28-Gb/s ×4-channel solderable optical transceiver module for QSFP28

A solderable 28-Gb/s × 4-channel VCSEL-based optical transceiver module was designed for QSFP28 MPO-type transceiver and AOC applications. The module exhibits 28.05-Gb/s × 4-channel simultaneous operation with a jitter margin of −0.4 U.I. at the case temperature of 70 °C. The 4-channel module can be simply mounted on a PCB in compliance with the standard of QSFP28 edge connector, together with other electronics components through a solder reflow process. The module was controlled by a look-up table written in an MCU. The PCBA was built in a die-cast housing. As we performed a loop back test of QSFP28 MPO-type transceiver, a BER characteristic for 28.05-Gb/s × 4-channel operation achieves a total jitter margin of −0.4 U.I. over the operating housing temperature range.