International Journal of Optics and Applications 2015, 5(4): 121-132 DOI: 10.5923/j.optics.20150504.03 Modeling and Analysis of a Miniaturized Ring Modulator Using Silicon-Polymer-Metal Hybrid Plasmonic Phase Shifter. Part I: Theoretical Framework Alhuda A. Al-mfrji 1 , Shelan K. Tawfeeq 1 , Raad S. Fyath 2,* 1 Institute of Laser for Postgraduate Studies, University of Baghdad, Iraq 2 College of Engineering, Al-Nahrain University, Iraq Abstract This paper presents comprehensive analysis and investigation for 1550nm and 1310nm ring optical modulators employing an electro-optic polymer infiltrated silicon-plasmonic hybrid phase shifter. The paper falls into two parts which introduce a theoretical modeling framework and performance assessment of these advanced modulators, respectively. In this part, analytical expressions are derived to characterize the coupling effect in the hybrid phase shifter, transmission function of the modulator, and modulator performance parameters. The results can be used as a guideline to design compact and wideband optical modulators using plasmonic technology. Keywords Ring modulator, Hybrid plasmonic phase shifter, Electro-optic polymer 1. Introduction Silicon-based photonic integrated circuits (PICs) are an attractive solution for next generation high-speed data transmission [1, 2]. Usually these circuits are realized using standard complementary metal-oxide semiconductor (CMOS) fabrication technology [3, 4] where silicon photonics offer low cost, low power consumption, and high bandwidth [2]. Recently silicon PICs have been demonstrated for both intra- or inter chip -link, and long haul telecommunication links [2]. Optical interconnects have recently emerged as promising solution for alleviating the bandwidth in modern computing electronics [5]. As a key part of optical interconnect on silicon chips, electro-optic (EO) modulators have been made great progress in recent years and attracted many interests [6]. In addition to that, optical networks have been growing up and integrated components such as optical modulators are widely developed and employed as key components for such application. Especially, the next generation optical networks are demanded to have the features of high capacity, high-speed and high- agility which require the aggregate carrier data per optical fiber to be extended toward 100 Tb/s [7]. This requires high performance modulators capable to deal with ultrahigh speed data rate of single-channel optical signals (100 Gb/s and higher in the future compared with current * Corresponding author: rsfyath@nahrain-eng.org (Raad S. Fyath) Published online at http://journal.sapub.org/optics Copyright © 2015 Scientific & Academic Publishing. All Rights Reserved 10 and 40 Gb/s) [7, 8]. Conventional CMOS-compatible silicon optical modulator are usually realized using the linear EO (Pockels) effect rather than carrier depletion effect in order to achieve high speed operation [9-11]. Unfortunately, these modulators suffer from two main limitations (i) CMOS compatibility sets limit to the required operating voltages [6]. Silicon is characterized by relatively low linear EO coefficients and hence requires relatively high modulating voltages. This problem has been solved by incorporating polymer with higher EO coefficient in the active region of the modulator leading to silicon-polymer hybrid modulators [12-15]. (ii) Advances in CMOS technology enable the fabrication of integrated electronics on nano-scale size. In contrast, the size of a conventional optical modulator is in order of operating wavelength or higher. A technology emerging recently which can scale down the dimensions of optical devices far beyond the diffraction limit is plasmonics [16]. This technology is based on surface plasmon polariton (SPP) which travels through a form of hybrid electrical/optical propagation [17-19]. A plasmon is a quasi-particle formed from the coupling of a photon and a travelling electron density wave at the interface between a metal and a dielectric [20]. Recently, plasmonic technology has been used to realize ultra-compact modulators suitable for integration with electronic components and hence meet footprint and efficiency requirement of PICs [21].