An unequal arm-length Mach-Zehnder interferometer type temperature sensor has been fabricated using Ti-indifusion method in the $LiNbO_3$ substrate. As temperature increases, the variation of interferometric output intensity changed almost periodically with a period of about 40℃.
For a Mach-Zehnder interferometer a single mode channel waveguide and Y-branch power divider have been fabricated by using laser direct writing system. The power division ratio of the fabricated Y-branch waveguide is 5:7.
