A 35 Gb/s junction-less dual parallel Mach-Zehnder modulator for short reach interconnects

An electrostatic doping (ED) based 35 Gb/s dual-parallel Mach-Zehnder modulator (DP-MZM) for photonic integrated circuits (PICs) is proposed and analyzed. Theoretical formulation of the transfer function and linearity analysis of the proposed modulator is also presented here. The proposed modulator contains two ED-aided sub-MZMs and an ED-aided optical phase shifter (PS) in a MZI structure. Numerical simulations are performed using commercially available tools and the simulation results are presented here. From the results we estimate that the proposed DP-MZM with 400 μm long sub-MZMs can offer peak dynamic extinction ratio (ER) of 14 dB with maximum 8.7 dB of insertion loss (IL) at 10 Gb/s data rate. Using dual-tone test method, the predicted spurious free dynamic range (SFDR) of the modulator are 62.74 dB·Hz1/2 and 99.35 dB·Hz2/3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{2/3}$$\end{document} for second and third harmonic intermodulation distortions (IMD2 and IMD3), respectively. From the transient analysis, the estimated maximum operating frequency and 3-dB EO bandwidth of the modulator are approximately 35.5 GHz and 32.37 GHz, respectively. At maximum data rate, 5.89 dB of dynamic ER is offered by the proposed DP-MZM for OOK modulation. Simulation verifies successful transmission of 25 Gb/s OOK modulated PRBS data stream over a 10 km standard single mode fiber (SSMF) link. Furthermore, we have shown that the proposed DP-MZM is capable of generating 50 Gb/s PAM-4 signal, which makes the modulator suitable for next-generation short-reach interconnects.