Multimeter application: fiber optic testing parameters and testing methods
After the installation of the fiber optic cabling system is completed, it is necessary to test the transmission characteristics of the link, among which the most important test items are the attenuation characteristics of the link, insertion loss of the connector, return loss, etc. Below, we will provide a brief introduction to the measurement of key physical parameters in fiber optic cabling, as well as troubleshooting and maintenance in the network.
Key physical parameters of fiber optic links
1. Attenuation is the reduction of optical power during the transmission of light along optical fibers.
2. The calculation of total attenuation in fiber optic networks: Fiber loss (LOS) refers to the ratio of the power output at the fiber optic end, Powerout, to the power transmitted to the fiber optic.
3. The loss is directly proportional to the length of the fiber, so the total attenuation not only indicates the fiber loss itself, but also reflects the length of the fiber.
4. Fiber loss factor (α): To reflect the characteristics of fiber attenuation, we introduce the concept of fiber loss factor.
5. Measurement of attenuation: Because connecting the fiber optic to the light source and measuring the optical power inevitably introduces additional losses. Therefore, during on-site testing, it is necessary to first set the testing reference point of the tester (i.e. reset to zero). There are several methods for testing reference points, mainly selected based on the tested link object. In fiber optic cabling systems, due to the short length of the fiber itself, more emphasis is placed on connectors and test jumpers in the testing method, making the method more important.
Return loss: Reflection loss, also known as return loss, refers to the decibel ratio of backward reflected light to input light at the fiber optic connection. The greater the return loss, the better, in order to reduce the impact of reflected light on the light source and system. The method to improve return loss is to choose to process the fiber end face into a spherical or oblique spherical surface as much as possible, which is an effective method to improve return loss.
