Development trend of optical modules and multimode optical fibers in data centers

Today, with the rapid development of big data, cloud computing, the Internet of Things, and mobile Internet, banks, taxation, hospitals, e-commerce, and other industries all rely on the support of the data center. The traffic of the data center is growing day by day. In the future, the data center must be the data warehouse and heart of the social information system. In order to meet the huge data transmission demand, more and more enterprises choose to build multiple data centers. Next, we will introduce the optical modules and multimode optical fibers that are currently used well.

As an important component of optical fiber communication, optical modules are used to transmit and receive optical signals. Through market exploration, it is found that 25G, 40G and 100G optical modules are the most popular at present, which are mainly used in the core switch of the data center. 40G port switches form 40G Ethernet by matching QSFP+optical modules. From the port on the convergence layer switch to the core layer routing switch, the 100G port is now used. The 100G QSFP28 optical module has won the favor of the market due to its low power consumption, small size, and low use of optical fiber, and is widely used in the matching scheme of 100G Ethernet switch optical modules.

The interconnection between network element equipment in the data center mostly uses multimode optical fiber. Although multimode optical fiber is more expensive than single-mode optical fiber, and the transmission bandwidth is not as high as single-mode optical fiber, the comprehensive cost of indoor multimode optical fiber communication system is lower than single-mode optical fiber communication system due to the low price of multimode optical fiber transceiver. OM1 and OM2 are the first multimode fibers, and OM3 and OM4 are later optimized by VCSEL laser. Since the distance between devices in medium and large data centers is generally within 500M, multimode OM3 and OM4 optical fibers are usually used.

Until recent years, the multimode fiber has been upgraded to OM5, which has four channels, extending the wavelength range supported by OM3 and OM4 fiber horizontally, and increasing the bandwidth requirements of 953 nm wavelength, which has improved the transmission capacity of OM5 by four times. The OM5 optical fiber can be compatible with the original traditional parallel optical module and can support the optical module of duplex transmission. Therefore, from the perspective of the overall investment cost, return on investment and risk control of the data center, OM5 optical fiber will be the preferred transmission medium for optical interconnection of new data centers in the future.