Temperature Controller Features - Newport 6100 User Manual

36 System Operation
The default mode of operation is Constant Current. The operator can select
Constant Power mode by making the desired selection from instrument's front
panel menu or by sending appropriate commands to the instrument from a
host PC via USB interface (located on the rear of the unit).
Constant Laser Diode (LD) Current Mode (Const Ild)
In Constant Laser Diode Current mode, the operator explicitly sets the amount
of current flow through the attached laser diode using the "Ild" variable. The
LDD uses a control loop comparing the Model 6100's internal current sense to
the current set point, raising or lowering the amount of current to reach and
maintain that set point.
Constant Photodiode (PD) Current Mode (Const Ipd)
In Constant Photodiode Current mode, the LDD subsystem holds the attached
laser diode output current constant based on feedback from the laser diode's
integrated back-facet diode. The LDD uses a control loop comparing the
current from the back-facet diode to the current set point (Ipd), raising or
lowering the output current to reach and maintain that set point.
Constant Photodiode (PD) Power Mode (Const Ppd)
In Constant Photodiode Power mode, the LDD subsystem holds the attached
laser diode output power constant based on feedback from the laser diode's
integrated back facet diode. The photodiode current measured is converted to
optical power based on user specified photodiode responsivity. The LDD uses
a control loop comparing the current from the back facet diode to the power
set point (Ppd), raising or lowering the amount of current to reach and
maintain that set point.
4.1.2

Temperature Controller Features

The Temperature Controller subsystem of the Model 6100 can be operated in
one of the following modes:
 Constant Temperature
 Constant Resistance / Reference
 Constant Current
The default mode of operation is Constant Laser Diode Current. The operator
can select Constant Photodiode Current or Constant Photodiode Power mode
by making the desired selection from the instrument's front panel menu or by
sending appropriate commands to the instrument from a host PC via USB
interface (located on the rear of the unit).