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Unidirectional vs. Bidirectional Fibers

White Paper

looptelecom.com 2 May 28, 2004

Unidirectional vs. Bidirectional Fiber

The following figure illustrates a typical unidirectional fiber application (unprotected). The signals are carriedby two unidirectional fibers.

Two unidirectional fibers

E1 E1

Loop-O9300 Loop-O9300

Unprotected Unidirectional Fiber Application

The following figure depicts a bidirectional, unprotected fiber application. A Wave Division Multiplexer optionbuilt into this Loop-O9300 allows signals to travel in opposite directions on a single fiber.

1310nm

1550nm

Loop-O9300

Master with

built-in WDM

TX

1310nm

RX

1550 nm

TX

1310nm

RX

1550 nm

Loop-O9300

Slave with

built-in WDM

E1E1

Unprotected Bidirectional Fiber Application

If you desire to use unidirectional fiber, then you should select either the SDor DD(protection) option. If youwill be using bidirectional fiber, your choices are master or slave units with single or dual (protection)modules.

There are two main advantages to unidirectional fiber. One is a longer transmission range than bidirectionalfiber. The other is that considerable cost savings if signals from many fibers are multiplexed into oneunidirectional fiber for transmission purposes.

8/12/2019 Unidirectional+vs+Bidirectional+Fibers

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Unidirectional vs. Bidirectional Fibers

White Paper

looptelecom.com 3 May 28, 2004

The following figure shows a unidirectional fiber application where an external WDM accepts the signals frommany unidirectional fiber optic cables and multiplexes them for transmission onto a single unidirectional fiber.At the far end of the fiber another external Wave Division Multiplexer de-muxes them back into separate

fibers. In this case, you invest more money into equipment now in order to obtain inexpensive expansion andlower fiber line transmission costs in the future.

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In Out In

uni-directional fiber

Out

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Out InIn Out

uni-directional fiber

Wave Division

Multiplexer

(mux)

Wave Division

Multiplexer

(de-mux)

Wave Division

Multiplexer

(de-mux)

Wave Division

Multiplexer

(mux)

Wave Division Multiplexing on Unidirectional Fiber