New materials for fiber optic amplifiers

Summary form only given. To further exploit the bandwidth potential of EDFA's, materials research has led to development of fibers offering flatter gain, increased bandwidth and red-shifted signal excited state absorption (ESA). While fluoride based glasses, were an early candidate for flat gain their narrow bandwidth meant that they were not suitable for broadband WDM. Alternative materials based on multi-component tellurite or silicate glasses have recently emerged as serious candidates for extending the gain bandwidth. These materials have the necessary properties for extending the bandwidth available in a single amplifier to approximately 60nm or for increasing the total bandwidth of a split band EDFA from 64nm to 90nm.