High-speed undercut-wet-etching-active-region traveling-wave electroabsorption modulator

In this work, a novel traveling-wave electroabsorption modulator (TWEAM) by double undercut-etching i-layers are proposed and successfully fabricated with high-efficiency and high-speed performance.

Electro-absorption modulators (EAM) has been widely used in high-speed optical communication due to their high extinction ratio, low driving power and the capability of integrating with other semiconductor devices. Broad-band and high-electrical-to-optical efficiency are two main criterions in the design of EAM. Toward the high performance in the EAM application, traveling-wave (TW) structure is one of candidates to overcome the conventional RC-lump limitation. Therefore, the waveguide can be made long to enhance the extinction ratio and high modulation efficiency without losing its high-speed performance [1]‑[4]. However, in practical, the limitation of TWEAM in p-i-n layers is generally restricted by the high microwave propagation loss because of the metal skin effect, highly-loaded capacitance and the high resistance in n- and players [5]. In this work, a novel TWEAM by double undercut-etching i-layers are proposed and successfully fabricated with high-efficiency and high-speed performance.