External Power Control - THORLABS MLDEVAL User Manual

10. Set SW1 (9) to ON. The green LED1 next to SW1 lights up.
11. Turn the potentiometer P2 clockwise in order to increase optical output power. This way,
the control voltage at the P
and the internal reference voltage V
power will be equal to the maximum that you have defined (see topic 1 of this section).

4.1 External Power Control

As described in the previous section, the potentiometer P2 is used for adjusting the optical out-
put power of the MLD203P1E or MLD203P2E module. Using P2, the control voltage at the P
input of the MLD203PxE module can be changed between 0 and the internal reference voltage
V (2.5 V DC).
REF
The same can be achieved from an external voltage source.
Attention
The external voltage must not exceed the range from 0 to +2.5 V DC in order to avoid damage
to the MLDEVAL and the MLD203PxE!
1. Prepare the MLDEVAL as described on
2. Set the mode switches SW4.1 to 4.2 (4):
SW4.1 Pset / Iset
SW4.2 Mod. In
SW4.3 Comp
SW4.4 Comp
3. Connect an ohmmeter to the constant power monitor connector pins J7 (5) and adjust the
potentiometer P1 (12) to the calculated above value R
J7.
4. Connect the external voltage source via the Mod. In SMA connector (11). Set the output
voltage of the external source to 0.
5. Insert the MLD203P1E (MLD203P2E) into the sockets J8/J9 (3). Make sure that the white
triangle matches with pin 1 of the adapter PCB.
6. Connect the laser diode as described in topic 7 on
7. Make sure that SW1 (9) is set to off.
8. Connect the power supply (external 5 V DC via or a USB power) to the MLDEVAL.
9. Set SW1 (9) to ON. The green LED1 next to SW1 lights up.
10. Now, the external control voltage can be changed within the range from 0 to +2.5 V.
Note
The external control voltage can be used for modulation. However, the modulation frequency is
limited by the feedback loop of the monitor current control. For a laser current modulation, the
constant current MLD203Cxx Miniature Driver Series is better suited.
© 2021 Thorlabs
input of the MLD203PxE module can be changed between 0
SET
(2.5 V DC). At the right stop of P2, the laser output
REF
page
6
OFF
ON
ON
ON
4 Operating a MLD203PxE Module (CP)
in steps 1 and 2.
. Disconnect the ohmmeter from
COMP
page .
6
SET
7