A Proposal for an Electrostatic Doping-Assisted Electroabsorption Modulator for Intrachip Communication

Abstract

In this paper, we report a CMOS compatible novel penta-electrode charge-plasma diode-based optical electroabsorption modulator (EAM). The proposed integrated EAM is junctionless and employs electrostatic doping in the semiconductor to change its absorption coefficient. The proposed EAM has a vertical metal–insulator–semiconductor (MIS) and lateral metal–semiconductor (MS) junctions. Using this novel MIS–MS-based charge plasma diode, EAM with various lengths are designed on the standard 220-nm silicon-on-insulator (SOI) platform. The numerical simulations, using commercially available TCAD tools and mode solvers, are performed to estimate the performances of the proposed modulators. A couple of combinations of materials having different work functions are used as electrodes to realize this MIS–MS charge plasma diode and their performances are extensively studied. The results predict that 550 $\mu \text{m}$ -long EAM with electrodes made of palladium and aluminum offers ~ 3.4 dB of dynamic extinction ratio (ER). Approximately 8.1 dB of insertion loss (IL) will be introduced by the proposed EAM with a length of $550~\mu \text{m}$ . The proposed modulator is expected to provide a maximum of 30.3 GHz operating speed with 26.2 GHz of 3-dB electrooptic bandwidth. Also, the simulation result indicates that the maximum dynamic energy consumption for the proposed EAM is approximately 39.1 fJ/bit at 12.5-Gb/s data rate.