Dense Wavelength DivisionMultiplexer(DWDM) is based on thin film filter technology and proprietary non flux metal bonded micro optical packaging design, achieving uplink and downlink within the wavelength range of ITU. It provides ITU channel center wavelength, low insertion loss, high channel isolation, low power consumption, wide passband characteristics, no adhesive loop, excellent thermal stability and reliability, etc. In telecommunications network systems, it can be used for uplink or downlink optical signals.