The basic indicators of fiber optical modules mainly include the following,
Output Optical Power
The output optical power refers to the output optical power of the light source at the transmitting end of the fiber optical module. It can be understood as the intensity of light in W or mW or dBm. Among them, W or mW is a linear unit, and dBm is a logarithmic unit. In communication, we usually use dBm to represent optical power.
The optical power is attenuated by half and reduced by 3dB. The optical power of 0dBm corresponds to 1mW.
Maximum Receiving Sensitivity
Receiving sensitivity refers to the minimum received optical power of an fiber optical module at a certain rate and bit error rate, in dBm.
In general, the higher the rate, the worse the receiving sensitivity, that is, the greater the minimum received optical power, and the higher the requirements for the receiving end of the fiber optical module.
Extinction Ratio
The extinction ratio is one of the important parameters used to measure the quality of the fiber optical module.
It refers to the minimum value of the ratio of the average optical power of the signal to the average optical power of the space signal under the condition of full modulation, and represents the distinguishing ability of 0 and 1 signals. The two factors that affect the extinction ratio in the fiber optical module,bias current (bias) and modulation current (Mod), tentatively regarded as ER=Bias/Mod.
The value of the extinction ratio is not that the larger the fiber optical module, the better, but the fiber optical module with the extinction ratio that meets the 802.3 standard.
Light Saturation
Also known as saturated optical power, it refers to the maximum input optical power when a certain bit error rate (10-10～10-12) is maintained at a certain transmission rate, in dBm.
It should be noted that the photodetector will experience photocurrent saturation under strong light irradiation. When this phenomenon occurs, the detector needs a certain time to recover. At this time, the receiving sensitivity decreases, and the received signal may be misjudged. It can cause bit errors, and it is also very easy to damage the receiving end detector. During the operation, try to avoid exceeding its saturated optical power.
Tags : fiber optical module
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