▎ 摘　　要

NOVELTY - The ring cavity laser device (200) has an optical ring cavity that is defined by first, second and third mirrors (110A,120,110B) to establish a resonant optical cavity in which electromagnetic energy is amplified by stimulated emission of coherent radiation transmitted through the second mirror. An electrical or optical pump (150) provides energy to an optical gain medium (180) that is disposed at least partially between first and second mirrors. A graphene saturable absorber (130) is disposed at least partially between the reflective surfaces (122,112B) of second and third mirrors. USE - Ring cavity laser device for producing light at predetermined gain bandwidth. ADVANTAGE - Reflection of light back into semiconductor optical amplifier is reduced through second facet end. Enhanced sensing of gas molecules within sensing region is permitted since the laser device can be operated in Frequency Comb Spectroscopy mode. Feedback such as minimized or reduced Fabry-Perot resonances due to residual facet reflectivity is prevented by providing anti-reflection coating at output end. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a linear cavity laser device. DESCRIPTION OF DRAWING(S) - The drawing shows the schematic diagram of the ring cavity laser device. First, second and third mirrors (110A,120,110B) Reflective surfaces (122,112B) Graphene saturable absorber (130) Electrical or optical pump (150) Optical gain medium (180) Ring cavity laser device (200)