What is Wavelength Division Multiplexing?

WDM refers to transmitting two or more optical signals at different wavelengths along a single fiber. Multiple wavelengths traveling down a fiber is similar to multiple radio signals traveling through the air at different frequencies. Each wavelength can carry a different signal that is independent of the other wavelengths.

Figure 1 WDM Fiber Optic Transmitter and Receiver for HDMI/DVI

Additionally, the different wavelengths can travel in the same or opposite directions, enabling bidirectional optical communication over a single fiber as shown in Figure 1. As long as the optical converters have a sufficiently high bandwidth, WDM enables the original signal format and data rate to be maintained in both the electrical and optical domains.

DWDM Mux and Demux

WDM is suitable for any application where multiple signals are transmitted over fiber optic cabling. The signals can be completely independent, such as for different channels in a cable television environment, bidirectional USB or RS-232 signals, components of a multi-lane HDMI or DVI signal, or a combination of these. Each signal is applied to a different wavelength for independent transmission along the same fiber optic cable.

The WDM transmitter and receiver shown in Figure 1 enable transmission of an HDMI/ DVI signal over fiber optic cable. The transmitter has five inputs and one output. Each input has its own E-to-O converter with a laser diode that operates at a unique wavelength. A special device called a WDM multiplexer/de-multiplexer combines the various wavelengths for transmission down a fiber optic cable.

The WDM multiplexer/demultiplexer also separates the optical signal used for the return data, which operates at a wavelength different from the inputs. The return data optical signal passes through an O-to-E converter to recover the original signal.

The WDM receiver shown in Figure 1 has one input and five outputs. The WDM multiplexer/demultiplexer in the receiver separates the optical signals, sending each to a separate O-to-E converter.

Sopto supplies high quality communication products, like 1-64 Channels Video Multiplexers, Phone Optical Multiplexers and so on. Please contact a Sopto representative by calling 86-755-36946668, or by sending an email to info@sopto.com.