In the 5G network architecture, the front-pass optical module is upgraded from 10G to 25G. This article ETU-LINK will introduce the application of 25G SFP28 optical module in 5G fronthaul.

25G SFP28 dual fiber gray optical module

25G typical dual-fiber gray optical module supports transmission distances of 300 meters and 10 kilometers, 25G SFP28 300meters multimode optical module is mainly used for interconnection under the base station tower, and 25G SFP28 10 km single-mode optical module is mainly used for long distances of stations or links with larger link losses between AUU and access to the machine room (site) between the fiber direct connection scenario. 25G multimode optical module center wavelength of 850nm, duplex LC interface, multimode, operating temperature of 0 °C ~ 70 °C, transmitted optical power of -8.4 to +2.4dBm, the use of OM4 multimode fiber can be transmitted to 100 meters.

25G SFP28 10km single-mode optical module center wavelength of 1310nm, duplex LC interface, single-mode, support commercial (0 °C ~ 70 °C) and industrial grade (-45 °C ~ 85 °C) operating temperature range, transmit optical power of -7 ~ +3dBm, with single-mode OS2 optical fiber transmission distance of up to 10 km.

25G SFP28 BIDI single fiber gray optical module

BIDI optical transceiver has the advantages of saving optical fiber resources and high-precision time synchronization, and can support transmission distances of 10 kilometers, 15 kilometers and 20 kilometers. The transmitter of the 25G BIDI optical transceiver product adopts the uncooled DFB TO form, the center wavelength is 1270nm/1330nm, and the receiving end adopts the high-sensitivity 25G PIN TO form, and the receiving wavelength is 1330nm/1270nm, respectively. The product follows the mature optical device coaxial packaging process platform to achieve single fiber bidirectional and optical interface rate of 25.78Gbps.

25G SFP28 CWDM module

In the early stage of 5G network construction, the fronthaul is mainly based on optical fiber direct drive, accompanied by high-frequency networking and deep coverage of low-frequency add-points, in order to make full use of existing optical fiber resources, the use of CWDM optical modules will become a useful supplement. The 25G SFP28 CWDM uses a 1270nm-1370nm (20nm interval) CWDM DML laser and PIN receiver, or a 1470nm-1570nm (20nm interval) CWDM EML laser and APD receiver, which has a built-in CDR circuit in the receive and transmit channels, with a maximum speed of up to 25.78Gbps.

The number of optical transceivers used in 5G fronthaul on base stations has increased from 6 to 12 in the original 4G, and it is estimated that the construction volume of 5G base stations will reach 600,000-800,000 stations, so the demand for 25G fronthaul optical modules will reach 7.2 million to 9.6 million. In addition, with the improvement of operators' CRAN deployment requirements, it will bring about the growth of demand for wavelength division multiplexing IPL Modules, and 25G CWDM Modules may become mainstream.