MKS Instruments – Ophir

Power consumption is critical in many sensing applications that use VCSELs. This whitepaper discusses how the characterization of VCSELs in both continuous wave (CW) and pulsed operation mode can be simplified.

The whitepaper compares achievable accuracy of Rayleigh Scatter based beam profiling with conventional methods and builds the link to ISO11146 compliance although non-contact beam profiling isn’t listed in the ISO yet.

Measuring optical signals in the femtowatt (10-15) to nanowatt (10-9) range can be a daunting task. In order to achieve significant improvements in noise rejection we need to turn to a lock-in amplifier, which can improve noise rejection by 3 orders of magnitude or more.

We present a novel photometric test system for LED luminaires. The new photometric system called 'FluxGage' uses solar panels to detect and measure light. By placing a diffuser and a black pinhole array over a solar panel we achieve a detection surface that is also an absorber. This enables the system to be the same size as the DUT (Device Under Test), as opposed to an integrating sphere, which is at least 3 times larger than the DUT. Simulations and experimental results show that this system can measure total flux with an uncertainty of 4.3%.