Views: 0 Author: Site Editor Publish Time: 2022-10-12 Origin: Site
The electrical signal and optical signal of the 0G SFP56 SR optical module are PAM4 modulated, and the working wavelength is 850nm. The SFP56 package is adopted, and the transmission distance through multimode optical fiber can reach 70m (OM3) or 100m (OM4).
As our society's desire for data continues to grow, not only is there more data, but also the data transmission speed is faster. The old modulation schemes based on NRZ type coding are increasingly inadequate. Generally, there are three ways to improve the transmission rate of optical communication: increasing the modulation rate, increasing the number of WDM channels, and increasing the number of levels.
Since each symbol cycle of PAM4 signal can transmit 2 bit information, to achieve the same signal transmission capability, the symbol rate of PAM4 signal only needs to reach half of the NRZ signal, so the loss caused by the transmission channel is greatly reduced. With the development of future technology, it is not ruled out that more PAM8 or even PAM16 signals are used for information transmission.
PAM4 technology can effectively improve bandwidth utilization efficiency. At the same time, PAM4 uses high-order modulation format, which is an effective way to reduce the number of optical devices used, reduce the requirements for optical device performance, and achieve a balance between performance, cost, power consumption and density in different applications.
