The Optical Calculator - Help
- INTRODUCTION
The Optical Calculator is a Javascript based utility which aims to automate optical budget calculations.
- EQUIPMENT SPECS
In this section, you can select pre-defined kit for TX or RX or select manual and enter your own power specs. At the
time of writing, no confirmed figures were available for the Lancast equipment.
- FIBRE SPECS
In this section, select whether you are using single-mode or multi-mode fibre. Next, you can either enter your own link
attenuation figure and select manual calculation, or enter a total fibre run length and select automatic calculation.
- GENERATED RESULTS
Once you have entered the RX and TX specs and the fibre information, click on the "CALCULATE" button and results will
be displayed.
- DYNAMIC CHART
The Optical Calculator now attempts to represent the results generated with a chart. Three boxes will hopefully be visible
on the chart. The green box is the TX specs, the blue box is the RX specs and the red box represents the results. If the
red box is entirely within the blue box, the optical levels are okay. If the red box is partly outside of the blue box, then
you may encounter problems. If the red box is entirely outside of the blue box, the optical levels are so far out that they
probably will not work.
- EXAMPLE
Select Cisco LX GBIC specs for RX and TX, select singlemode fibre and enter a distance of 15km. Now select "CALCULATE" and
results should be visible.
- NOTES
Limited checking is done for compatibility of wavelengths. Calculations for link attenuation are as follows:
- 850nm - 3.3 dB per km + 1 dB for connectors
- 1300nm - 0.45 dB per km + 1 dB for connectors
- 1550nm - 0.32 dB per km + 1 dB for connectors
- ABOUT
This is a BETA tool, written in Javascript by Stewart Bamford. Any questions, comments or other feedback should go to
stewart@whoever.com.
Version 1.3 - August 2003