Epsilon-Near-Zero Material based C-Band Electro-absorption Modulator for Integrated Nanophotonic Systems

Electro-absorption Modulators are an essential part of the integrated photonic system which allows changing the characteristics of an optical signal through electrical excitation. A C-band electro-absorption modulator based on metaoxide-semiconductor structure is proposed in this study. This modulator comprises two MOS structures consisting of cascaded layers of n-type silicon (Si), hafnium oxide (HfO
2
), indium tin oxide (ITO), Hf0
2
, and n-type Si. The proposed device can modulate the incoming beam, which is of transverse magnetic (TM) in nature, entering into the silicon rib-waveguide, due to the electro-tunable epsilon-near-zero (ENZ) phenomenon of ITO. The extinction ratio (ER) is achieved as high as ~16.5 dB with a 2.5 V applied bias. Electro-absorption modulators have several advantages, such as small device footprint, high ER, and compatibility with complementary metal oxide semiconductors.