In Reflective EDFAs, a device (e.g. mirror, grating) is placed at the EDFA output end to reflect whether the pump or the signal (double-passing the pump or signal through the EDFA) produces a net gain enhancement.

There are three basic configurations:

  • EDFA with reflected pump only
  • EDFA with reflected signal only
  • EDFA with reflected pump and signal

The configuration presented here is with reflected signal only. The signal is reflected using a reflective filter.

Loading the project

  • Go to the OptiSystem sample files folder, “…Optiwave Software\OptiSystem 9\Samples\Optical amplifiers”.
  • Open the Project “Reflective Amplifier.osd”.

Figure 1 displays the amplifier layout.

Observe that a circulator and a reflective filter are responsible for sending the signal to the fiber and reflecting it back.

Optical System - Figure 1 - Project Reflective Amplifier osd

Figure 1: Project “Reflective Amplifier.osd”

Observe that the reflective signal wavelength is selected by changing the filter center wavelength at the reflective filter properties dialog box (Figure 2).

Optical System - Figure 2 - Filter component parameters

Figure 2: Filter component parameters

The global parameter Iterations (Figure 3) is very important to obtain a steady state output power.

The user must find the minimum number of iterations to obtain correct results.

Optical System - Figure 3 - Global parameters iterations

Figure 3: Global parameters: iterations

Running the simulation

  • To run the simulation, you can go to the File menu and select Calculate. You can also press Control+F5 or use the calculate button in the toolbar. After you select Calculate, the calculation dialog box should appear.

Viewing results

  • Double click on the visualizers (Dual Port WDM Analyzer and Optical Spectrum Analyzer).
  • Increase signal index parameter to 20 (max value – same as global parameter Iterations).

Figure 4 displays the WDM Analyzer showing the Gain.

The signal can be followed with the OSA tool to verify how the signal is changing along the amplifier.

Figure 5 shows the signal at the coupler output port.

Optical System - Figure 4 -  WDM Analyzer

Figure 4: WDM Analyzer

Optical System - Figure 5 - Signal spectrum at the coupler output

Figure 5: Signal spectrum at the coupler output