Instrument Systems | Photodiodes | Featured | Trends | Jun 05, 2024

PD 100 Photodiodes for Radiant Power Measurements in VIS-IR

Instrument Systems’ new PD 100 photodiodes enables absolute LIV measurements of pulsed light sources.

The new PD 100 photodiodes are Instrument Systems’ high-performance detectors for emission power measurements of devices in the VIS to IR spectral region. They cover a spectral range from 400 nm up to 1100 nm (Si photodiode) or from 900 to 1700 nm (InGaAs photodiode). In combination with an integrating sphere, the PD 100 enables fast measurement of radiant power and therefore increases productivity in production line applications. The photodiode is particularly suitable for sources of low intensity. With the slanted design, the photodiode is fully compatible to Instrument Systems’ integrating spheres. 

The metrological traceability can be guaranteed by calibration of the PD 100 in the test labs of Instrument Systems. A sensitivity curve is stored on the PD 100, read out and used by Instrument Systems’ software SpecWin Pro for further calculations. To evaluate the absolute power of a PD 100 measurement with high accuracy, it is beneficialto know the spectral distribution of the DUT. For highly accurate and absolute power measurements a traceably calibrated spectroradiometer should be used whilst connected to a separate port of the integrating sphere. Alternatively, any reference spectrum can be uploaded and used. By taking the calibrated spectral sensitivity of the PD 100 and the DUT spectrum into account, a calibration factor can be calculated in SpecWin Pro and subsequently used for measurements of the DUT power.

The determination of electronic parameters as well as the optical characterization play a major role in the developing and manufacturing processes of laser diodes. Test systems usually consist of photodiodes, integrating spheres and source-measure-units (SMUs). In combination with a spectroradiometer, additional spectral properties of the laser diodes such as peak wavelength and FWHM half-band widths can be determined. The complete system has to be calibrated to assure accurate and traceable radiometric measurements. The PD 100 offers fast response times and allows short overall measurement times. This enables also the investigation of the temporal waveform when the laser diode is operated in pulsed mode.

The most common subset of the direct current (DC) parameters can be measured in a test known as the “LIV test sweep”. LIV curves, a combination of the L/I curve and the V/I curve, are a fast and simple method to identify failed laser diodes early in the test process. Some types of VCSEL require testing with short current pulses in the microsecond range to limit their self-heating. Especially for these applications, the fast PD 100 is designed. For acquisition and evaluation of LIV curves, the SpecWin Pro software provides an appropriate Commander module.

For more information please visit  

About Instrument Systems GmbH
Instrument Systems GmbH, founded in Munich in 1986, develops and manufactures high-end light measurement applications that are indispensable to the manufacturers of consumer electronics, AR/VR displays, microLED wafers, VCSEL laser systems, automotive lighting and LED/SSL modules. Its core products are array spectrometers and imaging colorimeters. All solutions profit from our CAS series of high-precision spectroradiometers that are recognized and in use worldwide. In combination with 2D imaging colorimeters, integrating spheres and goniometer systems, they enable high-precision and accurate measurements in the entire range from UV to IR, traceable to the PTB or NIST. 

For further details refer to:
Instrument Systems GmbH, Kastenbauerstr. 2, 81677 Munich, Germany
Phone: +49-89-454943-0, E-Mail:

© 2024 Luger Research e.U. – Institute for Innovation & Technology