Cavity ringdown detection of losses in thin films in the telecommunicationwavelength window

The method of cavity ringdown spectroscopy (when a tunable pulsed optical p arametric oscillator was used) was extended for the loss evaluation in thin films (2-20-mum thickness). The technique was applied in two key telecommu nication wavelength ranges of 1260-1330 and 1480-1650 nm. The measurement s ensitivity was determined to be 50 ppm (5 X 10(-5)). The results for polyme r films are in close correlation with conventional spectrophotometric data and propagation loss for planar waveguides. Films of greater thickness and better optical quality are expected to provide an even higher loss resoluti on. (C) 2001 Optical Society of America.