Nondestructive measurement of the propagation losses in active planar waveguides

Abstract

A nondestructive loss-measurement method for active planar waveguides has been developed. It is based on the determination of the longitudinal distribution of fluorescence light along the waveguiding direction, obtained at different excitation wavelengths. First measurements have been performed on a 10 μm thick Nd:Sc2O3 waveguiding film, deposited on a sapphire substrate by pulsed laser deposition, and on a 35 μm thick diffusion-bonded Nd:YAG waveguide between sapphire layers. Their scattering losses have been determined to be (11.6±0.9) and (6.9±0.9) dB/cm, respectively.