An Ultra-Compact CPO Transceiver Based on a 1060-nm Single-Mode VCSEL Array and Multicore Fibers

We propose an ultra-compact 25-Gb/s NRZ × 16-channel optical transceiver based on a 1060-nm coupled-cavity single-mode vertical cavity surface emitting laser (VCSEL) array and single-mode 19-core fibers for Co-Packaged Optics (CPO). The CPO transceiver has a unique packaging structure adopted with double-sided flip-chip-bonding and direct MCF butt-coupling. In order to reduce a footprint of the CPO transceiver, a 0.3-mm-pitch land grid array is adopted for an electrical pluggable interface. The mechanical size of the 25-Gb/s × 16-channel CPO transceiver is as small as <1 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. A 25-Gbaud testing station with 3-dB bandwidth of >12.5 GHz is built to evaluate a loopback optical link using the CPO transceiver and a 2-km 19-core fiber. When operating 16 channels simultaneously, a measured total jitter margin at BER of 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−12</sup> is as wide as >0.25 U.I. at a monitor channel without any clock-data-recovery as well as feed-forward error correction.