Transmission penalties due to EDFA gain transients in add-drop multiplexedWDM networks

We analyze fiber transmission penalties due to erbium-doped fiber amplifier (EDFA) gain transients in a chain of 10-20 EDFA's with as many as 32 wavel ength-division-multiplexed channels. Penalties are a result of increased fi ber nonlinearity during channel deletion and amplified-spontaneous-emission noise during channel addition. We find that: 1) the system performance is severely degraded both in single-mode fiber and dispersion shifted fiber du e to fiber nonlinearities; 2) the signal-to-noise ratio (SNR) can be reduce d by up to 8 dB in a 32-channel system; and 3) a control channel to suppres s EDFA-gain and SNR transients may impose an additional penalty which incre ases with the bit rate.