Gain peak wavelength measurements using a polarization scrambled fiber loop configuration

We present a quick and accurate method to measure the gain peak wavelength (GPW) of concatenated optical amplifiers in a long haul optical fiber communication system. This method utilizes a simple fiber-amplifier loop with polarization scrambling. We verify that the GPW of an amplifier is completely determined by the operating gain per unit erbium doped fiber length and changes linearly with compressed gain near 1.558 μm. The data presented, indicates how the GPW can be controlled for a broad range of operating gains by adjusting the erbium fiber length. The temperature and pump power dependence of GPW were found to be negligible for typical undersea system amplifier conditions. The gain bandwidth for concatenated amplifier systems appears to be a function of compression not operating gain, implying that wavelength division multiplexing systems requiring a flattened gain response should take this into consideration.