Instruments Help European Space Agency to Test High-Power Laser Diodes for Space Missions

The European Space Agency (ESA) is using Yokogawa digital oscilloscopes, including the recently launched DL850 ScopeCorder, at its European Space Research and Technology Centre (ESTEC) in Noordwijk, the Netherlands, to carry out key evaluation tests on different high-power laser systems for use on space satellites.

Typical laser system applications in space include precision range measurements, radar-like ’lidar’ systems to gather a complete picture of surface terrain or three-dimensional samplings of planetary atmospheres, and laser-based space communications with high bandwidth and minimal electromagnetic interference.

ESTEC is the largest ESA research centre in Europe, and is responsible for developing and managing all types of space missions for scientific exploration, satellite-based navigation and communication, and earth observation purposes. It operates an environmental test centre for spacecraft, with supporting engineering laboratories specialised in systems engineering, components and materials, including an opto-electronics laboratory focusing on the performance verification of active optical instruments, including high-power laser systems and components of solid-state lasers

The laboratory includes a Class 10,000 (ISO 7) clean room, two fully equipped optoelectronics laboratories designed for the operation of Class 4 laser systems, workshop and storage rooms. It has the equipment necessary to measure the optical spectrum, beam profile, power and energy, stability and modulation response, in free space as well as optical fibres.

The Yokogawa test equipment - initially a DL6154 oscilloscope, which is currently being supplemented by a DL850 ScopeCorder - is used specifically to complement test set-ups developed for investigating laser-induced contamination or endurance testing on laser diodes used as pump sources for solid-state lasers. These tests involve the recording of large amounts of data over considerable periods of time: several weeks or even months in
some cases.

The key electrical parameters involved in the tests are voltage and current in well-controlled environmental conditions. Moreover, for endurance testing, the instruments need to be able to automatically detect and store very short and intermittent transient events such as current spikes.

In addition, the DL6154 is used to monitor the pulse shape of an injection seeded high power solid state laser used in the context of laser induced contamination and damage experiments. This equipment has proven to be able to successfully detect the intra-pulse modulation at laser output occurring when the seeding mechanism is not effective, and therefore gives reliable and crucial information on the laser behaviour.