Multi-wavelength all-optical networks with wavelengths outside the erbium-doped fiber amplifier bandwidth

Erbium-doped fiber amplifiers have become the dominating technology for signal amplification in all-optical networks. One constraint of EDFA's is that they have a much narrower bandwidth (/spl ap/25 nm) compared to the low-loss region (/spl ap/200 mn) of optical fiber. Instead of using only wavelengths within the bandwidth of EDFA's (i.e. the inband channels) for communication, we propose to include wavelengths outside the EDFA bandwidth (i.e. the outband channels) as well in order to increase the number of wavelengths and/or channel spacings that can be accommodated. Using outband wavelengths for sending messages presents a new constraint, namely that only if the power loss for transmitting a message is small enough can this message be transmitted on the outband wavelength. We develop wavelength-routing algorithms on arbitrary network topologies and wavelength assignments in hierarchical networks for sending messages subject to this constraint. We also analyze the SNR for inband/outband WDM signals.<
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