Hot Electron Injection Laser Controlled Carrier-Heating Induced Gain Switching

The novel hot electron injection laser (HEL), a three-terminal vertically integrated transistor-laser structure, is designed to investigate and possibly utilize the effects of carrier-heating on the optical gain and wavelength chirp. Simulations show the potential of carrier heating assisted gain switching to directly modulate the optical field intensity at frequencies up to 100 GHz while maintaining control over the wavelength chirp. The HEL is designed to demonstrate these results through independent but complementary control over the concentration and the energy of the electrons injected into the active layer. Previous research has shown though that proper LIV behavior and a strong carrier heating efficiency requires a trade-off between electron heating and hole leakage current. Furthermore, stringent control over the epitaxial growth is crucial for these devices. Recent devices now show proper LIV behavior and strongly reduced threshold current densities around 2 kA/cm² at room temperature. They also show the external `heating´ voltage modulating the intensity of the lasing mode. The possible link between this modulation and carrier heating is further explored