A High-efficiency Silicon Nitride Edge Coupler for the Monolithically Integrated III-V-on-Si Laser

We demonstrate a bi-layer 5-tip edge couplers on a silicon nitride (SiN)-on-silicon platform for the monolithically integrated III-V-on-Si laser. The measured coupling efficiency between a lensed fiber and a single-mode SiN waveguide is 76 ± 3%. The vertical and horizontal 1-dB alignment tolerances are ± (0.6 ± 0.1) μm and ± (0.9 ± 0.1) μm, respectively. Experimental results show that the bi-layer 5-tip edge couplers can achieve high coupling efficiency and large alignment tolerance at the wavelength around 1550 nm with a short coupling length of 38.2 μm.