4$\,\times\,$25-Gb/s 40-km PHY at 1310 nm for 100 GbE Using SOA-Based Preamplifier

We present extensive numerical simulations of an optical link deploying four electroabsorption modulated lasers (EMLs) at 25 Gb/s over up to 40 km of standard single-mode fiber. The receiver comprises a semiconductor optical amplifier (SOA) as a preamplifier. We analyze the bit error ratio (BER) along different link lengths under varying conditions such as output power and extinction ratio of the EML transmitters, the noise figure of the SOA preamplifier and the bit and word alignment of the four wavelength channels. We demonstrate that the EML transmitters require a minimum extinction ratio of 8 to 10 dB and a minimum output power of +2 to +4 dBm in order to meet the BER requirements for 100 Gigabit Ethernet (100 GbE) using 4 times 25-Gb/s physical media dependent (PMD) devices. Furthermore, we show that single-channel performance analyses can be used to estimate the behavior for multichannel amplification in the SOA preamplifier.