Loss measurement in optical waveguide devices by coherent frequency-modulated continuous-wave reflectometry

We describe experimental results of loss measurement in optical waveguide devices by coherent frequency-modulated continuous-wave reflectometry composed of a frequency-swept semiconductor laser and a two-beam interferometer. The backscattered light in a potassium-ion-exchanged single-mode optical waveguide is successfully detected, and the loss along the optical waveguide is evaluated to be 1.0 dB/cm.