  We demonstrate an electrically driven compact hybrid lithium niobate
microring laser by butt coupling a commercial 980-nm pump laser diode chip with
a high quality Er3+-doped lithium niobate microring chip. Single mode lasing
emission at 1531 nm wavelength from the Er3+-doped lithium niobate microring
can be observed with the integrated 980-nm laser pumping. The compact hybrid
lithium niobate microring laser occupies the chip size of 3 mmx4mmx0.5 mm. The
threshold pumping laser power is 6 mW and the threshold current is 0.5 A
(operating voltage 1.64 V) in the atmospheric temperature. The spectrum
featuring single mode lasing with small linewidth of 0.05 nm is observed. This
work explores a robust hybrid lithium niobate microring laser source which has
potential applications in coherent optical communication and precision
metrology.
