title: Photonic generation of ultra-wide-band doublet pulse through monolithic integration of tapered directional coupler and quantum well waveguide.
abstract: We proposed and demonstrated a novel scheme of photonic ultra-wide-band (UWB) doublet pulse based on monolithic integration of tapered optical-direction coupler (TODC) and multiple-quantum-well (MQW) waveguide. TODC is formed by a top tapered MQW waveguide vertically integrating with an underneath passive waveguide. Through simultaneous field-driven optical index- and absorption- change in MQW, the partial optical coupling in TODC can be used to get a valley-shaped of optical transmission against voltage. Therefore, doublet-enveloped optical pulse can be realized by high-speed and high-efficient conversion of input electrical pulse. By just adjusting bias through MQW, 1530 nm photonic UWB doublet optical pulse with 75-ps pulse width, below -41.3 dBm power, 125% fractional bandwidth, and 7.5 GHz of -10 dB bandwidth has been demonstrated, fitted into FCC requirement (3.1 GHz~10.6 GHz). Doublet-pulse data transmission generated in optical fiber is also performed for further characterization, exhibiting a successful 1.25 Gb/s error-free transmission. It suggests such optoelectronic integration template can be applied for photonic UWB generation in fiber-based communications.
authors.affiliation: Institute of Electro-Optic Engineering and Department of Photonics, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
authors.forename: Yu-Zheng
authors.initials: YZ
authors.lastname: Kuo
authors.forename: Jui-Pin
authors.initials: JP
authors.lastname: Wu
authors.forename: Tsu-Hsiu
authors.initials: TH
authors.lastname: Wu
authors.forename: Yi-Jen
authors.initials: YJ
authors.lastname: Chiu