Through WDM technology, the smooth evolution and comprehensive upgrade of G/EPON to NG-PON1 system (10GEPON, XGPON, XGS-PON) to NG-PON2 system (OFDM-PON, DWDM-PON, TWDM-PON) have been in place as early as EPON when it first came out. 12 years is the big boom in EPON construction, 14 years is GPON, and 16/17 GPON construction is still continuing, I believe that the day of doing 10GPON is not far away. But to abandon the original system, this cost is too great.

The optical ring is a non-reciprocal, multi-port optical passive device. Its core function is that optical signals can only be transmitted in one direction from the port to the terminal in a specific order.

In modern optical communication networks, fiber optic couplers play a crucial role. It is like an invisible "traffic command", silently completing the distribution and combination of optical signals in scenarios such as 5G base stations, data centers, and optical fiber sensing, supporting high-speed and efficient information transmission networks.