The technical parameters of the optical module are explained in detail

Technical parameters of optical modules

1. Optical module transmission rate: refers to the number of bits transmitted per second, in Mb/s or Gb/s.

2. Transmitting optical power and receiving sensitivity of the optical module: Transmitting optical power refers to the light intensity of the transmitting end, and receiving sensitivity refers to the detectable light intensity. Both are in dBm and are important parameters that affect the transmission distance. The distance that an optical module can transmit is limited mainly by loss and dispersion.

The loss limit can be estimated according to the formula: loss limited distance = (transmitting optical power - receiving sensitivity) / fiber attenuation. The fiber attenuation is related to the actual selected fiber. Generally, the current G.652 fiber can achieve 0.5dB/km in the 1310nm band and 0.3dB/km in the 1550nm band or even better. 50um multimode fiber is 4dB/km in the 850nm band and 2dB/km in the 1310nm band. For 100M and 1000M optical modules, the dispersion limitation is far greater than the loss limitation, so it can be ignored.

ZR Cable Optical Module

3. The 10GE optical module follows the 802.3ae standard, and the transmission distance is related to the type of optical fiber selected and the optical performance of the optical module.

4. The saturated optical power value refers to the maximum optical power that can be detected by the receiving end of the optical module, generally -3dBm. When the received optical power is greater than the saturated optical power, bit errors will also occur. Therefore, there will be bit errors in the loopback test without attenuation for the optical module with high transmit optical power.

5. Transmission distance

The transmission distance of the optical module is divided into three types: short distance, medium distance and long distance. It is generally considered that 2km and below are short distances, 10-20km are medium distances, and 30km, 40km and above are long distances. The transmission distance of the optical module is limited, mainly because the optical signal will have a certain loss and dispersion when it is transmitted in the optical fiber.

Loss is the loss of light energy due to absorption, scattering and leakage of the medium when light is transmitted in the optical fiber. This part of the energy is dissipated at a certain rate with the increase of the transmission distance. Dispersion is mainly caused by the fact that electromagnetic waves of different wavelengths travel in the same medium at different speeds, resulting in different wavelength components of the optical signal reaching the receiving end at different times due to the accumulation of transmission distances, resulting in pulse broadening and inability to distinguish the signal. value.

Therefore, users need to select appropriate optical modules according to their actual networking conditions to meet different transmission distance requirements.

6. Center wavelength

The central wavelength refers to the optical band used for optical signal transmission. At present, there are mainly three central wavelengths of optical modules: 850nm band, 1310nm band and 1550nm band

850nm band: mostly used for short-distance transmission

1310nm and 1550nm bands: mostly used for medium and long distance transmission

The above are the detailed technical parameters of the optical module explained to you by ZR Cable.