Optical module extinction ratio is too low
A low extinction ratio makes it hard for your device to tell "on" from "off. What tools can you use to measure extinction ratio? You can use a photodetector, oscilloscope, or polarizer. For instance, in long-haul transmission, even a slight degradation can accumulate over distance. If very little power is used to transmit a zero level relative to the one level power, the ER will be high which indicates that the laser power is efficiently being used as modulation power. Although specifications are defined by industry standards and test method-ologies loosely described, historically it has been. ER, extinction ratio, refers to the ratio of light powers when the signal is sent at high level and low level, namely: Formula (1) However, what is usually seen in the manual is its logarithmic form, that is, ERdB = 10*log10 (ER).
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