Nowadays, it is in an important stage of the development and construction of the 5th Generation Mobile Communication Technology (5G) network, and the problems such as large bandwidth demand, high cost of optical modules and difficulty in laying in the construction of fronthaul networks need to be solved urgently. Quad Small Form-factor Pluggable (QSFP) packages are known to have four channels, while traditional QSFP28 50 Gbit/s optical module designs use only two of them. In this study, a Small Form-factor Pluggable (SFP) package smaller than the QSFP package is used to make a 50 Gbit/s optical module, which reduced the bottom area by 40.5%, the volume by 52.2%, the power consumption by 42.1%, and the cost of transmitting the same distance optical module by 73.4%. 4 Pulse Amplitude Modulation (PAM4) technology enables 25 Gbit/s optical devices to transmit signals at 50 Gbit/s, doubling the single wavelength rate. Through the comparative test, the room temperature Transmitter Dispersion Eye Closure Quaternary (TDECQ) is reduced by 20.5%, the sensitivity is increased by 0.6 dB, and the remaining parameters meet the relevant requirements of Institute of Electrical and Electronics Engineers (IEEE) 802.3cd 50 GE Ethernet, which can stably transmit distance of 40 km.