Ultra-broadband amplification through nanotechnology

Abstract

As demands for bandwidth continue to increase, telecommunication networks would greatly benefit from the development of broader-band amplifiers. The currently erbium doped fiber amplifiers are limited to amplification of approximately 100 nm bandwidth window. One method to increase the bandwidth of the fiber amplifier would be to incorporate multiple rare earths (REs) into a single fiber which exhibit emissions from ~1000-1800 nm. Unfortunately, energy transfer between rare earth ions typically results in quenching all but selected emissions negating this approach to potential ultra-broadband amplification. It would be ideal if one could take the individual spectra of an ion and place that ion into a host with no regard to other lanthanides that also are present in the host. This problem can be solved by using a composite material that utilizes nanoparticles to constrain different REs to individual particles thereby controlling or preventing energy transfer. In order to control energy transfer, RE doped LaF₃ nanocrystals were grown in an aqueous solution using a core/shell technique to constrain different rare earth into separate particles or shells within a single particle. Using these techniques, we show that energy transfer can be controlled.