NonlinearChannel_v1 Class Reference

Nonlinear fiber optical channel model using SSF method class. More...

Inherits unit.

Public Member Functions
function	NonlinearChannel_v1 (in param)
	Class constructor. More...
function	traverse (in obj, in in)
	Main function call.
Public Member Functions inherited from unit
function	traverseNode (in obj)
	Set unique ID when creating a unit. More...
function	connectOutput (in obj, in uobj, in unitOutput, in nextUnitInput)
	Specify where signal should go next. More...
function	connectOutputs (in obj, in units, in destInputs)
	Specify where signal should go next. More...
function	writeInputBuffer (in obj, in sig, in inputId)
	write input buffer
function	horzcat (in varargin)
	horizontal concatenation
function	vertcat (in varargin)
	vertical concatenation
function	setparams (in obj, in params, in REQUIRED_PARAMS, in QUIET_PARAMS)
	set parameters More...
function	view (in obj)
	Show interactive GUI through unit_view-class.

Static Public Member Functions
static function	randPolRotation (in in, in lambda)

Public Attributes
Property	nSpans
	Number of fiber spans (fiber + amplifier)
Property	L
	Length of each span in km: 1-by-nSpans vector;.
Property	stepSize
	Step size for the Split Step Fourier Method in km: 1-by-nSpans vector;.
Property	iterMax
	Maximum of split step iterations.
Property	alphaa
	Fiber attenuation coefficient for polarization (a) in km^-1: 1-by-nSpans vector;.
Property	alphab
	Fiber attenuation coefficient for polarization (b) in km^-1: 1-by-nSpans vector;.
Property	gamma
	Nonlinear coefficient of the fiber in W^-1*km^-1;.
Property	D
	Dispersion coefficient.
Property	S
	Dispersion slope.
Property	EDFAGain
	Gain of each optical amplifier (linear): 1-by-nSpans vector;.
Property	EDFANF
	Noise figure of the optical amplifiers (linear): 1-by-nSpans vector;.
Property	dispersionCompensationEnabled
	Dispersion compensation 0/1.
Property	dispersionCompensationFraction
	Fraction of chromatic dispersion to compensate.
Property	polarizationMixingEnabled
	Polarization Mixing: 0/1.
Property	doublePrecisionEnabled
	SSF precision flag.
Property	noEDFAEnabled
	Don't put EDFA.
Property	nInputs
	Number of inputs.
Property	nOutputs
	EDFA spontaneous emission factor (population inversion factor)
Public Attributes inherited from unit
Property	inputBuffer
	Buffer for storing inputs as we traverse the graph.
Property	nextNodes
	Children nodes.
Property	destInputs
	Destination inputs in children.
Property	results
	For storing results.
Property	label
Property	draw
	enable/disable plotting
Property	nInputs
	Number of signals traverse expects.
Property	nOutputs
	Number of outputs traverse expects.

Detailed Description

Nonlinear fiber optical channel model using SSF method class.

This class implements the optical channel propagation model based on the numeric solution of the Non-Linear Schrodinger Equation (NLSE) using Split Step Fourier (SSF) method.

Observations:

1. Please, pay attention to the dimensions. Make sure that the parameters are passed with the correct value in the correspondent unit.
2. For the traverse method, only the two first columns of the signal vector will be considered (i.e., two polarization modes)
3. Polarization mixing is implemented as a unitary transformation between spans. Polarization mode dispersion is not currently included. The core fiber model comes from ssprop from the Photonics Research Laboratory at the University of Maryland (Baltimore). ssprop has PMD included, but this unit does not have an interface to support it.

Conventions:

• Dispersion coeff.: D = 2*pi*c/lambda^2, (2.3.5) [1]
• Dispersion slope : S = (2*pi*c/lambda^2)^2*Beta3 +(4*pi*c/lambda^3)*Beta2, (2.3.13)[1]
• ASE power calculation: Pase = 2*nsp*h*f0*nSpans*(G-1)*BWopt, (6.5.18) [1]
  • f0 = c/lambda, BWopt = bandwidth of interest
  • NF = 2*nsp*(G-1)/G = 2nsp (aprox.), (6.1.19) [1]

Example:

param.nlinch.nSpans      = 2;
param.nlinch.dispersionCompensationEnabled  = 1;
param.nlinch.polarizationMixingEnabled = 0;
param.nlinch.L          = [50 80];
param.nlinch.stepSize   = 5;
param.nlinch.iterMax    = 15;
param.nlinch.alpha      = 0.2;
param.nlinch.D          = 17;
param.nlinch.S          = [0.1 0.2];
param.nlinch.gamma      = 1.7;
param.nlinch.EDFANF    = [3 5];
param.nlinch.EDFAGain  = [10 16];

fiberChannel = NonlinearChannel_v1(param.nlinch);

Ein = signal_interface(param.sig);

traverse(obj, Ein, InputPower, InputOSNR);

References:

• [1] Agrawal, Gowind P.: Fiber-Optic Communication Systems. 3rd : John Wiley & Sons, 2002.
• [2] http://www.photonics.umd.edu/software/ssprop/

Author

Edson Porto da Silva

Simone Gaiarin

Version

3

Definition at line 70 of file NonlinearChannel_v1.m.

Constructor & Destructor Documentation

function NonlinearChannel_v1::NonlinearChannel_v1

(

in

param

)

Class constructor.

Constructs an object of type NonlinearChannel_v1.

Parameters

param.nSpans	Number of spans to be simulated.
param.L	Span lengths [km]. Vector [1 x nSpans] or scalar. [Default: 80]
param.stepSize	Step size for the SSF method [km]. Vector [1 x nSpans] or scalar. [Default: 10]
param.iterMax	Maximum of SSF iterations per step size [km]. [Default: 10].
param.alpha	Fiber attenuation coefficients [dB/km]. Vector [1 x nSpans] or scalar. [Default: 0.2]. Not used if alphaa and alphab specified.
param.alphaa	Fiber attenuation coefficients polarization X [dB/km]. Vector [1 x nSpans] or scalar. [Default: 0.2].
param.alphab	Fiber attenuation coefficients polarization Y [dB/km]. Vector [1 x nSpans] or scalar. [Default: 0.2]
param.D	Fiber dispesion coefficients [ps/nm/km].Vector [1 x nSpans] or scalar. [Default: 17]
param.S	Fiber dispesion slope [ps/nm^2/km]. Vector [1 x nSpans] or scalar. [Default: 0.1]
param.gamma	Fiber nonlinear coefficients [W^-1*km^-1]. Vector [1 x nSpans] or scalar. [Default: 1.2]
param.noEDFAEnabled	If true and there is only one link, the EDFA is not put at the end of the link
param.EDFANF	EDFA's noise figure [dB]. Vector [1 x nSpans] or scalar. [Default: 16]
param.EDFAGain	EDFA's gain [dB]. Vector [1 x nSpans] or scalar. [Default: 3]
param.dispersionCompensationEnabledion	Dispersion compensation flag. [Default: 0]
param.dispersionCompensationFraction	Fraction of span dispersion to compensate. [Default: 1]
param.polarizationMixingEnabled	Polarization mixing flag. [Default: 0]
param.doublePrecisionEnabled	Precision flag. Set to 0 for speed. [Default: 1]

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The documentation for this class was generated from the following file:

• library/ch/NonlinearChannel_v1.m