Development Trend of Optical Transceiver Industry in 5G Era

As the demand for computing and storage capacity continues to migrate to the “cloud” and the explosion of traffic in the era of 5G Internet, the optical communications industry has a long-term boom, and “digital communication & telecom” will be the core driver of the optical communications industry.

Optical transceivers are the basic building blocks of 5G networks and account for a large proportion of the network cost, which is a key element of low cost and wide coverage in 5G. 5G fronthaul, middlehaul and backhaul has put forward differentiated requirements for optical transceivers, with higher speed, longer distance, wider temperature range and lower cost optical transceivers in urgent demand. As a leading supplier of optical network solutions, NADDOD summarizes the following 5 optical transceiver development trends.

5G demand for optical transceivers increases, 25/50/100Gb/s optical transceivers become mainstream demand for fronthaul, middlehaul and backhaul.

In order to meet the requirements of large bandwidth, low latency and wide coverage, the 5G radio access network (RAN) architecture has evolved from the 4G Baseband Unit (BBU) and Remote Radio Unit (RRU) two-stage structure to the Centralized Unit (CU), Distribution Unit (DU) and Active Antenna Unit (AAU) three-stage structure, and the corresponding bearer network architecture has also been decomposed from the fronthaul and backhaul network to the fronthaul, middlehaul and backhaul network. The new business characteristics and higher index requirements of 5G also put forward higher requirements on the speed of the fronthaul, middlehaul and backhaul optical transceivers.

5G Fronthaul demand for colored optical transceiver increases, colored optical transceiver solutions show diversification.

The Centralized Radio Access Network (CRAN) will become the mainstream construction mode of 5G network for operators in the future, as the C-RAN deployment mode requires more fiber resources for the fronthaul network, the application scenario of direct fiber connection is greatly restricted, and the fronthaul solution based on WDM technology has become the consensus of operators. The WDM solution uses different wavelengths of colored optical transceivers to transmit signals, and then multiplexes the signals into a single fiber for transmission, thus saving a large amount of fiber resources. With the gradual implementation of the forward WDM solution, the demand for colored optical transceivers will continue to grow.

5G fronthaul semi-active WDM has obvious advantages, optical layer modulating transmission technology to achieve OAM.

In the WDM scenario of 5G fronthaul, the passive WDM scheme deploys passive WDM devices for wavelength multiplexing and demultiplexing on the remote AAU side and the local DU side, which is simple to deploy but lacks the protection mechanism and the control means, and has problems such as no fault management and difficult maintenance. Active WDM solution supports control and protection functions by deploying active WDM devices on the remote AAU side and local DU side for electrical or/and optical layer multiplexing, but it is costly and limited in power supply and deployment at the remote end. The semi-active WDM solution deploys passive WDM devices on the remote AAU side and active WDM devices on the local DU side, and implements Administration and Maintenance(OAM) mechanisms through optical layer modulating transmission technology of colored optical transceivers to meet the requirements of service performance monitoring and communication fault location, which can solve the problems of fiber resources and maintenance management at a lower cost.

5G demand for high-performance optical transceivers will promote the application of silicon optical technology.

The fronthaul optical transceiver works in the harsh outdoor environment and needs to meet the industrial temperature requirements of -40℃～85℃. At the same time, due to the evolution of 5G network architecture from CPRI to eCPRI, the BBU side of the function to the RRU side of the partial migration, so that the RRU side of the power consumption increases, the need for optical transceivers with stronger heat resistance, the temperature in extreme environments may be as high as 90 ℃ ~ 95 ℃, "silicon optical modulator & heterogeneous laser " is useful in this high temperature environment.

Optical transceivers and communications equipment gradually decoupled, optical transceiver industry more open.

Out of consideration for system compatibility, communication equipment vendors often package optical transceivers and communication equipment together to provide operators, who can only passively accept the type of optical transceivers and technical solutions provided by equipment vendors. As 5G network architectures and deployments become more complex and diverse, the pressure for autonomous control of technology solutions and cost reduction will drive operators to gradually decouple optical transceivers from communication equipment.

NADDOD 25G Fronthaul Optical transceiver Recommendations

25Gb/s Dual Fiber Bi-directional Gray Optical transceiver

Typical transmission distances for dual-fiber bi-directional 25Gb/s grey optical transceivers include 300m and 10km. 300m optical transceivers are typically used for tower site interconnections at base stations, while 10km optical transceivers are mainly used for direct fiber connection scenarios between AAUs and access rooms (sites) where the transmission distance is longer or the link loss is higher.

25Gb/s single fiber bi-directional grey optical transceiver

BiDi optical transceiver has the advantages of saving 50% of fiber resources, equal spacing between upstream and downstream can effectively ensure high-precision time synchronization, etc. Typical transmission distance 10km, 20km, and 40km.

25Gb/s colored optical transceiver

25G colored optical transceivers are widely used in passive WDM applications where multiple optical transceivers are required to multiplex a single fiber at different wavelengths.