Then, when you build the physical system, your simulation won’t be a fantasy—it will be a .
Now enable the full nonlinear Manakov solver. Re-run the launch power sweep. At low power, you’ll match Step 2. At high power, BER will degrade above a certain threshold. That threshold (e.g., 0 dBm launch power per channel) is your nonlinear limit . In a WDM system, this threshold will drop by ~1 dB per extra channel due to XPM. optiwave optisystem
Add fiber with loss and CD only (disable SPM/XPM/FWM). Sweep launch power from -10 dBm to +10 dBm. The BER should improve with power (more OSNR) until you hit thermal noise. This curve is your linear baseline. Then, when you build the physical system, your
Simulate the Tx + Rx directly connected (0 km fiber). Adjust the LO power and receiver ADC bits until you hit the theoretical BER for your modulation format. If you can’t match theory here, you won’t match reality later. At low power, you’ll match Step 2
Discipline is key. Start with datasheet values from real components (Finisar, II-VI, Broadcom). Add realistic connector loss (0.5 dB per mated pair). Include filter penalties from ROADMs. Add a safety margin of 2 dB OSNR to your target.