The normal loss range of optical power will vary depending on a number of factors, and the following are some common reference values:
• Fiber type: Different types of fiber have different loss characteristics. For example, the loss of ordinary single-mode fiber at 1310nm wavelength is generally about 0.3-0.4dB /km, and the loss at 1550nm wavelength is usually about 0.2-0.25dB /km. The loss of multimode fiber is relatively large, the loss at 850nm wavelength may be about 2-3dB /km, and the loss at 1300nm wavelength is about 0.8-1.5dB /km.
• Connection mode: Fiber optic connection points introduce additional losses. The loss of active connections (such as fiber optic connectors) is generally around 0.2-0.5dB per connection point; The loss of the welding connection is relatively small, and the loss of each welding point is usually about 0.05-0.1dB.
• Transmission distance: In general, the longer the transmission distance, the greater the optical power loss. In the actual optical fiber communication system, for short distance transmission (such as within a few kilometers), the total loss may be within a few decibels; For long-distance transmission (such as tens of kilometers or even hundreds of kilometers), the total loss may reach ten decibels or even higher.
GPON ONU is generally a class B+ standard, using single-mode fiber, its receiving sensitivity should be greater than -27dBb is more stable
