GaAs based photovolatic cells

Photovoltaic cell of GaAs to convert monochromatic radiation with a wavelength of 800-850 nm.


R&D Services

Our R&D services comprise:

Epitaxy Development

Due to excellent material quality, our laser power converters achieve the highest efficiencies. The semiconductor material is optimally matched to the laser wavelength, and therefore thermalization losses are reduced to a minimum.

Photovoltaic Cell Development

We optimize cell designs for the various application needs and laser wavelengths. With advanced cell architectures we realize monolithic series-connected devices with higher output voltages.

Characterization of Laser Power Converters

At our laser-based measurement station, we investigate laser power converters under monochromatic light. We also measure the spectral response and quantum efficiency. Our spectrally and spatially resolved electroluminescence measurements provide us with information about the material properties and quality.

Automated Packaging

To assemble the laser power converters, we use our in-house industry-level packaging equipment. This equipment is also used for pilot and small series production.

System Integration

To reach our goal of an all-inclusive system integration, we consider the optical coupling, the thermal connection between the cell and package and the integration of the downstream electronics. Additionally we work on combining power and data transmission.

Reliability Investigations

Using degradation studies and accelerated aging tests, we investigate the reliability of components and assemblies, focusing on packaging.

Optical power transmission with Power-by-Light systems (also known as Power-over-Fiber) is an elegant method for powering sensors or actuators, when a conventional power supply with copper cables is limited or not available. The reasons for this are manifold, for example: the need for galvanic isolation, high voltage or lightning protection, electromagnetic interference, wireless transmission, weight reduction, spark protection, corrosion resistance, high magnet fields or rotating systems. There are a wide variety of applications for Power-by-Light systems such as structural health monitoring of wind turbines, fuel gauges in airplanes, monitoring of high voltage lines, optical power supply of automotive sensors, biosensors in smart implants, or the monitoring of passive optical networks.

At Fraunhofer ISE we develop special photovoltaic cells for Power-by-Light applications. These so-called laser power converters convert monochromatic light into electricity with highest efficiency. Currently our research focuses on developing materials for specific laser wavelengths, optimizing the cell structure for converting monochromatic light and developing advanced cell concepts for increasing the output voltage. Our other research topics consist of characterizing cells under monochromatic light, reliability investigations, as well as packaging and system integration. The latter also includes the combination of power and data transmission and coupling the systems to the electronics or electronic circuitry.

For a laser power converter based on GaAs, we achieved an opto-electric conversion efficiency of 57.4%, measured with a laser wavelength of 805 nm at an irradiance of 124.0 W/cm².

Selected Research Projects



Avionics Systems Hosted on a Distributed Modular Electronics Large Scale Demonstrator for Multiple Type of Aircraft




Current publications - Power-by-Light:

YearTitle/AuthorDocument Type
2017On the alignment tolerance of photovoltaic laser power converters
Wagner, L.; Bett, A.W.; Helmers, H.
Journal Article
2017On the temperature dependence of dual-junction laser power converters
Reichmuth, S.K.; Helmers, H.; Philipps, S.P.; Schachtner, M.; Siefer, G.; Bett, A.W.
Journal Article
2017Reliable and lightning-safe monitoring of wind turbine rotor blades using optically powered sensors
Worms, K.; Klamouris, C.; Wegh, F.; Meder, L.; Volkmer, D.; Philipps, S.P.; Reichmuth, S.K.; Helmers, H.; Kunadt, A.; Vourvoulakis, J.; Bett, A.W.; Koos, C.; Freude, W.; Leuthold, J.; Stork, W.
Journal Article
2016Determining the optimal laser wavelength for laser power conversion depending on operation temperature
Höhn, O.; Walker, A.W.; Bett, A.W.; Helmers, H.
Conference Paper
2016Influence of injection current and temperature on electroluminescence of GaAs laser power converters: Presentation held at 3rd Euroregional Workshop on Photovoltaics & Nanophotonics 2016, Ljubljana, Slovenia, 21.09.2016-23.09.2016
Kimovec, R.; Helmers, H.; Bett, A.W.; Topic, M.
2016Integrated Power and Data Transceiver Devices for Power-by-Light Systems - A Concept Study
Helmers, H.; Lackner, D.; Siefer, G.; Oliva, E.; Dimroth, F.; Bett, A.W.
Conference Paper
2016Optical power supply of smart sensors using photovoltaic laser power converters: Presentation held at microTEC Südwest Clusterkonferenz 2016, Freiburg, Germany, 14.03.2016-15.03.2016
Helmers, H.
2016Optimal laser wavelength for efficient laser power converter operation over temperature
Höhn, O.; Walker, A.W.; Bett, A.W.; Helmers, H.
Journal Article
2016Photovoltaic laser power converters for wireless optical power supply of sensor systems
Helmers, H.; Bett, A.W.
Conference Paper
2016Temperature and injection current dependent electroluminescence for evaluation of single-junction single-segment GaAs laser power converter
Kimovec, R.; Helmers, H.; Bett, A.W.; Topic, M.
Journal Article
2016Transient I-V Measurement Set-up for Photovoltaic Laser Power Converters under Monochromatic Irradiance
Reichmuth, S.K.; Helmers, H.; Garza, C.E.; Vahle, D.; Boer, M. de; Stevens, L.; Mundus, M.; Helmers, H.; Bett, A.W.; Siefer, G.
Conference Paper
2015Photovoltaic Cells with Increased Voltage Output for Optical Power Supply of Sensor Electronics
Helmers, H.; Wagner, L.; Garza, C.E.; Reichmuth, S.K.; Oliva, E.; Philipps, S.P.; Lackner, D.; Bett, A.
Conference Paper
2014Lightning-Safe Monitoring of Wind Turbine Rotor Blades Using Optically Powered Sensors
Worms, K.; Klamouris, C.; Wegh, F.; Meder, L.; Volkmer, D.; Phillips, S.; Reichmuth, S.; Helmers, H.; Bett, A.W.; Vourvoulakis, J.; Freude, W.; Leuthold, J.; Stork, W.
Conference Paper
2014Photovoltaic cells for optical power and data transmission: Presentation held at 34. European Telemetry and Test Conference, etc 2014, Nürnberg, Germany, 03.06.2014-05.06.2014
Helmers, H.; Philipps, S.P.; Reichmuth, S.K.; Oliva, E.; Lackner, D.; Bett, A.W.
2014Power by light: Optical power transmission replaces copper wiring
Henning, H.
Journal Article
2009High-voltage GaAs photovoltaic laser power converters
Schubert, J.; Oliva, E.; Dimroth, F.; Guter, W.; Löckenhoff, R.; Bett, A.W.
Journal Article
2009An optically powered fibre network for heterogeneous subscribers
Freude, W.; Roger, M.; Dreschmann, M.; Hübner, M.; Bett, A.W.; Becker, J.; Leuthold, J.
Conference Paper
2008GaAs converters for high power densities of laser illumination
Oliva, E.; Dimroth, F.; Bett, A.W.
Journal Article
2008III-V solar cells under monochromatic illumination
Bett, A.W.; Dimroth, F.; Löckenhoff, R.; Oliva, E.; Schubert, J.
Conference Paper
2008Optically powered fiber networks
Roger, M.; Böttger, G.; Dreschmann, M.; Klamouris, C.; Hübner, M.; Bett, A.W.; Becker, J.; Freude, W.; Leuthold, J.
Journal Article
2008An optically powered video camera link
Böttger, G.; Dreschmann, M.; Klamouris, C.; Hübner, M.; Roeger, M.; Bett, A.W.; Kueng, T.; Becker, J.; Freude, W.; Leuthold, J.
Journal Article
2007Optically powered video camera link
Böttger, G.; Dreschmann, M.; Klamouris, C.; Hübner, M.; Röger, M.; Bett, A.W.; Kueng, T.; Becker, J.; Freude, W.; Leuthold, J.
Conference Paper
2006Optically powered platform with Mb/s transmission over a single fiber
Klamouris, C.; Böttger, G.; Hübner, M.; Dreschmann, M.; Paulsson, K.; Bett, A.W.; Kueng, T.; Becker, J.; Freude, W.; Leuthold, J.
Conference Paper
2002GaAs photovoltaic cells for laser power beaming at high power densities
Riesen, S. van; Schubert, U.; Bett, A.W.
Conference Paper
This publication list has been generated from the publication database Fraunhofer-Publica.