Laser Diode Driver LD8000
15
Ver. 1.0
t
T
B
IN
I V
4.3 Laser modulation modes
There are six modes to modulate the diode current available (the numbers represent the code for
the RLMM instruction, see chapter 5. Protocol description):
10. Continuous Wave (CW)
: the
T
arget current will permanently be
driven through the diode.
20. Internal Pulse
: the current will change between
B
ase and
T
arget,
following hereby the given pulse
W
idth and pulse
P
eriod times.
30. External Analog
: the current will be driven by voltage at the
MOD-connector (14, Figure 4), limited by
L
imit. The amplification
ratio is 2A/V.
40. External Pulse
: the current will change between
B
ase and
T
arget, following the IN-signal at TTL-input connector (16, Figure
4). Low level means
B
ase current, high level means
T
arget current.
50. Periodic Burst
: this mode is similar to the internal pulse mode,
but the given
N
umber of pulses is followed by given number of
S
uppressed pulses. During suppressed pulses, the current is being
hold on the
B
ase level. The pulses are formed with given width and
periode.
60. Single Burst
: in this mode, the device will drive given
N
umber
of current pulses and stop, waiting for a further laser ON signal. That
is: user presses the Laser ON button (7, Figure 3) or the TTL-input
(16, Figure 4) goes high in gate mode (s. below).
Gate Mode
In modes with internal pulse generation (2, 5 and 6), the TTL input
connector (16, Figure 4) can be used to turn the laser on or off. This
behaviour is called gate mode and can be entered using the
corresponding button. Please make sure, that the external pulse
frequency is much lower than the laser pulse frequency.
t
I
T
B
N=4
t
I
T
B
N=4 S=5
t
I V
T
B
IN
t
I
L
t
I
T
t
I
T
B
W P
