LAUSR

We demonstrate a narrow-linewidth heterogeneously integrated Si/III–V laser, where the current confinement in the III–V structure is obtained by oxide isolation rather than by the prevailing ion-implantation technique. This method provides effective electrical isolation as well as III–V surface passivation, and a pathway for high-efficiency diode injection laser performance. This method also offers increased compatibility with potentially high-temperature annealing processes. The lasers shown here possess a threshold current of as low as 60 mA and a single-facet output power of more than 3 mW at 20 °C. A linewidth of 28 kHz at 1574.8 nm is obtained at a current of 200 mA ( $I = 3.3 \times I_{\mathrm{ th}}$ ). Single-mode operation is achieved with a side-mode suppression ratio larger than 55 dB.