Atec Agilent-81618A - Manual (Page 24)

Specifications Definition of Terms
24
Agilent 81618A/9A and Agilent 81622B/3B/4B/6B/7B/8B User’s Guide, Second Edition
Linewidth
FWHM spectral bandwidth. The 3 dB width of the optical spectrum,
expressed in Hertz. Symbol:
∆f.
Noise
The peak-to-peak change of displayed power level with zero input
power level (dark).
Conditions: Zero prior to measurement, averaging time and
observation time as specified, lowest power range selected and
wavelength range as specified.
Measurement: the measurement result is obtained by:
Noise = P
max
− P
min
expressed as peak-to-peak
within the given time span. Any
offset is automatically excluded
this way.
Power range
The power range is defined from the highest specified input power
level to the smallest input power level that causes a noticeable change
of displayed power level.
Conditions: wavelength, averaging time as specified.
Reference conditions
The specified conditions during the spectral responsivity calibration,
or conditions which are extrapolated from the conditions during
calibration.
Conditions: power level, beam diameter or fiber type, numerical
aperture, wavelength, spectral width, ambient temperature as
specified, at the day of calibration.
→Noise and drift observed over a
specified observation time, with a temperature change of not more
than ±
∆T.
Relative uncertainty (spectral ripple) due to
interference
Uncertainty of power reading when using a coherent source, due to a
periodic change of the power meter's responsivity caused by optical
interference between reflective interfaces within the power meter's
optical assembly.