Hi, everyone!
Today I'm going to introduce you about the system structure of OTN equipment
The OTN device mainly contains five parts, they are OTU(Optical Transponder Unit), XCS(Cross-connection Unit), OMU/ODU(Optical Multiplex Unit/Optical Demultiplex Unit), OA(Optical Amplifier) and OSC/ESC(Optical/Electrical Supervisory Channel).
The OUT boards convert the non-standard wavelength into the standard wavelength specified by the ITU-T. The system uses the optical/electrical/optical (O/E/O) conversion. That is the received optical signal is converted into the electrical signal by using the photodiode PIN or APD, and then the electrical signal modulates the laser of the standard wavelength, in this way, a new optical wavelength signal that meets requirements is obtained.
The XCS boards receive data from service boards (line boards and tributary boards), cross-connects ODUk(k=0, 1, 2, 2e, 3, 4, flex)/VC-4 service signals at the electrical layer, and then transmits the signals to service boards for service cross-connection.
The OMU boards ware used at the transmit end. Each input port of the OMU boards inputs one pre-selected wavelength of optical signals, and the input wavelengths are output through the same output port. The ODU boards are used at the receiving end. They have one input port and multiple output ports to classify signals of different wavelengths.
The OA boards can directly amplify optical signals and provide real-time, high-gain, broadband, online, low-noise, and low-loss all-optical amplifiers. Currently, EDFAs and FRAs are commonly used, erbium-doped fiber amplifiers (EDFAs) are widely used as preamplifiers, line amplifiers and power amplifiers in long-distance, large-capacity, and high-speed fiber communication systems.
The OSC/ESC boards are used to monitor the WDM optical transmission system. ITU-T recommends that you use the 1510 nm wavelength with a capacity of 2Mbit/s. The receiver sensitivity (better than –48dBm) is normal when the rate is low. The optical signals must be dropped before the EDFA and added after the EDFA.
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That's all, thank you!
