What are the effects of transmitting optical power and receiving sensitivity on optical modules.onu xpon wholesaler

When selecting optical modules, we need to pay attention to the two parameters of the transmitting optical power and the receiving sensitivity, because these two parameters are one of the key factors to ensure the normal communication of optical modules. Now, what are the transmitting light power and receiving sensitivity? And how to test the optical power of the optical module in the normal range?

Transmitting optical power

Transmitting light power refers to the output light power of the light source at the transmitting end of the optical module, which can be understood as the light intensity, in dBm.

Receiving sensitivity

The receiving sensitivity refers to the minimum received optical power of the optical module at a certain rate and bit error rate, in dBm. In general, the higher the rate, the worse the reception sensitivity, that is, the greater the minimum received optical power, and the higher the requirements for the optical module receiver devices. Considering the increase of link loss caused by optical fiber aging or other unforeseen factors, the optimal optical power range is controlled from 2-3dB above the receiving sensitivity to 2-3dB below the overload point.

Example of normal range of transmitting optical power and receiving sensitivity: the transmitting optical power of 1.25G SFP SX 550m optical module (center wavelength is 850nm) is between - 3dBm and - 10dBm, and the maximum receiving sensitivity is - 18dBm; 1.25G SFP LX 10km optical module (center wavelength is 1310nm) has a transmitting optical power of - 9dBm~- 3dBm and a maximum receiving sensitivity of - 24dBm.

Generally speaking, the customer can directly monitor whether the transmitted optical power and reception sensitivity of the optical module are normal through the DDM function (digital diagnostic monitoring function) of the optical module. In addition, you can also use the optical power meter to obtain the transmitted optical power value of the optical module. Taking 10GBASE-LR SFP+optical module as an example, the test steps are as follows:

1. Plug the 10GBASE-LR SFP+optical module into the SFP+port of the 10G switch;

2. Use LC-LC optical fiber jumper to connect the optical module to the optical power meter;

3. Press the ON key to turn on the optical power, press“ λ” The key modulates the wave band to 1310nm. The value may change during the test. When the value is still, the test is completed. At this time, the optical power displayed on the screen is the transmitted optical power of the optical module.

In a word, as one of the important parameters affecting the communication quality of optical modules, it is necessary to ensure that the transmitted optical power and reception sensitivity are within the normal range