Compact PIN-Diode-Based Silicon Modulator Using Side-Wall-Grating Waveguide

作者：Suguru Akiyama, Masahiko Imai, Takeshi Baba, T. Akagawa, Naoki Hirayama, Yoshiji Noguchi, Miyoshi Seki, Keiji Koshino, Munehiro Toyama, Tsuyoshi Horikawa, Tatsuya Usuki · 发表于：IEEE Journal of Selected Topics in Quantum Electronics · 年份：2013 · DOI：10.1109/jstqe.2013.2278438 · 被引用次数：56 · 研究领域：Photonic and Optical Devices、Semiconductor Lasers and Optical Devices、Advanced Photonic Communication Systems

We developed PIN-diode-based silicon Mach-Zehnder modulators, which have side-wall-gratings in the phase-shifter sections. Such passive waveguides with gratings were fabricated using ArF immersion lithography, which showed a small scattering loss of 0.4 dB/mm. We extensively investigated the forward-biased operation of the modulators by using equivalent circuit analysis and the measurement of the fabricated devices. We argue carrier recombination time only plays a minor role for the overall performance of the modulator. Dependences of the modulation efficiency on other various critical parameters are discussed. In particular, if we use relatively short phase shifter, the forward-biased operation provides smaller VπL than reversed one even at high frequency of 20 GHz, at the expense of the narrow bandwidth. Our approach enables high-speed operation up to 50 Gb/s, by using phase shifter as short as 250 μm and preemphasis signals. For 12.5-Gb/s operation, the modulator cell size was only 300 μm × 50 μm, which was suitable for the applications of high-density optical interconnects.