Improvement of bandwidth-to-drive-voltage of an electroabsorption modulator employing a double-pass configuration

We propose and demonstrate an electroabsorption modulator using a double-pass configuration that enabled us to overcome the tradeoff between expanding modulation bandwidth and increasing extinction efficiency. The 130-μm device, which has a bulk absorption layer, demonstrated a 10 dB extinction ratio with an applied voltage ranging from 0 to -0.9 V and a modulation bandwidth exceeding 20 GHz corresponding to a 200% improvement in the bandwidth-to-drive-voltage over a conventional single-passing modulator.