[21p-A205-1~21] 3.14 Silicon photonics and integrated photonics (formerly 3.15)

[21p-A205-7] Evaluation of Absorption Losses in Each Arm Separately in Mach-Zehnder Silicon Optical Modulators: How to Include Effect of Power-Split Imbalance

〇Tadashi Murao¹, Jun Ushida¹, Hiroyuki Takahashi¹, Masatoshi Tokushima¹, Akemi Shiina¹, Tsuyoshi Horikawa¹ (1.PETRA)

Keywords:silicon photonics, optical modulator, wafer-level testing

Geometric variation caused by nonuniformities in the photolithography, plasma etch process, and SOI thickness has been a major issue affecting silicon waveguides. Besides, the additional nonuniformity of the carrier-density distributions caused by ion implantation in optical phase shifters is inevitable in carrier-depletion Mach-Zehnder silicon optical modulators. We have shown that the chirp parameter can be estimated by establishing an evaluation methodology that treats the absorption losses, as well as the modulation efficiency, in each arm separately. Here, we present the detailed mechanism of this method and show how to include the influence of power-split imbalance in Mach-Zehnder interferometers.