4 – 26
Remote Operation
When controlling a laser diode in CP mode, phase shifts introduced
either from photodiode bandwidth or cable capacitance can influence
overall stability. For some configurations,
SIBW
HIGH
might lead to
instability and oscillations; in these cases, the LDC500 should be left
set to
SIBW
LOW
.
Front panel:
LD :9-
46;;<=
.
SIBW?
Example:
HIGH
Photodiode Milliwatt Units
PDMW(?)
{
z
}
Set (query) the CP mode power units selection
{
to
z
=
(
NO 0
,
YES 1
)
}
.
When set to
PDMW
YES
, the LDC500 will display mW units when
controlling in CP mode. When set to
PDMW
NO
, the CP mode display
is
μ
A (photodiode current).
Note that the value of
PDMW
has a subtle e
ff
ect on the photodiode
setpoint parameters
SIPD
and
SWPD
, and the limit values
PILM
and
PWLM
. If
PDMW
YES
, and the value of
RESP
is changed (either
directly, or as a result of the
CALP
command), then the mW parame-
ters (
SWPD
and
PWLM
) remain unchanged, and the
μ
A parameters
(
SIPD
and
PILM
) are adjusted accordingly. The converse is true when
PDMW
NO
is set.
Front panel:
LD :%#
%#- 48
.
PDMW?
Example:
NO
Photodiode Bias Voltage
BIAS(?)
{
f
}
Set (query) the monitor photodiode bias voltage
{
to
f
}
, in V.
The valid range is 0
<
f
<
5
.
0; setting
BIAS
0
operates the photodiode
in the “photovoltaic” mode.
Front panel:
LD :
9# )
.
BIAS 2.5
Example:
LDC500 Series Laser Diode Controllers
