Single Fiber – Why Choose it for Gigabit Optical Communications?

Advanced applications, including voice and data convergence, as well as storage area networking, are putting burdens on today’s fiber optic networking infrastructure, especially on the fiber cabling. With speeds in data centers now increasing from 10Gbps to 40Gbps, to 100Gbps, and 120Gbps, etc., different fiber technologies are required for Gigabit optical communications, like single strand fiber (simplex fiber cable) and duplex fiber cable. This text mainly introduces the single strand fiber, a relatively simple solution chosen for fiber optimization, and its benefits that drive the need to deploy single strand fiber for Gigabit optical communications.

Single Fiber Technologies

Single strand fiber, just as its name shows, uses one strand of glass instead of two dedicated strands with one for receiving and the other for transmitting. It doubles the capacity of the installed fiber plant, which in turn doubles the per fiber return on investment (ROI) with no need for more physical fiber.

Early single fiber solutions were based on single wavelength directional coupler technologies. With these solutions, the same wavelength (1310nm for up to 50km or 1550nm for longer distances) travels in each direction (transmit & receive). At the edges, the two signals are coupled into a single fiber strand with a directional coupler (splitter-combiner). This coupler identifies the direction of the two signals (ingress or egress) and separates or combines them. This kind of solution is normally very reliable and cost effective, as long as special installation and connector type (APC -angle polished connector) requirements are observed. Otherwise, this solution is prone to reflections when traversing patch panels and in the cases of fiber cuts or dirty connectors.

single fiber 1310nm TX/1510nm Rx

In recent years, a new single strand fiber technology has emerged based on two wavelengths traveling in opposite directions. External WDM couplers (multiplexers) combine or separate the two wavelengths at the edges. As technology progressed, the external passive WDM coupler became integrated into a standard interface fixed optic transceiver.

Single Fiber SFP (Small Form Pluggable)

The growing demand of single fiber solutions driven by the Ethernet bandwidth has led to the development of a wide range of single fiber pluggable SFP transceivers. These hot-pluggable optic transceivers are designed in small-form factor for high-density solutions, covering many industrial protocols and allowing flexibility in distance choices. Besides, they provide advanced optical performance, Digital Diagnostics Monitoring (DDM). Commonly-used single SFPs include 1000BASE-LX SFPs (eg.EX-SFP-1GE-LX shown below), 1000BASE-ZX SFPs, etc.

EX-SFP-1GE-LX,single fiber SFP

Single Fiber Benefits

The benefits of the single strand versus the dual strand fiber implementation can be considerable.

  • Operational and Capital Expense Savings

Single fiber solutions, like any other fiber optimization methods, affect both the capital expenses (CAPEX) and the operational expenses (OPEX). For fiber users like carriers and enterprises that lease dark fiber from their provider rather than owning the fiber plant, the OPEX savings is extremely significant by avoiding avoid the need to install additional fiber strands to accommodate growth without imposing limitations due to engineering capabilities.

  • Fiber Run — Engineering Cost

The design and engineering of a fiber run is a complex process. It may require crossing roads or freeways, which leads to possible thorough design, and inflexible work scheduling. The deployment cost might include trenching or other expenses. In many cases, the price of labor, services, and licenses required to install new cabling can far exceed the cost of the media and supporting electronics.

  • Fiber Termination and Accessories Cost

New fiber runs require terminating and connecting any fiber strand. This process requires qualified labor that will polish, connectorize, and test every fiber strand. Reducing the number of terminated fiber strands by half results in a significant cost reduction.

  • Network Reliability and Maintenance Cost

Reliability and availability are key in any communications system. Use of single fiber pluggable-based transceivers in an existing dual fiber link opens the possibility of creating redundant link solutions. In fiber assembly, a larger number of fiber strands increase the chance of fiber failure. The larger the fiber strands are, the higher the failure chances are, thus the maintenance cost increase accordingly. This can be reduced through the simplicity of single fiber technology.


Single fibers are considered as the simple way for fiber optimization, for they not only double the capacity of the installed fiber plant, but also help to achieve overall savings in Gigabit optical communications. Fiberstore offers single fibers available in both single-mode and multi-mode versions, which are all quality assured. In addition, single fiber optical transceivers can also be found in Fiberstore, such as 1000BASE-LX SFP (EX-SFP-1GE-LX mentioned above), 10GBASE-ZR SFP+ (SFP-10G-ZR). For more information about single fibers, you can visit Fiberstore.

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