Avalanche-mode operation of a simple vertical p-i-n germanium photodiode coupled with a silicon waveguide

Avalanche-mode operation has been observed in a simple p-i-n germanium photodiode coupled with a silicon waveguide. Avalanche gain of ∼ 3 was observed when a 15-V reverse bias was applied to a 1-µm-thick epitaxially-grown germanium layer. This result suggests the possibility of a simple avalanche structure without a silicon multiplication layer.