Cascading gain-saturation semiconductor laser-amplifier wavelength translators

Wavelength translators are expected to become important components in future wavelength division multiplexed optical networks. A strong candidate for a wavelength translator device is the gain-saturated semiconductor laser amplifier. The effect of cascading such devices on the bit error rate of a signal is investigated theoretically. It is found that the optical filtering associated with conversion makes noise growth in transmission through the network unimportant. The important factor in the bit error rate degradation is loss of extinction ratio. Using practical values for system parameters, it is found that transmission is likely to be limited to passage through five or less wavelength converters for bit rates of a few gigabit/s.