OsTech Laser Lab Source LDC Series, Руководство по эксплуатации

Страница: 20 / 36

t
I
laser
0
laser bias current – LCB
laser current target –
LCT
LMW
LMP
LMW
: 100 . . . 2
32
µ
s
LMP
: 200 . . . 2
32
µ
s
LMP
≥
LMW
+
100
µ
s
Figure 5.2:
continuous pulse mode
menu
show the mean values
not the peak values. These measured values may differ
from the adjusted ones caused by the low speed of the AD converter. Don’t care
about this. The real values are within the limits as described above.
5.4.1 Internal digital modulation mode
The driver is able to modulate the laser current by internally generated pulses. This
internal modulation mode may be activated by checking the
LMDI
input field in the
laser menu or entering the LMDIR command.
Continuous pulse mode
Unless configured otherwise, pulses are generated continuously as you can see in
figure 5.2 . You have to enter the pulse width (duration) and pulse period in
µ
s. Take
care of the right proportions of these values. The pulse width is in the range of
100
µ
s . . . 4
×
10
9
µ
s and may be changed by the LMW command. The pulse period
(
LMP
command) is in the range of
(
LMW
+
100
µ
s
)
. . . 4
×
10
9
µ
s, so it is always at least
100
µ
s larger than the pulse width.
Newer devices are not subject to these limitations. Here,
LMW
and
LMP
can be set
freely in steps of 1 µs.
You can run and stop the laser by the commands
LR
and
LS
.
Single pulse mode, n-pulses mode
This mode—which is illustrated in figure 5.3 —is useful if you want to generate only
a single pulse or a certain number of pulses. To activate it first select the internal
digital modulation mode as stated above. Then enter the command
LMDIC
n where n
is the number of pulses you want to be generated. After entering the
LR
command
20