LOW-CHIRP 85-GB/S DUOBINARY MODULATOR IN INP USING ELECTROABSORPTION MODULATORS

In 2005, Griffin showed that an InP phase-shift-keying/duobinary Mach-Zehnder interferometer (MZI) modulator could achieve good transmission performance at 10 Gb/s, despite modest residual amplitude modulation in the phase modulators in the MZI (ratio of real to imaginary part of index change was ~0.1). Here we show that even strong amplitude modulation in the ldquophaserdquo modulators (ratio of real to imaginary part of index change is ~1.0) gives good transmission performance. Allowing for strong amplitude modulation allows a significant increase in modulator bandwidth. We demonstrate low-chirp 85.4-Gb/s optical duobinary generation in a fully packaged InP photonic integrated circuit.