A Quick Guide to Gray Light Module and Colored Light Module
25G gray light and color light modules shine in 5G fronthaul solutions. In the DRAN scenario, a 25G 300m gray light module is used. In the CRAN scenario, when fiber resources are insufficient, a 10km bidirectional gray light (BiDi) module is used. If necessary, the required fiber resources can be further reduced by using passive WDM and semi-active WDM equipment. In this case, a 25G IPL module is required.
Definition of Gray Light and Colored Light
The wavelength range used in optical communication is 850 ~ 1650 nm, and the optical module emits “color light” or “white light”, which are invisible to human eyes.
Gray: The wavelength fluctuates within a certain range, and there is no specific standard wavelength. For example, the client-side optical port of a WDM device, the corresponding interface is called a gray light interface.
Colored: It fluctuates in a small range near a certain central wavelength, and can be directly connected to the multiplexing equipment, with standard wavelengths. In the WDM system, the wavelength division side optical signal of the line board, the corresponding interface is called Colored interface.
The Difference Between Gray Light Module and Colored Light Module
Color optical modules can be divided into (coarse wavelength division multiplexing) CWDM optical modules and (dense wavelength division multiplexing) DWDM optical modules according to different wavelength densities. The color light module is combined with the multiplexer to combine the optical signals of different wavelengths for transmission, which greatly reduces the link cost.
Corresponding to the colored light module is the gray light module. Gray light module is also called white light module or black and white light module. Generally, the customer-side optical module will use a gray optical module.
Application of Gray Light Module and Color Light Module
CWDM optical modules are suitable for short-distance transmission and are generally used in Gigabit, 10 Gigabit Ethernet and point-to-point networks. DWDM optical modules are suitable for long-distance transmission and are generally used in large-scale network environments such as metropolitan area networks and local area networks.
25G gray light and color light module: 5G fronthaul optical module solution
Typical architectures for wireless fronthaul are distributed RAN (DRAN) or centralized RAN (CRAN).
DRAN: In the DRAN scenario, the AAU and DU are deployed at a distance of 300 km or less on the tower and below the tower, respectively. In the CRAN scheme, the maximum distance between two cells is 10 km. Considering cost-effectiveness and maintenance, both DRAN and CRAN use optical fiber direct connection. In this case, a 25G 300m gray light module is used.
CRAN: In the CRAN scenario, fiber direct connections require many fibers and cables. In the case of insufficient fiber resources, 10km bidirectional gray light (BiDi) modules are used, because they require half the amount of fiber, so the cost can be reduced. If necessary, the required fiber resources can be further reduced by using passive WDM and semi-active WDM equipment. In this case, a 25G IPL module is required.
The 25G color light module can be divided into 25G CWDM6 wave and adjustable 25G DWDM module. Customers can choose from different options depending on their performance needs and budget. The full series of fronthaul 25G optical modules cover various DRAN and CRAN application scenarios.
25G gray light and CWDM6 wave optical module
There are several types of 25G gray light and CWDM6 wave light modules:
25G 300m: dual-fiber bidirectional interface
25G 10km: dual-fiber bidirectional interface
25G 10km BiDi: single fiber bidirectional interface
25G 10km CWDM6 wave: dual-fiber bidirectional interface; a set of six modules
All optical modules with center wavelengths of 1271, 1291, 1311, 1331, 1351, and 1371nm comply with the SFP28 protocol SFF-8419 and SFF8472. Electrical ports comply with CEI-28G-VSR. 25G 10km dual-core optical fiber and 25G 10km BiDi optical port comply with IEEE 802.3CC 25GBase-LR.
Tunable 25G DWDM and DWDM12 wave optical module
There are two types of 25G DWDM optical modules:
C-band 48 wavelengths adjustable, support 10km transmission
Cost-effective C-band 12-wavelength tunable, supports 10km transmission Both comply with SFF-8419 and SFF-8472 protocols. Electrical ports comply with CEI-28G-VSR.
NADDOD Optical Module Solution
As a leading supplier of optical network solutions, NADDOD optical module series products:
Complete speed: 1G-400G full range of products, which can meet the needs of customers in different scenarios.
Excellent quality: With industry-leading R&D, production and service capabilities, it ensures that every module delivered to customers can communicate normally.