Abstract

Measurement of optical loss represents a vital component in the assessment of semiconductor waveguides for nonlinear frequency conversion in the near- and mid-infrared region. Accurate knowledge of this parameter is particularly important in the implementation of resonant devices, most notably integrated optical parametric oscillators (OPOs), where due to the small nonlinear gains the magnitude of loss can have a dramatic impact on the OPO oscillation threshold. In single-pass devices, such as nonlinear frequency shifters, wavelength mixers, and harmonic generators,^1,2 optical loss clearly sets an upper limit to the maximum output power and conversion efficiency that can be achieved in the process. Over the last few years several techniques including cutback method, the prism coupling method, the Fabry-Perot technique, the photothermal deflection technique, the internal modulation method, and the scattering technique³ have been tried and tested. Here we present our results on the loss measurements from 1.3 to 2.1 μm in GaAs/Al₂O, waveguides obtained with a scattering technique using femtosecond pulses for the first time to our knowledge.

© 2002 Optical Society of America