DWDM (DWDM: Dense Wavelength Division Multiplexing) is a combination of a set of optical wavelengths that can be transmitted by one fiber. DWDM SFP is a wavelength division multiplexing technology that can couple different wavelengths of light into a single-core fiber for transmission. The channel spacing of the DWDM SFP is 0.4 nm, 0.8 nm, 1.6 nm, etc., and the spacing is small, requiring additional wavelength control devices. A key advantage of the DWDM SFP is that its protocol and transmission speed are irrelevant. The DWDM-based network can transmit data using IP protocol, ATM, SONET/SDH, and Ethernet protocols, and the processed data traffic is between 100Mb/s and 400Gb/s. In this way, a DWDM-based network can transmit different types of data traffic at different speeds on a single laser channel. From a QoS (Quality Service) perspective, DWDM-based networks respond quickly to customer bandwidth requirements and protocol changes in a cost-effective manner.