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Using the Instrument
Analyzer Operating Modes
Time Resolved Chirp
For Agilent 86146B option DPC only
The Agilent 86146B, with the filter mode capability, will measure side mode suppression ratio
(SMSR), wavelength, and power. With the addition of an Agilent 86100 Infinium Digital Commu-
nications Analyzer (DCA), dedicated software (86146B Option TRL), and a personal computer,
time resolved chirp (TRC) of a modulated laser can be calculated.
TRC provides frequency (or wavelength) vs time information about a modulated lightwave signal.
Also called dynamic chirp, the TRC graph provides useful information on the ability of a modu-
lated signal to propagate over long distances in optical fiber. In dense wavelength division multi-
plexing (DWDM) systems, excessive chirp also can cause inter-channel interference. The two
significant factors of chirp are:
• dispersion which is a function of the transmission link’s length and fiber type
• cross talk caused by chirp due to closely spaced channels
A measurement could show the modulated signal (square wave) and the chirp. The chirp fluctu-
ates with time and the frequency change, seen at the falling and rising edge of the time domain.
The time resolved chirp solution measures:
• intensity versus time
• frequency versus time
• calculates the alpha factor
The alpha factor is also referred to as linewidth enhancement factor. One definition of a is:
a= 2P(Df) /(Dp)
During initialization, the instrument does an auto peak, gathers information about the peaks, and
tunes the filter marker. The unmodulated data in shown in the square wave pattern and the chirp
is the frequency which runs through the square wave pattern.
To smooth the chirp signal, increase the averages taken which will decrease the noise found on
the signal. Increasing the number of averages and using the longer patterns will increase the
measurement processing time. To shorten the measurement processing time, either increase the
power or decrease the number of averages. See the TRC Option User’s Guide for more details.
Содержание 8614 B Series
Страница 1: ...Agilent 8614xB Series Optical Spectrum Analyzer User s Guide ...
Страница 12: ...1 4 Getting Started Product Overview Agilent 8614xB Front and Rear Panels ...
Страница 13: ...1 5 Getting Started Product Overview ...
Страница 15: ...1 7 Getting Started Product Overview Figure 1 2 Display Annotations ...
Страница 16: ...1 8 Getting Started Setting Up the Analyzer Setting Up the Analyzer Step 1 Receive and Inspect the Shipment ...
Страница 26: ...1 18 Getting Started The Softkey Panels ...
Страница 31: ...1 23 Getting Started The Softkey Panels The Systems Menus continued ...
Страница 40: ...1 32 Getting Started Product Options and Accessories ...
Страница 75: ...3 Function Reference ...
Страница 186: ...4 16 Remote Front Panel Operation Remote Front Panel ...
Страница 226: ...6 2 Maintenance Changing the Printer Paper Changing the Printer Paper ...
Страница 264: ...7 16 Specifications and Regulatory Information Declaration of Conformity Declaration of Conformity ...
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