Reflective Type Multi-Nanolayer Electro-Optical Modulator for Free Space Chip-to-Chip Optical Interconnection: Electromagnetic Modelling by the Method of Single Expression

Electro-optical modulators (EOMs) play an essential role of modulating light for free space chip-to-chip optical interconnection. Optical properties of reflective type multi-nanolayer EOM are modelled numerically by the method of single expression. Reflective properties of Fabry-Perot type EOM consisting of electro-optical spacer of LiNbO
3
covered by thin conducting nano-layers of ITO material embedded between asymmetric Si/SiO
2
distributed Bragg reflectors (DBRs) are analysed. Two semi-transparent ITO nano-layers of the EOM operate as electrodes for supplying electrical signal to the electro-optical material. The layers of DBRs adjacent to the spacer are of higher permittivity and DBRs are asymmetric regarding the spacer to provide the necessary reflectance of the EOM structure. As an external light source, a conventional laser diode at 1.55 μm wavelength is considered. Distributions of amplitude of optical wave and energy flow within the EOM structure are obtained, which are important for optimization of reflective properties of the structure. The optimal structure of the EOM providing a narrow dip in the reflectance is suggested. An essential shift of the narrow dip in the reflectance of the EOM structure is observed at the change of permittivity of electro-optical spacer. The suggested reflective type multi-nanolayer EOM can be used for free space chip-to-chip optical interconnection.