Optical Low Coherence Reflectometry (OLCR) is na important non-destructive method for characterization of optical waveguides. This work presents a study of the plurality of solutions that appear with a new configuration, which places the device out of both arms of the interferometer. Two techniques were developed to solve this problem. One of them is based on the correlation of measurements made with the device in two different positions. The other technique removes the ambiguity by modulating the phase of the reflections from the interferometer. Both techniques have eliminated the undesirable peaks sucessfully, making the observation of the reflections more easy. The resolution was not changed by the modulation, and a high sensitivy was achieved. A method for attenuation measurements, based on OLCR systems, was presented. If the reflection coefficient is well know, its use for measurements of optical waveguides, such as modulators, could be very interesting.