Phase-shift-keying and on-off-keying with improved performances using electroabsorption modulators with interferometric effects

We present methods of optical modulation employing electroabsorption in an interferometric structure. The interferometric operation enables electroabsorption modulators for phase-shift keying and allows generation of on-off-keying signals with much improved extinction ratios. We demonstrate 40-Gb/s phase-shift-keying modulation, and up to 8.7 dB improvement in extinction ratio in 40-Gb/s on-off-keying modulation with 0.8V driving voltage using a commercial electroabsorption modulator. Methods of applying electroabsorption modulators for high spectral-efficiency formats generation are also proposed. (c) 2007 Optical Society of America.