  We demonstrate monolithic integration of an electro-optically (EO) tunable
microring laser on lithium niobate on insulator (LNOI) platform. The device is
fabricated by photolithography assisted chemo-mechanical etching (PLACE), and
the pump laser is evanescently coupled into the erbium (Er3+) doped LN
microring laser using an undoped LN waveguide mounted above the microring. The
quality factor of the LN microring resonator is measured as high as 1.54x10^5
at the wavelength of 1542 nm. Lasing action can be observed at a pump power
threshold below 3.5 mW using a 980 nm continuous-wave pump laser. Finally,
tuning of the laser wavelength is achieved by varying the electric voltage on
the microelectrodes fabricated in the vicinity of microring waveguide, showing
an EO coefficient of 0.33 pm/V.
