No abstract

We performed an endurance test with single-mode vertical-cavity surface-emitting lasers (VCSEL) under vacuum condition and increased operational parameters (laser current and laser temperature) to accelerate the aging of the lasers. During the endurance test the emitted polarization-dependent and polarization-independent optical light power from the lasers was detected. Additionally, electro-optical characterisations including measurements of the combination of laser current and laser temperature to excite the 87 Rb D 1 transition (λ = 795 nm), the current and temperature tuning coefficients, laser line width, threshold current and the polarization ellipse were performed for the aged lasers. The test was started with a number of 12 VCSELs consisting of 4 lasers each from 3 different suppliers. The aging behaviour of VCSELs was investigated with respect to the development of a new optical magnetometer prototype for space missions with a mission duration of up to 17 years. Only a limited change of the electro-optical parameters can be tolerated by the instrument design over the mission duration. The endurance test and the electro-optical characterizations revealed clear differences in the aging behaviour of the three suppliers. Lasers from one supplier showed that they can be operated for more than 17 years under vacuum conditions without major degradation of their operational parameters.

The space-qualified design of a miniaturized laser for pulsed operation at a wavelength of 1064 nm and at repetition rates up to 10 Hz is presented. This laser consists of a pair of diode-laser pumped, actively q-switched Nd:YAG rod oscillators hermetically sealed and encapsulated in an environment of dry synthetic air. The system delivers at least 300 million laser pulses with 50 mJ energy and 5 ns pulse width (FWHM). It will be launched in 2017 aboard European Space Agency's Mercury Planetary Orbiter as part of the BepiColombo Laser Altimeter, which, after a 6-years cruise, will start recording topographic data from orbital altitudes between 400 and 1500 km above Mercury's surface.

No abstract

No abstract