Application of Multimeters: Optical Fiber Testing Parameters and Testing Methods
1. Attenuation is the reduction of optical power during the transmission of light along an optical fiber.
2. Calculation of total attenuation in fiber optic networks: Fiber optic loss (LOSS) refers to the ratio of the power Powerout at the output end of the fiber optic to the power Powerin when transmitted to the fiber optic.
3. The loss is 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. Measuring attenuation: Because connecting optical fibers to light sources and optical power meters inevitably introduces additional losses. Therefore, during on-site testing, it is necessary to first set the testing reference point of the tester (i.e. zero setting). There are several methods for testing reference points, mainly based on the tested link object. In fiber optic cabling systems, since the length of the fiber itself is usually not long, more attention will be paid to connectors and test jumpers in testing methods, and methods are more important.
Return loss: Reflection loss, also known as return loss, refers to the decibel ratio of the backward reflected light to the input light at the fiber optic connection. The larger the return loss, the better, in order to reduce the impact of reflected light on the light source and system. The method to improve the return loss is to choose to process the fiber end face into a spherical or oblique spherical shape as much as possible, which is an effective way to improve the return loss.
Insertion loss: Insertion loss refers to the decibel ratio of the output optical power to the input optical power of an optical signal in an optical fiber after passing through a movable connector. The smaller the insertion loss, the better. The measurement method for insertion loss is the same as that for attenuation.
