Enhancement of the bandwidth of p-i-n photodiodes by utilizing tandem structures

We propose a new method of increasing the maximum 3dB-bandwidth of InGaAs/I nP p-i-n photodiodes for optical communication applications. It is demonstr ated by calculation that employing tandem structures (p-i-n)(N) (N greater than or equal to 2) enhances the maximum 3dB-bandwidth by a factor of rootN after optimizing the i-layer thickness for the side illumination case, alt hough the photosensitivity decreases by a factor of N. Conditions imposed o n the i-layer thickness for complete carrier recombination in the intermedi ate n-p junctions are derived.