Optical module classification By package: 1*9, GBIC, SFF, SFP, XFP, SFP+, X2, XENPARK, 300pin, etc. By rate: 155M, 622M, 1. 25G, 10G, 40G, etc. By mode: single-mode fiber (yellow) . Optical modules are very important in today's networks. Then, they send these signals through fiber. Network engineers use them to link switches, routers, and other. QSFP-DD (Quad Small Form-factor Pluggable-Double Density) Optical Module: Double-density four-channel small pluggable packaged optical module, defined by the QSFP-DD MSA group as a high-speed pluggable module. OSFP (Optical Small Form Factor Pluggable) is a standardized interface for high-speed. The Transmitter Optical Sub Assembly (TOSA) is responsible for the emission of light. Its primary function entails converting electrical signals into optical signals. These modules are typically installed in Optical Line Terminals (OLTs) at the service provider's central office and Optical Network Units (ONUs) or Optical Network. Haoyu Wang School of Physics and Telecommunication Engineering, Shaanxi University of Technology, HanZhong, 723000, China Yanmin Zhu Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR Tong Fu School of Physics and Telecommunication Engineering, Shaanxi.