Electro-optical modulator in a polymerinfiltrated silicon slotted photonic crystal waveguide heterostructure resonator

Jan H Wülbern,Alexander Petrov,Manfred Eich

doi:10.1364/oe.17.000304

Abstract

We present a novel concept of a compact, ultra fast electro-optic modulator, based on photonic crystal resonator structures that can be realized in two dimensional photonic crystal slabs of silicon as core material employing a nonlinear optical polymer as infiltration and cladding material. The novel concept is to combine a photonic crystal heterostructure cavity with a slotted defect waveguide. The photonic crystal lattice can be used as a distributed electrode for the application of a modulation signal. An electrical contact is hence provided while the optical wave is kept isolated from the lossy metal electrodes. Thereby, well known disadvantages of segmented electrode designs such as excessive scattering are avoided. The optical field enhancement in the slotted region increases the nonlinear interaction with an external electric field resulting in an envisaged switching voltage of approximately 1 V at modulation speeds up to 100 GHz.

Highlights

The strong research interest in micro photonics stems from the ever increasing demand for bandwidth in information processing on all levels
photonic crystals (PhCs) slabs are implemented as an array of holes in a high index slab surrounded by a low index material providing confinement of light by total internal reflection [6]
The former we considered in the previous section and the latter is controlled by the length of the reflector region PhC2

Summary

Introduction

The strong research interest in micro photonics stems from the ever increasing demand for bandwidth in information processing on all levels. Polymers themselves only offer moderate refractive indices (n ≈ 1.6) and a less developed nano-structuring fabrication technology compared to silicon Both PhC structures with a direction independent band gap for transverse electric (TE) polarization in hexagonal lattices [14] as well as EO modulation in PhCs have been demonstrated for polymer based PhC slabs [15,16,17]. Brosi et al [18] discussed a concept to combine both material types to achieve high speed modulation in a PhC based Mach-Zehnder interferometer Their concept uses silicon as core material surrounded by polymer replacing all air regions, including the infiltration of holes. In the third section we show that variations of the refractive index in the slotted region due to the Pockels effect can shift the resonance frequency of the device, allowing its operation as an EO modulator

Unloaded resonator performance

Loaded resonator performance

Electro-optic modulation

Findings

Summary and conclusion