Exfo FTB-5500B PMD Analyzer Manuel d'utilisateur télécharger pdf (Page 112)

Using Third-Party Broadband Light Sources

104 FTB-5500B

Compliance Criteria

The rms width of the auto-correlation determines the basic uncertainty

of the interferometric method (Equation 4 on page 105). The smaller

the rms width of the auto-correlation, the smaller the basic uncertainty.

If the uncertainty is critically required to be equal to or smaller than the

specified uncertainty using dedicated EXFO sources, the rms width of

the auto-correlation, , must be smaller than .

Equation 2

In the particular case of a Gaussian-shaped spectrum with no ripple,

Equation 2 corresponds to

Equation 3

(30.0 nm @ 1550 nm, 21.5 nm @ 1310 nm)

If criterion 2 is not met, the instrument will still operate normally, but

the uncertainty specification will change according to the uncertainty

formula given on the next page (Equation 4 on page 105).

It is useless to ask for a general specification regarding ripples or

FWHM: it is impossible to precisely quantify the condition via these

parameters. The auto-correlation interferogram is the relevant function

to examine, through its rms width.

0.1 ps∼

0.1 ps≤

FWHM 3.75 THz≥

1 2 ... 107 108 109 110 111 112 113 114 115 116 117 ... 120 121

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Exfo FTB-5500B PMD Analyzer Manuel d'utilisateur Page 112