Zener tunnel-injection for Ge optical amplifiers, lasers and modulators (invited). 2017 IEEE 14th International Conference on Group IV Photonics (GFP), 11-12, August 2017. [PUMA: indirect electroabsorption characteristics generic optical electro-absorption iht amplifiers amplifier injection Schulze Gain modulation semiconductor shift Doping germanium Electroluminescence siliconsend:unibiblio gain integrated optics platform energy Modulation Absorption extinction ratios Ge-SI gap electro-optical Zener-emitter photonic Silicon Junctions germanium-on-silicon mechanism lasers Moss-Burstein]