Reliability of 1300 nm laser diode for space applications.

The use of electro-optic devices for high speed digital links in space on-board systems or high bandwidth analogue links for diagnostics in large physics experiments could be limited by their reliability in radiative environment. The technology of emitters, and specially the laser diodes, is in rapid progress, driven by ground applications such as telecommunication systems. New structures created to increase performances introduce radiation sensitive areas. In space applications, particles (protons, heavy ions) can induce permanent damages as well as transient errors. Thus it is of major interest to study the vulnerability of new laser diodes structure to single particles and determine their role in the reliability of st whole data link. A transmission data link has been simulated using a high speed digital signal to modulate a 1300 nm laser diode. A Nd:YAG laser was used to simulate ionizing effects induced by transient particle irradiation on the laser diode by creating carriers only in the laser cavity. With this method, calibration of ionizing effects, error amplitude and influence of operational parameters of the link (frequency, amplitude of modulation...) have been studied. Heavy ions at different energies have been used to confirm transient effects, but the perturbation duration, too short compared with the Nd:YAG, have limited observation of the transient error due to ionizing effects. Permanent damages have been observed and their origin linked with the particle.