Enhanced Performance of ITO-Assisted Electro-Absorption Optical Modulator Using Sidewall Angled Silicon Waveguide

The balance between extinction ratio and insertion loss is a stringent condition while realizing efficient optical modulators with a higher figure-of-merit (FOM), lower power consumption, and wider modulation bandwidth. The higher value of FOM is associated with the requirement of a larger extinction ratio and a smaller insertion loss. In the model presented here, the balance between the extinction ratio and insertion loss is maintained by the device architecture and choosing ON-state of the modulator at a lower carrier concentration regime. An electroabsorption (EA) optical modulator architecture comprised of Si/HfO
₂
/ITO/Si stack upon a silica substrate offers an extinction ratio of 6.81 dB/μm, insertion loss of 0.019 dB/μm, and FOM of 337. The modulation bandwidth is as high as 78.85 GHz with active 3-dB length of 440 nm at the expense of 20 fJ/bit. The optical bandwidth is excess of 220 nm operating between ~1440 and ~1660 nm.