Ageing tests of radiation damaged lasers and photodiodes for the CMS experiment at CERN

The effects of thermally accelerated ageing in irradiated and unirradiated 1310nm InGaAsP edge-emitting lasers and InGaAs p-i-n photodiodes are presen ted. 40 lasers (20 irradiated) and 30 photodiodes (19 irradiated) were aged for 4000 hours at 80 degrees C. Periodic measurements were made of laser t hreshold and efficiency, and p-i-n leakage current and photocurrent. There were no sudden failures and there was very little wearout related deg radation in either unirradiated or irradiated sample groups. The results su ggest that the tested devices have a sufficiently long lifetime to operate for at least 10 years inside the Compact Muon Solenoid experiment despite b eing exposed to a harsh radiation environment.