An electro-optically tunable microring laser monolithically integrated on lithium niobate on insulator

TL;DR

This paper reports the monolithic integration of an electro-optically tunable microring laser on a lithium niobate on insulator platform, demonstrating high quality factors, low pump threshold, and voltage-controlled wavelength tuning.

Contribution

It introduces a novel fabrication of an EO tunable microring laser on LNOI with high quality factor and voltage-controlled wavelength tuning capabilities.

Findings

High quality factor of 1.54x10^5 at 1542 nm

Lasing threshold below 3.5 mW at 980 nm pump

EO tuning coefficient of 0.33 pm/V

Abstract

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.