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Optical modulators

Slow-wave modulator

Slow light for pushing forward the limits of silicon electro-optical modulators

In the context of an ever increasing demand for bandwidth, handling electrical-to-optical data conversion through compact and high speed electro-optical modulators is of paramount importance.

To tackle these challenges, we exploit the attractive properties of slow light propagation to demonstrate a highly efficient and mass-manufacturable 500 µm-long carrier-depletion silicon modulator device capable of transmitting digital data up to 40 Gbit/s with moderate insertion losses. The enhanced light-matter interaction enabled a modulation efficiency up to 8 times greater than that of a conventional rib modulator (VπLπ ~0.45 The obtained results position our slow light modulator amongst the state-of-the-art of current silicon modulators. A low power version of the slow-wave modulator was also demonstrated showing up to 10Gb/s transmission with 1.5 Vpp driving voltage.

This work was made in the framework of FP7 project HELIOS in collaboration with the Silicon Photonics Group of the University of Surrey (now at the University of Southampton) led by Professor Graham T. Reed and CEA-Leti.

Figure: silicon electro-optical modulators

(a) Picture of a single silicon chip consisting of 26 electro-optical modulators. (b) 500µm long slow wave optical modulator under test. (c) Scanning electron microscope (SEM) image of the periodic corrugated waveguide. (d) 40 Gb/s eye diagram.


[1] "High-contrast 40 Gb/s operation of a 500 μm long silicon carrier-depletion slow wave modulator", A. Brimont; D. Thomson; F.Y. Gardes; J. M. Fedeli; G. T. Reed; J. Martí; P. Sanchis, OPTICS LETTERS, Vol. 37, n. 17, pp. 3504-3506, September 2012

[2] "Slow-Light-Enhanced Silicon Optical Modulators Under Low-Drive-Voltage Operation", A. Brimont; A. M. Gutierrez; M. Aamer; D. Thomson; F.Y. Gardes; J. M. Fedeli; G. T. Reed; J. Martí; P. Sanchis, IEEE PHOTONICS JOURNAL, Vol. 4, n. 5, pp. 1306 - 1315, October 2012

[3] "High speed silicon electro-optical modulators enhanced via slow light propagation", A. Brimont; D. Thomson; P. Sanchis; J. Herrera; F.Y. Gardes; J. M. Fedeli; G. T. Reed; J. Martí, OPTICS EXPRESS, Vol. 19, n. 21, pp. 20876-20885, October 2011

[4] "Demonstration of 40Gbit/s slow light-enhanced optical modulator" (Press release)