High-speed InGaAsP electroabsorption modulators: dependence of the device characteristics on the mesa design

We present characteristics of InGaAsP electroabsorption modulators with variable length and mesa width. We demonstrate devices with return loss below -10 dB, bandwidth above 40 GHz and extinction ratio of 10 dB/2 V. We show that low capacitance is advantageous for high-speed operation even when achieved at the expense of increased series resistance.