Routing for all-optical networks using wavelengths outside erbium-doped fiber amplifier bandwidth

In wavelength-division multiplexed wide-area optical networks, erbium-doped fiber amplifiers (EDFAs) are usually employed to boost lightwave power. However, EDFAs can only cover 35 nm of the 200 nm fiber bandwidth at 1.55 μm, and therefore messages transmitted on the remaining fiber bandwidth cannot be amplified. The authors propose to use wavelengths outside the EDFA bandwidth for sending messages over short distances in which amplification is not necessary. Routing determines which wavelength and links a message is routed on, and hence whether or not a message needs amplification. The authors design static and dynamic routing algorithms in circuit-switched networks and analyze the performance using simulation. The results show that use of wavelengths outside the EDFA bandwidth can decrease blocking and increase the network capacity