Radiation hardness of the 1550Â nm edge emitting laser for the optical links of the CDF silicon tracker

Radiation hardness is investigated for the laser transmitter of the optical links used for the CDF Run II silicon tracker. Beam tests were conducted with 30, 63, and 200 MeV protons with radiation doses up to 2 Mrad. The laser transmitter consists of an edge-emitting-type laser diode array and a BiCMOS driver chip. The laser light degradation is approximately linear to the radiation dose. The light degradation is about 10% at 200 krad. The radiation tolerance is expected to suffice for the CDF Run II operation.