Patent ID: 8598673

Claim:
A large-area low-noise quad photoreceiver comprising: a quad InGaAs photodiode structure including: an n + doped InP substrate having top and bottom surfaces; a buffer layer provided by n + doped InP material deposited on the top of said substrate for reducing the capacitance to enhance the speed of said photodiode; an n + metal back contact deposited on the bottom of said substrate, said contact serving as a common cathode for receiving a bias voltage; an intrinsic (i) InP drift layer deposited on the top of said buffer layer; an InGaAs absorption layer deposited on the i InP drift layer, said drift layer and said absorption layer providing low-capacitance high-speed operation; InP cap layer deposited on said absorption layer; said InP cap layer being divided into four quadrants of equal area, each quadrant being p + doped, the p + doping extending into a top portion of said absorption layer, with the four quadrants being spaced apart from one another and each serving as the light receiving area for an individual associated p-i-n photodiode; an individual p + metal contact being deposited in an outermost portion of each one of said four quadrants, respectively, with each contact serving as an output terminal for its associated p-i-n photodiode; and four transimpedance amplifiers (TIA) each having an individual input terminal electrically connected to an output terminal of an individual one of said p-i-n photodiodes, and each TIA having an individual output terminal.