A communication theoretical modeling of single-layer graphene photodetectors and efficient multireceiver diversity combining

Abstract

Graphene with groundbreaking properties has tremendous impact on physical sciences as 2-D atomic layer carbon sheet. Its unique electronic and photonic properties lead to applications such as transistors, graphene photodetectors (GPDs), and electronic circuit components. Metal-graphene-metal (MGM) GPDs with single-or multilayer graphene sheets are promising for future nanoscale optical communication architectures because of wide range absorption from far infrared to visible spectrum, fast carrier velocity, and advanced production techniques due to planar geometry. In this paper, signal-to-noise ratio (SNR), bit-error rate (BER), and data rate performances of nanoscale single-layer symmetric MGM photodetectors are analyzed for intensity modulation and direct detection (IM/DD) modulation. Shot and thermal noise limited (NL) performances are analyzed emphasizing graphene layer width dependence and domination of thermal NL characteristics for practical power levels. Tens of Gbit/s data rates are shown to be achievable with very low BERs for single-receiver (SR) GPDs. Furthermore, multireceiver (MR) GPDs and parallel line-scan (PLS) network topology are defined improving the efficiency of symmetric GPDs. SNR performance of SR PLS channels are both improved and homogenized with MR devices having the same total graphene area by optimizing their positions with maxmin solutions and using maximal ratio and equal gain diversity combining techniques.