2 x 56 GB/s from a double side electroabsorption modulated DFB laser and application in novel optical PAM4 generation

In this paper, we present a novel device which comprises a DFB laser with electroabsorption modulators integrated on both sides. This integrated chip provides two independently modulated optical outputs from a single laser source and thus cuts the required number of chips for multilane applications in half. Both outputs can be simultaneously operated with 56 Gb/s NRZ leading to 112 Gb/s from a single chip. The performance of the chip is further tested in an optical PAM4 generation experiment. The two NRZ modulated outputs are combined with a polarization combiner to generate an optical PAM4 signal which on the receiver side is measured with a polarization insensitive photodetector