A single frequency fiber laser with an on-chip high-Q silicon microring cavity

A single frequency erbium-doped fiber laser with an on-chip high-Q silicon nitride (Si3N4) microring cavity is demonstrated. The laser linear cavity is composed of a microring with a Q of up to 2.5×10⁵ and a free spectral range (FSR) of 2 nm, a 12 cm erbium-doped fiber and a fiber Bragg grating (FBG). The linewidth of 8 kHz is achieved.