Dense Wavelength Division Multiplexing (DWDM) technology can carry 8 to 160 wavelengths. With the continuous development of DWDM technology, the upper limit of the number of sub-wavelengths is still increasing. The interval is generally less than or equal to 1.6 nm, and it is mainly applied to long wavelengths. Distance transmission system. Dispersion compensation techniques are required in all DWDM systems (overcoming the nonlinear distortion in multi-wavelength systems - four-wave mixing). In a 16-wave DWDM system, conventional dispersion compensation fibers are generally used for compensation. In a 40-wave DWDM system, dispersion slope compensation optical fiber compensation must be used. DWDM can combine and transmit different wavelengths at the same time in the same fiber. To ensure effective transmission, one fiber is converted into multiple virtual fibers. With DWDM technology, a single optical fiber can transmit data traffic up to 400 Gbit/s. As manufacturers add more channels to each optical fiber, the transmission rate of bits per second is just around the corner.