Waveguide dual-depletion region (ddr) photodiodes

An optical receiver, comprising:

• a substrate;
• an optical waveguide provided on a first region of the substrate;
• and
• a photodiode provided on a second region of the substrate, such that an interface between the optical waveguide and the photodiode constitutes a butt joint, the photodiode includes:
• a first semiconductor layer having a p-conductivity type, the first semiconductor layer being a p-type cladding layer,
• a second semiconductor layer having n-conductivity type, the second semiconductor layer being an n-type cladding layer,
• an absorber layer provided between the p-type cladding layer and the n-type cladding layer, the absorber layer including a first undoped semiconductor layer, such that the absorber layer is aligned with the core layer of the optical waveguide to receive, via the interface, an optical signal propagating in the optical waveguide,
• a second undoped semiconductor layer provided between the absorber layer and the second semiconductor layer, such that, in an absence of a reverse bias applied to the photodiode, a first depletion region forms in the absorber layer and a second depletion region forms in the second undoped semiconductor layer, and
• a band smoothing region provided between the p-type cladding and the absorber layer, the band smoothing region including a quaternary semiconductor alloy,
• wherein the photodiode is configured to receive an optical signal supplied by the optical waveguide, the optical signal having a propagation direction in the optical waveguide, such that the interface between the optical waveguide and the photodiode is provided at a non-orthogonal angle relative to the direction of propagation of the optical signal.