ILX Lightwave LDC-3700 Series User Manual

Constant I mode is the normal mode for driving lasers. This mode uses a low-pass filter on the laser drive current
output to significantly reduce noise. In ths mode a modulation input of up to 10
kHz may be used, via the front
panel MOD
EXTERNAL connector.
Constant
P mode is also a low bandwidth mode. It is used when it is desired to control the optical power of the
laser via a monitor photodiode feedback arrangement.
When
P mode is selected, the unit will be in either IpD or PPD modes, depending on the setting of the CAL PD
(monitor photodiode responsivity) parameter. If the CAL PD value is non-zero, the unit will operate in constant
PpD. monitor photodiode power (light power) mode. (For more information on the CAL PD parameter, see
Section
2.13.5).
However, the LDC-3700 Series Laser Diode Controller has a special mode for operating at a constant monitor
photodiode current when the
CAL PD parameter value is set to zero. This constant IpD mode is usell for driving a
laser when the monitor photodiode's responsivity is not known, but a desired constant light output can
be
determined to produce a constant monitor photodiode current. The constant IpD mode is also used for monitor
feedback calibration.
Constant
IHBW is a high bandwidth constant current mode. This mode allows the laser drive current output to be
modulated via the front panel MOD EXTERNAL connector. See Chapter 1 for bandwidth specifications.
I LASER MODE -
SELECT
Figure 2.6 LDC-3700 Series LASER MODE Section
2.1 1.1 LASER MODE SELECT
The (LASER MODE) SELECT sv itch is used to select one of the three available LASER operating modes. When a
mode is selected, the corresponding LED becomes lit.
If the (LASER MODE) SELECT su~rch is pressed repeatedly, the modes are cycled through in the order I, P,
IF,,,. and back to I, and so on, n~th the appropriate mode indicator being lit.
2.1 1.2 LASER MODE Indicators
The
I indicator becomes lit when the unit is in the constant current control mode. When constant I mode is
selected. the LASER output is controlled to the constant I set point value.
The
P md~cator becomes lit when the unit is in constant optical power control mode. When constant P mode is
selected, the LASER output is controlled to the constant IPD (monitor PD current) or PpD (monitor
PD power,
hen the
C.% PD lalue 1s non-zero) set point value.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com

ILX Lightwave LDC-3700 Series Specifications

General

Brand	ILX Lightwave
Model	LDC-3700 Series
Category	Controller
Language	English