HP 8167A, User Manual, Page: 48 / 262

2
Attenuator
If you have the optional attenuator installed, the Analog Output
signal depends on the power mode you have chosen.
In P ower Mode the laser output power , and therefore the
Analog Output signal, is not linearly proportional to the output
power . This is because the actual output optical power is
derived by the optimum combination of the laser output power
and the attenuation.
In Attenuation Mode the relationship between the Pref and
the voltage level is approximately 1.35mV for each 1W . (The
dierence between this value and that of the tunable laser
source without the attenuator is due to the insertion loss of the
attenuator). This value is only proportional to the output power
if the attenuation remains constant. Here , the attenuator adds a
constant oset to the voltage level.
Example T o set the power to -10dBm.
1. Press 4 OUTPUT POWER 5 .
2.
Press
NNNNNNNNNNNNNNNNNNNN
Mod/CW , and
NNNNNNNN
CW if necessary , so that the display looks
as shown in Figure 2-7.
3.
Press
NNNNNNNNNNNNNNNNN
W/dBm , if necessary , so that the power is displayed in
dBm.
4. Type -10 on the numeric keypad, and press 4 ENTER 5 .
Setting a Modulated Signal
There are two ways of modulating the amplitude of the optical output.
Using the internal modulation, and
using external modulation.
2-10 Setting Wavelength and P ower