Optical modules are also affected by many factors during use. This article summarizes 8 common elements that can affect the overall performance of optical modules and require more attention during use.
1. Types of optical modules
SFP module, a small hot swappable optical transceiver module. The standard transmission rates are 155M and 1.25G. SFP+module, high-speed SFP module, and SFP module have basically the same appearance, with a standard transmission rate of 10G. QSFP+module, which is a four channel SFP+module, has a standard transmission rate of 40G.
2. Transmitting optical power
Transmitting optical power refers to the light intensity at the transmitting end, measured in dBm, and is an important parameter that affects the transmission distance.
3. Receiving sensitivity
Receiver sensitivity refers to the detectable light intensity, measured in dBm. In general, the higher the speed, the worse the receiving sensitivity, that is, the larger the minimum received optical power, and the higher the requirements for the receiving end devices of the optical module.
4. Bias current
In order to ensure the normal operation of the laser LD high-speed switch, a DC bias current IBIAS slightly greater than the threshold current ITH must be applied to it, which is directly represented by BIAS. BIAS too large will cause aging of the accelerator components, and the BIAS is too small for the laser to function properly.
5. Extinction ratio
The ratio of the optical power when the signal logic is 1 to the optical power when it is 0, in dB. The extinction ratio is inversely proportional to the optical power, and during the debugging process, it will be found that increasing the optical power will result in a smaller extinction ratio, while decreasing the optical power will result in a larger extinction ratio.
6. Saturated optical power
The maximum input optical power that maintains a certain bit error rate at a certain transmission rate. When the received optical power is greater than the saturated optical power, it can also cause errors. Therefore, for optical modules with high emission power, testing without attenuation loop will result in errors.
7. Working temperature
The working temperature of the optical module is divided into two types. Commercial grade: 0~70 ℃, industrial grade: -40~85 ℃.
8. Classification of optical modules
Classified by optical module mode: Single mode: Long transmission distance. Multimode: Transmission distance is short, generally less than or equal to 2km according to link resources.
