A modal analysis is conducted for analyzing
the absorption profile of high power waveguide photo-
diodes designed for analog optical link. The excitation of
guided modes with large filling factor in the absorber is
identified as a limiting factor for the performance of
waveguide photodiodes at high optical power, including
power handling capability, and bandwidth-efficiency
product. A waveguide photodiode design, which spatially
separates the input waveguide from the absorber in the
lateral direction, is analyzed and experimentally demon-
strated to suppress the excitation of mode with large filling
factor. Photocurrent > 60 mA under – 4 V bias is mea-
sured, with 0.80 A/W responsivity. This design illustrates
that high power handling capability can be achieved
without compromising the bandwidth-efficiency product.

• Absorption density control in waveguide photodiode--- analysis, design, and demonstration