Mitigation of radiation-induced attenuation of optical fibers through photobleaching: study of power dependence at cryogenic temperatures

Radiation-induced attenuation can pose a great challenge to the implementation of optical sensors in extreme environments. Photobleaching is known to mitigate the damage caused by radiation but a lot is yet to be investigated. In this work, we look at the power-dependence of the photobleaching phenomenon at cryogenic temperature. We used three standard fibers carrying around 2mW of light at 1550nm and 4, 0.4, 0.09 of the light at 1050nm respectively; and a fourth standard control fiber that carried no photobleaching light. We observed a large reduction in radiation-induced attenuation in all of the fibers with light at 1050nm when compared to the control fiber. This reduction, however is not linear and saturates for higher powers. These results are consistent with our theoretical models.