2-28
Operation
The Review Data Window
relative group delay measurements. Use the option buttons above the tables to
change the type of curve fit. The statistics for the five-term Sellmeier fit can
contain multiple zero-dispersion wavelengths. To view them, scroll horizon-
tally across the displayed data.
The curve fit selection
Curve fitting algorithms
improve the measure-
ment precision of chro-
matic dispersion measurements. Even in fiber, some noise is present with the
group delay and, since dispersion is the derivative of the group delay, the
effect of any noise is exaggerated. The dispersion at any wavelength can be
calculated from a fitted curve which, by definition, has no noise.
These curve fit algorithms are primarily meant for measurements made on
fiber based devices. If you select
Absolute Group Delay Measurement
in the
Grating
Related Parameters
area in the main window, the curve fit selection will automat-
ically be set to
none
.
• The quadratic curve fit is commonly used for dispersion-shifted fiber, in which
waveguide dispersion is dominant.
• The 3 term Sellmeier curve fit is commonly used for dispersion-unshifted fiber
in which material dispersion plays the major role.
• The 5 term Sellmeier curve fit , although more affected by noise and instabili-
ties in the measurement path, provides more general purpose curve fitting. The
five-term Sellmeier fit can yield multiple zero-dispersion wavelengths. All the
values and their associated slopes are shown in the graphs. The system search-
es for dispersion zeros in a wavelength range equaling approximately five times
the measurement span (2.5 times each side of the center wavelength). This al-
lows identification of zero-dispersion wavelengths which fall outside of the
measurement range. In some cases, due to the peculiarity of the five-term Sell-
meier fit, zero-dispersion wavelengths found outside of the measurement range
may not correspond to actual zero-dispersion wavelengths of the device under
test.
Содержание 86037B
Страница 1: ...User s Guide HP 86037B Chromatic Dispersion Test System ...
Страница 31: ...2 13 Operation The Main Window Figure 2 4 Repeat Measurement Selector ...
Страница 72: ...3 16 Normalization Setting Normalization Preferences ...
Страница 94: ...4 22 Remote Control TES Parameters Main chromatic dispersion screen ...
Страница 100: ...4 28 Remote Control TES Parameters CD and Gain Measurement Settings Dialog Box ...
Страница 102: ...4 30 Remote Control TES Parameters Length Measurement Settings Dialog Box ...
Страница 104: ...4 32 Remote Control TES Parameters Normalization Settings Dialog Box ...
Страница 106: ...4 34 Remote Control TES Parameters New Normalization Button Dialog Box ...
Страница 120: ...4 48 Remote Control Output Parameters ...
Страница 158: ...5 38 Maintenance Hewlett Packard Sales and Service Offices ...
Страница 165: ...6 7 Installation Installation 2 3 4 5 1 8 7 Fan Pack 6 6 Power Distribution Assembly 1 7 Power Distribution Assembly 2 ...
Страница 170: ...6 12 Installation Installation ...
Страница 174: ...7 4 Reference Theory of Operation Figure 7 3 HP 86037B Block Diagram Options 121 and 122 ...
Страница 175: ...7 5 Reference Theory of Operation Figure 7 4 The HP 86037B Option 114 block diagram ...
Страница 190: ...7 20 Reference System Options ...
Страница 191: ...8 Specifications 8 3 Regulatory Information 8 7 Specifications and Regulatory Information ...
Страница 198: ...8 8 Specifications and Regulatory Information Regulatory Information Declaration of Conformity ...
Страница 204: ...Index 6 Index ...