Title :
Enhanced Temperature
Stability of Type-IIa FBG Written by 255 nm Beam
Author :
Prakash, Om ; Kumar, Jayant ; Mahakud, Ramakant ; Agrawal, Sunil K. ; Dixit, S.K. ; Nakhe, Shankar V.
Author_Institution :
Laser Syst. Eng. Sect., Raja Ramanna Centre for Adv. Technol., Indore, India
Abstract :
This letter reports a first time study on enhanced temperature (~800°C) stability of type-IIa as compared with type-I fiber Bragg gratings (FBGs) written by high repetition rate (5.5 kHz) 255 nm UV beam. Both the FBGs were written in high photosensitive Ge doped (~10 mole%) single mode fiber without hydrogen loading. Both the FBGs survived 800°C over 9 h, however, time rate of fall of type-IIa FBG reflectivity was ~3 times lower as compared with type-I. The high temperature stability of 255 nm written FBGs is attributed to enhanced core-cladding stress release in the strong seed grating written by highly stabilized interference fringes and high cumulative fluence of 255 nm, 5.5 kHz UV pulses.
Keywords :
Bragg gratings; fibre optic sensors; germanium; optical fibre cladding; photochemistry; temperature sensors; UV beam; enhanced core-cladding stress release; enhanced temperature stability; high cumulative fluence; high photosensitive Ge doped single mode fiber; high repetition rate; high temperature stability; hydrogen loading; stabilized interference fringes; strong seed grating; temperature 800 degC; time rate; type-I fiber Bragg gratings; type-IIa FBG reflectivity; wavelength 255 nm; written FBG; Fiber gratings; Gratings; Laser stability; Optical fiber sensors; Reflectivity; Thermal stability; Fiber Bragg gratings; optical fiber; optical fiber devices; temperature sensors; ultraviolet sources;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2013.2289967