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Electro-optical test module

Imaging technologies are constantly evolving, which requires electro-optical test modules to evolve as well during manufacture. A leader in the design and manufacture of semiconductor components asked PISÉO to design and produce custom electro-optical test modules. With our skills in optical metrology and the design of optical systems integrating cutting-edge technologies, PISÉO’s experts were able to offer extremely innovative, robust solutions that integrate VCSEL-type LASER sources.

Innovative design

To design these electro-optical test modules, PISÉO’s experts started with a blank slate. In collaboration with the client, we first defined the requirements that the modules had to meet. For example, surfaces to be illuminated, uniformity, incidence of the optical beam, pulse frequencies, temperature, geometry, tolerances, and laser safety. These are all constraints that had to be accounted for in the design. Subsequently, PISÉO’s solutions were imagined, calculated, simulated, modeled, and tested to arrive at a completely new concept for development.

VCSEL LASER source for electro-optical testing

Electro-optical test benches for imaging sensors usually use LEDs.

For our client, the operating frequency requirements were such that only LASER diode-type sources – in particular VCSELs – had the necessary temporal dynamics to meet them.

With the help of our partner, Yole Group, PISÉO’s experts were able to quickly identify the VCSEL die suppliers in the United States and Asia that were likely to meet the client’s needs. The selected component was assembled by our partner, Serma Microelectronics, using microelectronics techniques, and then extensively tested by PISÉO in our optical laboratory.

Finally, since these components are generally used for optical fiber telecommunications links, our choice to control them quickly fell to a telecom-type driver.

vcsel electro optique
TO46 package integrating the VCSEL source

Optical design and engineering

LASER sources, which are used for their dynamic temporal response, have very specific emission profiles requiring the design of a specific optical system to meet the needs of the application. To this end, our engineers, specializing in optical design and engineering, have defined a very precise multi-stage system that enables PISÉO to create controlled lighting from the point-of-view of spatial and incidence characteristics.

To do this, we first characterized the source beam using a beam profiler in the PISÉO optical laboratory.

Based on the measurement results, we then specified a system integrating optical geometry and materials to achieve the desired objectives. Our engineers also used Zemax Optics Studio software to perform this work.

electro optique test module
Simulation by PISÉO with Zemax Optic Studio of the illuminance obtained

Development of electro-optical test modules

Once the feasibility of the concept was demonstrated, PISÉO’s experts worked with our trusted partners to develop the opto-mechanical assembly as well as the electronics and on-board software. These allow for control of the VCSEL sources and the interfacing with the test bench.

Creation and validation of modules in several copies

Several electro-optical test modules were thus assembled in a clean room, and then calibrated and tested in the PISÉO optical laboratory according to a rigorous protocol and test plan. Numerous R&R, reliability, and lifespan tests were carried out to allow us, in agreement with the customer, to fully validate the design and manufacturing of the modules.

Example of an electro-optical test module developed and produced by PISÉO

PISÉO’s customers trust our experts for the development and manufacturing of complex, innovative, and robust optical test benches.