Dy-doped chlorides as gain media for 1.3 μm telecommunications amplifiers

Abstract

We propose that Dy/sup 3+/-doped chloride crystals be considered as candidates for amplification of the 1.3 /spl mu/m signal used by the telecommunications network. While several of these types of crystals can provide gain at the specified operating wavelength of 1.31 /spl mu/m, and furthermore offer adequate bandwidth, we have focused our attention on LaCl/sub 3/:Dy as an illustrative case to explore in greater depth. Spectroscopic measurements were made on un-oriented samples of this material; excited-state lifetimes and LaCl/sub 3/:Dy/sup 3+/ Judd-Ofelt parameters are reported. Wavelength-resolved absorption and emission cross sections are presented for the 1.3 /spl mu/m W/spl rlhar2/Z band. Pump-probe measurements (using 0.92 /spl mu/m and 1.32 /spl mu/m, respectively) prove that the observed gain properties of LaCl/sub 3/:Dy are consistent with those predicted on the basis of the spectroscopic cross sections. The Dy:chloride gain media appear to have fundamental optical characteristics amenable to superior 1.3 /spl mu/m telecom amplifier performance, although many fabrication issues would have to be addressed to produce a practical amplifier.