Ultralow-energy electro-absorption modulator consisting of InGaAsP-embedded photonic-crystal waveguide

• Published in: APL photonics 2017-05, Vol.2 (5), p.056105-056105-11
• Main Authors: Nozaki, Kengo, Shakoor, Abdul, Matsuo, Shinji, Fujii, Takuro, Takeda, Koji, Shinya, Akihiko, Kuramochi, Eiichi, Notomi, Masaya
• Format: Article
• Language: English
• ISSN: 2378-0967; 2378-0967
• DOI: 10.1063/1.4980036

Towards realizing highly integrable low-energy optical modulators, the small device capacitance (C) as well as the low driving voltage (V pp) is demanded for suppressing the charging energy during the dynamic operation. Although an electro-absorption modulator (EAM) has great potential in reducing them, the additional energy associated with the photocurrent flow will limit the lower-bound of the consumption energy. In this work, a broadband EAM based on an InGaAsP-embedded photonic crystal waveguide is demonstrated, revealing a high modulation bit rate of up to 56 Gbit/s. The air-bridge structure and a device length of 100 μm or less result in a small C ≤ 13 fF while operating with V pp < 1 V. Particularly, the operation in low reverse voltage for a p-i-n junction, that is, −0.2 V as the minimum value in this study, works effective for the reduction of energy involving the photocurrent. This results in the total electrical energy consumption of