Analysis of the space radiation effect on EDFA for inter-satellite optical communication

The fiber devices are sensitive to the radiation, and all of the devices used for inter-satellite optical communication are always exposed in radiation environment, so the feasibility of EDFA which is the key component of the external modulate technique must be analyzed in this environment before it is able to used in inter-satellite optical communication systems. The most important components of EDFA including the EDF, optical isolators and WDM couplers were irradiated with ⁶⁰Co gamma rays to simulate the radiation environment of the low dose orbits and the high dose orbits for the first time at home. The experiment results indicate that in the radiation environment of the low dose orbits whose typical total dose is about 5krad, when the input power of EDFA keeps-2dBm, the output power comes down to 14dBm from the initial 14.3dBm. And the optical isolators and WDM couplers change little. So the EDFA can be used directly on the low dose orbits. But in the radiation environment of the high dose orbits whose typical total dose is about 1000krad, at the same condition, the output power of EDFA comes down to-25.3dBm. And although optical isolators also change little, the additional insertion loss of WDM couplers jumps up to 8dB. So the characters of the EDFA degrade badly. If EDFA was used on the high dose orbits, it must be radiation protected.