METHOD FOR ADJUSTING CHARACTERISTIC OF OPTICAL CIRCUIT AND DEVICE THEREFOR

摘要

PURPOSE:To provide a method for adjusting the characteristics of an optical circuit capable of adjusting the characteristics of even the optical circuit having >=3 pieces of paths with high accuracy within a short period of time and a device for such adjustment. CONSTITUTION:The optical circuit is installed in the one optical path of an interferometer formed by using a light source having a coherence length (coherence distance shorter than the optical path difference between arbitrary two paths in the optical circuit to be subjected to the characteristic adjustment. The optical path length (x) of the other optical path which is a reference optical path is changed and an interferogram V(x) of the light waves propagating the respective paths and reference light is measured (S1). N-pieces of isolated signals Vk(x) (k=1, 2,..., N) are extracted from this interferogram V(x) (S2), and Fourier transform of the extracted beat signals Vk(x) is calculated (S3). The phase change rates that the light propagating the respective paths receive are led out of the phase of the Fourier transform (S4). The refractive indices of the optical waveguides constituting the respective paths are so controlled that the specified differences between the phase change rates in the respective paths and their design values are obtd.