| 摘要 |
PROBLEM TO BE SOLVED: To provide a quantum cascade semiconductor laser having a structure capable of suppressing a higher mode in a waveguide mode in horizontal direction.SOLUTION: In a quantum cascade semiconductor laser 11, a first semiconductor layer 19 in an embedded region 15, has a side part 19a contacting with a mesa waveguide 13, and a bottom part 19b contacting with a supporting substrate main surface 21a, and the first semiconductor layer 19 contains a p-type semiconductor. A second semiconductor layer 17 has a semi-insulating semiconductor. Leaking light component is absorbed and attenuated in the dopant in the semiconductor, because a semiconductor layer in the embedded region 15 contains the dopant. Therefore the above structure of the embedded region 15 hardly attenuates a fundamental transverse mode, and selectively attenuates a higher transverse mode. As a result, when a current is increased, the higher mode oscillation can be effectively suppressed, and a laser oscillation of the fundamental transverse mode can be stably achieved to a high current range. |
