Anritsu MS9740B - Calculation Method

Chapter 5 Measurement Functions
5-64
5.7.7 Calculation Method
This section explains the method for calculating the optical amplifier gain
and noise figure.
The noise figure calculation method differs according to the NF Select
setting.
Gain (dB) Calculation Method
Gain is a comparison of the optical signal level and the amplified signal
level. The optical amplifier output optical signal level includes the level of
the ASE generated in the optical amplifier. Consequently, the amplified
optical signal level is level of the optical output minus the level of the
ASE.
)
log(
10 GGain =
)(
)(
s
s
Pin
PasePout
G
l
l
−
=
G: Gain
λ
s
: Optical signal wavelength (nm)
Pin(λ
s
): Level of optical input to optical amplifier at optical signal
wavelength (W)
Pout(λ
s
): Level of optical output to optical amplifier at optical signal
wavelength (W)
Pase: Level of ASE output level at optical signal wavelength (W)
NF (dB) Calculation Method
When NF Select is S-ASE
The noise figure is calculated from the beat noise between the optical
signal and the ASE optical output.
)log(10
vsGh
Pase
kNF
∆⋅⋅⋅
⋅=
ν
9
10)
2
1
2
1
( ⋅⋅
+
−
−
=∆ c
ResRes
s
realsvrealsv
ll
ν
9
10⋅=
sv
c
l
ν
k: Correction value set by NF Cal
λsv: Wavelength of optical signal in vacuum (nm)
Δνs: Frequency bandwidth of actual resolution at Pase
measurement (Hz)
h: Planck’s Constant 6.626 × 10-34 (J•s)