增益腔模大失配型垂直外腔面发射激光器侧向激射抑制

Restraining Lateral Lasing Invertical External Cavity Surface Emitting Laser with Large Mismatch Between Gain and Cavity Mode

垂直外腔面发射激光器(Vertical external cavity surface emitting laser,VECSEL)的侧向激射是制约其高性能工作的关键。我们设计了室温下量子阱增益峰与表面腔模大失配(30 nm)的增益芯片结构,并证实该结构可以有效抑制泵浦功率增加时VECSEL的侧向激射增强问题。增益芯片基底温度为20℃时,VECSEL正向激射波长位于980 nm,侧向激射波长位于950 nm,当泵浦功率逐步增加时,侧向激射强度随着正向激射的出现而迅速降低。这是因为激光正向激射时量子阱的受激辐射能级与正向激射激光模式匹配,正向激射的激光模式可以获取更高的模式增益,在与侧向模式的竞争中处于优势地位。当基底温度控制在0℃与10℃时,量子阱本征增益峰值与表面腔模失配度增大,此时VECSEL仍然表现出稳定的侧向激射抑制效果。

The lateral lasing of vertical external cavity surface emitting laser(VECSEL)is the key to restrict its high performance.We designed a gain chip structure with a large mismatch(30 nm)between the quantum well gain peak and the surface cavity mode at room temperature,and confirmed that this structure can effectively suppress the lateral lasing enhancement of VECSEL when the pump power increases.When the substrate temperature of the gain chip is 20℃,the longitudinal lasing wavelength of VECSEL is 980 nm and the lateral lasing wavelength is 950 nm.As the pump power increases gradually,the lateral lasing intensity decreases rapidly with the emergence of longitudinal lasing.This is because the stimulated radiation level of the quantum well matches the longitudinal lasing laser mode when the laser is longitudinal lasing.The longitudinal lasing laser mode can obtain higher mode gain and have an advantage in the competition with the lateral mode.When the substrate temperature is controlled at 0℃and 10℃,the mismatch between the quantum well intrinsic gain peak and the surface cavity mode increases.At this time,VECSEL still shows a stable lateral lasing suppression effect.