Gamma-radiation effects in pure-silica-core photonic crystal fiber**Project supported by the National Natural Science Foundation of China (Grant Nos. 61575012 and 61575013) and the National Key Scientific Instrument and Equipment Development Project, China (Grant No. 2013YQ040877).

Abstract

We investigated the steady state gamma-ray radiation response of pure-silica-core photonic crystal fibers (PSC-PCFs) under an accumulated dose of 500 Gy and a dose rate of 2.38 Gy/min. The radiation-induced attenuation (RIA) spectra in the near-infrared region from 800 nm to 1700 nm were obtained. We find that the RIA at 1550 nm is related with hydroxyl (OH−) absorption defects in addition to the identified self-trapped hole (STH) defects. Moreover, it is proposed and demonstrated that reduced OH− absorption defects can decrease the RIA at 1550 nm. The RIA at 1550 nm has effectively declined from 27.7 dB/km to 3.0 dB/km through fabrication improvement. Preliminary explanations based on the unique fabrication processes were given to interpret the RIA characteristics of PSC-PCFs. The results show that the PSC-PCFs, which offer great advantages over conventional fibers, are promising and applicable to fiber sensors in harsh environments.