Edfa simulink Model for Analyzing Gain Spectrum and ase by Stephen Pinter

EDFA Simulink Model for Analyzing Gain Spectrum and ASE by Stephen Pinter

Presentation Overview

• Project objectives

• Gain characteristics of EDFA

• wavelength dependant gain

• Gain flattening

• non-uniform gain over the spectrum
• implications

Project Objectives

• Determine the optimum length for simulations

• ASE not considered – optimum length is shorter when ASE taken into account

• Expand the current EDFA Simulink model to show the gain over the entire 1550nm window

• important to know gain in range 1530nm – 1560nm

• Consider gain flattening, and

• Integrate forward ASE into the EDFA model

• Why Simulink?

Why use Simulink when an EDFA can be simulated using simulation tools such as OASIX or PTDS?

• Why use Simulink when an EDFA can be simulated using simulation tools such as OASIX or PTDS?

• OASIX or PTDS
• static model
• input pump power is a static input internal to the EDFA module
• Simulink
• dynamic model
• input pump power as well as other EDFA parameters can be easily modified

EDFA Gain characteristics

• Significant equations governing EDFA dynamics

• Output pump and signal power:

 and  are wavelength dependant as shown in the figure

•  and  are wavelength dependant as shown in the figure

•  and  are the absorption and emission coefficients, respectively

• so, the quantities B and C are wavelength dependant

• this relationship is how the wavelength dependency of the gain arises

• EDFA gain  ratio between the absorption and emission at a particular wavelength is critical in determining the gain

Note on Aspects of Simulation

• when performing simulations on the EDFA model it is important to simulate all the wavelengths simultaneously instead of one at a time

• EDFAs work in the nonlinear regime, so properties like linear superposition don’t hold true

• when there are several channels in an EDFA there is an effect called gain stealing

• the energy that each of the channels takes from the pump depends on the details of the emission and absorption spectra

• before simulating the gain, the optimum length was determined

Optimum Length

Simulink Models

• implementation of the ordinary nonlinear differential equation used for studying EDFA gain dynamics

• rate equation

• input/output

EDFA Gain

Gain Flattening

• using the equations shown earlier, I derived an equation relating the pump gain (GP) to the signal gain (GS)

• the resultant equation is:

for a GS of 30dB, GP should follow the curve shown in the figure

• for a GS of 30dB, GP should follow the curve shown in the figure

• theoretical view of what the pump should be

• practically, in order to get a different power at each wavelength might be difficult

• something to be further analyzed

Thank You