We propose a novel 16-quadrature amplitude modulation (QAM) transmitter based on two cascaded IQ modulators driven by four separate binary electrical signals. The proposed 16-QAM transmitter features scalable configuration and stable performance with simple bias-control. Generation of 16-QAM signals at 40 Gbaud is experimentally demonstrated for the first time and visualized with a high speed constellation analyzer. The proposed modulator is also compared to two other schemes. We investigate the modulator bandwidth requirements and tolerance to accumulated chromatic dispersion through numerical simulations, and the minimum theoretical insertion attenuation is calculated analytically.
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This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.18.023062. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Lu, G-W., Sköld, M., Johannisson, P., Zhao, J. A., Sjödin, M., Sunnerud, H., Westlund, M., Ellis, A., & Andrekson, P. A. (2010). 40-Gbaud 16-QAM transmitter using tandem IQ modulators with binary driving electronic signals. Optics Express, 18(22), 23062-23069. https://doi.org/10.1364/OE.18.023062