Improved light transmission for III-V lasers monolithically integrated on Si platforms.

We propose a strategy to monolithically integrate active III-V lasers and passive dielectric devices, where the passive waveguides are fabricated after the MBE growth of the III-V semiconductors on a planar Si substrate. This avoids any airgap at the active/passive interface, replaced by a thin dielectric interface layer which improves the light coupling efficiency. We demonstrate GaSb DLs butt-coupled to SiN waveguides with ∼23% transmission after 2 mm SiN, corresponding to ∼35% transmission at the active/passive interface.

Unlocking the monolithic integration scenario: optical coupling between GaSb diode lasers epitaxially grown on patterned Si substrates and passive SiN waveguides.

Silicon (Si) photonics has recently emerged as a key enabling technology in many application fields thanks to the mature Si process technology, the large silicon wafer size, and promising Si optical properties. The monolithic integration by direct epitaxy of III-V lasers and Si photonic devices on the same Si substrate has been considered for decades as the main obstacle to the realization of dense photonics chips. Despite considerable progress in the last decade, only discrete III-V lasers grown on bare Si wafers have been reported, whatever the wavelength and laser technology.