Abstract
Dimensional parameters are optimized comparing stoichiometric and Si-rich silicon nitride-based push-pull modulators using a slot waveguide structure, electro-optic polymer cladding, and in-plane ground-signal-ground electrode. An optical power confinement in slot spacing is examined for choosing the optimal device parameters for wavelength of 1550 nm. The electrical simulations are set to calculate an asymmetric spatial distribution of poling efficiency and modulating refractive index change in polymer. The influence of carrier charge in Si-substrate is also considered. The voltage-length products as well as the poling efficiency of Si-rich SiN are calculated as 1.47 V·cm and 0.74 respectively for a polymer with a γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33,bulk</sub> of 100 pm/V. For the selected polymer the calculated efficiency comparable to standard silicon based plasma dispersion depletion modulators. The efficiency can be increased more than two times for demonstrated polymers with a γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33,bulk</sub> of ~230. Low metal absorption loss of ~ 1dB/cm can be achieved from the optimal designed device. Comparing to the conventional simulation method without Si-substrate effect, a more accurate simulation method is also presented in this work.
Highlights
There is a growing demand for low cost devices targeted at enabling high speed data traffic of optical interconnects
Alternative concepts of optical modulator which are simpler in terms of fabrication and are compatible with back end of the line (BEOL) multi-layer processing are based on the integrations or bonding of other non CMOS active material such as, lithium niobite (LiNbO3) [5], [6], barium titanate (BTO) [7], [8], electro-optic PZT [9]
The results show that the poling efficiency for both devices is higher when biasing the Si-substrate rather than the central electrode
Summary
There is a growing demand for low cost devices targeted at enabling high speed data traffic of optical interconnects. Slot waveguides coupled to a pn-junction have been adopted in high confinement materials [26]–[29] such as Si to enable a high overlap between the optical mode, the E-field and the EO material, this method does not provide any gain in terms of fabrication complexity or BEOL due to the necessity of forming doped areas within the silicon waveguide. Such method has not been demonstrated in SiN due to the insulator nature of the material. A comparison of two different guiding materials based on [11], [36] (stoichiometric and Si-rich SiN) is presented to compare performances
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
