Dual fiber uses the same wavelength on two fiber strands; one for transmit, and one for receive.  Single-fiber operates with bi-directional wavelengths, often referred to as BIDI. Typically BIDI single-fiber uses 1310nm and 1550nm wavelengths over the same fiber strand in opposite directions. The development of bi-directional wavelengths over the same fiber strand was the precursor to Wavelength Division Multiplexing.

Dual fiber to single-fiber conversion can be required when:

1. Connecting dual fiber equipment to a single-fiber network
2. A building has dual fiber, while the connection to the Service Provider or outside plant is single-fiber
3. Splitting dual fiber into two single-fiber strands to increase fiber capacity

Dual Fiber to Single-Fiber Conversion Products

Convert Dual Fiber to Single-Fiber

Networks may require conversion between dual and single-fiber, depending on the type of equipment and the fiber installed in the facility. In this application, two dual fiber switches are connected via single-fiber using dual fiber to single-fiber media converters. Since BIDI single-fiber uses two separate wavelengths over the same fiber strand, the transmit (Tx) on the media converter at one end of the fiber link matches the receive (Rx) from the media converter other end, and vice versa.

Double Fiber Capacity with Dual Fiber to Single-Fiber Conversion

Dual fiber can be converted to single-fiber as a technique to double the capacity of the existing dual fiber infrastructure.

In example A, a dual fiber link connects two switches in different buildings.

In example B, new switches are added to each location, and fiber-to-fiber media converters double the capacity of the dual fiber link by converting each strand of the dual fiber to a BIDI single-fiber link. This can also be used as a technique to create redundant fiber links between two locations with dual fiber switches.