Demonstration of a dual-depletion-region electroabsorption modulator at 1.55-μm wavelength for high-speed and low-driving-voltage performance

We demonstrate a novel structure of electroabsorption modulator (EAM) at a 1.55-μm wavelength: the dual-depletion-region EAM. After an n⁺ delta-doped layer was inserted into the thick intrinsic region (550 nm) of a tradition p-i-n modulator, the tradeoff between driving-voltage and electrical bandwidth performance can be released effectively. This new structure can also release the burden imposed on downscaling the width or length of high-speed EAM with low driving-voltage performance. The microwave and electrical-to-optical measurement of this novel device with traveling-wave electrodes show very convincing results.