1 – 8
Overview
1.4.4
Hardware reset
To restore the LDC500 to its factory default state, press and hold the
[Clear
/
Cancel] button while turning on the power keyswitch. Note
10
1
that this performs a full low-level reset of the instrument, and will
erase all saved user configurations, limits, sensor calibrations, and
network parameters. After this, all parameters are set to their default
settings. See section 2.4 for more details.
1.5
Cable Interfaces
Two separate rear-panel subminiature-D connectors provide the in-
terface from the LDC500 to the laser diode assembly. Additionally,
a front-panel input allows for analog modulation, and a rear-panel
output provides synchronization for multi-step scans.
1.5.1
Modulate
The front-panel BNC input “Modulate” accepts
±
10 V inputs to mod-
ulate the laser diode operating point.In CC mode, the scale factor is
2
either 25 mA
/
V (when on the 250 mA current range), or 50 mA
/
V (on
the 500 mA current range). When operating in CP mode, the scale
factor is 500
μ
A
/
V, independent of the instrument current range.
Analog modulation is DC-coupled, with a total bandwidth set by the
SIBW
command (see section 3.2.3.3).
The modulation input can be enabled or disabled through an inter-
nal relay by using the
MODU
command (see section 3.2.3.2). When
unused, the modulation input should be disabled for best noise per-
formance.
1.5.2
Sync
The rear-panel BNC output “SYNC OUT” provides low-going timing
pulses for synchronizing external instrumentation after each step in
15
a multi-step scan. See the
SCAN
command (4 – 21 ) for more details.
1.5.3
Laser diode
The DB–9 female connector marked “LASER DIODE” provides the
electrical connection to the laser diode itself.
11
LDC500 Series Laser Diode Controllers
