Numerical Modeling and Analysis for High-Efficiency Carrier-Depletion Silicon Rib-Waveguide Phase Shifters

In this paper, we report the efficiency and loss performance of a depletion silicon rib phase shifter with an overlayer of 220 nm and doping concentration of 5 × 10
¹⁷
cm
^–3
for both p and n regions. A
${{\rm{V}}_{\rm pi}}$
of 3.6 V and a loss of 5.2 dB, 4-mm device is reported. We identified a range of doping concentrations that allow the phase shifter to operate at <6 V and <5-dB loss. Junction placement variances suggested that with the reduced p dopant concentration (2 × 10
¹⁷
cm
^–3
), better loss and phase performance can be achieved with a larger p-type region and smaller n-type region.