Graded interface 9.3 μm quantum cascade lasers

摘要

Pulsed operation of two different designs with abrupt and graded interfaces in the active region are compared. Junction up mounted devices are tested in pulsed mode at room temperature for both designs. Lasers based on the graded interface design exhibited a lower threshold current density but also a lower optical output power due to a higher operating voltage compared to the abrupt interface design. Junction down mounted graded interface devices which were fabricated as buried heterostructure lasers with high-reflection coatings on both facets could be operated in continuous wave up to a temperature of 268°K with an optical power of 0.5 mW.