VCSEL Near-field Measurement Flexible and precise testing at single emitter level

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Comprehensive characterization of VCSEL arrays with an IR camera

The VTC 4000 laboratory system was specially developed for the flexible, high-precision near-field-characterization of VCSEL arrays without diffractive optical elements (DOE). It combines the high precision of the VTC 4000 IR camera with the flexibility of a 3D traversing unit for the DUT, thus enabling comprehensive analysis of all relevant parameters at single emitter level.

The precision of the VTC 4000 relies on an innovative calibration concept that corrects the polarization dependence of the single emitter power, thus achieving hitherto unparalleled measurement precision. Power and polarization properties are determined with only one measurement in the field of view of the camera. Additionally, a high-resolution spectrometer from the CAS series (e.g. CAS 140CT-HR) can be connected with the aid of the optional fiber output for the measurement of spectral properties of the single emitters.

Key Features:

  • Precise and fast measurement with the VTC 4000
  • Characterization of all single emitters of the array for power, polarization and divergence properties and M² value
  • Screening of spatial radiation properties for characterization of the emission waist
  • XYZ traversing unit extends camera field of view
  • Optional with fiber output and spectrometer for additional determination of wavelength


Due to the diverse test parameters and strict specifications based on industrial standards, very strict requirements are placed on VCSEL test systems.

Our calibrated, high-precision test systems have a minimum absolute error budget. This enables the performance efficiency of VCSELs to be fully exploited with simultaneously safe operation. The test system is of modular design and can be tailored to customer requirements.

The VTC 4000 is a high-precision measuring camera, also suitable for fast cycle times in the production line.

For the spectral measurement of VCSELs we offer the CAS-HR series of spectroradiometers that enable a high spectral resolution of up to 0.09 nm.

System configuration

A laboratory measuring station for the characterization of VCSELs in the near-field is typically made up of the following components:

Component Description


IR camera VTC 4000 for VCSEL near-field characterization with 12-megapixel resolution and field of view of 1.4 mm x 1.0 mm. Optional with fiber output for the connection of a high-resolution spectrometer.


High-resolution CAS 140CT-HR with up to 0.2 nm spectral resolution as a high-end measurement solution with cooled CCD detector for the highest degree of stability, e.g. in a reference system. High-resolution CAS 120B-HR with a spectral resolution of up to 0.1x nm as a simultaneously high performant and cost-efficient alternative to the CAS 140CT-HR.

3-axis traversing unit

XYZ positioning system for extended measuring tasks.


Traceable calibration to national standards such as PTB and NIST in the 910–980 nm range possible.


LumiSuite SDK for easy integration into customized production processes.

Advice on our systems

Our system experts will be pleased to provide competent advice on your particular application. Just ask us!

Examples of applications