Determination of losses in lithium niobate optical waveguides using a single-frequency semiconductor laser

A description is given of a method for determination of the optical losses in a waveguide using a waveguide resonator in which the difference between the paths of interfering beams is altered by varying the emission wavelength of a single-frequency semiconductor laser. The measurements made on lithium niobate waveguides yielded the losses of 0.6 dB/cm at the rate of change of the laser emission frequency when the pump current was altered at a rate of 1.3 GHz/mA.