High Resolution Optical Frequency Domain Reflectometry for Analyzing Intra-Chip Reflections

We present a method for high-resolution optical frequency domain reflectometry by de-embedding group-velocity dispersion in the device under test. The method is shown to provide an accurate estimation of the wavelength-dependent group refractive index, and provides a spatial resolution of 5.3 +/- 1.7 mu m for intra-chip reflections. We applied this method to characterize localized reflections from a number of waveguide crossings. The minimum distance of 30 mu m between two crossings could easily be resolved. The reflection of waveguide crossings was analyzed to be (2.5 +/- 1.2) . 10(-6).