Abstract

In commununicat ions technology 1.3µm is an important transfer wavelength because of an absorption and dispersion minimum at 1.3µm of typical optical silicon fibers. In order to realize an all-optical communications system for 1.3µm one essential component is still lacking, the optical amplifier. For integrated optical systems in the future it would be desirable to have 1.3µm waveguide amplifiers. Therefore the three-valent rare earth ion Pr is used as an optical active medium. The Pr³⁺-level ^lG₄ is activated by a pump laser at 1020nm. A simultaneous signal beam of 1.31µm photons stimulates the Pr³⁺-transition ¹G₄→ ³H₅ and thus amplifies the intensity of the signal. Competing non-radiative processes are multiphonon-relaxation from ¹G₄ to ³F₄ and cross-relaxation among two Pr-ions (e. g. ¹|G₄-->³H₆ / ³H₄-->³F₂), respectively energy transfer along several Pr-ions to a quenching center. It is necessary to have a host material with low-energy phonons to suppress the multiphononrelaxation. Chalcogenides with a typical quantum efficiency of more than 40% are more convenient for this than fluorides with a quantum efficiency of about 3-5%¹.

© 1996 IEEE