Reconstruction of a unitary transformation of an integrated interferometer using coherent light

Integrated optics fastens its place in taken important part of most promising fields of technology including communication and optical modulators, optical neural networks and quantum computing. Once optical integrated chip is fabricated it is essential to characterize its unitary transformation. The unitary provides a complete knowledge about chip operation. Therefore, trustful methods of chip transformation reconstruction are of interest. Here we have performed unitary transformation reconstruction of the femtosecond laser written optical chip with coherent light.