Most recently, a research team from Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences, has succeed prepared a radiation-resistant Er-doped silica fiber by pretreating the fiber preform. The related research results have been published in Optics Express on February 10, 2022.

Erbium-doped fibers (EDFs) and amplifiers (EDFA) have been customized for use in various domains, such as deep-space, laser communication, and laser radar, owing to their outstanding performance in the field of telecommunication and optical signal amplifiers operating at 1.53–1.62 μm. However, the space radiation environment can lead to a sharp increase in the optical loss, and a sharp decrease in the gain performance. Therefore, it is very important to improve the radiation-resistance property of Er-doped silica fiber.

After pretreatment, the optical loss at 1200 nm reduced from 75 to 17 dB/km, and the gain increased from 25.9 to 27dB. Under 98-krad online X-rays irradiation, the gain of the pretreated EDF were only reduced by 1.3 dB (corresponding to the reduction of 19 dB for commercial EDF). This result suggests that the pretreated EDF exhibited excellent radiation resistance behavior.

Researchers point it out that this pretreated method can maintain long-term stable high radiation resistance in a vacuum environment, such as space applications.

Fig. 1. Setup of the online amplifier test under X-rays irradiation. (Image by SIOM)

Fig.2 Gain comparison of the radiation-hardened EDFs studied in this paper and #Commercial EDF as a function of the cumulative dose. (Image by SIOM)