Patent ID: 8148794

Claim:
A photodetector structure, comprising: a silicon-based waveguide in which optical signals to be detected travel in a given direction and are confined therein; a germanium layer disposed on a portion of said silicon-based waveguide so that an evanescent tail of the propagating optical signal in said waveguide is coupled into said germanium layer, said germanium layer comprising a mesa having a length along the signal propagating direction and a width in a direction substantially perpendicular to the propagating direction, and in which the width of said mesa is smaller than its length; and a first and a second metal contact, said first metal contact being located on said germanium layer, and said second metal contact being located on said silicon-based waveguide and in contact with said silicon-based waveguide, said first and second contacts being used to collect electrons generated by light absorption to obtain an output electric signal; wherein said first metal contact comprises a first and a second metallic strip disposed on said germanium layer.