IQModulator_v1 Class Reference

I-Q modulator model. More...

Inherits unit.

Public Member Functions
function	IQModulator_v1 (in varargin)
	Class constructor. More...
function	traverse (in obj, in varargin)
	Applies drive signal to laser. More...
function	checkParamSizes (in obj)
	Checks input signals for consistency with model parameters.
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.

Public Attributes
Property	nInputs
	Number of inputs.
Property	nOutputs
	Number of outputs.
Property	Vb
	Bias voltage [V].
Property	Vpi
	Vpi [V].
Property	IQphase
	I-Q phase angle [rad].
Property	IQGainImbalance
	I-Q gain imbalance [dB].
Property	rescaleVdrive
	Force peak drive voltage to a certain value?
Property	Vamp
	What value should it be forced to?
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.

Private Attributes
Property	nModes
	Number of output modes.

Detailed Description

I-Q modulator model.

Basic model of an IQ optical modulator. In principle, this should work for an arbitrary number of modes.

Observations

1. Number of inputs-checking is done upon traverse
2. Noise from the electrical drive is not passed through to the output signal_interface
3. The modulator has unlimited bandwidth
4. By default, the input drive signal is rescaled to an appropriate value for the given Vpi; this can be disabled

Conventions

• The laser signal_interface is passed last

Example

 % The IQ modulator with no input parameters should behave like an
 % ideal IQ modulator

drive = createDummySignal();        %2-pol complex drive input

param.laser.Power = pwr(150, {14, 'dBm'});
param.laser.linewidth = 100;
param.laser.Fs = 160e9;
param.laser.Rs = 1e9;
param.laser.Fc = const.c/1550e-9;
param.laser.Lnoise = drive.L;

laser = Laser_v1(param.laser);
laserSig = laser.traverse();

 IQ = IQModulator_v1();

 sigOut = IQ.traverse(drive, laser);

Advanced Example

 % One can also set any parameters

drive = createDummySignal();        %2-pol complex drive input

param.laser.Power = pwr(150, {14, 'dBm'});
param.laser.linewidth = 100;
param.laser.Fs = 160e9;
param.laser.Rs = 1e9;
param.laser.Fc = const.c/1550e-9;
param.laser.Lnoise = drive.L;

param.IQ.Vpi = 4;                 %all child MZMs have a Vpi of 4 V
param.IQ.Vb = [3.5, 4, 4, 4];     %the first child MZM is biased
                                    %incorrecty
IQphase = [deg2rad(80), deg2rad(90)];    %the first polarization has 10
                                        %degrees of quadrature error; the second is OK
IQGainImbalance = 0;                 %there is no gain imbalance anywhere

laser = Laser_v1(param.laser);
laserSig = laser.traverse();

IQ = IQModulator_v1(param.IQ);

sigOut = IQ.traverse(drive, laser);

Author

Molly Piels

Version

1

Definition at line 85 of file IQModulator_v1.m.

Constructor & Destructor Documentation

function IQModulator_v1::IQModulator_v1

(

in

varargin

)

Class constructor.

Constructs an object of type IQModulator_v1

Most parameters (Vb, Vpi, IQphase, IQGainImbalance)can be passed as either a scalar or a vector. If they are passed as a scalar, the same value is applied to all relevant sub-components. If they're passed as vectors, there must be one value for each subcomponent (4x Vpi's and Vb's and 2x imbalances and phase angles for a standard dual-pol IQ modulator). Mixtures of scalars and vectors are acceptable.

Parameters

param.Vb	Bias voltage [V]. [Default: Vpi=4]
param.Vpi	V pi for child modulators [V] [Default: 4].
param.IQphase	IQ phase angle [rad] [Default: pi/2].
param.IQGainImbalance	Gain imbalance in I and Q [dB] [ Default: 0].
param.rescaleVdrive	Force drive signal to a certain value [boolean] [Default: on]
param.Vamp	What drive voltage should be forced to, if rescaling is enabled [V] [Default: 1];

Return values

obj	An instance of the class IQModulator_v1

Member Function Documentation

function IQModulator_v1::traverse ( in  obj, in  varargin  )

virtual

Applies drive signal to laser.

There is some flexibility in how drive signals are specified. The following are acceptable:

1. A single signal_interface with multiple complex baseband columns
2. Several signal_interface objs with one complex baseband column each
3. A single signal_interface with an even number of columns, or an even number of single-column signal_interfaces.

Parameters

varargin

Drive1, Drive2, ... laser

Return values

out	Modulated laser

Reimplemented from unit.

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

• library/tx/IQModulator_v1.m