Investigation of a contact between a channel waveguide in LiNbO3 and a single-mode fiber

A study was made of a joint between a single-mode channel waveguide and a single-mode fiber. The measured parameters of the mode field distributions in the waveguide and fiber were used to calculate the sensitivity of an end-to-end joint to the magnitude of the gap and to angular transverse displacements between the ends. The parameters of a channel waveguide fiber should, in principle, allow formation of a joint with an efficiency of 90%. The experimental value of the joint efficiency was 86%.