Contents I. Introduction
In light of the construction of ITER (International Thermonuclear Experimental Reactor) in Cadarache, the development of highly radiation tolerant electronic circuits is becoming an increasingly important issue [1]. One of the areas where such circuits will be needed is the required periodic remote maintenance of the fusion reactor internals [2]. As the expected radiation levels are very high owing to the incurred radio activation of the reactor walls, the maintenance tasks will need to be performed by remotely operated robots. For the control of these robots, a robust communication link between the reactor core and the control room will be indispensable. The obvious advantage of immunity to electromagnetic interference makes an optical fiber link [3] a strong candidate to serve this umbilical function. Moreover, as many optical signals at different wavelengths may use the same fiber through Wavelength Division Multiplexing (WDM), a more compact and less heavy umbilical with a high data throughput could be realized [1]. One of the crucial electronic circuits required to build such a radiation hard optical communication link is the laser driver which converts digitized data into an appropriate steering current for the laser.
