Improving the Selected Stages of Integrated-Optic Chip Structure Formation and Its Interfacing with Optical Fibers

The paper considers experimental technological regimes at different stages of integrated optical chips creation for modern applications: optoelectronics, fiber-optic sensors, microfluidics. The considered experimental regimes demonstrate not only qualitative, but also quantitative efficiency: at the stage of the ridge waveguides formation, there is a possibility of achieving high etching rates of lithium niobate - up to 950 nanometers per minute in fluorine-containing plasma with an increased consumption of plasma gases without forced thermostating of the sample. Using scanning electron microscope, structural changes in the surface have been demonstrated: clustering of surface etching foci, indicating the uniformity of etching at the macroscale, and changes in the thickness and structure of the near-surface defect layer, indicating the possibility of its complete removal by the plasma-chemical method. The method can be applied both for the manufacturing of ridge waveguides and optical elements based on them, and for microfluidics elements. Then, the efficiency of the waveguides and optical fibers interfacing method has been confirmed with frequency domain reflectometry. The algorithmic details of the interfacing by the modified Newton's method are also described. The modified Newton’s method allowed to simplify the alignment process by performing coarse alignment based on reflections from the far end face of the waveguide, speed up the alignment process at fine mode, and fully automate the alignment of the waveguide and optical fiber at any initial displacements. All the proposed technological process modernization leads to the improvement of technological characteristics and the individual stages production time reduction.