Black Box 39005, 39004 manual Appendix Fiber Optic Planning Guidelines, Introduction

T1 FIBER OPTIC LINE EXTENDER/SIMULATOR

Appendix: Fiber Optic Planning

Guidelines

A.1 Introduction

Designing a fiber optic link means considering two main physical limitations: System attenuation and fiber optic dispersion.

Attenuation results when properties of the fiber optic link reduce the intensity of the fiber optic signals. Dispersion occurs in high-speed links and causes degradation of fiber optic signals, disabling the receiver that would interpret them correctly.

The analysis of the planned fiber optic link is a two-step process. First, you must calculate the attenuation of the complete system to ensure that the units can cope with the losses of the link. Then, you must enter the intended distance between the units into the operation diagram (see Figure A-2). (Make sure the distance is confirmed by the calculation above.) These calculations are explained in Section A.2.

When you calculate the maximum range, keep in mind that extremely short cabling can be problematic, too. Avoid receiver overload conditions for proper data transmission.

For wavelength/multiplexing (WDM) equipped units, you must perform the calculations for each wavelength independently (twice total). You must operate the WDM-equipped counterparts within the restrictions defined by both resulting operation diagrams.

Please observe that the optical power budget stated in the documentation of a WDM-equipped unit is valid for the transmitted wavelength only. The optical power budget for the received wavelength can be found in the documentation of the counterpart unit.

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