Stimulated emission in single tensile-strained Ge photonic wire

We have investigated the room temperature optical properties of 50 μm length, 11 μm large and 500 nm thick tensile-strained germanium photonic wires. Tensile strain is transferred in the germanium layer using a Si₃N₄ film stressor. An optical recombination of tensile-strained germanium involving light hole band is observed around 1690 nm at room temperature corresponding to a strain magnitude around 0.4%. We show that the waveguided emission associated with a single tensile-strained germanium wire increases superlinearly as a function of the illuminated length. A decrease of the spectral broadening is observed as the pump intensity is increased. A 80 cm^-1 modal optical gain is derived from the variable strip length method.