Low V_πL_π 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 18 cm −3 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 π •L π 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.

X-Intersected Silicon Modulator of Well-Rounded Performance

“… Loss is applied to compare the DC performance. The design in this work provides low with a doping level of /cm , which can be increased to /cm in [ 20 ] to obtain much lower , yet sacrificing the carrier-induced loss. The great improvement of our work is the bandwidth broadening, which is raised up to 35 GHz, addressing the problem of high capacitance in the interleaved PN junctions.…”

“…Moreover, lower doping levels are required in interleaved modulators to achieve high modulation efficiency, so the carrier-induced loss is also reduced. Nevertheless, the interleaved combinations of pure p-type and pure n-type implantation have been trapped in high capacitance due to the large area of the PN junction, while the PN overlap in the corners of the cross-section contributes little to improving the modulation efficiency [ 18 , 19 , 20 ]. Therefore, the improvement of the frequency response is the limitation of the interleaved modulator and its use in high rate applications.…”

Integrated Photonic Passive Building Blocks on Silicon-on-Insulator Platform

“…Various structures of free-carrier-depletion-based phase shifters. (a) Phase shifter with offset carrier doping[152,153], (b) PIPIN phase shifters[154], (c) phase shifter with counter doping at corners[155], (d) phase shifter with epitaxy fabrication[156], (e) phase shifters with substrate removement[157], (f) interleaved structure phase shifter[158], (g) zig-zag structure phase shifter[159]. Image reproduced by[131].…”