New structure of photoreceivers for optic communications

Abstract

New p-i-n photodiodes on the basis of InP-InGaAs-InGaAsP heterostructures for optic communications, possessing original characteristics, are presented in the paper. Their specific photosensibility was achieved by placing the p-n junction in InGaAsP frontal layer near the interface with InGaAs active layer. The photosensibility of realized photodiodes can be controlled in spectral range 1 .31.6 im by reverse voltage. For reverse voltage less than a threshold one Urev < Uthr between frontal and active layers there is a potential barrier of about 0.4 eV for holes generated in active layer and they don't participate in photocurrent. For voltage Urev> Utir the boundary of space charge region extends into the lnGaAs active layer and the potential barrier disappears. Thus, charge carriers generated in active layer are easy separated and a photosensibility in spectral range 1 .3-1.65 im appears for Urev > Uthr. These photodiodes haven't analog and can be successfully used in many fields of functional optoelectronics for receiving, decoding and processing the signals transferred by optic fibers.