Fabrication of a novel lumped electro-absorption modulator with a lower RC-time constant

A novel lumped electro-absorption modulator with a charge layer and an undercut ridge waveguide (DU-EAM) was fabricated and measured.Also,two other kinds of EAM with straight ridge waveguides,one with a charge layer(D-EAM) and another with no charge layer(N-EAM),were fabricated and tested to ensure that the design of the DU-EAM would reduce the RC-time constant.The measured capacitance of the D-EAM and the DU-EAM is lower than that of the N-EAM under reverse bias voltage from -1 to -8 V due to the inserted ...