How to test the return loss of an optical module
Optical return loss (ORL) measures how much light reflects back in fiber optic systems. Reflectance (which has also been called "back reflection" or optical return loss) of a connection is the amount of light that is reflected back up the fiber toward the source by light reflections off the interface of the polished end surface of the mated connectors and air. the reflection above the fiber backscatter level, relative to the source pulse, is called reflectance. When high-speed signals enter or exit a part of an optical fiber, such as an optical fiber connector, discontinuity and impedance mismatch may cause reflection, which is the return loss of an optical fiber. In modern networks running at 10G, 100G, or even 800G speeds, poor RL can increase bit errors, reduce system reliability, and shorten component lifespan.
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