Quantum-well laser diodes operating at 1.28um monolithically integrated on Ge substrate (Conference Presentation)

Here we demonstrate for the first time a GaInNAsSb/GaAs quantum well based laser diode with emission beyond 1.25 µm that is monolithically integrated on an artificial Ge substrate. Molecular beam epitaxy grown GaInNAsSb quantum wells enable gain from silicon transparency wavelength up to 1.55µm. Proposed material system paves the way for silicon photonics with high density monolithically integrated temperature insensitive gain elements (and electro-absorption in case of modulators). Compared with QD gain structures monolithically integrated on Ge/Si demonstrated earlier QW-based material system important advantages in single pass gain enabling the realization of devices with very short lengths and volume. Moreover, GaInNAsSb/GaAs QWs can exhibit efficient uncooled operation at temperatures as high as 80°C reducing the energy consumption imposed by active cooling of PICs. Presentation demonstrates low threshold (sub-25mA) directly modulated laser diodes using a short cavity (250µm) enabled by the high gain. Bandwidth characteristics of the material is studied with relative intensity noise (RIN) measurement. Hakki-Paoli measurement show gain up to 68 1/cm from a short gain element of 250µm in length. Preliminary burn-in results show that lasers operate hundreds of hours without any sign of degradation contributed by the close lattice matching between III-V and Ge.