Micro-structured integrated electro-optic LiNbO3 modulators

In this paper, we will review the state-of-the-art of LiNbO3 based integrated electro-optic modulators and will show how micro-structuring techniques such as etching, domain inversion and thin film processing can be used to realize new configurations which can take the performance to unprecedented levels. in particular, we will review recent results on the use of domain inversion on a micron scale and we report on the fabrication of a chirp-free modulator having similar to 2 V switching voltage and bandwidth of 15 GHz designed by placing the waveguide arms I of the Mach-Zehnder interferometer in opposite domain oriented regions. We also review some of the new modulation formats (e.g. DQPSK) that can represent an application development of the presented micro-structured devices. Finally, we address the issue of the integration of the modulator chip in a transmitter board comprising tunable laser, bias-control electronics and RF driver. The requirement,,, of integration can even push further the reduction in size of modulator chips, thus making more crucial the use of micro - and nano-structuring techniques. [GRAPHICS] Mach-Zehnder modulator exploiting domain inversion for ultra-low voltage operation. (c) 2009 by WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim