
"region": "",
"latitude": 0,
"longitude": 0
}
},
"type": "Fused",
"params": {
"loss": 0.5
}
}Fiber element with its parameters.
{"uid": "fiber (Site_A \\u2192 Site_B)",
"metadata": {
"location": {
"city": "",
"region": "",
"latitude": 0.0,
"longitude": 0.0
}
},
"type": "Fiber",
"type_variety": "SSMF",
"params": {
"length": 40.0,
"length_units": "km",
"loss_coef": 0.2
}
}{
"uid": "Span1",
"type": "RamanFiber",
"type_variety": "SSMF",
"operational": {
"temperature": 283,
"raman_pumps": [
{
"power": 200e-3,
"frequency": 205e12,
"propagation_direction": "counterprop"
},
{
"power": 206e-3,
"frequency": 201e12,
"propagation_direction": "counterprop"
}
]
},
"params": {
"type_variety": "SSMF",
"length": 80.0,
"loss_coef": 0.2,
"length_units": "km",
"att_in": 0,
"con_in": 0.5,
"con_out": 0.5
},
"metadata": {
"location": {
"latitude": 1,
"longitude": 0,
"city": null,
"region": ""
}
}
}EDFA element with its parameters.
{"uid": "Edfa1",
"type": "Edfa",
"type_variety": "std_low_gain",
"operational": {
"gain_target": 16,
"tilt_target": 0
},
"metadata": {
"location": {
"city": "Site_A",
"region": "",
"latitude": 2,
"longitude": 0
}
}
}Each unidirectional connection object in connections array consist of two unordered ”from_node” and ”to_node” name pair with values corresponding to element ”uid”
{"from_node": "roadm Site_C",
"to_node": "trx Site_C"
}Additional details of the simulation are controlled via sim_params.json:
{
"raman_computed_channels": [1, 18, 37, 56, 75],
"raman_parameters": {
"flag_raman": true,
"space_resolution": 10e3,
"tolerance": 1e-8
},
"nli_parameters": {
"nli_method_name": "ggn_spectrally_separated",
"wdm_grid_size": 50e9,
"dispersion_tolerance": 1,
"phase_shift_tollerance": 0.1
}
}