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As discussed in the previous chapter, carrier-depletion PN-junction ribwaveguide phase shifters are suitable for high-speed phase shifters on siliconphotonics platforms for small-footprint integrated MZ optical modulators operating in broad spectral ranges over the C and L bands with high temperature stability. In this chapter, the optical, electrical, and electro-optical characteristics of the integrated MZ optical modulators on a silicon-photonics platform are reviewed on the basis of experimental data. It starts with a review of the optical-loss characteristics of the building blocks in the integrated silicon-based MZ optical modulators. Plasma-refraction phase shift in the carrier-depletion rib-waveguide phase shifters and chromatic dispersion of passive optical waveguides are then discussed. Chromatic dispersion in the spectral phase of passive optical waveguides, which, in general, may deteriorate the dynamic performance of high-speed integrated optical modulators, is proved to be negligible in terms of inter-symbol interference. The electrical characteristics of the phase shifters are described with respect to the electrical and structural characterization of PN junctions in phase shifters on siliconphotonics platforms. Electro-optic responses in the RF frequency domain and optical modulation characteristics in the time domain, which are studied in the last two sections in this chapter, are essential to evaluate the dynamic performance of high-speed silicon-based integrated optical modulators.
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