Characterization of a distributed feedback laser with air/semiconductor gratings embedded by the wafer fusion technique

Wafer fusion between patterned or structured wafers is very useful in the construction of new optical materials and/or devices that have submicrometer-order structures inside semiconductors. In order to investigate the feasibility of wafer fusion for this purpose, a distributed feedback (DFB) laser wafer developed which has air/semiconductor gratings that are embedded using the wafer fusion technique. In this paper, the characteristics of the newly developed DFB laser and the coupling coefficient are investigated. Single-longitudinal-mode oscillation at 1.28 μm is achieved under pulsed conditions at room temperature with a low threshold current density of 1.3 kA/cm², and the coupling coefficient is estimated to he approximately 100 cm^-1. In addition, high-power surface emission (over 6 mW) is demonstrated due to the large difference between the refractive index of air and that of InP. These results indicate the feasibility of applying wafer fusion techniques to form submicrometer structures in semiconductors, and several other applications are expected