Monolithic 300 Gb/s Parallel Transmitter in InP-Based Generic Photonic Integration Technology

In order to meet the constantly rising traffic demands in optical transport systems for data and telecommunications, compact, power efficient, and low-cost optical transmitters are needed that offer easy scalability toward higher transmission capacities. Photonic integrated circuit technology based on the InP material has long enabled the monolithic integration of tunable sources with modulators and opened the way toward large-scale wavelength-division multiplexed parallel transmitters. In this paper, we present the design and performance of a monolithic tunable 8 x 40 Gb/s parallel transmitter chip with more than 220 components and state-of-the-art capacity density metric. A generic photonic integration approach was followed, in which the transmitter is constituted from well-developed subcircuits and building blocks, facilitating its design and manufacturing. With the trend toward large-scale integration with increasing component densities and smaller chip sizes, proximity effects in form of crosstalk are limiting further miniaturization efforts. We analyze electrical, thermal, and optical crosstalk effects that are relevant to the transmitter design, discuss appropriate mitigation techniques, and indicate the limitations of the current technology.