Hello, friend!
WDM is a wavelength division multiplexing technology. It combines multiple modulated optical signals (carrying useful information) at the transmit end through a multiplexer (also called a multiplexer, Mux) into the same optical fiber of an optical line (fiber transmission link) for transmission, at the receive end, the demultiplexer (demultiplexer, also called demultiplexer, demultiplexer) is used to receive signals of different wavelengths separately. A WDM system consists of many functional units, such as the OTU, which is used to forward client-side data services to the line-side optical interface. An optical multiplexer unit (OMU) and an optical demultiplexer unit (ODU), respectively, are used to combine and separate multiple wavelength optical signals. Optical amplifier (OBA), optical line amplifier (OLA), and optical preamplifier (OPA) are used to amplify optical signals at the transmit end, link, and receive end. The optical supervisory channel (OSC) should also be included to monitor services and links for network management and maintenance.
OTN is a WDM optical network that inherits powerful OAM concepts and functions from SDH. Specifically, OTN is a technology that introduces electrical sublayers to transmit, multiplex, switch, monitor, and protect client signals over wavelengths or sub-wavelengths. At the electrical layer, packet-based functions are gradually implemented to implement functional entities based on packet, VC, and ODUk cross-connections. In fact, the physical basis of OTN depends on the WDM technology in terms of links. Similar to SDH, OTN introduces encapsulation and overhead management to improve management and interoperability capabilities and cross-connect wavelengths and sub-wavelengths to improve networking, protection, and grooming capabilities. In short, OTN is an IP-based WDM with optical and electrical cross-connections. It emphasizes a node technology.
Thanks!
