The application of CWDM technology in telecommunication networks is very mature. The International Telecommunication Union defines 18 CWDM channels with 20 nm interval in 1271-1611 nm band. The CWDM4 standard in data communication adopts four wavelengths, namely 1271-1331 nm, which are close to the zero dispersion point of G652 single-mode fiber. Data Center 100G Optical transceiver module, the current mainstream packaging form is QSFP28, integrated 4 semi-conductor laser, optical detector array and its driver circuit, as well as passive CWDM4 components. In order to integrate CWDM4 component into QSFP28 module, it is necessary to make the design as small as possible, and the size requirement is more strict than CCWDM module (a compact CWDM module) in telecom application.