Long-Term Degradation Behavior of 2.3- $\mu\hbox {m}$ Wavelength Highly Strained InAs/InP MQW-DFB Lasers With a p-/n-InP Buried Heterostructure

We investigate the long-term degradation of 2.3-μm wavelength InAs/InP highly strained multiquantum-well distributed-feedback lasers with a p- and n-type InP buried heterostructure during constant power aging. Stable operation beyond 20 000 h is confirmed at an ambient temperature of 45 ^°C and with a constant output power of 3 mW, and we successfully fabricate a practical optical source for trace gas monitoring applications. A conventional diffusion process dominates the main degradation mechanism as found with conventional telecommunication lasers. Furthermore, we show that some defects are located in the regrown p-type InP layer above the active layer and that downward diffused defects degrade the guide, upper separate confinement heterostructure (SCH), and active layers.