InP-Based Comb Generator for Optical OFDM

• Published in: Journal of lightwave technology Vol. 30; no. 4; pp. 466 - 472
• Main Authors: Dupuis, N., Doerr, C. R., Liming Zhang, Long Chen, Sauer, N. J., Po Dong, Buhl, L. L., Dongwahn Ahn
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 15.02.2012; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Circuit properties; Comb generator; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Generators; indium phosphide; Information, signal and communications theory; Integrated optics; Integrated optics. Optical fibers and wave guides; Modulation, demodulation; Multiplexing; OFDM; Optical and optoelectronic circuits; Optical waveguides; Phase modulation; phase modulator; Semiconductor optical amplifiers; Signal and communications theory; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Integrated optics; Comb generator; Tunable circuit; Quantum well; Phase modulation; Mach Zehnder interferometer; Phase modulator; indium phosphide; Optical frequency; Line spectrum; Harmonic generator; Frequency multiplier; Line width; Frequency converter; Orthogonal frequency division multiplexing
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2011.2173463

We describe in more detail a novel InP-based comb generator for optical orthogonal frequency division multiplexed (OFDM) transmission. The device integrates a Mach-Zehnder interferometer inside an amplified ring. In order to maximize the number of lines in the spectrum, the phase modulators were designed with a 3-step asymmetric quantum well structure to maximize the index change with voltage change. We demonstrate a 6-line frequency comb which is tunable over 80 nm. The linewidth of the comb is limited by only the input laser, which makes this device especially suitable for coherent optical OFDM applications.