Optical Absorption in Commercial Single Mode Optical Fibers in a High Energy Physics Radiation Field

Abstract

Abstract-This paper reports on the radiation induced attenuation of light at 1310 nm and 1550 nm in 12 commercially available single mode (SM) optical fibers. The fiber samples are exposed to gamma rays from a 60 Co source and to a high energy physics radiation field. The attenuation is studied as a function of total dose, dose rate, light power and temperature. Radiation hard fibers from one manufacturer show an extraordinary low attenuation for light at 1310 nm that does not exceed 5 dB/km even after a total dose of 1 MGy. 2500 km of this type of fiber have been produced by the manufacturer and quality assurance measurements of the production batches are presently ongoing.

Macro-Bending Influence on Radiation Induced Attenuation Measurement in Optical Fibres

“…As in the telecom standard fibre case (Ge-doped core and pure silica cladding) a higher RIA is expected at 1310 nm than at 1570 nm for lower doses, with the RIA at 1570 nm becoming higher than the RIA at 1310 nm when the accumulated dose reaches a typical level (crossing point) that varies in function of the dose rate [13]. Moreover, at both wavelengths, the high dose rate tests are expected to show higher RIA than the low dose rate tests [15].…”

“…strained bonds) that lead to colour centers when irradiated [12]. Fewer NBOHC ( Si-O ) are then created, thus lowering the formation of silanol (Si-OH, -OH absorption band being centered around 1380 nm) under irradiation [13] [14].…”

Femtosecond laser induced fiber Bragg gratings for harsh environment sensing applications

“…The RIA process is similar to the defect formation mechanism that is occurs during UV Type I grating inscription in Ge-doped fibers. For sensing it is therefore necessary to inscribe FBGs in radiation hardened fibers resistant to RIA, such as fluorine-doped silica fibers [13]. Gratings were easily inscribed in highly radiation harden F-doped fiber using the fs-IR approach with a phase mask, both in the Type I and Type II regime [14].…”

Beam loss monitors for FEL using optical fiber

“…This type of fiber is in general radiation resistant. However, F-doped fiber can reach higher radiation level without increasing the RIA [17]. The presented BLM systems use a multi-mode step-index fiber with a core diameter of 300 µm.…”