Passive Optical Devices for 5G Application(Part III)

In the Passive Optical Devices for 5G Application(Part II), we introduce Tunable Optical Filter (TOF) for Coherent Receiving, Optical Performance Monitoring (OPM) Module, Optical Channel Monitoring (OCM) Module. This article will show you other important passive optical devices for 5G application.

Dynamic Gain Equalization (DGE) Filter
For the complicated fiber links transmitting DWDM signals, OPM and OCM just provide solutions for monitoring of OSNR and channels. However, the DWDM signals need to be equalized before they leave each ROADM node or relay station. In the ROADM-based optical network, the power levels of the DWDM channels are always changing. Thus DGE is required to provide dynamic equalization of the DWDM channels, which is different from the fixed GFF (Gain Flattening Filter) for an EDFA.

Passive Optical Devices for 5G Application(Part I)

With the rise of 5G technologies and massive deployment of 5G base stations, wireless access of terminals with high speed and large capacity is realized. Meanwhile, the traffic in optical fiber network increases rapidly. It is predicted that the current optical fiber network will become the bottleneck of information exchange in the future 12-18 months. The upgrading of optical fiber network is urgent. The representative trend is that the technologies for long-haul network (LHN) will be sunk to metropolitan area network (MAN), including DWDM (Dense Wavelength Division Multiplexing), ROADM (Reconfigurable Optical Add-Drop Multiplexer) and coherent receiving techniques. This paper discusses some of the passive optical devices for the coming 5G applications.

1. CDC ROADM Based on MCS
The demand for increasing bandwidth promotes the upgrading of all-optical network (AON). As key parts of AON, the market of ROADM and related passive optical devices is expected to grow rapidly. In the nodes of optical fiber network, any wavelengths can be downloaded/uploaded via ROADMs. With the rapid growth of Internet traffic, the traditional ROADM nodes can’t meet the requirements. The new generation of ROADMs are required to be colorless, directionless and contentionless (CDC ROADM).