Integrated Lithium Niobate Mach-Zehnder Interferometers for Advanced Modulation Formats

Tetsuya KAWANISHI  Takahide SAKAMOTO  Akito CHIBA  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.7   pp.915-921
Publication Date: 2009/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.915
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Section on Recent Advances in Ultra-high-speed Photonic Devices for Next-generation Optical Fiber Communications)
optical modulator,  quadrature amplitude modulation,  lithium niobate,  Mach-Zehnder interferometer,  

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We present recent progress of high-speed Mach-Zehnder modulator technologies for advanced modulation formats. Multi-level quadrature amplitude modulation signal can be synthesized by using parallel Mach-Zehnder modulators. We can generate complicated multi-level optical signals from binary data streams, where binary modulated signals are vectorially summed in optical circuits. Frequency response of each Mach-Zehnder interferometer is also very important to achieve high-speed signals. We can enhance the bandwidth of the response, with thin substrate. 87 Gbaud modulation was demonstrated with a dual-parallel Mach-Zehnder modulator.