Low VπLπ and Driving Voltage Interleaved Silicon Phase Shifter for Modulation Applications

Abstract

Interleaved doped Mach-Zehnder Modulators (MZMs) are one solution to attaining higher modulation efficiencies compared with lateral junction structures, due to greater modal overlap with the depletion regions of the PN junctions. In this work, we present an interleaved Si modulator device design and process simulation based on a three-step ion implantation process that aims to obtain a realistic PN junction doping profile using a Monte Carlo simulation method. A high doping concentration on the order of 5×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> for the P and N regions is explored. Device simulations to track the carrier motion under different voltage biases are performed. Using equivalent medium theory, we calculated the modulation efficiency V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> ·L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> of the interleaved Si modulator to be 0.19 V·cm under 1V reverse bias. This work is among the highest reported modulation efficiencies thus far in MZMs without photonic resonance structures.