THORLABS SLS301 User Manual page 8

Stabilized Benchtop Halogen Light Source Chapter 3: Product Overview
3.4. Output Stabilization
Unlike traditional Halogen light sources, the SLS301 will not suffer either from a gradual decrease or short term
fluctuation in brightness during its lifetime.
SLS301 tungsten halogen light source is equipped with an internal feedback loop and therefore can ensure a
constant intensity, low noise and long life span. The principle of operation is depicted in the block diagram below.
The optical intensity is measured by an internal photodiode, which feeds its monitor signal to the controller unit.
The controller unit then adjusts the driving current of the power supply to compensate any drift or fluctuation in the
optical output.
Figure 3.6 Closed Feedback Loop in SLS301
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