The FiberPlex WDM8 is an 8 Channel Active Wavelength Division Multiplexer. Simply put, it is a device which allows the user to combine up to 8 sources of data on a single fiber pair. Each channel can be linked via fiber with selected FiberPlex FOM, FOI or TD Series fiber modules, FiberPlex LightViper or with virtually any third party fiber optic equipment with data rates from 155 megabits up to 3 gigabits per channel, for a possible maximum aggregate data rate of 24 Gbps. Alternately, the WDM8 can be combined with our vast selection of copper SFP modules and connect HD Video, Ethernet, audio and more directly into a channel.
WDM Theory of Operation
Infrared light has a frequency of approximately 400 Terahertz (400,000 Gigahertz). That is about 125,000 times higher than the data rate of a typical 3 Gigabit SFP, which means a large proportion of the bandwidth of a fiber optic cable is wasted. The current state of the art does not allow utilizing all of that bandwidth, but we can recover some of it by a technique called "Coarse Wave Division Multiplexing," or "CWDM."
Essentially, it is the simple technique of taking each 3 Gigabit channel and using it to modulate a different frequency in that 400 Terahertz bandwidth. This is done through a series of optical filters and combiners, along with lasers and photodiodes tuned to a particular infrared center frequency. Historically, however, optics are referred to, not by their frequency, but by their wavelength, which is the speed of light divided by the frequency.
In the traditional implementation of a CWDM, it is the user's responsibility to provide the tailored SFPs and the CWDM itself, which may require adapters to interface with the user equipment. The FiberPlex WDM line, on the other hand, is an active WDM, with the wavelength-specific components already tested and configured. Instead of a wavelength-specific optical fiber, a generic SFP electrical interface is provided for each channel. Any SFP that conforms to the SFP Multi Source Agreement (MSA) can be inserted, even copper-based SFPs like gigabit Ethernet, 3G-SDI video, HDMI or MADI.
The internal SFPs have a full 3 Gigabit bandwidth, video-optimized for SMPTE video signals. Generic fiber SFPs may exhibit limitations in passing SMPTE video signals as they have problems maintaining a constant DC bias with the SMPTE encoded data.