PD_v1 Class Reference

photodiode model More...

Inherits unit.

Public Member Functions
function	PD_v1 (in param)
	Class constructor. More...
function	traverse (in obj, in in)
	Traverse function. More...
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	responsivity
	Responsivity in A/W.
Property	bandwidth
	Bandwidth in Hz.
Property	rTherm
	Noise equiv. thermal resistance (ohms)
Property	T
	Noise equiv. temperature (K)
Property	iDark
	Dark current (A)
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

photodiode model

This class models a photodiode with responsivity, noise, and bandwidth. The new output power is the electrical power calculated assuming a 50 ohm environment. The noise includes both shot and thermal noise. The bandwidth is modeled using a 2nd order butterworth filter.

Example

% Detect a garbage signal
param=struct('Responsivity', 1, 'Bandwidth', 20e9, 'Idark', 1e-9);
detector = PD_v1(param);

sigIn = createDummySignal(); 
sigDetected = detector.traverse(sigIn);

Author

Miguel Iglesias Modified 15/8/2014 Molly Piels - added noise

Version

1

Definition at line 28 of file PD_v1.m.

Constructor & Destructor Documentation

function PD_v1::PD_v1

(

in

param

)

Class constructor.

Constructs a photodiode

Parameters

param.responsivity	Responsivity [A/W] [Default: 1]
param.bandwidth	3dB elect. bandwidth [Hz] [Default: 50GHz]
param.rTherm	Resistance for Johnson noise [Ohm] [Default: 50 ohm]
param.T	Temperature for Johnson noise [K] [Default 290]
param.iDark	Dark current [A] [Default: 0]

Return values

obj	instance of the PD_v1 class

Member Function Documentation

function PD_v1::traverse ( in  obj, in  in  )

virtual

Traverse function.

Calculates appropriate shot noise (2qI) and thermal noise (4kT/R) currents, then applies square-law detection (current is proportional to (Ex^2+Ey^2), not (Ex+Ey)^2) and adds that noise current. Finally, low-pass filters.

Return values

out	photodiode output
results	no results

Reimplemented from unit.

---

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

• library/rx/PD_v1.m