100GBASE-SR4 QSFP28 is one kind of parallel transceiver. VCSEL and PIN array package is key technique, through I2C system can contact with module.

The FiberHTT Technology's HSP100G-AOC-xx is a Four-Channel, Pluggable, Parallel, Fiber-Optic QSFP+ SR4 for 100 or 40 Gigabit Ethernet , Infiniband FDR/EDR and 32GFC Applications. This transceiver is a high performance module for short-range multi-lane data communication and interconnect applications. It integrates four data lanes in each direction with 112.2 Gbps bandwidth. Each lane can operate at 28.05Gbps up to 70 m using OM3 fiber or 100 m using OM4 fiber. These modules are designed to operate over multimode fiber systems using a nominal wavelength of 850nm. The electrical interface uses a 38 contact edge type connector. The optical interface uses an 12 fiber MTP (MPO) connector. This module incorporates FiberHTT Technologies proven circuit and VCSEL technology to provide reliable long life, high performance, and consistent service.