The evolution of WDM systems stemmed from a need to increase the capacity of a single fiber, and thus the network traffic volume is increasing and the demand for more network bandwidth is also on the rise. By converting incoming optical signals into the precise ITU-standard wavelengths to be multiplexed, OEO media converters are currently a key determinant of the openness of CWDM and DWDM systems. This article is mainly to introduce the OEO-based WDM system.
OEO media converter, also called WDM transponder or wavelength converter, is an optical-electrical-optical (O-E-O) wavelength converter which is designed to perform an O-E-O operation to convert wavelengths of light.
Figure 1: What Is a OEO Converter
The transponder can convert Ethernet signals into a corresponding wavelength in CWDM and DWDM network infrastructures. From left to right, the CWDM/DWDM transponder receives an optical bitstream operating at one particular wavelength. And then it converts the operating wavelength of the incoming bitstream to an ITU-compliant wavelength and transmits its output into a CWDM or DWDM system. On the receiving side (right to left), the process is reversed.
Figure 2: Signal Conversion Inside an OEO Media Converter
OEO media converter realizes wavelength conversion based on the Optical-Electrical-Optical transformation technology. Firstly, the OEO optical transponder receives the optical signals and converts them into electrical signals through the Optical-Electrical conversion. And then, the 3R technology (re-amplifying, re-shaping, and re-timing) is used to handle the signals. At last, electrical signals are modulated to the optical laser and then output. By this process, optical signal transmission distance therefore can be longer than before. As shown in the figure below, by using the media converter, the transmission distance reaches up to 40 km.
Figure 3: Working Principle of OEO Media Converter
Besides the wavelength conversion, CWDM/DWDM transponders can also be deployed in the seamless integration of different fiber types by converting multimode fiber to single-mode fiber, dual fiber to single fiber. It can also be used as a repeater to convert the weak optical signals from the fiber into electrical signals and regenerates or amplifies, then recovers them into strong optical signals for continuous transmission.
As we all know, when adding a CWDM or DWDM Mux/Demux into a WDM network, there is a requirement to convert the optical wavelengths like 850 nm, 1310 nm, and 1550 nm to CWDM or DWDM wavelengths. Then the OEO transponder comes to assist. Wavelength conversion is the most common function of the OEO media converter.
In general, multimode fiber (MMF) is used for short-distance transmission while single mode fiber (SMF) is used for the longer-distance transmission. If our network equipment is designed with a multimode port, but we want to achieve longer transmission distance only single mode fiber can achieve, then we need OEO media converter to complete mode conversion.
Dual fiber transmission and single fiber transmission are two transmission modes applied in the network. Depending on the type of equipment and the fiber installed facility, dual fiber to single fiber conversion is required sometimes. OEO media converter can be used to solve this problem.
In the long haul, fiber optic transmission and OEO transponder also can work as a repeater to extend network distance by converting wavelengths and amplifying optical power. The OEO converter converts the weak optical signals from the fiber into electrical signals, regenerates or amplifies them, then recovers them into strong optical signals for continuous transmission. For this reason, the OEO media converter is also called an OEO fiber optic repeater.
Normally, OEO CWDM/DWDM transponders have various types featuring different functions. For example, the 3R function can support long-distance transmission. It can convert 1G~11.3 Gbps Ethernet signals into a corresponding wavelength in CWDM and DWDM network infrastructures. For specific needs such as easy installation & removal and slot occupation in 1U/2U/4U chassis, etc., one should choose a reliable supplier like FS with customized service provided.