Single-mode optical-waveguide fiber coupler

A single-mode fiber coupler to the Ti diffused LiNbO(3) strip waveguide has been devised. The influences of three axial displacements and two angular misalignments on the coupling efficiency have been investigated at 6328-A wavelength. The coupler has a special feature wherein coupling degradation caused by fiber displacement after connection can be recovered to the initial state. The total optical insertion loss is 3 dB after fixing the fiber to the LiNbO(3) strip waveguide, which is 4 microm wide and 8 mm long.