Improved implementation of optical space domain reflectometry for characterizing the complex coupling coefficient of...

Optical space domain reflectometry (OSDR) implemented with a novel interferometric characterization method is demonstrated to be an accurate technique for characterizing the complex coupling coefficient of strong fiber Bragg gratings. A theoretical model is also presented, incorporating the effect of the heat perturbation shape, which accurately predicts the measurement behavior. It is shown that the measurement accuracy and spatial resolution are dramatically improved by removing the effect of the heat perturbation shape on the reconstructed profile using a deconvolution technique. The improvement in accuracy is illustrated by the excellent agreement between a weak grating reconstructed with OSDR and the same grating reconstructed with optical frequency domain reflectometry and a layer-peeling method. Reconstruction of a strong grating with an integrated coupling coefficient, qL=8.14, demonstrates the utility of this technique.