High-efficiency waveguide InGaAs pin photodiode with bandwidth of over 40 GHz

A waveguide pin photodiode structure was designed in consideration of both wide bandwidth and highly efficient coupling to the fiber. The device performed with a bandwidth higher than 40 GHz, and had high responsivity of 0.55 A/W (external quantum efficiency of 44%), showing superiority of bandwidth-efficiency product over the surface-illuminated photodiodes in the ultrahigh-frequency region. Based on the authors' calculations, coupling efficiency can be increased much more with an optimized layer structure.>